In a box of nails, there are 75 iron nails weighing 0.250

Gold, one of the most sought-after metals in the world, has a density of \(19.3 \mathrm{~g} / \mathrm{cm}^{3}\), a melting point of \(1064^{\circ} \mathrm{C}\), and a specific heat of \(0.129 \mathrm{~J} / \mathrm{g}^{\circ} \mathrm{C}\). A gold nugget found in Alaska in 1998 weighs \(20.17 \mathrm{lb}\). a. How many significant figures are in the measurement of weight of the nugget? b. What is the mass of the nugget in kilograms? c. If the nugget were pure gold, what would its volume be in \(\mathrm{cm}^{3}\)? d. What is the melting point of gold in degrees Fahrenheit and kelvins? e. How many kilojoules are required to heat the nugget from \(27^{\circ} \mathrm{C}\) to \(358^{\circ} \mathrm{C} ?\) How many kilocalories is that? f. In 2010 , the price of gold was $61.08 per gram. What was the nugget worth, in dollars, in 2010 ? Gold nuggets, also called native gold, can be found in streams and mines.

Problem 1QP Indicate whether each of the following statements describes potential or kinetic energy: a. water at the top of a waterfall b. kicking a ball c. the energy in a lump of coal d. a skier at the top of a hill

Problem 1SC The burning of 1.0 g of coal produces 8.4 kcal. How many kilojoules are produced?

The mileage for a motorcycle with a fuel-tank capacity of 22 L is 35 mi/gal. The density of gasoline is 0.74 g/mL. a. How long a trip, in kilometers, can be made on one full tank of gasoline? b. If the price of gasoline is $3.59 per gallon, what would be the cost of fuel for the trip? c. If the average speed during the trip is 44 mi/h, how many hours will it take to reach the destination? d. What is the mass, in grams, of the fuel in the tank? e. When 1.0 g of gasoline burns, 47 kJ of energy is released. How many kilojoules are produced when the fuel in one full tank is completely burned? When 1.0 g of gasoline burns in a motorcycle, 47 kJ of energy is released.

Problem 2QP Indicate whether each of the following statements describes potential or kinetic energy: a. the energy in your food b. a tightly wound spring c. an earthquake d. a car speeding down the freeway

Problem 2SC In the process of making ice cream, rock salt is added to crushed ice to chill the ice cream mixture. If the temperature drops to ?11 °C, what is the temperature in degrees Fahrenheit?

Problem 3CI Answer the following for diagrams A and B: (2.4) a. In which sample (A or B) does the water have its own shape? b. Which diagram (1, 2, or 3) represents the arrangement of particles in water sample A? c. Which diagram (1, 2, or 3) represents the arrangement of particles in water sample B? 1 2 3 Answer the following for diagrams 1, 2, and 3: (2.4, 2.5) d. The state of matter indicated in diagram 1 is a_; in diagram 2, it is a_; and in diagram 3, it is a_ e. The motion of the particles is slowest in diagram_ f. The arrangement of particles is farthest apart in diagram_ g. The particles fill the volume of the container in diagram_ h. If the water in diagram 2 has a mass of 19 g and a temperature of 45 °C, how much heat, in kilojoules, is removed to cool the liquid to 0 °C?

Problem 3QP State whether each of the following involves an increase or decrease in potential energy: a. A roller coaster climbs up a ramp in a roller-coaster ride. b. A skier at the top of the jump begins to ski down the course. c. Water at the top of a waterfall drops to the pool below.

Problem 24QP Describe each property of the element zirconium as physical or chemical. a. melts at 1852 °C b. is resistant to corrosion c. has a grayish white color d. ignites spontaneously in air when finely divided e. is a shiny metal

Problem 25QP Identify each of the following changes of state as melting, freezing, sublimation, or deposition: a. The solid structure of a substance breaks down as liquid forms. b. Coffee is freeze-dried. c. Water on the street turns to ice during a cold wintry night. d. Ice crystals form on a package of frozen corn.

Problem 26QP Identify each of the following changes of state as melting, freezing, sublimation, or deposition: a. Dry ice in an ice-cream cart disappears. b. Snow on the ground turns to liquid water. c. Heat is removed from 125 g of liquid water at 0 °C. d. Frost forms on a cold morning.

