Answer: Apothecaries (druggists) use the following set of

The scanning tunneling microscope allows us to see atoms. What if you were sent back in time before the invention of the scanning tunneling microscope? What evidence could you give to support the theory that all matter is made of atoms and molecules?

In analyzing a sample of polluted water, a chemist measured out a 25.00-mL water sample with a pipet (see Fig. 1.6). At another point in the analysis, the chemist used a graduated cylinder (see Fig. 1.6) to measure 25 mL of a solution. What is the difference between the measurements 25.00 mL and 25 mL?

What if everyone in the government used the scientific method to analyze and solve societys problems, and politics were never involved in the solutions? How would this be different from the present situation, and would it be better or worse?

To check the accuracy of a graduated cylinder, a student filled the cylinder to the 25-mL mark using water delivered from a buret (see Fig. 1.6) and then read the volume delivered. Following are the results of five trials: Trial Volume Shown by Graduated Cylinder Volume Shown by the Buret 1 25 mL 26.54 mL 2 25 mL 26.51 mL 3 25 mL 26.60 mL 4 25 mL 26.49 mL 5 25 mL 26.57 mL Average 25 mL 26.54 mL Is the graduated cylinder accurate?

What if you were not allowed to use units for one day? How would this affect your life for that day?

Give the number of significant figures for each of the following results. a. A students extraction procedure on tea yields 0.0105 g of caffeine. b. A chemist records a mass of 0.050080 g in an analysis. c. In an experiment a span of time is determined to be 8.050 3 1023 s.

Carry out the following mathematical operations, and give each result with the correct number of significant figures. a. 1.05 3 1023 4 6.135 b. 21 2 13.8 c. As part of a lab assignment to determine the value of the gas constant (R), a student measured the pressure (P), volume (V), and temperature (T) for a sample of gas, where R 5 PV T The following values were obtained: P 5 2.560, T 5 275.15, and V 5 8.8. (Gases will be discussed in detail in Chapter 5; we will not be concerned at this time about the units for these quantities.) Calculate R to the correct number of significant figures.

A pencil is 7.00 in long. What is its length in centimeters?

You want to order a bicycle with a 25.5-in frame, but the sizes in the catalog are given only in centimeters. What size should you order?

A student has entered a 10.0-km run. How long is the run in miles?

The speed limit on many highways in the United States is 55 mi/h. What number would be posted in kilometers per hour?

A Japanese car is advertised as having a gas mileage of 15 km/L. Convert this rating to miles per gallon.

The latest model Corvette has an engine with a displacement of 6.20 L. What is the displacement in units of cubic inches?

Normal body temperature is 98.68F. Convert this temperature to the Celsius and Kelvin scales.

One interesting feature of the Celsius and Fahrenheit scales is that 2408C and 2408F represent the same temperature, as shown in Fig. 1.9. Verify that this is true.

Liquid nitrogen, which is often used as a coolant for low-temperature experiments, has a boiling point of 77 K. What is this temperature on the Fahrenheit scale?

A chemist, trying to identify an unknown liquid, finds that 25.00 cm3 of the substance has a mass of 19.625 g at 208C. The following are the names and densities of the compounds that might be the liquid: Compound Density in g/cm3 at 208C Chloroform 1.492 Diethyl ether 0.714 Ethanol 0.789 Isopropyl alcohol 0.785 Toluene 0.867 Which of these compounds is the most likely to be the unknown liquid?

Define and explain the differences between the following terms. a. law and theory b. theory and experiment c. qualitative and quantitative d. hypothesis and theory

Is the scientific method suitable for solving problems only in the sciences? Explain.

Which of the following statements could be tested by quantitative measurement? a. Ty Cobb was a better hitter than Pete Rose. b. Ivory soap is 99.44% pure. c. Rolaids consumes 47 times its weight in excess stomach acid

For each of the following pieces of glassware, provide a sample measurement and discuss the number of significant figures and uncertainty

A student performed an analysis of a sample for its calcium content and got the following results: 14.92% 14.91% 14.88% 14.91% The actual amount of calcium in the sample is 15.70%. What conclusions can you draw about the accuracy and precision of these results?

Compare and contrast the multiplication/division significant figure rule to the significant figure rule applied for addition/subtraction in mathematical operations

Explain how density can be used as a conversion factor to convert the volume of an object to the mass of the object, and vice versa.

On which temperature scale (8F, 8C, or K) does 1 degree represent the smallest change in temperature?

Distinguish between physical changes and chemical changes

Why is the separation of mixtures into pure or relatively pure substances so important when performing a chemical analysis?

a. There are 365 days per year, 24 hours per day, 12 months per year, and 60 minutes per hour. Use these data to determine how many minutes are in a month. b. Now use the following data to calculate the number of minutes in a month: 24 hours per day, 60 minutes per hour, 7 days per week, and 4 weeks per month. c. Why are these answers different? Which (if any) is more correct? Why?

