Ch 1: Essential Ideas in Chemistry Studyguide

What started the base for chemistry?

Greek philosophers believed everything was made of or by Earth, Air, Water, Fire, and Eather (godly material)

Chemistry

study of the composition, properties, and interactions of matter

Scientific Method

leads from question/observation to a law/hypothesis/theory

Hypothesis

editable explanation of observations and is tested by experiments/calculations/comparisons with other experiments

What do hypotheses make?

laws and theories

Laws

summarize large amounts of hypotheses, typically contain mathematical equations, and allows us to make predictions of the natural world

Theories

explain a large amount of data; very comprehensive and if anything disproves it, it isn't a theory anymore; testable explanations of nature

Macroscopic

visible to the naked eye

Microscopic

too small to be seen except under a microscope

Matter

Anything that has mass and takes up space

4 types of matter

1. Solid 2. Liquid 3. Gas 4. Plasma

Solid (S)

fixed shape and volume

Liquid (L)

fixed volume and takes shape of container

Gas (G)

no fixed volume or shape

Plasma

gaseous state; electrically charged particles

Mass

amount of matter; typically measured in kg

Weight

force exerted by gravity (Newtons)

What is equal to a Newton?

(kg*m)/s^2

Law of Conservation of Matter

no change in total quantity of matter present in a chemical/physical change

things that make up matter:

1a. Pure Substance 2a. Element 2b. Compound 1b. Mixture 2c. Homogenous 2d. Heterogeneous

Pure Substances

constant composition (same percentage of each element)

What make up pure substances?

1. element 2. compound

Element

can't be broken down

Compound

can be broken down via chemical change; 2+ elements joined together

Mixture

2+ types of matter; can be separated by physical changes

What make up mixtures?

1. Heterogeneous 2. Homogeneous

Heterogeneous

varying composition, multiple layers

Homogeneous

aka solution; uniform composition (visually looks the same; no chunks or layers)

Atoms

smallest particle of an element that retains the properties of the element

Molecules

2+ atoms joined by chemical bonds

Physical Property

can be observed; doesn't change the chemical composition

What are examples of physical property?

1. density 2. color 3. melting point and boiling point (change of state_)

Physical Change

change in state/property of matter; DOESN'T CHANGE CHEMICAL COMPOSITION

What are examples of physical change?

1. melting wax 2. sugar dissolving 3. Steam/condensation

Chemical Property

matter changing from one type to another

What are examples of chemical property?

1. flammability 2. chemical reactivity 3. toxicity

Chemical Change

produces 1+ type of matter

What are examples of chemical change?

formation of rust, explosion of nitroglycerin

What are the 2 types of properties?

1. Extensive Property 2. Intensive Property

Extensive Property

depends on the amount of matter

Intensive Property

Doesn't depend on the amount of matter

What does each measurement contain?

1. Magnitude/size 2. Standard of Comparison 3. An Indication of Uncertainty

Magnitude/size

means a number

Standard of Comparison

a unit (ex. lbs, kgs, mL, cm)

An Indication of Uncertainty

significant figures

What are the 2 different ways to write measurements?

1. Decimal Form 2. Scientific Notation

Important Prefixes

1. Tera (T)- 10^12 2. Giga (G) - 10^9 3. Mega (M) - 10^6 4. Kilo (K) - 10^3 5. Deci (d) - 10^-1 6. Centi (c) - 10^-2 7. Milli (m) - 10^-3 8. Micro - 10^-6 9. Nano (n) - 10^-9 10. Pico (p) - 10^-12

What do you do when you don't know what the objects volume is?

Use a graduated cylinder, fill it with water, and use displacement to find the volume

Exact number

counting number

Significant figures

every measurement has uncertainty

How to count significant figures:

1. all counting numbers (not including 0) are significant 2. 0's between nonzero numbers are significant] 3. 0's before and after a nonzero number only when there is a decimal point are significant

Calculations of significant figures:

1. Adding/subtracting 2. Multiplying/dividing

Adding/subtracting with significant figures:

round the results to the same number of decimal places as the number with the least number of decimal places

Multiplying/dividing with significant figures:

round the result to the same number of digits as the number with the least amount of significant figures

Accuracy

value is very close to the accepted value

Precision

the measurements results are the same/similar

Dimensional Analysis

math operations apply to units and numbers

Conversion factors

ratio of 2 equivalent quantities expressed with different units

Celsius equation

C=5/9(F-32)

Kelvins equation

K = C + 273