Problem 28QP Identify each of the following changes of state as evaporation, boiling, or condensation: a. At 100 °C, the water in a pan changes to steam. b. On a cool morning, the windows in your car fog up. c. A shallow pond dries up in the summer. d. A teakettle whistles when the water is ready for tea.

Problem 29QP Draw a heating curve for a sample of ice that is heated from ?20 °C to 140 °C. Indicate the segment of the graph that corresponds to each of the following: a. solid b. melting c. liquid d. boiling e. gas

Problem 30QP Draw a cooling curve for a sample of steam that cools from 110 °C to ?10 °C. Indicate the segment of the graph that corresponds to each of the following: a. solid b. freezing c. liquid d. condensing e. gas

Problem 31QP If the same amount of heat is supplied to samples of 10.0 g each of aluminum, iron, and copper all at 15.0 °C, which sample would reach the highest temperature (see Table) ? Table Substance Specific Heat (J/g °C) Elements Aluminium, Al(s) 0.897 Copper, Cu(s) 0.385 Gold, Au(s) 0.129 Iron, Fe(s) 0.452 Silver, Ag(s) 0.235 Titanium, Ti(s) 0.523 Components NH3(g) 2.04 Ethanol, C2H5OH(l) 2.46 Sodium Chloride, NaCl(s) 0.864 Water, H2O(l) 4.184 Water, H2O(s) 2.03

Problem 32QP Substances A and B are the same mass and at the same initial temperature. When the same amount of heat is added to each, the final temperature of A is 55 °C higher than the temperature of B. What does this tell you about the specific heats of A and B?

Problem 33QP Calculate the specific heat (J/g °C) for each of the following: a. a 13.5-g sample of zinc (Zn) heated from 24.2 °C to 83.6°C that absorbs 312 J of heat b. a 48.2-g sample of a metal that absorbs 345 J with a temperature increase from 35.0 °C to 57.9 °C

Problem 64AQP Calculate each of the following temperatures in kelvins and degrees Fahrenheit: a. The highest recorded temperature in the world was 58.0 °C in El Azizia, Libya, on September 13, 1922. b. The lowest recorded temperature in the world was ?89.2 °C in Vostok, Antarctica, on July 21, 1983.

Problem 65AQP What is ?15 °F in degrees Celsius and in kelvins? (2.2)

Problem 66AQP The highest recorded body temperature that a person has survived is 46.5 °C. Calculate that temperature in degrees Fahrenheit and in kelvins. (2.2)

Problem 67AQP Classify each of the following as an element, a compound, or a mixture: (2.3) a. carbon in pencils b. carbon dioxide (CO2) we exhale c. orange juice d. neon gas in lights e. salad dressing of oil and vinegar

Problem 68AQP Classify each of the following as a homogeneous or heterogeneous mixture: (2.3) a. hot fudge sundae b. herbal tea c. vegetable oil d. water and sand e. mustard

Problem 69AQP Identify each of the following as solid, liquid, or gas: a. vitamin tablets in a bottle b. helium in a balloon c. milk in a bottle d. the air you breathe e. charcoal briquettes on a barbecue

Problem 70AQP Identify each of the following as solid, liquid, or gas: a. popcorn in a bag b. water in a garden hose c. a computer mouse d. air in a tire e. hot tea in a teacup

Problem 71QP Identify each of the following as a physical or chemical property: (2.4) a. Gold is shiny. b. Gold melts at 1064 °C. c. Gold is a good conductor of electricity. d. When gold reacts with yellow sulfur, a black compound forms.

Problem 72AQP Identify each of the following as a physical or chemical property of a candle: (2.4) a. The candle is 20 cm high with a diameter of 3 cm. b. The candle burns. c. The wax of the candle softens on a hot day. d. The candle is blue.

Problem 73AQP Identify each of the following as a physical or chemical change: (2.4) a. A plant grows a new leaf. b. Chocolate is melted for a dessert. c. Wood is chopped for the fireplace. d. Wood burns in a fireplace.

Problem 7QP Your friend who is visiting from Canada just took her tempera­ture. When it reads 99.8, she becomes concerned that she is quite ill. How would you explain this temperature to your friend?

Problem 7SC What is the specific heat of sodium metal (J/g °C) if 123 J are needed to raise the temperature of 4.00 g of sodium by 25.0 °C?

