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Chemistry µIB
1.3c Reacting Masses
10 quick questions

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An IB Periodic Table is required. Calculators should not be used!

(Molar volume of gas at stp is 22.7 dm3 mol-1)

 

1. What amount (in moles) of carbon monoxide is required to produce 56.0g of iron according to the following equation?

Fe2O3(s)  +  3CO(g) → 2Fe(s)  +  3CO2(g)

  • A.   0.667
  • B.   0.750
  • C.   1.50
  • D.   3.00
2. What is the theoretical yield of sodium oxide when 4.60g of sodium is burned in excess oxygen?

4Na(s)  +  O2(g) →2Na2O(s)

  • A.   1.55g
  • B.   3.10g
  • C.   6.20g
  • D.   12.40g
3. Ammonia is manufactured by the Haber Process as shown:

N2(g)   +   3H2(g) → 2NH3(g)

280kg of nitrogen produced 170kg of ammonia. What was the percentage yield?

  • A.   39%
  • B.   50%
  • C.   61%
  • D.   100%
4. How many moles of carbon monoxide are produced during the incomplete combustion of 4.4g propane?

2C3H8(g)  +  7O2(g) → 6CO(g)   +   8H2O(l)

  • A.   0.15
  • B.   0.30
  • C.   0.60
  • D.   1.2
5. 0.6mol of tetrachloromethane, CCl4, and 0.6mol of antimony(III)fluoride, SbF3, react to form the refrigerant freon-12 as shown below.

3CCl4   +  2SbF33CCl2F2  +  2SbCl3

What is the limiting reactant and how many moles of the excess reactant remain unreacted?

 
  Limiting Reactant Moles of excess reactant unreacted
A tetrachloromethane 0.2
B tetrachloromethane 0.3
C Antimony(III)chloride 0.2
D Antimony(III)chloride 0.3
6. Iron metal is formed by the reduction of Fe3O4 as shown below.

Fe3O4(s)  +  4H2(g) → 3Fe(s)  +  4H2O(l)

What amount (in moles) of hydrogen is required to produce 9.3 mol of iron?

  • A.   3.1
  • B.   6.2
  • C.   9.3
  • D.   12.4
7. Sodium hydroxide and chlorine react as follows:

3Cl2  +   6NaOH → NaClO3  +  5NaCl   +  3H2O

How many moles of sodium chlorate(V), NaClO3, are produced in the reaction between 0.60 moles of Cl2 and 0.60 moles of NaOH?

  • A.   1.2
  • B.   0.20
  • C.   0.13
  • D.   0.10
8. 2.0g of impure magnesium carbonate reacted with excess hydrochloric acid producing 0.010mol of carbon dioxide.

MgCO3(s)  +  2HCl(aq) → MgCl2(aq)   +  CO2(g)   +  H2O(l)

Assuming magnesium carbonate is the only substance reacting to produce carbon dioxide, what was the percentage purity of the magnesium carbonate?

  • A.   22%
  • B.   42%
  • C.   50%
  • D.   84%
9. What is the theoretical yield (in grams) of iron(II)iodide, FeI2, when 5.0g of iron and 10.0g of iodine are heated together?

Fe (s)  +  I2(s) → FeI2(s)

  • A. 
$${10.0 \times 309.65} \over{253.80}$$
  • B. 
$${5.0 \times 309.65} \over{55.85}$$
  • C. 
$${5.0 + 5.0}$$
  • D. 
$${5.0 + 10.0}$$
10. Hydrogen sulfide, H2S, reacts with oxygen as shown:

2H2S   +   3O2 2H2O   +  2SO2

If 22.7dm3 (measured at stp) of H2S and 32g O2 are reacted, what is the limiting reactant and how many moles of SO2 are produced?

 
  Limiting Reactant Moles of SO2
A H2S 0.67
B H2S 1.00
C O2 0.67
D O2 1.00