Chemistry Chapter 3 Definitions

Matter

Anything that takes up space and has mass

3 states of matter

solid, liquid, gas

2 types of solids

amorphous and crystalline

Solid molecular motion

oscillation/vibration about fixed point

Liquid and Gas atomic/molecular motion

free to move relative to one another

Solid and Liquid atomic/molecular spacing

close together

Gas atomic/molecular spacing

far apart

Solid shape

definite

Liquid and Gas shape

indefinite

Solid and Liquid volume

definite

Gas volume

indefinite

Solid and Liquid compressibility

incompressible

Gas compressibility

compressible

2 types of pure substances

element or compound

Element

a pure substance that cannot be broken down into simpler substances

Define Helium

element

Compound

a pure substance that is composed of two or more elements bonded in a fixed ratio.

Define H20

compound

Pure substance

composed of only one type of atom or molecule

Mixture

composed of two or more different types of substances not chemically united by mixed together in varied proportions

2 types of mixtures

homogenous and heterogenous

Homogenous

having the same composition throughout

Number of phases in a homogenous mixture

1

Heterogenous

having a composition that varies from region to region

Number of phases in a heterogeneous mixture

2

Physical property

property a substance displays without changing its composition

Odor type of property

physical

Chemical property

property a substance displays through changing its composition

Change of states type of change

physical

Physical change

The appearance of matter may change but the composition does not.

Water type of change

physical

Chemical change

the composition of matter changes.

When does matter undergo a chemical change

when it undergoes a chemical reaction

Law of conservation of mass

Matter cannot be created nor destroyed

Matter is always what?

conserved

During a chemical change what must the sum of the mass of the reactants equal?

the sum of the mass of the products

Law of conservation of energy

Energy cannot be created nor destroyed

Energy

the capacity to do work

Work

the result of a force acting on a distance

Types of energy (KEPTC)

kinetic, electrical, potential, thermal, chemical

Energy is always what?

conserved

Units of energy

Joules, calories, nutritional Calories, kilowatt/hour

kWh

kilowatt/hour

2 types of chemical reactions

endothermic and exothermic

Endothermic

chemical reactions that absorb energy

Exothermic

chemical reactions that emit energy

The temperature of the matter is related to what?

random motions of the molecules and atoms

Heat

the exchange of thermal energy caused by a temperature difference

Temperature

the measure of the thermal energy of matter

3 scales of temperature measurement

Kelvin, Fahrenheit, and Celsius

Heat capacity

the amount of heat energy you need to change the temperature of the amount of a substance by 1 degree Celsius.

More matter in terms of heat capacity

higher heat capacity

Celsius and Kelvin are identical except for what?

the constant 273.15

Is Fahrenheit bigger or smaller than the Kelvin/Celsius degree?

smaller