Problem 8SC Some cooking pans have a layer of copper on the bottom. How many kilojoules are needed to raise the temperature of 125 g of copper from 22 °C to 325 °C (see Table 2.8)? TABLE 2.8 Specific Heats of Some Substances Substance (J/g °C) (Cal/g °C) Elements Aluminum, Al(s) 0.897 0.214 Copper, Cus(s) 0.385 0.0920 Gold, Au(s) 0.129 0.0308 Iron, Fe(s) 0.452 0.108 Silver, Ag(s) 0.235 0.0562 Titanium, Ti(s) 0.523 0.125 Compounds Ammonia, NH3(g) 2.04 0.488 Ethanol, C2H5OH(l) 2.46 0.588 Sodium chloride, NACL(s) 0.864 0.207 Water, H2Ol 4.184 1.00

Problem 8QP You have a friend who is using a recipe for flan from a Mexi­can cookbook. You notice that he set your oven temperature at 175 °F. What would you advise him to do?

Problem 9QP Solve the following temperature conversions: a. 37.0 °C =_°F b. 65.3 °F =_°C c. ?27 °C =_K d. 224 K =_°C e. 114 °F =_°C

Problem 9SC If you buy the same hamburger as described in Sample Problem 2.9 at a fast-food restaurant in Canada, what is the energy content for each food type and the total energy content, in kJ? Round off the kilojoules for each food type to the tens place. Sample Problem 2.9 At a fast-food restaurant, a hamburger contains 37 g of carbohydrate, 19 g of fat, and 24 g of protein. What is the energy content for each food type and the total energy content, in kcal? Round off the kilocalories for each food type to the tens place.

Solve the following temperature conversions: a. 25 \({ }^{\circ} \mathrm{C}\) =_____\({ }^{\circ} \mathrm{F}\) b. 155 \({ }^{\circ} \mathrm{C}\) =_____\({ }^{\circ} \mathrm{F}\) c. - 25 \({ }^{\circ} \mathrm{F}\) = _____\({ }^{\circ} \mathrm{C}\) d. 62 \({ }^{\circ} \mathrm{C}\) =_____K e. 545 K =_____\({ }^{\circ} \mathrm{C}\)

Problem 11QP a. A patient with hyperthermia has a temperature of 106 °F. What does this read on a Celsius thermometer? b. Because high fevers can cause convulsions in children, a doctor wants to be called if a child’s temperature goes over 40.0 °C. Should the doctor be called if a child has a temperature of 103 °F?

Problem 12QP a.Water is heated to 145 °F. What is the temperature of the hot water in degrees Celsius? b. During extreme hypothermia, a boy’s temperature dropped to 20.6 °C. What was his temperature in degrees Fahrenheit?

Classify each of the following as an element, compound, or mixture: a. baking soda \(\left(\mathrm{NaHCO}_{3}\right)\) b. a blueberry muffin c. ice \(\left(\mathrm{H}_{2} \mathrm{O}\right)\) d. zinc (Zn) e. Trimix (oxygen, nitrogen, and helium) in a scuba tank

Problem 44QP A high-protein diet contains 70. g of carbohydrate, 5.0 g of fat, and 150 g of protein. How much energy, in kilojoules and kilocalories, does this diet provide? (Round off the kilojoules or kilocalories to the tens place.)

Problem 45QP Select the warmer temperature in each of the following pairs: (2.2) a. 10 °C or 10 °F b. 30 °C or 15 °F c. ?10 °C or 32 °F d. 200 °C or 200 K

Problem 46UTC State the temperature, including the estimated digit, on each of the following Celsius thermometers: (2.2)

Problem 47UTC Compost can be made at home from grass clippings, some kitchen scraps, and dry leaves. As microbes break down organic matter, heat is generated and the compost can reach a temperature of 155 °F, which kills most pathogens. What is this temperature in degrees Celsius and kelvins? (2.2)

Problem 48UTC After a week, biochemical reactions in compost slow, and the temperature drops to 45 °C. The dark brown organicrich mixture is ready for use in the garden. What is this temperature in Fahrenheit degrees? In kelvins?

Problem 49UTC Identify each of the following as an element, compound, or mixture: a. b. c.

Problem 50UTC Which diagram illustrates a homogeneous mixture? Explain your choice. Which diagrams illustrate heterogeneous mixtures? Explain your choice. a. b. c.

