Unit 8 - Stoichiometry Review

Which of the following shows the correct way to balance the chemical equation?
Fe + O₂ -> Fe₂O₃

• 4Fe + 3O₂ -> 2Fe₂O₃
• 2 Fe + 3O₂ -> Fe₂O₆
• 4 Fe + O₆ -> 2Fe₂O₃
• None of the options are correctly balanced.

Balance this equation
_Zn+_HCl-->_ZnCl₂ +_H₂

• 1,1,2,1
• 1,1,1,2
• 1,2,1,1
• 2,1,1,1

Using the following equation:
Fe₂O₃(s) + 3H₂(g) → 2Fe(s) + 3H₂O(l)
How many moles of iron can be made from  6 moles H₂? 

• 4 moles Fe
• 6 moles Fe
• 9 moles Fe
• 2 moles Fe

6CO₂ + 6H₂O --> C₆H₁₂O₆ + 6O₂ 
What is the total number of moles of water needed to make 2.5 moles of C₆H₁₂O₆?

• 2.5
• 6
• 12
• 15

4NH₃ + 5O₂-->4NO + 6H₂O
What is the total number of moles of H₂O produced when 12 mole of NH₃ is completely consumed?

• 15
• 18
• 20
• 24

For the reaction represented by the equation Cl₂ + 2KBr → Br₂ + 2KCl, how many grams of potassium chloride can be produced from 356 grams potassium bromide?

• 749 g
• 225 g
• 479 g
• 814 g

How many grams are in 7.8 moles of NaCl?

• 476 grams

• 460 grams

• 452 grams

• 462 grams

2Na + 2H₂O → 2NaOH+ H₂
How many grams of hydrogen are produced if 120 g of Na are available?

• 5.2 g
• 2.6 g
• 690 g
• 45 g

When does a chemical reaction stop?

• When the lab is finished
• When the excess reactant is used up
• When the limiting reactant is used up
• Chemical reactions never stop

9. Complete the equation for the percent yield of a chemical reaction:
Percent yield=(________)÷(________)×100%

• actual yield; theoretical yield
• theoretical yield; actual yield