Limited and Excess Reactants

What is a limiting reactant?

• the reactant that determines how much product can be made
• the reactant that is in excess
• the product that you can make the most of
• the amount of reactants that react with each other

Tags

NGSS.HS-PS1-7

A reactant that remains after a chemical reaction stops

• stoichiometry
• mole ratio
• excess reactant
• limiting reactant

What is the limiting reactant if 10 moles of NH₃  react  with 30.0 moles of NO?

(hint: solve for the amount of N₂ that each reactant could make)
4NH₃ + 6NO --> 5N₂ + 6H₂O

• NH₃
• NO
• N₂
• water

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-7

SO₂ + PCl₅ --> SOCl₂ + POCl₃
How much SOCl₂ is produced when 16.2g SO₂ react with 13.7g PCl_5? 

• 7.87g

• 30.1g

• 26.4g

• 19.8g 

Tags

NGSS.HS-PS1-7

2 NaCl + Pb(NO₃)₂ --> 2 NaNO₃ + PbCl₂
 
How many grams of lead II chloride are produced from the reaction of 15.3 g of NaCl and 60.8 g of Pb(NO₃)₂? 

• 21.5g
• 51.1g
• 43.4g
• 36.4g

Tags

NGSS.HS-PS1-7

Using the following equation:

Fe₂O₃(s) + 3H₂(g) → 2Fe(s) + 3H₂O(l)

How many moles of the excess reactant are left over if 7 moles H₂ and 2 moles Fe₂O₃ react together?

(hint: You have to determine how many moles of the excess reactant are USED first)

• 1 mol

• 4.667 mol

• 0.667 mol

• 4 mol

Tags

NGSS.HS-PS1-7

SO₂ + PCl₅ --> SOCl₂ + POCl₃

How many grams of the excess reactant are left over when when 16.2g SO₂ reacts with 13.7g PCl₅?

Molar Mass: SO₂ = 64.07 g/mol & PCl₅ = 208.24 g/mol

& SOCl₂ = 118.97 g/mol

(Hint: First determine how many grams of the excess reactant will be USED)

• 7.83 g

• 11.98 g

• 30.08 g

• 19.8 g

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-7

What is the percent of Magnesium in magnesium bromide (MgBr₂) ?

• 13%

• 43%

• 63%

• 87%

What is the percent composition by mass of sulfur in the compound MgSO₄ (molar mass = 120 g/mol)?

• 20%
• 27%
• 46%
• 53%

What is the empirical formula if you have 88.80% copper and 11.20% oxygen?

• Cu₃O₈
• CuO₄
• Cu₂O
• Cu₄O₁₀