Problem 51UTC Classify each of the following as a homogeneous or heterogeneous mixture: (2.3) a. lemon-flavored water b. stuffed mushrooms c. eye drops

Problem 52UTC Classify each of the following as a homogeneous or heterogeneous mixture: (2.3) a. ketchup b. tortilla soup c. hard-boiled egg

Problem 53UTC Indicate if heat is added or removed in each of the following: (2.4) a. water freezing b. copper melting c. dry ice subliming

Problem 84CQ A 125-g piece of metal is heated to 288 °C and dropped into 85.0 g of water at 26 °C. If the final temperature of the water and metal is 58.0 °C, what is the specific heat (J/g °C) of the metal? (2.5)

Problem 85CQ A metal is thought to be titanium or aluminum. When 4.7 g of the metal absorbs 11 J, its temperature rises by 4.5 °C. (2.5) a. What is the specific heat, in J/g °C, of the metal? b. Would you identify the metal as titanium or aluminum (see Table 2.8)? TABLE 2.8 Specific Heats of Some Substances Substance (J/g °C) (Cal/g °C) Elements Aluminum, Al(s) 0.897 0.214 Copper, Cus(s) 0.385 0.0920 Gold, Au(s) 0.129 0.0308 Iron, Fe(s) 0.452 0.108 Silver, Ag(s) 0.235 0.0562 Titanium, Ti(s) 0.523 0.125 Compounds Ammonia, NH3(g) 2.04 0.488 Ethanol, C2H5OH(l) 2.46 0.588 Sodium chloride, NACL(s) 0.864 0.207 Water, H2Ol 4.184 1.00

Problem 86CQ A metal is thought to be copper or gold. When 18 g of the metal absorbs 58 cal, its temperature rises by 35 °C. (2.5) a. What is the specific heat, in cal/g °C, of the metal? b. Would you identify the metal as copper or gold (see Table 2.8)? TABLE 2.8 Specific Heats of Some Substances Substance (J/g °C) (Cal/g °C) Elements Aluminum, Al(s) 0.897 0.214 Copper, Cus(s) 0.385 0.0920 Gold, Au(s) 0.129 0.0308 Iron, Fe(s) 0.452 0.108 Silver, Ag(s) 0.235 0.0562 Titanium, Ti(s) 0.523 0.125 Compounds Ammonia, NH3(g) 2.04 0.488 Ethanol, C2H5OH(l) 2.46 0.588 Sodium chloride, NACL(s) 0.864 0.207 Water, H2Ol 4.184 1.00

Problem 87CQ When a 0.660-g sample of olive oil is burned in a calorimeter, the heat released increases the temperature of 370. g of water in the calorimeter from 22.7 °C to 38.8 °C. What is the energy value, in kJ/g and kcal/g, of the olive oil? (2.6)

Problem 88CQ When a 1.30-g sample of ethanol (alcohol) is burned in a calorimeter, the heat released increases the temperature of 870. g of water in the calorimeter from 18.5 °C to 28.9 °C. What is the energy value, in kJ/g and kcal/g, of ethanol? (2.6)

Problem 89CQ If you want to lose 1 lb of “body fat,” which is 15% water, how many kilocalories do you need to expend?

Problem 90CQ A patient receives 2500 mL of an IV solution containing 5 g of glucose per 100 mL. How much energy, in kilojoules and kilocalories, does the patient obtain from glucose, a carbohydrate? (2.6)

Problem 3SC A child has a temperature of 103.6 °F. What is this temperature on a Celsius thermometer?

Problem 4QP State whether each of the following involves an increase or decrease in potential energy: a. A gondola goes to the top of a mountain. b. Water is pumped up to a high water tower. c. Gasoline is added to a gas tank.

Problem 4CI The label of a black cherry almond energy bar with a mass of 68 g lists the “nutrition facts” as 39 g of carbohydrate, 5 g of fat, and 10 g of protein. (2.1, 2.6) a. Using the energy values of carbohydrates, fats, and proteins (see Table 2.9), what are the kilocalories (Calories) listed for the black cherry almond bar? (Round off answers for each food type to the tens place.) b. What are the kilojoules for the black cherry almond bar? (Round off answers for each food type to the tens place.) c. If you obtain 160 kJ, how many grams of the black cherry almond bar did you eat? d. If you are walking and using energy at a rate of 840 kJ/h, how many minutes will you need to walk to expend the energy from two bars? An energy bar contains carbohydrate, fat, and protein. TABLE 2.9 Typical Energy (caloric) Values for the Three Food Types Food Type KJ/g Kcal/g Carbohydrate 17 4 Fat 38 9 Protein 17 4

