Stoichiometry and Limiting Reactant

What is the first thing you must do to solve a stoichiometry problem?

• Write a Balanced Equation
• Panic
• Write an Unbalanced Equation
• Avogadro's Number

Balance the following reaction :
 
CaC₂(s)   +   H₂O(l)   -->   C₂H₂(g)   +   Ca(OH)₂(aq)

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

What is the mole ratio of water to hydrogen phosphate in the equation for the reaction between tetraphosphorus decaoxide and water to form hydrogen phosphate?  

• 6:4
• 4:6
• 1:3
• 3:1

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

Write the balanced equation for the reaction between aluminum and hydrogen sulfate to form aluminum sulfate and hydrogen gas. How many grams of aluminum sulfate would be formed if 250g H₂SO₄ completely reacted with aluminum?

• 0.85 g
• 290 g
• 450 g
• 870 g

The limiting reactant

• slows the reaction down
• is used up first
• is the reactant that is left over
• controls the speed of the reaction

Use the equation 2 Al + 3 Cl₂ ---> 2 AlCl₃.  If 2 moles of aluminum and 2 moles of chlorine are reacted, identify the limiting reactant.

• AlCl3
• Cl2
• Al

CH₄ + 2H₂O --> CO₂ + 4H₂
What is the limiting reactant when 20g CH₄ react with 15g H₂O?

• CH₄
• H₂O
• CO₂
• H₂