You go to a convenience store to buy candy and find the owner to be rather odd. He allows you to buy pieces in multiples of four, and to buy four, you need $0.23. He only allows you to do this by using 3 pennies and 2 dimes. You have a bunch of pennies and dimes, and instead of counting them, you decide to weigh them. You have 636.3 g of pennies, and each penny weighs 3.03 g. Each dime weighs 2.29 g. Each piece of candy weighs 10.23 g. a. How many pennies do you have? b. How many dimes do you need to buy as much candy as possible? c. How much should all these dimes weigh? d. How many pieces of candy could you buy? (number of dimes from part b) e. How much would this candy weigh? f. How many pieces of candy could you buy with twice as many dimes?

When a marble is dropped into a beaker of water, it sinks to the bottom. Which of the following is the best explanation? a. The surface area of the marble is not large enough to be held up by the surface tension of the water. b. The mass of the marble is greater than that of the water. c. The marble weighs more than an equivalent volume of the water. d. The force from dropping the marble breaks the surface tension of the water. e. The marble has greater mass and volume than the water. Justify your choice, and for choices you did not pick, explain what is wrong about them

You have two beakers, one filled to the 100-mL mark with sugar (the sugar has a mass of 180.0 g) and the other filled to the 100-mL mark with water (the water has a mass of 100.0 g). You pour all the sugar and all the water together in a bigger beaker and stir until the sugar is completely dissolved. a. Which of the following is true about the mass of the solution? Explain. i. It is much greater than 280.0 g. ii. It is somewhat greater than 280.0 g. iii. It is exactly 280.0 g. iv. It is somewhat less than 280.0 g. v. It is much less than 280.0 g. b. Which of the following is true about the volume of the solution? Explain.i. It is much greater than 200.0 mL. ii. It is somewhat greater than 200.0 mL. iii. It is exactly 200.0 mL. iv. It is somewhat less than 200.0 mL. v. It is much less than 200.0 mL.

You may have noticed that when water boils, you can see bubbles that rise to the surface of the water. a. What is inside these bubbles? i. air ii. hydrogen and oxygen gas iii. oxygen gas iv. water vapor v. carbon dioxide gas b. Is the boiling of water a chemical or physical change? Explain

If you place a glass rod over a burning candle, the glass appears to turn black. What is happening to each of the following (physical change, chemical change, both, or neither) as the candle burns? Explain each answer. a. the wax b. the wick c. the glass rod

Which characteristics of a solid, a liquid, and a gas are exhibited by each of the following substances? How would you classify each substance? a. a bowl of pudding b. a bucketful of sand

Sketch a magnified view (showing atoms/molecules) of each of the following and explain: a. a heterogeneous mixture of two different compounds b. a homogeneous mixture of an element and a compound

Paracelsus, a sixteenth-century alchemist and healer, adopted as his slogan: The patients are your textbook, the sickbed is your study. Is this view consistent with using the scientific method?

What is wrong with the following statement? The results of the experiment do not agree with the theory. Something must be wrong with the experiment.

Why is it incorrect to say that the results of a measurement were accurate but not precise?

What data would you need to estimate the money you would spend on gasoline to drive your car from New York to Chicago? Provide estimates of values and a sample calculation.

Sketch two pieces of glassware: one that can measure volume to the thousandths place and one that can measure volume only to the ones place

You have a 1.0-cm3 sample of lead and a 1.0-cm3 sample of glass. You drop each in separate beakers of water. How do the volumes of water displaced by each sample compare? Explain

Consider the addition of 15.4 to 28. What would a mathematician say the answer is? What would a scientist say? Justify the scientists answer, not merely citing the rule, but explaining it.

Consider multiplying 26.2 by 16.43. What would a mathematician say the answer is? What would a scientist say? Justify the scientists answer, not merely citing the rule, but explaining it.

The difference between a law and a theory is the difference between what and why. Explain

The scientific method is a dynamic process. What does this mean?

Explain the fundamental steps of the scientific method.

What is the difference between random error and systematic error?

A measurement is a quantitative observation involving both a number and a unit. What is a qualitative observation? What are the SI units for mass, length, and volume? What is the assumed uncertainty in a number (unless stated otherwise)? The uncertainty of a measurement depends on the precision of the measuring device. Explain.

To determine the volume of a cube, a student measured one of the dimensions of the cube several times. If the true dimension of the cube is 10.62 cm, give an example of four sets of measurements that would illustrate the following. a. imprecise and inaccurate data b. precise but inaccurate data c. precise and accurate data Give a possible explanation as to why data can be imprecise or inaccurate. What is wrong with saying a set of measurements is imprecise but accurate?

What are significant figures? Show how to indicate the number one thousand to 1 significant figure, 2 significant figures, 3 significant figures, and 4 significant figures. Why is the answer, to the correct number of significant figures, not 1.0 for the following calculation? 1.5 2 1.0 0.50 5

A cold front moves through and the temperature drops by 20 degrees. In which temperature scale would this 20 degree change represent the largest change in temperature?