Problem 5CI In a box of nails, there are 75 iron nails weighing 0.250 lb. The density of iron is 7.86 g/cm3. The specific heat of iron is 0.452 J/g °C. (1.10, 2.5) a. What is the volume, in cm3, of the iron nails in the box? b. If 30 nails are added to a graduated cylinder containing 17.6 mL of water, what is the new level of water in the cylinder? c. How many joules must be added to the nails in the box to raise their temperature from 16 °C to 125 °C?

Problem 4SC On the planet Mercury, the average night temperature is 13 K, and the average day temperature is 683 K. What are these temperatures in degrees Celsius?

Problem 5QP The energy needed to keep a 75-watt lightbulb burning for 1.0 h is 270 kJ. Calculate the energy required to keep the lightbulb burning for 3.0 h in each of the following energy units: a. joules b. kilocalories

Problem 5SC A salad dressing is prepared with oil, vinegar, and chunks of blue cheese. Is this a homogeneous or heterogeneous mixture?

Problem 6CI A hot tub is filled with 450 gal of water. (1.9, 1.10, 2.5) a. What is the volume, in liters, of water in the tub? b. What is the mass, in kilograms, of water in the tub? c. How many kilocalories are needed to heat the water from 62 °F to 105 °F? d. If the hot tub heater provides 1400 kcal/min, how long, in minutes, will it take to heat the water in the hot tub from 62 °F to 105 °F? A hot tub filled with water is heated to 105 °F?

Problem 6QP A person uses 750 kcal on a long hike. Calculate the energy used for the hike in each of the following energy units: a. joules b. kilojoules

Which of the following are chemical changes? a. Gas bubbles form when baking powder is mixed with vinegar. b. A log is chopped for firewood. c. A log is burned in a fireplace.

Problem 34QP Calculate the specific heat (J/g °C) for each of the following: a. an 18.5-g sample of tin (Sn) that absorbs 183 J of heat when its temperature increases from 35.0 °C to 78.6 °C b. a 22.5-g sample of a metal that absorbs 645 J when its temperature increases from 36.2 °C to 92.0 °C

Problem 35QP What is the amount of energy involved in each of the following? a. calories to heat 25 g of water from 15 °C to 25 °C b. joules to heat 15 g of water from 22 °C to 75 °C c. kilocalories to heat 150 g of water in a kettle from 15 °C to 77 C

Problem 36QP What is the amount of energy involved in each of the following? a. calories given off when 85 g of water cools from 45 °C to 25 °C b. joules given off when 25 g of water cools from 86 °C to 61 °C c. kilocalories absorbed when 5.0 kg of water warms from 22 °C to 28 °C

Problem 38QP Calculate the energy in joules and calories, for each of the following (see Table 2.8): a. required to heat 5.25 g of water from 5.5 °C to 64.8 °C b. lost when 75.0 g of water cools from 86.4 °C to 2.1 °C c. required to heat 10.0 g of silver from 112 °C to 275 °C d. lost when 18.0 g of gold cools from 224 °C to 118 °C TABLE 2.8 Specific Heats of Some Substances Substance (J/g °C) (Cal/g °C) Elements Aluminum, Al(s) 0.897 0.214 Copper, Cus(s) 0.385 0.0920 Gold, Au(s) 0.129 0.0308 Iron, Fe(s) 0.452 0.108 Silver, Ag(s) 0.235 0.0562 Titanium, Ti(s) 0.523 0.125 Compounds Ammonia, NH3(g) 2.04 0.488 Ethanol, C2H5OH(l) 2.46 0.588 Sodium chloride, NACL(s) 0.864 0.207 Water, H2Ol 4.184 1.00

