3 Quantitative

Question 1

If 24 g of magnesium reacts with 16 g of oxygen to produce 40 g of magnesium oxide, what mass of magnesium would you need to start with to produce 10 g of magnesium oxide?

Answer 1

6g

Question 2

What is the relative formula mass of calcium carbonate, CaCO3?

Answer 2

100

Question 3

The relative formula mass of CaO is 56 and the relative formula mass of CO2 is 44. Work out the mass of CaO that can be obtained from 200 g of CaCO3. CaCO3 ? CaO + CO2.

Answer 3

112 g

Question 4

What mass of CO2 will be produced when 50 g of CaCO3 decomposes?

Answer 4

22 g

Question 5

What is 20 cm3 in dm3?

Answer 5

0.020 dm3

Question 6

What is the concentration of a solution if 0.25 mol is dissolved in 500 cm3 of solution?

Answer 6

0.5 moldm-3

Question 7

How many moles of solute are there in 25 cm3 of a solution that has a concentration of 0.4 mol/dm3?

Answer 7

0.01 moles

Question 8

If a solution of NaOH is 0.1 mol/dm3, what is its concentration in g/dm3?

Answer 8

4 g/dm3

Question 9

In a reaction, the predicted yield was 80 g, but the actual yield was 60 g. What was the percentage yield?

Answer 9

75%

Question 10

What is the percentage yield if the actual yield was 2.4 g and the predicted yield was 3.0 g?

Answer 10

80%

Question 11

__ H2 + O2 –> __ H2O

Answer 11

2 H2 + O2 –> 2H2O

Question 12

__ Na + __ H2O –> __ NaOH + __H2

Answer 12

2Na + 2H2O –> 2NaOH + 1H2

Question 13

__ Zn + __ S –> __ ZnS

Answer 13

1Zn + 1S –> 1ZnS

Question 14

__ Ca + __ HCl –> __ CaCl2 + __ H2

Answer 14

1 Ca + 2HCl –> 1 CaCl2 + 1 H2

Question 15

__ Al + __ Cl2 –> __ AlCl3

Answer 15

2Al + 3Cl2 –> 2 AlCl3

Question 16

__ Al + __ O2 –> __ Al2O3

Answer 16

4Al + 3O2 –> 2 Al2O3

Question 17

How many atoms are there in 1.2 g of carbon?
The Avogadro constant is 6.02 x 10 to the power 23 particles per mole.
The relative atomic mass oc carbon is 12.

Answer 17

0. 602 x 10 to the power 23 =

6. 02 x 10 to the power 22

Question 18

How many moles of Aluminium are there if there are 1.51 x 10 to the power 23 particles?

Answer 18

6.02 x 10 tp 23 particles ……………. 1 mole
divide by 6.02 x 1.51
1.51 x 10 tp 23 particles…………………1 divided by 6.02 x 1.51
=0.25 moles