When the temperature in degrees Fahrenheit (TF) is plotted vs. the temperature in degrees Celsius (TC), a straight-line plot results. A straight-line plot also results when TC is plotted vs. TK (the temperature in kelvins). Reference Appendix A1.3 and determine the slope and y-intercept of each of these two plots.

Give four examples illustrating each of the following terms. a. homogeneous mixture d. element b. heterogeneous mixture e. physical change c. compound f. chemical change

Which of the following are exact numbers? a. There are 100 cm in 1 m. b. One meter equals 1.094 yards.c. We can use the equation F 5 9 5C 1 32 to convert from Celsius to Fahrenheit temperature. Are the numbers 9 5 and 32 exact or inexact? d. p 5 3.1415927

Indicate the number of significant figures in each of the following: a. This book contains more than 1000 pages. b. A mile is about 5300 ft. c. A liter is equivalent to 1.059 qt. d. The population of the United States is approaching 3.1 3 102 million. e. A kilogram is 1000 g. f. The Boeing 747 cruises at around 600 mi/h

How many significant figures are there in each of the following values? a. 6.07 3 10215 e. 463.8052 b. 0.003840 f. 300 c. 17.00 g. 301 d. 8 3 108 h. 300

How many significant figures are in each of the following? a. 100 e. 0.0048 b. 1.0 3 102 f. 0.00480 c. 1.00 3 103 g. 4.80 3 1023 d. 100. h. 4.800 3 1023

Round off each of the following numbers to the indicated number of significant digits, and write the answer in standard scientific notation. a. 0.00034159 to three digits b. 103.351 3 102 to four digits c. 17.9915 to five digits d. 3.365 3 105 to three digits

Use exponential notation to express the number 385,500 to a. one significant figure. b. two significant figures. c. three significant figures. d. five significant figures.

You have liquid in each graduated cylinder shown: 5 4 mL 2 1 3 1 mL 0.5 You then add both samples to a beaker. How would you write the number describing the total volume? What limits the precision of this number?

The beakers shown below have different precisions. 34 33 32 50 40 30 32.9 32.8 32.7 a. Label the amount of water in each of the three beakers to the correct number of significant figures. b. Is it possible for each of the three beakers to contain the exact same amount of water? If no, why not? If yes, did you report the volumes as the same in part a? Explain. c. Suppose you pour the water from these three beakers into one container. What should be the volume in the container reported to the correct number of significant figures?

Evaluate each of the following, and write the answer to the appropriate number of significant figures. a. 212.2 1 26.7 1 402.09 b. 1.0028 1 0.221 1 0.10337 c. 52.331 1 26.01 2 0.9981 d. 2.01 3 102 1 3.014 3 103 e. 7.255 2 6.8350

Perform the following mathematical operations, and express each result to the correct number of significant figures. a. 0.102 3 0.0821 3 273 1.01 b. 0.14 3 6.022 3 1023 c. 4.0 3 104 3 5.021 3 1023 3 7.34993 3 102 d. 2.00 3 106 3.00 3 1027

Perform the following mathematical operations, and express the result to the correct number of significant figures. a. 2.526 3.1 1 0.470 0.623 1 80.705 0.4326 b. (6.404 3 2.91)y(18.7 2 17.1) c. 6.071 3 1025 2 8.2 3 1026 2 0.521 3 1024 d. (3.8 3 10212 1 4.0 3 10213)y(4 3 1012 1 6.3 3 1013) e. 9.5 1 4.1 1 2.8 1 3.175 4 (Assume that this operation is taking the average of four numbers. Thus 4 in the denominator is exact.) f. 8.925 2 8.905 8.925 3 100 (This type of calculation is done many times in calculating a percentage error. Assume that this example is such a calculation; thus 100 can be considered to be an exact number.)

Perform the following mathematical operations, and express the result to the correct number of significant figures. a. 6.022 3 1023 3 1.05 3 102 b. 6.6262 3 10234 3 2.998 3 108 2.54 3 1029 c. 1.285 3 1022 1 1.24 3 1023 1 1.879 3 1021 d. 11.00866 2 1.007282 6.02205 3 1023 e. 9.875 3 102 2 9.795 3 102 9.875 3 102 3 100 1100 is exact2 f. 9.42 3 102 1 8.234 3 102 1 1.625 3 103 3 13 is exact2

Perform each of the following conversions. a. 8.43 cm to millimeters b. 2.41 3 102 cm to meters c. 294.5 nm to centimeters d. 1.445 3 104 m to kilometers e. 235.3 m to millimeters f. 903.3 nm to micrometers

a. How many kilograms are in 1 teragram? b. How many nanometers are in 6.50 3 102 terameters? c. How many kilograms are in 25 femtograms? d. How many liters are in 8.0 cubic decimeters? e. How many microliters are in 1 milliliter? f. How many picograms are in 1 microgram?

