1. Reacting Masses and Volumes

2. Question
What volume of CO2 will be produced when 20g of calcium carbonate reacts with excess HCl?

3. Step 1 Step 2 you know the amount of and
Write a Balanced Equation for the reaction
CaCO3 + 2HCl = CaCl2 + CO2 + H2O
Step 2
Underline the substances that
you know the amount of and
you are asked to work out the amount of
CaCO3 + 2HCl = CaCl2 + CO2 + H2O

4. Step 3
Write down the number of moles of each underlined substance in the equation
CaCO3 + 2HCl = CaCl2 + CO2 + H2O
1 mole = mole
Step 4
Write down the units given and asked for in the question
CaCO3 + 2HCl = CaCl2 + CO2 + H2O
1 mole = mole
g = cm3

5. Step 5 Convert the number of moles to the units given and asked for
CaCO3 + 2HCl = CaCl2 + CO2 + H2O
1 mole mole
100 g cm3

6. Step 6 Bring the substance you are given the amount of down to 1
Divide the other substance by the value of the substance brought down to 1
CaCO3 + 2HCl = CaCl2 + CO2 + H2O
1 mole mole
100 g cm3
1 g = /100 cm3

7. Step 7
Bring the substance you know the amount of up to the asked amount
Multiply the other substance by the value of the substance you know the amount of
CaCO3 + 2HCl = CaCl2 + CO2 + H2O
1 mole mole
100 g cm3
1 g /100 cm3
20 g = 20 * 22400/100 = 4480 cm3

8. Question
How many molecules of hydrochloric acid would be needed to produce 10g of CO2?

9. Answer CaCO3 + 2 HCl = CaCl2 + CO2 + H2O 2 mole 1 mole
2 * 6 * 1023 molecules 44 g
2*6*1023 / g
10 * 2*6*1023 / g
2.7 * 1023

10. What mass of CaCO3 would be needed to produce 600 cm3 of CO2 [measured at STP]? 2.68g
What volume would this gas occupy at RTP?