Chapter 4 - Stoichiometry

A 25.0 mL solution of HCl is neutralized with 19.5 mL of 0.115M Sr(OH)₂. What is the concentration of the original HCl solution

• 0.179

• 0.154

• 0.0191

• 0.0207

To make a s'more snack, it takes 2 marshmallows, 1/3 of chocolate bar, and 1 graham cracker. However, these ingredients are sold in ratios that do not allow you to use up all of the ingredients. Based on the packaging of the ingredients (shown below), what is the limiting reagent?

• Marshmallows

• Chocolate bars

• Graham Crackers

Calculate the grams of AlI₃ from the complete reaction of 18.3 grams of Al according to the following balanced equation:

Al(s) + 3I₂(s) → 2AlI₃(s)

• 407.7

• 26.98

• 277

If 8.00 moles of NH₃ of and 10.00 moles of O₂ react in the following reaction, how many moles of which reactant will be left over?

4 NH₃ (g) + 5 O₂ (g) → 4 NO (g) + 6 H₂O (g)

• 2.00 mol O₂

• 2.00 mol NH₃

• 8.00 mol NO

• no moles will be left over of either reactant because both are limiting.

How many liters of a 0.209 M KI solution is needed to completely react with 2.43 g of Cu(NO₃)₂ according to the balanced chemical reaction:

2 Cu(NO₃)₂ + 4 KI--> 2 CuI + I₂ + 4KNO₃

• 0.124 L KI

• 0.287 L KI

• 0.528 L KI

• 0.391 L KI

When copper is heated with an excess of sulfur, copper(I) sulfide is formed. In a given experiment, 1.50 g of copper was heated with excess sulfur to yield 1.71 g copper(I) sulfide. What is the percent yield?

• 76%

• 50%

• 82%

• 91%

Write a balanced chemical equation based on the following description: butane gas reacts with oxygen gas to produce carbon monoxide gas and water vapor:

C₄H₁₀(g) + O₂(g) →

• 18 CO(g) + 100 H₂O(g)

• 10 CO(g) + 8 H₂O(g)

• 8 CO(g) + 10 H₂O(g)

• 6 CO(g) + 8 H₂O(g)

According to the balanced reaction below, calculate the quantity of moles NH₃ gas that form when 4.20 mol of N₂H₄ liquid completely reacts:

3 N₂H₄(l) → 4 NH₃(g) + N₂(g)

• 5.37 mol NH₃

• 5.60 mol NH₃

• 4 mol NH₃

• 3.65 mol NH₃

What is the mass percentage of C in caffeine, C₈H₁₀N₄O₂? Provide an answer to two decimal places.

• 49.98%

• 28%

• 51%

• 36%

What is the concentration of lithium ions in 0.375 M Li₂HPO₄?

• .800 Li

• .705 Li

• .750 Li