Perform the following unit conversions. a. Congratulations! You and your spouse are the proud parents of a new baby, born while you are studying in a country that uses the metric system. The nurse has informed you that the baby weighs 3.91 kg and measures 51.4 cm. Convert your babys weight to pounds and ounces and her length to inches (rounded to the nearest quarter inch). b. The circumference of the earth is 25,000 mi at the equator. What is the circumference in kilometers? in meters? c. A rectangular solid measures 1.0 m by 5.6 cm by 2.1 dm. Express its volume in cubic meters, liters, cubic inches, and cubic feet

Perform the following unit conversions. a. 908 oz to kilograms b. 12.8 L to gallons c. 125 mL to quarts d. 2.89 gal to milliliters e. 4.48 lb to grams f. 550 mL to quarts

Use the following exact conversion factors to perform the stated calculations: 51 2 yd 5 1 rod 40 rods 5 1 furlong 8 furlongs 5 1 mile a. The Kentucky Derby race is 1.25 miles. How long is the race in rods, furlongs, meters, and kilometers? b. A marathon race is 26 miles, 385 yards. What is this distance in rods, furlongs, meters, and kilometers?

Although the preferred SI unit of area is the square meter, land is often measured in the metric system in hectares (ha). One hectare is equal to 10,000 m2 . In the English system, land is often measured in acres (1 acre 5 160 rod2 ). Use the exact conversions and those given in Exercise 43 to calculate the following. a. 1 ha 5 ________ km2 b. The area of a 5.5-acre plot of land in hectares, square meters, and square kilometers c. A lot with dimensions 120 ft by 75 ft is to be sold for $6500. What is the price per acre? What is the price per hectare?

Precious metals and gems are measured in troy weights in the English system: 24 grains 5 1 pennyweight 1exact2 20 pennyweight 5 1 troy ounce 1exact2 12 troy ounces 5 1 troy pound 1exact2 1 grain 5 0.0648 g 1 carat 5 0.200 g a. The most common English unit of mass is the pound avoirdupois. What is 1 troy pound in kilograms and in pounds? b. What is the mass of a troy ounce of gold in grams and in carats? c. The density of gold is 19.3 g/cm3 . What is the volume of a troy pound of gold?

Apothecaries (druggists) use the following set of measures in the English system: 20 grains ap 5 1 scruple 1exact2 3 scruples 5 1 dram ap 1exact2 8 dram ap 5 1 oz ap 1exact2 1 dram ap 5 3.888 g a. Is an apothecary grain the same as a troy grain? (See Exercise 45.) b. 1 oz ap 5 ________ oz troy. c. An aspirin tablet contains 5.00 3 102 mg of active ingredient. What mass in grains ap of active ingredient does it contain? What mass in scruples? d. What is the mass of 1 scruple in grams?

For a pharmacist dispensing pills or capsules, it is often easier to weigh the medication to be dispensed than to count the individual pills. If a single antibiotic capsule weighs 0.65 g, and a pharmacist weighs out 15.6 g of capsules, how many capsules have been dispensed?

A childrens pain relief elixir contains 80. mg acetaminophen per 0.50 teaspoon. The dosage recommended for a child who weighs between 24 and 35 lb is 1.5 teaspoons. What is the range of acetaminophen dosages, expressed in mg acetaminophen/kg body weight, for children who weigh between 24 and 35 lb?

Science fiction often uses nautical analogies to describe space travel. If the starship U.S.S. Enterprise is traveling at warp factor 1.71, what is its speed in knots and in miles per hour? (Warp 1.71 5 5.00 times the speed of light; speed of light 5 3.00 3 108 m/s; 1 knot 5 2030 yd/h.)

The world record for the hundred meter dash is 9.58 s. What is the corresponding average speed in units of m/s, km/h, ft/s, and mi/h? At this speed, how long would it take to run 1.00 3 102 yards?

Would a car traveling at a constant speed of 65 km/h violate a 40 mi/h speed limit?

You pass a road sign saying New York 112 km. If you drive at a constant speed of 65 mi/h, how long should it take you to reach New York? If your car gets 28 miles to the gallon, how many liters of gasoline are necessary to travel 112 km?

You are in Paris, and you want to buy some peaches for lunch. The sign in the fruit stand indicates that peaches cost 2.45 euros per kilogram. Given that 1 euro is equivalent to approximately $1.32, calculate what a pound of peaches will cost in dollars

In recent years, there has been a large push for an increase in the use of renewable resources to produce the energy we need to power our vehicles. One of the newer fuels that has become more widely available is E85, a mixture of 85% ethanol and 15% gasoline. Despite being more environmentally friendly, one of the potential drawbacks of E85 fuel is that it produces less energy than conventional gasoline. Assume a car gets 28.0 mi/gal using gasoline at $3.50/gal and 22.5 mi/gal using E85 at $2.85/gal. How much will it cost to drive 500. miles using each fuel?

