1. triangle calculations
Titrations and
triangle calculations
Nat 5 1 2 3 4 5 6 7 8 9 10

2. Calculate the formula mass of the following
CH H2O Na2 SO Ca(NO3)2
CH =16
H2O (2 x 1) = 18
Na2 SO4 (2 x 23) (4 x16) = 142 Ca(NO3) (2 x 14) + (6 x 16) =164

3. Calculate one mole of the following
Cl CaCO CO Mg(OH)2
Cl x = 71g
CaCO (3x16) = 100g
CO (2 x 16) = 44g
Mg(OH) (2 x 16) + (2 x 1) = 58.5 g

4. Calculate the number of moles in the following 88g CO2 10g CaCO3
10.1g KNO g O2
1 mole CO2 = 12 + (2 x 16) = 44g /44 = 2 moles
1 mole CaCO3 = (3 x 16) = 100g
10/100 = 0.1 moles
1 mole KNO3 = (3 x 16) = 101g
10.1/101 = 0.1 moles
1 mole O2 = 2 x 16 = 32 g /32 = 0.5 moles

5. Calculate the mass of the following 4 moles HCl 0.1 moles H2S
0.25 moles CaCO moles (NH4)2SO4
1mole HCl = 1 x 35.5 = 36.5g moles = 4 x 36.6 = 146g
1mole of H2S = (2 x 1) + 32 = 34 g
0.1 moles = 0.1 x 34 = 3.4g
1 moles CaCO3 = (3 x 16) = 100g
0.25 moles = 0.25 x 100 = 25g
1 mole (NH4)2SO4 = (2 x 14) + (8 x 1) (4 x 16) = 132g
0.5 moles = 0.5 x 132 = 66g

6. 1 mole of CH4 produced 1 mole of CO2 if 16g gives 44g
Calculate the mass of carbon dioxide is produced when
4g of methane burns completely in oxygen.
CH O CO H2O
1 mole of CH4 produced 1 mole of CO2
if 16g gives g
then 4g gives /16 x = 11g
( 4g is a 1/4 of 16g so a 1/4 of 44g is 11g)

7. Calculate the mass of water produced on
burning 2.8g of ethene.
C2H O CO H2O
1 moles of ethene C2H4 produced 2 moles water H2O
28g (1 mole) gives 36g (2 moles)
2.8g gives /28 x 36
= 3.6g
( 2.8g is a tenth of 28g so a tenth of 36g is 3.6g

8. What volume of HCl acid (conc 0
What volume of HCl acid (conc 0.1 mol/l) is required to neutralise 50 ml of NaOH (conc 0.2 mol/l)?
n= cv
n= 0.2 x 0.05
= 0.01 moles
HCl NaOH
1mole mole
50ml = 0.05 litres
V= n/ c = 0.01/ 0.1 = 0.1 litres = 100ml

9. What is the conc of HCl acid if 12
What is the conc of HCl acid if 12.6 ml neutralises 20ml of KOH (conc 0.1 mol/l)?
n= cv
n= 0.1 x 0.02
= moles
HCl KOH
1mole mole
20ml = 0.02 litres
C= n/ v = / = 0.16 mol L-1

10. Calculated the volume of Sodium hydroxide you would require if you know you need 2 moles and you have a concentration of 0.5mol L-1.
V= n/c
= 2/ 0.5
= 4 L

11. Calculated the number of moles of Nitric acid are in the beaker of solution if you have poured out 25ml and the acid is 0.5 mol L-1
N= c x v
= 0.5 x 0.025
= L = 12.5 ml