Chem (1-2)

Is the study of matter?

Chemistry

Chemistry studies:

1- Chemical & physical properties of matter

2- Chemical & physical Changes matter undergoes

3- Energy Changes (gains/loses) as matter changes

Anything that has mass & occupies space

Matter

Characteristics of matter used by scientists to categorize different types of matter ( Bp, Mp, density, reactivity)

Properties

Matter is categorized by

1- State
2- Composition

States of Matter

1- Solid
2- Liquid
3- Gas

Particles widely separated, no definite shape or volume

Gas

Particles closer together, definite volume but no definite shape

Liquid

Particles are very close together, definite shape & volume

Solid

Particles in solid are either

1- amorphous (random)
2- Crystalline (ordered)

Composition of matter

1- Pure substance
2- Mixture

A substance that has only one component & specific chem/phys properties

Pure substance

Combination of 2+ pure substances in which each substance retains its own identity (not undergoing chem reaction)

Mixture

Pure substances

1- Element
2- Compound

A pure substance, cannot be changed into simpler form by chemical reaction

Element

Pure substance, combination of 2+ elements in a definite, reproducible way, in a fixed ratio

Compund

Element + Element

Compound

Element + Compound

Mixture

Mixtures (types):

1. Homogeneous
2. heterogenous

Uniform composition, particles well mixed, thoroughly intermingled on molecular or atomic level

Homogenous mixture

Nonuniform composition, random placement

Heterogenous mixture

Observed without changing the composition or identity of a substance

Physical Property

Produces a recognizable difference in the appearance of a substance without causing any change in its composition or identity. Ex:melting an ice cube

Physical Change

Results in a Change in composition, can be observed only through a chemical reaction

Chemical Property

Chemical substance is converted into 1+ different substances by rearranging, removing, replacing, or adding atoms

Chemical Reaction (chemical change)

7 fundamental SI units

1. Length (meter; m)
2. Mass (Kilogram; kg)
3. Time (seconds; s)
4. Temperature (Kelvin; K)
5. Amt. substance (mole; mol)
6. Current (Ampere; A)
7. Luminous Intensity (candela; cd)

Units of quantity without any metric prefix

Basic units

Metric prefixes (8)

1- Mega (M) 10^6
2- Kilo (k) 10^3
3- Deka (da) 10^1
4- Deci (d) 10^-1
5- Centi (c) 10^-2
6- milli (m) 10^-3
7- micro (¥) 10^-6
8- Nano (n) 10^-9

Used to express very large/small numbers easily with correct value and accuracy

Scientific notation (represent number as power of 10)

Scientific notation

N x 10^-x Where. 1

Scientific notation rules:

1- Unit greater than 1; x places to the left (x 10^x)

2- Unit less than 1; x places to the right (x 10^-x)

Degree of “hotness” of an object

Temperature

Form of energy that spontaneously flows from a hot body to a cold one

Heat

Kelvin (K) scale is important because

Directly related to molecular motion.

As molecular speed increases, Kelvin temperature proportionately increases.

K & °C formula

T(K) = T (°C) + 273

°F & °C formula

°F = 1.8 x °C + 32

°C = (°F - 32) / 1.8

Density is

The ratio of mass to volume

Units of density

• g/mL
• g/cm^3
• g/cc

(cc = cm^3)

Density formula

Mass (m) / Volume (V)

Used to characterize a substance

Density; since each substance has a unique density

Volume =

Length x width x height

Volume conversions

• 1 cm^3 = 1 mL
• 1 m^3 = 1000 L
• 1 dm^3 = 1 L