CHEMICAL CHANGE: QUANTITATIVE ASPECTS OF CHEMICAL CHANGE

Question 1

Mole

Answer 1

One mole of a substance is the amount of substance having the same number of particles as there are atoms in 12 g carbon-12.

Question 2

Molar gas volume at STP

Answer 2

The volume of one mole of a gas. (1 mole of any gas occupies 22,4 dm3 at 0 °C (273 K) and 1 atmosphere (101,3 kPa).

Question 3

Molar mass

Answer 3

The mass of one mole of a substance. Symbol: M Unit: g∙mol-1

Question 4

Avogadro’s Law

Answer 4

Under the same conditions of temperature and pressure, the same number of moles of all gases occupy the same volume.

Question 5

Concentration

Answer 5

The amount of solute per liter/cubic decimeter of solution.
In symbols: c= n / V
Unit: mol∙dm-3

Question 6

Empirical formula

Answer 6

The simplest positive integer ratio of atoms present in a compound.

Question 7

Percentage yield

Answer 7

Yield is the amount of product obtained from a reaction.

Question 8

Percentage purity

Answer 8

percentage purity =
mass of pure chemical
over
total mass of sample
x 100

Question 9

Percentage composition

Answer 9

Yield is the amount of product obtained from a reaction.
percentage yield =
actual mass obtained
over
calculated mass
x 100

Question 10

Percentage purity

Answer 10

percentage purity =
mass of pure chemical
over
total mass of sample
x 100

Question 11

Percentage composition

Answer 11

The percentage of each of the components in a substance.
Percentage of component =
mass contributed by component
over
mass of all components
x 100

Question 12

Limiting reagents

Answer 12

The substance that is totally consumed when the chemical reaction is complete.