Mercury poisoning is a debilitating disease that is often fatal. In the human body, mercury reacts with essential enzymes leading to irreversible inactivity of these enzymes. If the amount of mercury in a polluted lake is 0.4 mg Hg/mL, what is the total mass in kilograms of mercury in the lake? (The lake has a surface area of 100 mi2 and an average depth of 20 ft.)

Carbon monoxide (CO) detectors sound an alarm when peak levels of carbon monoxide reach 100 parts per million (ppm). This level roughly corresponds to a composition of air that contains 400,000 mg carbon monoxide per cubic meter of air (400,000 mg/m3 ). Assuming the dimensions of a room are 18 ft 3 12 ft 3 8 ft, estimate the mass of carbon monoxide in the room that would register 100 ppm on a carbon monoxide detector.

Convert the following Fahrenheit temperatures to the Celsius and Kelvin scales. a. 24598F, an extremely low temperature b. 240.8F, the answer to a trivia question c. 688F, room temperature d. 7 3 107 8F, temperature required to initiate fusion reactions in the sun

A thermometer gives a reading of 96.18F 6 0.28F. What is the temperature in 8C? What is the uncertainty?

Convert the following Celsius temperatures to Kelvin and to Fahrenheit degrees. a. the temperature of someone with a fever, 39.28C b. a cold wintery day, 2258C c. the lowest possible temperature, 22738C d. the melting-point temperature of sodium chloride, 8018C

Convert the following Kelvin temperatures to Celsius and Fahrenheit degrees. a. the temperature that registers the same value on both the Fahrenheit and Celsius scales, 233 K b. the boiling point of helium, 4 K c. the temperature at which many chemical quantities are determined, 298 K d. the melting point of tungsten, 3680 K

At what temperature is the temperature in degrees Fahrenheit equal to twice the temperature in degrees Celsius?

The average daytime temperatures on the earth and Jupiter are 728F and 313 K, respectively. Calculate the difference in temperature, in 8C, between these two planets.

Use the figure below to answer the following questions. 0X 50X 10C 130C a. Derive the relationship between 8C and 8X. b. If the temperature outside is 22.08C, what is the temperature in units of 8X? c. Convert 58.08X to units of 8C, K, and 8F

Ethylene glycol is the main component in automobile antifreeze. To monitor the temperature of an auto cooling system, you intend to use a meter that reads from 0 to 100. You devise a new temperature scale based on the approximate melting and boiling points of a typical antifreeze solution (2458C and 1158C). You wish these points to correspond to 08A and 1008A, respectively. a. Derive an expression for converting between 8A and 8C. b. Derive an expression for converting between 8F and 8A. c. At what temperature would your thermometer and a Celsius thermometer give the same numerical reading? d. Your thermometer reads 868A. What is the temperature in 8C and in 8F? e. What is a temperature of 458C in 8A?

A material will float on the surface of a liquid if the material has a density less than that of the liquid. Given that the density of water is approximately 1.0 g/mL, will a block of material having a volume of 1.2 3 104 in3 and weighing 350 lb float or sink when placed in a reservoir of water?

For a material to float on the surface of water, the material must have a density less than that of water (1.0 g/mL) and must not react with the water or dissolve in it. A spherical ball has a radius of 0.50 cm and weighs 2.0 g. Will this ball float or sink when placed in water? (Note: Volume of a sphere 5 4 3pr3 .)

A star is estimated to have a mass of 2 3 1036 kg. Assuming it to be a sphere of average radius 7.0 3 105 km, calculate the average density of the star in units of grams per cubic centimeter.

A rectangular block has dimensions 2.9 cm 3 3.5 cm 3 10.0 cm. The mass of the block is 615.0 g. What are the volume and density of the block?

Diamonds are measured in carats, and 1 carat 5 0.200 g. The density of diamond is 3.51 g/cm3 . a. What is the volume of a 5.0-carat diamond? b. What is the mass in carats of a diamond measuring 2.8 mL?

Ethanol and benzene dissolve in each other. When 100. mL of ethanol is dissolved in 1.00 L of benzene, what is the mass of the mixture? (See Table 1.5.)

A sample containing 33.42 g of metal pellets is poured into a graduated cylinder initially containing 12.7 mL of water, causing the water level in the cylinder to rise to 21.6 mL. Calculate the density of the metal

The density of pure silver is 10.5 g/cm3 at 208C. If 5.25 g of pure silver pellets is added to a graduated cylinder containing 11.2 mL of water, to what volume level will the water in the cylinder rise?

In each of the following pairs, which has the greater mass? (See Table 1.5.) a. 1.0 kg of feathers or 1.0 kg of lead b. 1.0 mL of mercury or 1.0 mL of water c. 19.3 mL of water or 1.00 mL of gold d. 75 mL of copper or 1.0 L of benzene

a. Calculate the mass of ethanol in 1.50 qt of ethanol. (See Table 1.5.) b. Calculate the mass of mercury in 3.5 in3 of mercury. (See Table 1.5.)

