Target: 10 Questions in 10 minutes

An IB Chemistry data booklet is helpful

Q1-2: What is the sum of the coefficients when the following equations are balanced using the smallest possible whole numbers?

1.

__C4H10 + __O2   →  __CO2 +  __H2O

  • A. 16
  • B. 17
  • C. 32
  • D. 33

2.

__Fe3O4   +   __H2  →  __Fe   +   __H2O

  • A. 8
  • B. 11
  • C. 12
  • D. 14
3. Ethanol was previously used as a fuel for rocket engines and it was important to maintain the correct stoichiometry (molar ratios) of the reactants to ensure complete combustion of the fuel. What is the minimum number of moles of oxygen required for 1 mole of ethanol to burn completely?
  • A.   2
  • B.   2.5
  • C.   3
  • D.   3.5
4. 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
5. 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
6. 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%
7. 0.6mol of tetrachloromethane, CCl4, and 0.6mol of antimony(III)fluoride, SbF3, react to form the refrigerant freon-12 CCl2F2 as shown below:

3CCl4   +  2SbF3 → 3CCl2F2  +  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)fluoride 0.2
D antimony(III)fluoride 0.3
8. 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
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. Isoamyl acetate is an ester used to produce artificial banana flavouring. It is synthesised from an alcohol (isoamyl alcohol) and an acid anhydride (acetic anhydride), as shown in the equation below.

Isoamyl acetate symbol and word reaction

What is the atom economy for this reaction?

  
  • A.   50%
  • B.   68%
  • C.   73%
  • D.   100%