Chemistry Stoichiometry Percent Yield

Cl₂ + 2 KBr → Br₂ + 2 KCl
How many grams of potassium chloride can be produced from 356 g of chlorine and 356 g of potassium bromide?

• 749 g

• 223 g

• 479 g

• 814 g

Answer explanation

When given 2 values, you must first determine the limiting reactant. Then you must do the conversion/stoichiometry using the starting amount of the limiting reactant.

Tags

NGSS.HS-PS1-7

B₂H₆ + 3O₂ -->2 HBO₂ + 2 H₂O
 What mass of O₂ will be needed to burn 36.1 g of B₂H₆?

• 13.8 g O₂

• 3.86 mol of O₂

• 125 g O₂

Answer explanation

CO (g) + O₂(g) → 2 CO₂ (g)
In the formation of CO₂ from CO and oxygen, how many Liters of CO₂ are produced by the reaction of 8 mols of O₂ with an excess of carbon monoxide?

• 0.178 L

• 358.4 Liters

• 704 grams

• 0.36 grams

Answer explanation

The actual answer is 358.4, but due to sig. figs. it must be rounded up to 400 L.

Using the following balanced equation: Fe₂O₃(s) + 3H₂(g) → 2Fe(s) + 3H₂O(l) How many moles of iron can be made from 6.0 moles H₂ assuming there is excess Fe₂O₃?

• 4.0 moles Fe

• 6.0 moles Fe

• 9.0 moles Fe

• 2.0 moles Fe

Before performing a lab, a scientist calculates that a reaction should produce 12.3 grams of product in an experiment. When the reaction is performed, the product has a mass of 10.1 grams. What is the percent yield?

• 82.1 %

• 17.9 %

• 122 %

• 1.22 %

What would be the correct numbers of products and leftovers? (In the order shown for the chemicals in the image)

• 4, 6, 6, 1

• 2, 3, 7, 4

• 2, 3, 1, 3

• 4, 6, 2, 5

Tags

NGSS.HS-PS1-7

When calculating the percent yield, what is the measured amount of a product obtained from a chemical reaction?

• mole ratio

• theoretical yield

• percentage yield

• actual yield

Which setup of conversion factors shows the correct process in determining how many grams of iron can be created if the reaction below starts with 6.50 moles of Mg? 3 Mg + 1 Fe₂O₃ → 3 MgO + 2 Fe

• a

• b

• c

• d

Using the following balanced chemical equation: 4 Al + 3 O₂ –> 2 Al₂O₃ How many moles of aluminum would be needed to completely react with 55.0 grams of O₂?

• 73.3 moles

• 0.938 moles

• 1.88 grams

• 2.29 moles

Tags

NGSS.HS-PS1-7

If 55.6 grams of sodium hydroxide react with excess calcium carbonate, how many grams of Na₂CO₃ are produced in this reaction?

• 73.7 grams

• 27.8 grams

• 10.5 grams

• 295 grams

Tags

NGSS.HS-PS1-7