Problem 37QP Calculate the energy, in joules and calories, for each of the following (see Table 2.8): a. required to heat 25.0 g of water from 12.5 °C to 25.7 °C b. required to heat 38.0 g of copper from 122 °C to 246 °C c. lost when 15.0 g of ethanol cools from 60.5 °C to ?42.0 °C d. lost when 112 g of iron cools from 118 °C to 55 °C TABLE 2.8 Specific Heats of Some Substances Substance (J/g °C) (Cal/g °C) Elements Aluminum, Al(s) 0.897 0.214 Copper, Cus(s) 0.385 0.0920 Gold, Au(s) 0.129 0.0308 Iron, Fe(s) 0.452 0.108 Silver, Ag(s) 0.235 0.0562 Titanium, Ti(s) 0.523 0.125 Compounds Ammonia, NH3(g) 2.04 0.488 Ethanol, C2H5OH(l) 2.46 0.588 Sodium chloride, NACL(s) 0.864 0.207 Water, H2Ol 4.184 1.00

Problem 40QP Using the following data, determine the kilojoules for each food burned in a calorimeter: a. one cup of popcorn that changes the temperature of 1250 g of water from 25.5 °C to 50.8 °C b. a sample of butter that produces energy to increase the temperature of 357 g of water from 22.7 °C to 38.8 °C

Problem 39QP Using the following data, determine the kilojoules for each food burned in a calorimeter: a. one stalk of celery that heats 505 g of water from 25.2 °C to 35.7 °C b. a waffle that heats 4980 g of water from 20.6 °C to 62.4 °C

Problem 41QP Using the energy values for foods (see Table 2.9), determine each of the following (round off the answers for kilojoules and kilocalories to the tens place): a. the kilojoules for 1 cup of orange juice that contains 26 g of carbohydrate, no fat, and 2 g of protein b. the grams of carbohydrate in one apple if the apple has no fat and no protein and provides 72 kcal of energy c. the kilocalories in 1 tablespoon of vegetable oil, which contains 14 g of fat and no carbohydrate or protein d. the kilocalories for a diet that consists of 68 g of carbohydrate, 9.0 g of fat, and 150 g of protein TABLE 2.9 Typical Energy (caloric) Values for the Three Food Types Food Type KJ/g Kcal/g Carbohydrate 17 4 Fat 38 9 Protein 17 4

Problem 42QP Using the energy values for foods (see Table 2.9), determine each of the following (round off the answers for kilojoules and kilocalories to the tens place): a. the kilojoules in 2 tablespoons of crunchy peanut butter that contains 6 g of carbohydrate, 16 g of fat, and 7 g of protein b. the grams of protein in a cup of soup that has 110 kcal with 9 g of carbohydrate and 7 g of fat c. the grams of sugar (carbohydrate) in a can of cola if it has 140 Cal and no fat and no protein d. the grams of fat in one avocado if it has 405 kcal, 13 g of carbohydrate, and 5 g of protein TABLE 2.9 Typical Energy (caloric) Values for the Three Food Types Food Type KJ/g Kcal/g Carbohydrate 17 4 Fat 38 9 Protein 17 4

Problem 43QP One cup of clam chowder contains 16 g of carbohydrate, 12 g of fat, and 9 g of protein. How much energy, in kilojoules and kilocalories, is in the clam chowder? (Round off the kilojoules and kilocalories to the tens place.)

Problem 74AQP Identify each of the following as a physical or chemical change: (2.4) a. A medication tablet is broken in two. b. Carrots are grated for use in a salad. c. Malt undergoes fermentation to make beer. d. A copper pipe reacts with air and turns green.

Problem 76AQP A pitcher containing 0.75 L of water at 4 °C is removed from the refrigerator. How many kilojoules are needed to warm the water to a room temperature of 22 °C? (2.5)

Problem 75AQP A hot-water bottle contains 725 g of water at 65 °C. If the water cools to body temperature (37 °C), how many kilojoules of heat could be transferred to sore muscles?

Calculate the Cal (kcal) in 1 cup of whole milk: 12 g of carbohydrate, 8 g of fat, and 8 g of protein. (Round off the answers to the tens place). (2.6)

Problem 78AQP Calculate the Cal (kcal) in 1/2 cup of soft ice cream that contains 18 g of carbohydrate, 11 g of fat, and 4 g of protein. (Round off the answers to the tens place). (2.6)

The combustion of 1.0 g of gasoline releases 11 kcal of heat (density of gasoline = 0.74 g/mL). a. How many megajoules are released when 1.0 gal of gasoline burns? b. When a color television is on for 2.0 h, 300 kJ are used. How long can a color television run on the energy from 1.0 gal of gasoline?