In each of the following pairs, which has the greater volume? a. 1.0 kg of feathers or 1.0 kg of lead b. 100 g of gold or 100 g of water c. 1.0 L of copper or 1.0 L of mercury

Using Table 1.5, calculate the volume of 25.0 g of each of the following substances at 1 atm. a. hydrogen gas b. water c. iron Chapter 5 discusses the properties of gases. One property unique to gases is that they contain mostly empty space. Explain using the results of your calculations.

The density of osmium (the densest metal) is 22.57 g/cm3 . If a 1.00-kg rectangular block of osmium has two dimensions of 4.00 cm 3 4.00 cm, calculate the third dimension of the block.

A copper wire (density 5 8.96 g/cm3 ) has a diameter of 0.25 mm. If a sample of this copper wire has a mass of 22 g, how long is the wire?

Match each description below with the following microscopic pictures. More than one picture may fit each description. A picture may be used more than once or not used at all. i ii iii iv v vi a. a gaseous compound b. a mixture of two gaseous elements c. a solid element d. a mixture of a gaseous element and a gaseous compound

Define the following terms: solid, liquid, gas, pure substance, element, compound, homogeneous mixture, heterogeneous mixture, solution, chemical change, physical change.

What is the difference between homogeneous and heterogeneous matter? Classify each of the following as homogeneous or heterogeneous. a. a door d. the water you drink b. the air you breathe e. salsa c. a cup of coffee (black) f. your lab partner

Classify the following mixtures as homogeneous or heterogeneous. a. potting soil d. window glass b. white wine e. granite c. your sock drawer

Classify each of the following as a mixture or a pure substance. a. water f. uranium b. blood g. wine c. the oceans h. leather d. iron i. table salt e. brass Of the pure substances, which are elements and which are compounds?

Suppose a teaspoon of magnesium filings and a teaspoon of powdered sulfur are placed together in a metal beaker. Would this constitute a mixture or a pure substance? Suppose the magnesium filings and sulfur are heated so that they react with each other, forming magnesium sulfide. Would this still be a mixture? Why or why not?

If a piece of hard, white blackboard chalk is heated strongly in a flame, the mass of the piece of chalk will decrease, and eventually the chalk will crumble into a fine white dust. Does this change suggest that the chalk is composed of an element or a compound?

During a very cold winter, the temperature may remain below freezing for extended periods. However, fallen snow can still disappear, even though it cannot melt. This is possible because a solid can vaporize directly, without passing through the liquid state. Is this process (sublimation) a physical or a chemical change?

Classify the following as physical or chemical changes. a. Moth balls gradually vaporize in a closet. b. Hydrofluoric acid attacks glass and is used to etch calibration marks on glass laboratory utensils. c. A French chef making a sauce with brandy is able to boil off the alcohol from the brandy, leaving just the brandy flavoring. d. Chemistry majors sometimes get holes in the cotton jeans they wear to lab because of acid spills

The properties of a mixture are typically averages of the properties of its components. The properties of a compound may differ dramatically from the properties of the elements that combine to produce the compound. For each process described below, state whether the material being discussed is most likely a mixture or a compound, and state whether the process is a chemical change or a physical change. a. An orange liquid is distilled, resulting in the collection of a yellow liquid and a red solid. b. A colorless, crystalline solid is decomposed, yielding a pale yellow-green gas and a soft, shiny metal. c. A cup of tea becomes sweeter as sugar is added to it.

Lipitor, a pharmaceutical drug that has been shown to lower bad cholesterol levels while raising good cholesterol levels in patients taking the drug, had over $11 billion in sales in 2006. Assuming one 2.5-g pill contains 4.0% of the active ingredient by mass, what mass in kg of active ingredient is present in one bottle of 100 pills?

In Shakespeares Richard III, the First Murderer says: Take that, and that! [Stabs Clarence] If that is not enough, Ill drown you in a malmsey butt within! Given that 1 butt 5 126 gal, in how many liters of malmsey (a foul brew similar to mead) was the unfortunate Clarence about to be drowned?

The contents of one 40. lb bag of topsoil will cover 10. square feet of ground to a depth of 1.0 inch. What number of bags is needed to cover a plot that measures 200. by 300. m to a depth of 4.0 cm?

In the opening scenes of the movie Raiders of the Lost Ark, Indiana Jones tries to remove a gold idol from a booby-trapped pedestal. He replaces the idol with a bag of sand of approximately equal volume. (Density of gold 5 19.32 g/cm3 ; density of sand < 2 g/cm3 .) a. Did he have a reasonable chance of not activating the mass-sensitive booby trap? b. In a later scene, he and an unscrupulous guide play catch with the idol. Assume that the volume of the idol is about 1.0 L. If it were solid gold, what mass would the idol have? Is playing catch with it plausible?

A parsec is an astronomical unit of distance where 1 parsec 5 3.26 light years (1 light year equals the distance traveled by light in one year). If the speed of light is 186,000 mi/s, calculate the distance in meters of an object that travels 9.6 parsecs.

