Chapter 1: Introduction to Chemistry

Question 1

matter

Answer 1

anything that occupies space and has mass

Question 2

mass

Answer 2

quantity of matter that a substance possess

Question 3

weight

Answer 3

varies as the gravitational constant does

Question 4

inertia

Answer 4

property of an object that resists change of position or motion

Question 5

density

Answer 5

relationship of mass to a unit volume (m/V)

Question 6

states of matter

Answer 6

• solid (definite shape and size), liquid (definite volume, no definite shape), gas (no definite shape or volume)
• change states by adding or removing heat

Question 7

pure substance

Answer 7

-can be divided into the smallest particle that still holds the properties of the substance

Question 8

element

Answer 8

-only made of one kind of atom

Question 9

atom

Answer 9

-basic building block of matter, cannot be easily created or destroyed

Question 10

compound

Answer 10

• two or more atoms of an element joined together in a pure substance (usually ionic)
• properties of compounds are different than those of the individual elements that make it up
• homogeneous

Question 11

Law of Definite Proportion

Answer 11

-compound always contains its component elements in fixed ratio (by mass)

Question 12

molecule

Answer 12

two or more elements joined together (usually covalently) (compounds are molecules, not vice versa)

Question 13

mixture

Answer 13

• composition is indefinite (heterogeneous or homogeneous)

- parts of the mixture react differently (expand the solvent, etc.)

Question 14

physical property

Answer 14

• something that can be observed (no change occurring to the structure of it’s smallest component)
• ex: color, odor, solubility, density, melting point

Question 15

chemical property

Answer 15

• observation made when something changes chemically (reacts with another substance)
• iron rusting in moist air, water decomposition (any synthesis, decomposition, or reaction)

Question 16

physical change

Answer 16

• does not alter the composition of the matter, usually a change in form or state
• often a reversible process (water changing state)

Question 17

chemical change

Answer 17

• change in composition and structure of a substance

- always accompanied by energy changes

Question 18

exothermic reaction

Answer 18

-energy released from forming a substance is greater than the energy put in by reactants (ΔH<0 because released energy)

Question 19

endothermic reaction

Answer 19

-new structure absorbs more energy in formation than what the reactants add (ΔH>0 bc energy put in)

Question 20

activation energy

Answer 20

-the minimum quantity of energy that the reacting species must possess in order to undergo a specified reaction

Question 21

Law of Conservation of Matter

Answer 21

-matter can neither be created nor destroyed

Question 22

energy

Answer 22

• the capacity to do work (work is done when a force is applied over a distance, measured in Joules like energy)
  4. 18x10^3 J = 1 kilocalorie
• necessary for both physical and chemical changes
• converted from one form to another

Question 23

forms of energy

Answer 23

-heat, light, sound, mechanical energy, chemical energy, electrical energy

Question 24

potential energy

Answer 24

-stored energy from overcoming forces in nature

Question 25

kinetic energy

Answer 25

-energy of motion

Question 26

enthalpy (ΔH)

Answer 26

ΔH= Hproducts- Hreactants

-change in heat energy in a system

Question 27

Law of Conservation of Energy

Answer 27

energy is neither created nor destroyed, just transferred between the system and surroundings

Question 28

Law of Conservation of Mass and Energy

Answer 28

-mass and energy are interchangeable under certain conditions

Question 29

scientific method

Answer 29

logical approach to solving problems by observing and collecting data, formulating a hypothesis, and then theories

Question 30

qualitative/quantitative

Answer 30

• quantitative: making measurements to describe

- qualitative: descriptions of nature

Question 31

temperature

Answer 31

K= C+273

Question 32

specific heat capactiy

Answer 32

-amount of energy required to raise one gram of a substance by one degree

Question 33

precision vs. accuracy

Answer 33

• precision: how reliable or close each measurement was to another
• accuracy: how close a measurement is to the accepted value