Avogadro's number has a value of 10 and is the number of atoms/molecules/formula units in one of a substance. Flag this Question Question 2 6.

Avogadro's number has a value of   × 10  and is the number of atoms/molecules/formula units in one   of a substance.

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Question 2

6.25 pts

To the nearest tenth of a gram, what is the mass of 4 moles of silver?

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Question 3

6.25 pts

To the nearest tenth of a mole, how many moles of nitrogen gas has a mass of 194 g?

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Question 4

6.25 pts

Lead permanganate has the chemical formula Pb(MnO4)2. To the nearest hundredth of an atomic mass unit, what is the formula mass of lead permanganate?

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Question 5

6.25 pts

Given your result in the previous question, how many moles are present in 867 g of lead permanganate? Round to the nearest hundredth of a mole.

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Question 6

6.25 pts

To carry out a chemical reaction, you need 0.66 mol of HCl. If you have a 5.0 M solution of HCl, how many liters would need to be added to provide the necessary number of moles? Round your answer to the nearest hundredth of a liter.

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Question 7

6.25 pts

Copper(II) chloride has the chemical formula CuCl2. We wish to make a solution of copper(II) chloride by adding it to a volumetric flask, then filling the flask with water. If 200 g of copper(II) chloride is added to the volumetric flask and water is added to produce a 1.0 L solution, what is the molarity of the solution? Give your answer to the nearest hundredth molar (that is, mol/L).

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Question 9

6.25 pts

Oxygen gas (O2) is required to burn propane (C3H8), producing carbon dioxide (CO2) and water (H2O) in the process. This is represented by the chemical equation

5O2 + C3H8 → 3CO2 + 4H2O

How many grams of oxygen gas are required to burn 400 g of propane? Round to the nearest gram.

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Question 10

6.25 pts

 reactions give off energy;   reactions take in energy.

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Question 11

6.25 pts

Chunks of solid sodium bicarbonate react with acetic acid in solution, producing water, carbon dioxide, and sodium acetate in the process. How could this reaction be sped up? Select all that would apply!

substitute a higher molarity acetic acid solution

dilute the acetic acid solution by adding water

cool off the acetic acid solution

grind the chunks of sodium bicarbonate into powder first

stir the reactants together

warm up the acetic acid solution

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Question 12

25 pts

Sulfur dioxide and oxygen gas react to produce sulfur trioxide in an exothermic reaction

2SO2 + O2 → 2SO3

At the same time, the endothermic reverse reaction occurs, breaking the sulfur trioxide apart

2SO3 → 2SO2 + O2

Therefore, a chemical equilibrium is reached between the three gases:

2SO2 + O2 ⇌ 2SO3

This reaction is allowed to take place within a sealed container. If we want to produce more sulfur trioxide, we could