Review on Stoichiometry

What is the percent yield of the following reaction if 145g of P2O5 reacts with 40 grams of water, but you only collected 112 grams of phosphoric acid? 3 H2O + P2O5 -> 2H3PO4 (Hint: You must calculate your theoretical yield FIRST and then calculate percent yield!)

• 27%

• 94%

• 77%

• 58%

Tags

NGSS.HS-PS1-7

If 5.0 grams of A react with 3.0 grams of B to produce C, and after the reaction, there are still 1.0 grams of B left, which is the limiting reagent?

• A

• B

• C

• Both A and B

Tags

NGSS.HS-PS1-7

What is percent yield?

• The ratio of the actual yield to the theoretical yield, multiplied by 100%.

• The percentage of the reactant that remains unreacted.

• The percentage of the product that decomposes during the reaction.

• The ratio of the theoretical reactant to the theoretical yield, multiplied by 100%.

What happens to the excess reagent after the reaction has gone to completion?

• It continues to react until it is also consumed.

• It is automatically converted into the product.

• It remains in the reaction mixture.

• It disappears without a trace.

Tags

NGSS.HS-PS1-7

In a reaction where A reacts with B to form C, if increasing the amount of A does not increase the amount of C produced, what does this indicate about A?

• A is the limiting reagent.

• A is the excess reagent.

• A is not involved in the reaction.

• A is completely consumed before B.

Tags

NGSS.HS-PS1-7

Using the diagram, determine the limiting reactant. (The product formed is water.)

• oxygen

• hydrogen

• none of the reactant are limiting

• both hydrogen and oxygen

Tags

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

Using the following equation:Fe2O3(s) + 3H2(g) → 2Fe(s) + 3H2O(l)How many moles are left of the excess reactant if 7 moles H2 and 2 moles Fe2O3 react together?

• 1 mol

• 4.667 mol

• 0.667 mol

• 4 mol

SO₂ + PCl₅ --> SOCl₂ + POCl₃ How many grams are are left of the excess reactant 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

• 7.83 g

• 11.98 g

• 30.08 g

• 19.8 g

Tags

NGSS.HS-PS1-7

For the Balanced Reaction: 3 Mg + 1 Fe₂O₃ → 3 MgO + 2 Fe; What is the Ratio of moles of Mg to moles Fe?

• 3mol Mg / 2 mol Fe

• 2 mol Mg/ 3 mol Fe

• 1 mol Fe/ 2 mol Fe

• 3 mol MgO / 2 mol Fe

Tags

NGSS.MS-PS1-5