TEKS 9A

8E. (#1)

Use the balanced chemical reaction to answer the next question.

N₂ + 3 H₂ --> 2 NH₃

How many moles of ammonia, NH₃, are produced by reacting 5 moles of nitrogen gas, N₂, with excess hydrogen gas, H₂ ? Assume the nitrogen gas, N₂, the limiting reagent.

• 4 moles

• 8 moles

• 5 moles

• 10 moles

Tags

NGSS.HS-PS1-7

8E. (#2)

Use the equation below to answer the following question.

BaCl (aq) + Na_2SO₄ (aq) --> 2NaCl(aq) + BaSO₄ (s)

The theoretical yield of BaSO₄ is 58.35 g. If 44.34 g of BaSO₄ are produced from the reaction shown above, what is the percent yield of BaSO₄ ?

• 52.03%

• 75.99%

• 85.17%

• 1.32%

8E. (#3)

The complete combustion of 44.0 grams of propane (C3H8) is represented by:

C₃H₈ + 5 O₂ --> 3 CO₂ + 4 H₂O

How many grams of water are produced in the reaction?

• 7.0 grams

• 8.0 grams

• 22 grams

• 72 grams

8E. (#4)

How many molecules are in 0.500 mole of N₂O₅?

• 1.20 × 10²³ molecules

• 6.02 × 10²³ molecules

• 3.01 × 10²³ molecules

• 3.01 × 10²⁴ molecules

8E. (#5)

Some students burned magnesium in excess oxygen, as described by the equation

2Mg(s) + O₂ (g) --> 2MgO(s).

They recorded their data in the table below. What is the percentage yield of MgO in this reaction?

mass of crucible = 35.84

mass of crucible + magnesium = 38.85

mass of magnesium = ??

mass of crucible + MgO = 39.45

mass of MgO = ??

• 97.2%

• 58.0 %

• 86.8 %

• 51.0 %

Tags

NGSS.HS-PS1-7

9B. (#1)

The equation below represents a chemical reaction that produces a gas.

2Na(s) + 2H₂O(l) → 2NaOH(aq) + H₂(g)

What is the theoretical yield in liters of H gas if 5.00 g of Na are completely reacted and the 2 H gas is collected at STP?

• 0.109 L

• 4.88 L

• 2.44 L

• 5.09 L

Tags

NGSS.HS-PS1-7

9B. (#2)

Propane, C₃H₈, is a gas commonly used as fuel for cooking and heating. The combustion reaction for propane is

shown.

C₃H₈ + 5 O₂ --> 3 CO₂ + 4 H₂O

If 3.00 moles of propane gas are used for heating, assuming excess oxygen gas, how many liters of CO₂ at Standard Temperature and Pressure (STP) will be produced?

• 7.47 L

• 67.2 L

• 134 L

• 202 L

9B. (#4)

The equation shown represents a gas-producing reaction.

2 KNO₃ (s) --> 2 KNO₂(s) + O₂(g)

After 55.551 grams of solid KNO3 (molar mass = 101.102 g/mol) completely decomposes, what volume of oxygen gas

(O₂) is produced at Standard Temperature and Pressure (STP)?

• 6.154 L

• 8.000 L

• 12.31 L

• 22.4 L

Tags

NGSS.HS-PS1-7

9B.(#5)

What is the volume of 2.00 moles of chlorine (Cl₂ ) at STP, to the nearest tenth of a liter? Record your answer and fill in the bubbles on your answer document.

• 22.4 L

• 44.8 L

• 11.2 L

• 6.2 L

9A. (#1)

Oxygen gas in a 15.0 L container exerts a pressure of 0.48 atm at 21 ºC. How many moles of oxygen are in this container?

• 3.4 moles

• 8.7 x 10^-3 moles

• 4.2 moles

• 3.0 x 10^-1 moles