Problem 80CQ In a large building, oil is used in a steam boiler heating system. The combustion of 1.0 lb of oil provides 2.4 × 107 J. How many kilograms of oil are needed to heat 150 kg of water from 22 °C to 100 °C? (2.5)

Problem 81CQ The melting point of carbon tetrachloride is ?23 °C and its boiling point is 77 °C. Sketch a heating curve for carbon tetrachloride from ?100 °C to 100 °C. (2.4) a. What is the state of carbon tetrachloride at ?50 °C? b. What happens on the curve at ?23 °C? c. What is the state of carbon tetrachloride at 20 °C? d. What is the state of carbon tetrachloride at 90 °C? e. At what temperature will both solid and liquid be present?

Problem 82CQ The melting point of benzene is 5.5 °C and its boiling point is 80.1 °C. Draw a heating curve for benzene from 0 °C to 100 °C. a. What is the state of benzene at 15 °C? b. What happens on the curve at 5.5 °C? c. What is the state of benzene at 63 °C? d. What is the state of benzene at 98 °C? e. At what temperature will both liquid and gas be present?

Problem 83CQ A 70.0-g piece of copper metal at 86.0 °C is placed in 50.0 g of water at 16.0 °C. The metal and water come to the same temperature of 24.0 °C. What is the specific heat, in J/g °C, of copper? (2.5)

Problem 14QP Classify each of the following as an element, compound, or mixture: a. a soft drink b. propane (C3H8) c. a cheese sandwich d. an iron (Fe) nail e. salt substitute (KCl)

Problem 15QP Classify each of the following mixtures as homogeneous or heterogeneous: a. vegetable soup b. seawater c. tea d. tea with ice and lemon slices e. fruit salad

Indicate whether each of the following describes a gas, a liquid, or a solid: a. This substance has no definite volume or shape. b. The particles in a substance do not interact with each other. c. The particles in a substance are held in a rigid structure.

Problem 16QP Classify each of the following mixtures as homogeneous or heterogeneous: a. nonfat milk b. chocolate-chip ice cream c. gasoline d. peanut butter sandwich e. cranberry juice

Problem 18QP Indicate whether each of the following describes a gas, a liquid, or a solid: a. This substance has a definite volume but takes the shape of its container. b. The particles in a substance are very far apart. c. This substance°Ccupies the entire volume of the container.

Problem 19QP Describe each of the following as a physical or chemical property: a. Chromium is a steel-gray solid. b. Hydrogen reacts readily with oxygen. c. Nitrogen freezes at ? 210 °C. d. Milk will sour when left in a warm room.

Describe each of the following as a physical or chemical property: a. Neon is a colorless gas at room temperature. b. Apple slices turn brown when exposed to air. c. Phosphorus will ignite when exposed to air. d. At room temperature, mercury is a liquid.

Problem 21QP What type of change, physical or chemical, takes place in each of the following? a. Water vapor condenses to form rain. b. Cesium metal reacts explosively with water. c. Gold melts at 1064 °C. d. A puzzle is cut into 1000 pieces. e. Cheese is grated on top of pasta.

Problem 22QP What type of change, physical or chemical, takes place in each of the following? a. Gold is hammered into thin sheets. b. A silver pin tarnishes in the air. c. A tree is cut into boards at a saw mill. d. Food is digested. e. A chocolate bar melts.

Problem 23QP Describe each property of the element fluorine as physical or chemical. a. is highly reactive b. is a gas at room temperature c. has a pale, yellow color d. will explode in the presence of hydrogen e. has a melting point of ? 220 °C

Problem 54UTC Indicate if heat is added or removed in each of the following: (2.4) a. water boiling b. water condensing c. alcohol evaporating

Problem 55UTC Use your knowledge of changes of state to explain the following: (2.4) a. How does perspiration during heavy exercise cool the body? b. Why do towels dry more quickly on a hot summer day than on a cold winter day? Perspiration forms on the skin during heavy exercise.

Problem 56UTC Use your knowledge of changes of state to explain the following: (2.4) a. When a sports injury occurs during a game, a spray such as ethyl chloride (chloroethane) may be used to numb an area of the skin. Explain how a substance such as ethyl chloride that evaporates quickly can numb the skin. b. Why does water in a wide, flat, shallow dish evaporate more quickly than the same amount of water in a tall, narrow glass? A spray is used to numb a sports injury.