You are driving 65 mi/h and take your eyes off the road for just a second. What distance (in feet) do you travel in this time?

This year, like many past years, you begin to feel very sleepy after eating a large helping of Thanksgiving turkey. Some people attribute this sleepiness to the presence of the amino acid tryptophan in turkey. Tryptophan can be used by the body to produce serotonin, which can calm the brains activity and help to bring on sleep. a. What mass in grams of tryptophan is in a 0.25-lb serving of turkey? (Assume tryptophan accounts for 1.0% of the turkey mass.) b. What mass in grams of tryptophan is in 0.25 quart of milk? (Assume tryptophan accounts for 2.0% of milk by mass and that the density of milk is 1.04 kg/L.)

Which of the following are chemical changes? Which are physical changes? a. the cutting of food b. interaction of food with saliva and digestive enzymes c. proteins being broken down into amino acids d. complex sugars being broken down into simple sugars e. making maple syrup by heating maple sap to remove water through evaporation f. DNA unwinding

A column of liquid is found to expand linearly on heating. Assume the column rises 5.25 cm for a 10.08F rise in temperature. If the initial temperature of the liquid is 98.68F, what will the final temperature be in 8C if the liquid has expanded by 18.5 cm?

A 25.00-g sample of a solid is placed in a graduated cylinder, and then the cylinder is filled to the 50.0-mL mark with benzene. The mass of benzene and solid together is 58.80 g. Assuming that the solid is insoluble in benzene and that the density of benzene is 0.880 g/cm3 , calculate the density of the solid

For each of the following, decide which block is more dense: the orange block, the blue block, or it cannot be determined. Explain your answers.

According to the Official Rules of Baseball, a baseball must have a circumference not more than 9.25 in or less than 9.00 in and a mass not more than 5.25 oz or less than 5.00 oz. What range of densities can a baseball be expected to have? Express this range as a single number with an accompanying uncertainty limit.

The density of an irregularly shaped object was determined as follows. The mass of the object was found to be 28.90 g 6 0.03 g. A graduated cylinder was partially filled with water. The reading of the level of the water was 6.4 cm3 6 0.1 cm3 . The object was dropped in the cylinder, and the level of the water rose to 9.8 cm3 6 0.1 cm3 . What is the density of the object with appropriate error limits? (See Appendix 1.5.)

The chemist in Example 1.14 did some further experiments. She found that the pipet used to measure the volume of the liquid is accurate to 60.03 cm3 . The mass measurement is accurate to 60.002 g. Are these measurements sufficiently precise for the chemist to distinguish between isopropyl alcohol and ethanol?

The longest river in the world is the Nile River with a length of 4,145 mi. How long is the Nile in cable lengths, meters, and nautical miles? Use these exact conversions to help solve the problem: 6 ft 5 1 fathom 100 fathoms 5 1 cable length 10 cable lengths 5 1 nautical mile 3 nautical miles 5 1 league

Secretariat is known as the horse with the fastest run in the Kentucky Derby. If Secretariats record 1.25-mi run lasted 1 minute 59.2 seconds, what was his average speed in m/s?

The hottest temperature recorded in the United States is 1348F in Greenland Ranch, CA. The melting point of phosphorus is 448C. At this temperature, would phosphorus be a liquid or a solid?

The radius of a neon atom is 69 pm, and its mass is 3.35 3 10223 g. What is the density of the atom in grams per cubic centimeter (g/cm3 )? Assume the nucleus is a sphere with volume 5 4 3pr3

Which of the following statements is(are) true? a. A spoonful of sugar is a mixture. b. Only elements are pure substances.c. Air is a mixture of gases. d. Gasoline is a pure substance. e. Compounds can be broken down only by chemical means.

Which of the following describes a chemical property? a. The density of iron is 7.87 g/cm3 . b. A platinum wire glows red when heated. c. An iron bar rusts. d. Aluminum is a silver-colored metal.

A rule of thumb in designing experiments is to avoid using a result that is the small difference between two large measured quantities. In terms of uncertainties in measurement, why is this good advice?

Draw a picture showing the markings (graduations) on glassware that would allow you to make each of the following volume measurements of water, and explain your answers (the numbers given are as precise as possible). a. 128.7 mL b. 18 mL c. 23.45 mL If you made these measurements for three samples of water and then poured all of the water together in one container, what total volume of water should you report? Support your answer

Many times errors are expressed in terms of percentage. The percent error is the absolute value of the difference of the true value and the experimental value, divided by the true value, and multiplied by 100. Percent error 5 0 true value 2 experimental value 0 true value 3 100 Calculate the percent error for the following measurements. a. The density of an aluminum block determined in an experiment was 2.64 g/cm3 . (True value 2.70 g/cm3 .) b. The experimental determination of iron in iron ore was 16.48%. (True value 16.12%.) c. A balance measured the mass of a 1.000-g standard as 0.9981 g.

