Quantitative Chemistry

Question 1

Amount of substance

Answer 1

used to count the number of particles in a substance. It is measured in a unit called moles, mol.

Question 2

One Mole

Answer 2

Amount of substance that contains
6.02 x 1023 particles

Question 3

Avogadro constant

Answer 3

6.02 x 10^23 mol-1

Question 4

Molar mass

Answer 4

• gives the mass in grams in each mole of the substance
• The unit is g mol-1.

Question 5

Amount of substance, N ,Equation

Answer 5

• n=m/M
• mol=mass/molar mass

Question 6

Molar gas volume

Answer 6

Vm , is the volume per mole of gas molecules at a stated temperature and pressure.

Question 7

Vm at RTP

Answer 7

• 1 mole of gas molecules has a volume of approximately 24.0 dm³ = 24,000 cm³
• At RTP, the molar gas volume = 24.0 dm³.
• mol (n) = volume ÷ Molar gas Volume (24.0 Vm)

Question 8

Theoretical yield

Answer 8

Maximum possible amount of product

Question 9

Percentage Yield

Answer 9

• =(actual amount of product ÷ theoretical max amount of product) x100
  or
• (Actual yield ÷ theoretical yield) x100

Question 10

Atom Economy

Answer 10

• A measure of what mass of the atoms involved in the reaction end up in useful (desired) products
• Molecular mass of desired product ÷ Molecular mass of all product

Question 11

Molecular formula

Answer 11

Empirical Formula(EF)
x
[MR(compound) ÷MR(EF)]

Question 12

Concentration

Answer 12

• C = n ÷ v
• concentration = moles ÷ volume
• In cm³ C=(nx1000) ÷ volume

Question 13

Mass

Answer 13

mol dm-³ = mass dm-³ ÷ Mr

Question 14

Ideal Gas Equation

Answer 14

• pV=nRT
• p = pressure (in Pa)
• V = volume (in m³)
• n = no. of moles
• T = temperature ( in K)
• R = ideal gas constant ( in J/mol K