Problem 57UTC The following is a heating curve for chloroform, a solvent for fats, oils, and waxes: a. What is the melting point of chloroform? b. What is the boiling point of chloroform? c. On the heating curve, identify the segments A, B, C, D, and E as solid, liquid, gas, melting, or boiling. d. At the following temperatures, is chloroform a solid, liquid, or gas: ?80 °C; ?40 °C; 25 °C; 80 °C?

Problem 59UTC On a hot day, the beach sand gets hot, but the water stays cool. Would you predict the specific heat of sand is higher or lower than that of water? Explain. (2.5) The water, sand, and air gain energy from the Sun.

Problem 60UTC Determine the energy to heat three cubes (gold, aluminum, and silver), each with a volume of 10.0 cm3, from 15 °C to 25 °C. Refer to Tables 1.13 and 2.8. What do you notice about the energy needed for each? (2.5) TABLE 1.13 Densities of Some Common Substances TABLE 2.8 Specific Heats of Some Substances Substance (J/g °C) (Cal/g °C) Elements Aluminum, Al(s) 0.897 0.214 Copper, Cus(s) 0.385 0.0920 Gold, Au(s) 0.129 0.0308 Iron, Fe(s) 0.452 0.108 Silver, Ag(s) 0.235 0.0562 Titanium, Ti(s) 0.523 0.125 Compounds Ammonia, NH3(g) 2.04 0.488 Ethanol, C2H5OH(l) 2.46 0.588 Sodium chloride, NACL(s) 0.864 0.207 Water, H2Ol 4.184 1.00

Problem 58UTC Associate the contents of the beakers (1-5) with segments (A-E) on the heating curve for water.

Problem 61UTC A 70.0-kg person has just eaten a quarter-pound cheeseburger, french fries, and a chocolate shake. (2.6). a. Using Table 2.9, calculate the total kilocalories for each food type in this meal (round off the kilocalories to the tens place). Item Carbohydrate (g) Fat(g) Protein (g) Cheeseburger 34 29 31 French fries 26 11 3 Chocolate shake 60 9 11 ________________ b. Using Table 2.12, determine the number of hours of sleeping needed to burn off the kilocalories in this meal. c. Using Table 2.12, determine the number of hours of running needed to burn off the kilocalories in this meal. TABLE 2.9 Typical Energy (caloric) Values for the Three Food Types Food Type KJ/g Kcal/g Carbohydrate 17 4 Fat 38 9 Protein 17 4 TABLE 2.12 Energy Expended by a 70.0-kg (154-Ib) Adult Activity Energy (KJ/h) Energy (Kcal/h) sleeping 250 60 Sitting 420 100 Walking 840 200 Swimming 2100 500 Running 3100 70

Problem 62UTC For lunch, your friend, who has a mass of 70.0 kg, has a slice of pizza, a cola soft drink, and ice cream. (2.6) a. Using Table 2.9, calculate the total kilocalories for each food type in this meal (round off the kilocalories to the tens place). Item Carbohydrate (g) Fat (g) Protein (g) Pizza 29 10 13 Cola 51 0 0 Ice cream 44 28 8 TABLE 2.9 Typical Energy (caloric) Values for the Three Food Types Food Type KJ/g Kcal/g Carbohydrate 17 4 Fat 38 9 Protein 17 4 b. Using Table 2.12, determine the number of hours of sitting needed to burn off the kilocalories in this meal. c. Using Table 2.12, determine the number of hours of swimming needed to burn off the kilocalories in this meal. TABLE 2.12 Energy Expended by a 70.0-kg (154-Ib) Adult Activity Energy (KJ/h) Energy (Kcal/h) sleeping 250 60 Sitting 420 100 Walking 840 200 Swimming 2100 500 Running 3100 70

Problem 63AQP Calculate each of the following temperatures in degrees Celsius: (2.2) a. The highest recorded temperature in the continental United States was 134 °F in Death Valley, California, on July 10, 1913. b. The lowest recorded temperature in the continental United States was ?69.7 °F in Rodgers Pass, Montana, January 20, 1954.

Identify each of the following changes of state as evaporation, boiling, or condensation: a. The water vapor in the clouds changes to rain. b. Wet clothes dry on a clothesline. c. Lava flows into the ocean and steam forms. d. After a hot shower, your bathroom mirror is covered with water.