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Stoichiometry Make-Up Test

11/28/2017

Four points each. Each problem requires a balanced chemical equation. Be sure your answers include appropriate units and keep up with your sig figs.
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1. When propane is burned in oxygen, carbon dioxide and water are the products. If 1.55 moles of propane are burned, how many moles of water are produced? How many moles of carbon dioxide are produced?

2. Carbon dioxide gas is removed from spacecrafts by reacting with lithium hydroxide. Lithium carbonate and water are the products. How many moles of lithium hydroxide would be required to maintain one astronaut for five days if she exhales 22.5 moles of carbon dioxide per day?

3. Potassium chlorate (KClO3) breaks down into potassium chloride and oxygen gas. How much oxygen gas (in grams) is produced from 8.45 moles of potassium chlorate? How much potassium chloride (in grams) are produced?

4. How many moles of magnesium sulfate (MgSO4) are needed to react with 0.35 moles of sodium hydroxide (NaOH) to form magnesium hydroxide and sodium sulfate? How much magnesium hydroxide (in grams) is produced?

5. Calculate the mass of chlorine gas produced when 100 grams of sodium chloride decomposes. How much sodium (in grams) is produced from this amount of sodium chloride?

6. Calcium carbonate decomposes into calcium oxide and carbon dioxide. Determine the mass of calcium oxide AND carbon dioxide produced if 326 g of calcium carbonate is heated.

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Stoichiometry Problem Solving

11/23/2017

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So this is what we're going to do today and Tuesday. You take another test next Wednesday, and whatever that grade is, it goes into the gradebook.

1. Calcium carbonate decomposes into calcium oxide and carbon dioxide. Determine the mass of calcium oxide and carbon dioxide produced if 235g of calcium carbonate is heated.

2. When propane is burned in oxygen, carbon dioxide and water are the products. If 3.25 liters of propane are burned, how many moles of water are produced? What is the mass of that amount of water?

3. Sodium reacts vigorously with 127.8g of chlorine gas to form table salt. What is the mass of salt that is produced?

4. Car batteries use lead and lead(IV) oxide with sulfuric acid to produce current. Lead(II) sulfate and water are the products. What is the mass of lead(II) sulfate produced when 88.3g of lead reacts with an excess of lead(II) oxide and sulfuric acid?

5. Calculate the mass of sodium chloride when 5.50 moles of sodium reacts in excess chlorine gas.

6. Carbon dioxide gas is removed from spacecrafts by reacting with lithium hydroxide. Lithium carbonate and water are the products. How many moles of lithium hydroxide would be required to maintain two astronauts for three days if each astronaut exhales 20 moles of carbon dioxide per day?

7. Potassium chlorate breaks down into potassium chloride and oxygen gas. How many moles of oxygen gas are produced from 10 moles of potassium chlorate?

8. This is the reaction that occurs in plants undergoing photosynthesis:
CO2   + H2O --> C6H12O6 +   O2
How many grams of glucose are produced when 24 moles of carbon dioxide reacts in excess water?

9. How many grams of magnesium sulfate (MgSO4) are needed to react with 22.5 grams of sodium hydroxide (NaOH) to form magnesium hydroxide and sodium sulfate?

10. Potassium chlorate breaks down into potassium chloride and oxygen gas. How many moles of oxygen gas are produced from 30 moles of potassium chlorate? What is the mass of that amount of oxygen gas?

11. Calculate the mass of chlorine gas when 100 grams of sodium chloride breaks down.

12. If 38 moles of propane is burned in excess oxygen, with water and carbon dioxide as products, how many moles of water is produced?

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November 13 - 22, 2017

11/13/2017

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Today in class, you will complete a simple chemical reaction. You will measure out 0.25g of aluminum foil and combine that with 5.0mL of aqueous copper (II) chloride. Once you put the foil in the solution, allow the reaction to go for 10 minutes or until the bubbles stop forming, whichever comes first. While waiting, do the following:

1. Predict the products and write the balanced chemical equation.
2. Convert the given amounts into moles using the molar mass.
3. We will predict how much product you should obtain.

After 10 minutes, filter the solution into a graduated cylinder. What is the brown substance left on the filter paper? What is the liquid in the cylinder? Deduct the mass of the filter paper from the brown solid (1.5g).

Take the mass of the brown solid and record the volume of the remaining liquid. Did you get the amounts you were supposed to get? Why or why not?

Run the experiment for a second time. Did you get better results? You should.

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November 3 - 17, 2017

11/2/2017

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Housekeeping: You guys did well on your test. I'm pleased. Other than that, our house is clean. We're going to spend the next few days doing mole conversions, so you need to make sure you keep your calculator and periodic table handy.

Agenda:
1. Mole math

Content Review:
Links: Chemical Equations The Mole

Student Missions:
Mission 1: *sigh* Math
Mission Objectives: You should be able to...
1. Calculate the molar mass of compounds.
2. Complete mole conversion problems.

We will begin with identifying the different types of conversion problems and then we will practice using the image below. Then we will download these practice handouts and work through the problems. Bear in mind that we will be working on additional problems next week.

1. Molar Mass 2. Mole Conversions (I) 3. Mole Conversions (II)

Mission 2: *eye-roll and double sigh* More Math...This Time With Gas
Mission Objectives: You should be able to...
1. Solve molar volume conversion problems.
2. Understand the conditions that establish STP and what it means.
3. Determine the molar volume of a gas at STP.

Now we will continue on with solving molar volume problems.

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