Intro To Chem

Question 1

Matter

Answer 1

Anything that occupies space & has mass

Question 2

Mass

Answer 2

The quantity of matter that a substance possesses
Constant
Can be measured by its inertia
Not related to force of gravity

Question 3

Weight

Answer 3

Measure of force with which a body is attracted toward Earth by gravity
Varies

Question 4

Inertia

Answer 4

Resistance of an object to change in its position or motion

Question 5

Density

Answer 5

The mass per unit volume of a substance

D=m/V

Question 6

Atom

Answer 6

Smallest particle of an element that retains properties of that element & can enter into a chemical reaction

Question 7

Element

Answer 7

Consists of only one kind of atoms

Question 8

Compound

Answer 8

Substance composed of 2/more atoms joined together in a definite grouping

Question 9

Molecule

Answer 9

Smallest particle of a substance that retains physical & chemical properties of that substance

Question 10

Law of decomposition

Answer 10

A compound is composed of 2/more elements chemically combined in a definite ratio by weight

Question 11

Physical properties

Answer 11

Those we can observe with our senses

Colour, odor, density, taste

Question 12

Chemical properties

Answer 12

Those observed in regard to whether or not a substance changes chemically
Iron rusts in moist air, nitrogen does not burn, sodium reacts with water, Ag doesn’t react with water

Question 13

Physical change

Answer 13

Doesn’t alter the identity of the substance
A change that alters some aspects of properties of matter, but composition remains constant
Breaking glass, cutting wood, melting ice

Question 14

Chemical change

Answer 14

Alters the identity of the substance
Changes in the composition & structure of a substance
Always accompanied by energy changes
Burning wood, metabolism of food, milk going sour, baking a cake

Question 15

Exothermic reaction

Answer 15

Chemical reaction that results in giving off heat to its surrounding

Question 16

Endothermic reaction

Answer 16

Chemical reaction that results in overall absorption of heat from its surroundings

Question 17

Activation energy

Answer 17

The minimum energy needed to get reaction going by increasing the energy of the reactants so they can combine

Question 18

Law of conservation of matter

Answer 18

Matter can neither be created nor destroyed, only changed from one form to another

Mass of reactants = mass of products

Question 19

Energy

Answer 19

The capacity to do work

Question 20

Work

Answer 20

Work is done whenever a force is applied over a distance

Question 21

Potential energy

Answer 21

Stored energy due to overcoming forces in nature

Question 22

Kinetic energy

Answer 22

Energy of motion

Question 23

Law of conservation of energy

Answer 23

Energy can be neither created nor destroyed

If system lose energy, surrounding must gain the lost energy

Question 24

Law of conservation of mass & energy

Answer 24

Mass & energy are interchangeable under special conditions
Conditions have been created in nuclear reactors & accelerators
Einstein - E=mc^2

Question 25

Qualitative observations

Answer 25

Involves descriptions of the nature of the substance under investigation

Question 26

Quantitative observations

Answer 26

Involves making measurements to describe the substances under observation

Question 27

Heat energy

Answer 27

Form of energy that transfers among particles in a substance (or system) by means of the kinetic energy of those particles; under KE theory - heat is transferred by particles bouncing into each other

Question 28

Calorie

Answer 28

Unit of heat; the amount of heat needed to raise the temperature of 1g of water 1 degree Celsius
1 calorie = 4.18 joules

Question 29

Precision

Answer 29

How repeatable the results are

Indicates reliability/reproducibility of a measurement

Question 30

Accuracy

Answer 30

How close you are to the true value

Indicates how close a measurement is to its known/accepted value

Question 31

Significant figures

Answer 31

All certain digits in a measurement

Question 32

Solid

Answer 32

Definite size & shape

Question 33

Liquid

Answer 33

Definite volume but takes shape of container

Question 34

Gas

Answer 34

Neither definite size or shape

Question 35

Distinct Substance

Answer 35

Can be subdivided into the smallest particle that still has the properties of that substance
Compounds & Elements

Question 36

Mixture

Answer 36

Vary in their composition & constituents retain their properties
Heterogenous or Homogenous

Question 37

Charge

Answer 37

Stored energy, has capacity to do work

Question 38

Enthalpy

Answer 38

The heat content of a chemical system

Question 39

Model

Answer 39

Visual, verbal or mathematical means of explaining how data is related to phenomena

Question 40

Uncertainty

Answer 40

The limitation of the measuring instrument & the skill of the person making the measurement