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Lesson: Maximum and Percentage Yields

Worksheet • 15 Questions

Q1:

Urea can be synthesized by reacting carbon dioxide with gaseous ammonia:

Carbon dioxide is produced by complete combustion of carbon in excess oxygen. What is the maximum mass of urea that can be produced from 1.00 tonne of carbon?

Q2:

After weighing the solid product of their reaction, a student finds that their calculated yield is over 100%. Which of the following is not a potential cause?

  • AThe molar mass of the product is lower than calculated.
  • BThe balance was not properly tared.
  • CThe reactant was not accurately weighed.
  • DThe reaction generated other solid products.
  • EThe product has not been completely dried.

Q3:

How many molecules of 1,1,2,2-tetrachloroethane can be prepared from 13 molecules of ethane and 21 molecules of C l 2 ?

Q4:

Citric acid ( C H O ) 6 8 7 is prepared via the fermentation of sucrose. The chemical equation representing this process is

Calculate the mass of citric acid obtained from 2.50 tonnes of sucrose if the yield is 85.30%.

Q5:

When potassium iodide reacts with lead(II) nitrate, a yellow precipitate ( P b I 2 ) is produced. If 0.78 g of lead(II) iodide was produced, how many grams of lead(II) nitrate was used? You may assume the reaction yield was 1 0 0 % , and an excess of potassium iodide was used.

  • A 0.56 g
  • BNot enough information is given.
  • C 0.78 g
  • D 0.46 g
  • E 1.6 g

Q6:

Toluene ( C H C H ) 6 5 3 can be oxidized by air to benzoic acid ( C H C O O H ) 6 5 , with water as the only by-product. Calculate the percentage yield for a reaction that converts 1.00 kg of toluene to 1.21 kg of benzoic acid.

Q7:

Ether ( C H O ) 4 1 0 is prepared from ethanol by an acid-catalyzed condensation reaction, with water as the only by-product. The densities of ether and ethanol are 0.7134 g/mL and 0.7894 g/mL, respectively. Calculate the percentage yield of a reaction that produces 1.17 L of ether from 1.500 L of ethanol.

Q8:

Hydrogen chloride gas is produced by reacting 13.8 g of sodium chloride with excess sulfuric acid:

What volume of 0.530 M hydrochloric acid can be prepared by dissolving this gas in water?

Q9:

White phosphorus ( P ) 4 is oxidized by oxygen gas to phosphorus pentoxide ( P O ) 4 1 0 with no by-products. Calculate the percentage yield if 8.30 g of phosphorus pentoxide is obtained from the reaction of 40.0 mmol of white phosphorus with 240 mmol of oxygen gas.

Q10:

A sample of 0.56 g of carbon dioxide was obtained by heating 1.25 g of magnesium carbonate. Calculate the percentage yield for this reaction.

Q11:

Chromium and phosphoric acid react according to the equation:

Calculate the percentage yield if 0.50 mol of chromium and 0.75 mol of phosphoric acid react to produce 62.1 g of chromium(III) phosphate.

Q12:

Uranyl nitrate ( U O ( N O ) 2 3 2 ) can be precipitated from acidic solution by reaction with sodium oxalate ( N a C O 2 2 4 ):

Addition of 0.4031 g of sodium oxalate to a solution containing 1.481 g of uranyl nitrate yields 1.073 g of U O ( C O ) · 3 H O 2 2 4 2 . Calculate to 3 significant figures the percentage yield for this reaction.

Q13:

A student produces solid potassium chloride and oxygen gas via the thermal decomposition of 53.2 g of solid potassium chlorate ( K C l O 3 ). The mass of the remaining solid material is 38.5 g.

Calculate the number of moles of potassium chloride produced.

Calculate the percentage yield of this reaction.

Q14:

Freon-12 ( C C l F ) 2 2 is prepared from carbon tetrachloride by reaction with hydrogen fluoride. The other product of this reaction is hydrogen chloride. Calculate the percentage yield, to two significant figures, for a reaction that yields 12.5 g of Freon-12 from 32.9 g of carbon tetrachloride.

Q15:

A freshly-cut piece of strontium metal is left to oxidise completely in dry air. Its final mass is 5.95 g. What was the mass of the strontium metal?

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