Stoichiometry

Question 1

Relative atomic mass

Answer 1

Mass number of isotope

Question 2

Relative molecular mass (Mr)

Answer 2

Sum of RAM of each atom in a molecule

Question 3

Relative Formula Mass

Answer 3

RAM sum in a formula

Question 4

Amount of substance (n)

Answer 4

Number of a chemical species (e.g atoms) in a quantity

Question 5

Moles (mol)

Answer 5

n’s unit

Question 6

Avogadro’s Constant (L,Na)

Answer 6

6.02*10^23 mol-1

Question 7

Molar Mass, M

Answer 7

Mass per mol. Unit = g mol-1

Question 8

n=

Answer 8

Mass(g)/molar mass

Question 9

Moles from solutions

Answer 9

n=c*V

n= amount of substance, mol
c= solution concentration, mol dm-3
V= solution's volume, dm3

Question 10

Molarity

Answer 10

Concentration in dm-3 aka g dm-3

Question 11

r.t.p

Answer 11

298K (25degrees)

100kPa

Question 12

1mol gas

Answer 12

24dm3~

Question 13

Ideal Gas Equation

Answer 13

pV=nRT or pV=m/M RT

p= pressure (Pa)
V= volume (m3)
T= temperature (K)

m= gas sample (g)
M= gas' relative molecular mass
R= 8.31 J K-1 mol-1

Question 14

cm3 to m3

Answer 14

*10^-6

Question 15

dm3 to m3

Answer 15

*10^-3

Question 16

C to K

Answer 16

+273

Question 17

kPa to Pa

Answer 17

*10^3

Question 18

Limiting reactant

Answer 18

The reactant that limits the amount of product formed. Once it’s all gone, the reaction stops

Question 19

Excess reactant

Answer 19

Remaining reactant after the limiting reactant is consumed and the reaction stops

Question 20

Solving titrations

Answer 20

Need:
balanced eq,
concentration and reacting vol. of 1st reactant
concentration and reacting vol. of 1st reactant

Question 21

Solving mole questions

Answer 21

1) no. Of moles (rel eq)
2) mole ratio
3) rearrange relevant eq to calculate mass, concentration, volume or substance of interest