# 3 Quantitative Flashcards

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?

6g

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

100

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.

112 g

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

22 g

What is 20 cm3 in dm3?

0.020 dm3

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

0.5 moldm-3

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

0.01 moles

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

4 g/dm3

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

75%

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

80%

__ H2 + O2 –> __ H2O

2 H2 + O2 –> 2H2O

__ Na + __ H2O –> __ NaOH + __H2

2Na + 2H2O –> 2NaOH + 1H2

__ Zn + __ S –> __ ZnS

1Zn + 1S –> 1ZnS

__ Ca + __ HCl –> __ CaCl2 + __ H2

1 Ca + 2HCl –> 1 CaCl2 + 1 H2

__ Al + __ Cl2 –> __ AlCl3

2Al + 3Cl2 –> 2 AlCl3