A person weighed 15 pennies on a balance and recorded the following masses: 3.112 g 3.109 g 3.059 g 2.467 g 3.079 g 2.518 g 3.129 g 2.545 g 3.050 g 3.053 g 3.054 g 3.072 g 3.081 g 3.131 g 3.064 g Curious about the results, he looked at the dates on each penny. Two of the light pennies were minted in 1983 and one in 1982. The dates on the 12 heavier pennies ranged from 1970 to 1982. Two of the 12 heavier pennies were minted in 1982. a. Do you think the Bureau of the Mint changed the way it made pennies? Explain. b. The person calculated the average mass of the 12 heavy pennies. He expressed this average as 3.0828 g 6 0.0482 g. What is wrong with the numbers in this result, and how should the value be expressed?

On October 21, 1982, the Bureau of the Mint changed the composition of pennies (see Exercise 112). Instead of an alloy of 95% Cu and 5% Zn by mass, a core of 99.2% Zn and 0.8% Cu with a thin shell of copper was adopted. The overall composition of the new penny was 97.6% Zn and 2.4% Cu by mass. Does this account for the difference in mass among the pennies in Exercise 112? Assume the volume of the individual metals that make up each penny can be added together to give the overall volume of the penny, and assume each penny is the same size. (Density of Cu 5 8.96 g/cm3 ; density of Zn 5 7.14 g/cm3 .)

As part of a science project, you study traffic patterns in your city at an intersection in the middle of downtown. You set up a device that counts the cars passing through this intersection for a 24-hr period during a weekday. The graph of hourly traffic looks like this. Time Number of Cars 60 50 40 30 20 10 0 12 A.M. 6 A.M. noon 6 P.M. a. At what time(s) does the highest number of cars pass through the intersection? b. At what time(s) does the lowest number of cars pass through the intersection? c. Briefly describe the trend in numbers of cars over the course of the day. d. Provide a hypothesis explaining the trend in numbers of cars over the course of the day. e. Provide a possible experiment that could test your hypothesis

Sterling silver is a solid solution of silver and copper. If a piece of a sterling silver necklace has a mass of 105.0 g and a volume of 10.12 mL, calculate the mass percent of copper in the piece of necklace. Assume that the volume of silver present plus the volume of copper present equals the total volume. Refer to Table 1.5. Mass percent of copper 5 mass of copper total mass 3 100

Make molecular-level (microscopic) drawings for each of the following. a. Show the differences between a gaseous mixture that is a homogeneous mixture of two different compounds, and a gaseous mixture that is a homogeneous mixture of a compound and an element. b. Show the differences among a gaseous element, a liquid element, and a solid element

Confronted with the box shown in the diagram, you wish to discover something about its internal workings. You have no tools and cannot open the box. You pull on rope B, and it moves rather freely. When you pull on rope A, rope C appears to be pulled slightly into the box. When you pull on rope C, rope A almost disappears into the box.* A B C a. Based on these observations, construct a model for the interior mechanism of the box. b. What further experiments could you do to refine your model?

An experiment was performed in which an empty 100-mL graduated cylinder was weighed. It was weighed once again after it had been filled to the 10.0-mL mark with dry sand. A 10-mL pipet was used to transfer 10.00 mL of methanol to the cylinder. The sandmethanol mixture was stirred until bubbles no longer emerged from the mixture and the sand looked uniformly wet. The cylinder was then weighed again. Use the data obtained from this experiment (and displayed at the end of this problem) to find the density of the dry sand, the density of methanol, and the density of sand particles. Does the bubbling that occurs when the methanol is added to the dry sand indicate that the sand and methanol are reacting?Mass of cylinder plus wet sand 45.2613 g Mass of cylinder plus dry sand 37.3488 g Mass of empty cylinder 22.8317 g Volume of dry sand 10.0 mL Volume of sand plus methanol 17.6 mL Volume of methanol 10.00 mL

The U.S. trade deficit at the beginning of 2005 was $475,000,000. If the wealthiest 1.00% of the U.S. population (297,000,000) contributed an equal amount of money to bring the trade deficit to $0, how many dollars would each person contribute? If one of these people were to pay his or her share in nickels only, how many nickels are needed? Another person living abroad at the time decides to pay in pounds sterling (). How many pounds sterling does this person contribute (assume a conversion rate of 1 5 $1.869)?

The density of osmium is reported by one source to be 22610 kg/m3 . What is this density in g/cm3 ? What is the mass of a block of osmium measuring 10.0 cm 3 8.0 cm 3 9.0 cm?

At the Amundsen-Scott South Pole base station in Antarctica, when the temperature is 2100.08F, researchers who live there can join the 300 Club by stepping into a sauna heated to 200.08F then quickly running outside and around the pole that marks the South Pole. What are these temperatures in 8C? What are these temperatures in K? If you measured the temperatures only in 8C and K, can you become a member of the 300 Club (that is, is there a 300.-degree difference between the temperature extremes when measured in 8C and K)?