Ch 3

Question 1

Pure Substances

Answer 1

A form of matter that always has a definite and constant composition

Question 2

Element

Answer 2

• Pure substances that contains atoms of only one type
• The most basic form of matter.
• Each element can be found on the periodic table

Question 3

Each element has a unique name and is represented by a unique symbol

Answer 3

• Chemical symbol: a one- or two-letter designation for an element derived from the element’s name
• First letter of the symbol is always capitalized

Question 4

Mixtures

Answer 4

a physical combination of two or more pure substances in which each substance retains its own chemical identity

Question 5

A mixture is a type of matter that consists of:

Answer 5

• Two or more substances that are physically mixed, not chemically combined
• Two or more substances in different proportions
• Substances that can be separated by physical methods

Question 6

Homogeneous Mixtures (solutions)

Answer 6

• The composition is uniform throughout

* The different parts of the mixture are not visible

Question 7

Heterogeneous Mixtures

Answer 7

• The composition of substances is not uniform
• The composition varies from one part of the mixture to another
• The different parts of the mixture are visible

Question 8

Temperature

Answer 8

• Is a measure of how hot or cold an object is compared to another object
• Indicates that heat flows from the object with a higher temperature to the object with a lower temperature
• Is measured using a thermometer

Question 9

Conversions between Celsius and Kelvin

Answer 9

• (Temperature in K) = (temperature in oC) + 273

* (temperature in oC) = (temperature in K) – 273

Question 10

Conversions between Celsius and Fahrenheit

Answer 10

• oF = 9/5 (oC) + 32

* oC = 5/9(oF – 32)

Question 11

Energy:

Answer 11

• Makes objects move
• Makes things stop
• Is needed to “do work”

Question 12

Two main forms of energy:

Answer 12

• Potential

* Kinetic

Question 13

Potential Energy

Answer 13

is energy stored for use at

a later time.

Question 14

Kinetic energy

Answer 14

energy is the energy of matter in motion.

Question 15

Energy can take many forms:

Answer 15

Heat
Mechanical
Light 
Electrical
Chemical
Nuclear

Question 16

Energy is often converted

Answer 16

from one form to another.

Question 17

Heat (q):

Answer 17

*Most commonly required/released form of energy in chemical reactions

*Always flows from hotter objects to colder objects
Provides kinetic energy from the hot object to the cold object

• The energy lost by the hot object is equal to the energy gained by the cold object
• Units: calories (cal) or Joule (J)

Question 18

Specific heat (c):

Answer 18

• Quantity of heat energy needed to raise the temperature of 1 gram of a substance by 1 degree Celsius
• Units: J/goC or cal/goC
• The higher the specific heat of a substance, the less its temperature will change when heat is added to it

Question 19

Calculating Heat

Answer 19

q = m x c x DT
DT = T(final) – T(initial)