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WCUPA / Chemistry / CHE 107 / What is the definition of pure substances?

What is the definition of pure substances?

What is the definition of pure substances?

Description

School: West Chester University of Pennsylvania
Department: Chemistry
Course: General Chemistry for Health Science
Professor: Jacqueline butler
Term: Winter 2016
Tags:
Cost: 25
Name: Chem 107 Week 1 of notes
Description: This is Chapter one, so all of Tuesday's lecture. I am going to wait to post chapter two until we finish it next week. Almost all of this information will be on our quiz Tuesday,
Uploaded: 01/23/2016
4 Pages 44 Views 5 Unlocks
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Mr. Sienna Wuckert (Rating: )

I had to miss class because of a doctors appointment and these notes were a LIFESAVER



Unit 1: Basic Concepts in Chemistry and Atoms and the Periodic Table- Chapter 1  


What is the definition of pure substances?



1. Classification of Matter

a. States of matter

i. 3 states of matter

1. Solid- atoms are closely packed and hold a specific shape;

atoms vibrate

2. Liquid- atoms are packed together loosely and are able to  

move around one another; do not hold a shape, but  

instead take the shape of their container

3. Gas- atoms are very spread out and particles can move  

freely in all directions allowing it to diffuse and fill its  

container

ii. Molecules in all three are in constant motion unless at absolute 0 (0° Kelvin)

b. Composition

i. Types If you want to learn more check out What is the meaning of political economy?

1. Pure Substances

a. One type of particle


What is the definition of compounds?



b. Always remain the same between samples

c. Elements- substances that cannot be broken  If you want to learn more check out What question do fitzgerald and cook­martin seek to explain?

down into simpler substances by chemical  

reactions

i. Basic building blocks of matter

ii. Contain a single type of atom  

d. Compounds- combination of two or more kinds of  We also discuss several other topics like What is the meaning of addiction in drugs and behavior?

atoms and is able to be broken  

down/decomposed

2. Mixtures

a. Multiple types of particles

b. May show different intensive properties of its  

components

c. Types

i. Homogeneous- uniform throughout, looks  

same

1. Ex: tea, paper


What are the properties of physical and chemical?



ii. Heterogeneous- not uniform throughout

1. Ex: sand and water, salad dressing

c. Physical and Chemical Properties

i. Physical

1. Can be measured without changing the identity of the  Don't forget about the age old question of What is a mineral?

substance

2. Remain the same always in one substance

3. Ex: melting point, boiling point, color, etc.

ii. Chemical  

1. How a substance reacts with something else We also discuss several other topics like What is the maturational theory?

2. Look for the words react, burn, combustion, or other  

words that indicate a change

3. Ex: iron rusts, gasoline burns in air, nitric acid reacts with  sodium hydroxide, etc.  

d. Physical and Chemical Changes

i. Physical

1. Original substance still exists in a new form

2. Ex: boiling of water- the water can be recreated if you trap the vapor; the tearing of paper- it is still paper just smaller

ii. Chemical

1. A new substance has been created; you cannot get the  

old one back since it has become something else

2. Ex: a boiled egg- you cannot regain the uncooked egg  

since it has created a new substance; burnt paper- you  

cannot have white paper again as it has become ash We also discuss several other topics like How does specialization lead to global trade?

e. Intensive and extensive properties

i. Extensive

1. Depends on the amount of a substance

2. Think EXTERNAL

3. Mass and Volume are examples

ii. Intensive  

1. Is based on the substance itself not the quantity

2. Think INTERNAL

3. Color, Density, or hardness are considered intensive

f. Chemical Observations

i. Qualitative

1. Physical descriptions, properties, any word definitions of a substance

ii. Quantitative

1. Is any numerical value associated with a substance  

iii. Accuracy

1. Closeness to a true or accepted value

2. In darts, if you shoot all close to the bullseye

iv. Precision

1. Closeness of measurements to each other

2. In darts, if all shots are not close to the bullseye but close  to each other

**** The more tics on a ruler, thermometer, etc. make it more accurate and precision becomes easier

***Digit of inaccuracy/ uncertainty- the number you guess beyond the  closest known value (WHAT YOU KNOW PLUS ONE VARIABLE NUMBER)

2. Significant figures (REVIEW EXAMPLES AND HER WORKSHEETS) a. What

i. The digits displayed in any measurements that are known with a certainty plus the digit of uncertainty

b. Guidelines for significant digits

i. Digits 1-9 are ALWAYS significant

ii. Leading zeros are nit significant

iii. If a zero is surrounded by a 1-9, it is significant

iv. Trailing zeros are only significant if followed by a decimal point

c. Rules for sig figs in calculations

i. Addition/Subtraction

1. Line up

2. Draw a vertical line where the shortest number ends

3. Round if necessary

*YOU ARE LIMITED BY THE ACCURACY OF THE SHORTEST  

NUMBER

ii. Multiplication/Division

1. Multiply numbers

2. Round final number based on the number with the  

smallest number of sig figs at the end of the calculation  

not during

3. Scientific Notation

a. Always a multiple of ten

i. A x 10^B

1. A= coefficient that depends on the number of sig figs

2. B= exponent (number of digits after the first sig fig)

b. Numbers greater than 1 have a positive exponent, if between 0 and 1  have a negative

4. Temperature

a. Measure f the amount of kinetic energy (energy based in the  movement of atoms)

b. Vibrations/friction of atoms causes heat

c. High temperature= high thermal energy

d. Heat can only transfer from a warm substance to a colder substance by collision of molecules until they reach the same temperature

e. Scales

i. Fahrenheit

1. US only

2. Do not need to know conversions to or from Celsius

ii. Celsius

1. All other countries, general use

iii. Kelvin

1. Absolute scale

2. Directly proportional to amount of kinetic energy

3. Zero degrees kelvin is absolute zero

4. K= Celsius temp + 273

5. Metric Units (ONLY NEED TO KNOW METRIC TO METRIC CONVERSIONS) a. Units

i. Length= meter (m)

ii. Volume- liter (l)

iii. Mass- gram (g)

iv. Time- second (s)

v. Temperature – Kelvin (K)

vi. Energy- joule (j)

vii. Amount of a substance- mole (mol)

b. Prefixes

i. Giga- G 10^9

ii. Mega- M 10^6

iii. Kilo- k 10^3

iv. Deci- d 10^-1

v. Centi- c 10^-2

vi. Milli- m 10^-3

vii. Micro- ɥ 10^-6

viii. Nano- n 10^-9

ix. Pico- p 10^-12

6. Mathematical Operation

a. Make sure you have only one unit when adding and subtracting i. Use conversion factors to convert one unit to another  

ii.

oneof aunit

multiple of oneunit or  

multiple of oneunit oneof aunit

iii. Each conversion is basically multiplying by 1, and just allows for  a unit to be cancelled out

b. Dimensional analysis

i. Using multiple conversion factors to change the units of an  

equation

ii. Ex: miles per hour to feet per second

***** This is the end of the material that will be covered on Tuesday’s quiz

7. Density

a. Density is the ratio of an objects mass to its volume

b. d=mv

c. Normally expressed in:

i. g/mL for liquids

ii. g/cm3 for solids

iii. g/L for gases

***** mL and cm3 are equivalent when in conversions

***** A liter is 1000 mL so it is also 1000 cm3 

d. Solids are generally more dense that liquids which are more dense  than gases

I will post chapter 2 along with or included in the study guide! Send me an email if  you have any questions!

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