CH1) Matter and Measurements

Question 1

Chemistry

Answer 1

• Study of matter
• central to understanding a wide range of scientific disciplines.

Question 2

Matter phases

Answer 2

• solid: fixed shaped and volume
• Liquid: shape of container form horizontal surface
• Gas: Expands to fill container

Question 3

Matter: Gross classification

Answer 3

Mixture and Pure substance

Question 4

Atom

Answer 4

smallest particle of an element- has properties of that element and can enter into a chemical combination

Question 5

Molecule

Answer 5

Consists of 2 or more atoms connected by strong forces known as chemical bonds

Question 6

Physical and chemical properties

Answer 6

• characteristics enable us to distinguish our substance from another are called properties

Question 7

Physical property

Answer 7

• Characteristic of matter that is not associated with a change in its chemical composition
  ex: Density, color, hardness, melting and boiling points, and electrical conductivity

Question 8

physical change

Answer 8

change in the state or properties of matter without any accompanying in its chemical composition
ex: Butter undergoes physical change when solid butter melts

Question 9

Chemical property

Answer 9

• change of one type of matter into another type (or inability to change)
  ex: Flammability, toxicity, acidity, reactivity and heat of combustion

Question 10

Extensive property

Answer 10

• Depends on the amount of matter present
• EX: mass, volume, heat

Question 11

Intensive property

Answer 11

• Does not depend on the amount of matter present
  EX: Density, temperature

Question 12

Measurements

Answer 12

Provide information- basis of hypothesis, theories, and laws in chemistry.

Question 13

Every measurement provides 3 kinds of information:

Answer 13

1) Size or magnitude of the measurements: a Number
2) Standard of comparison for measurement: A Unit
3) indication of uncertainty of the measurement

Question 14

Units

Answer 14

• Without units, a number can be meaningless or confusing.
• In chem, we use updated version of metric system known as International System of units or SI units since 1964

Question 15

Converting Units

Answer 15

• Conversion factors used to convert one set of units to another
• Only units change
  Conversion factors are numerically equal to 1

Question 16

Density

Answer 16

• Substance is the ratio of the mass of a sample of the substance to its volume

Question 17

Standard SI unit for density is

Answer 17

The kilogram per cubic meter (kg/m^3)

Question 18

Commonly used density units based on state of matter

Answer 18

g/cm^3 (solid, liquids)
g/l (gases)