Reference no: EM132431825

1. Two molecules of one reactant combine with 3 molecules of another to produce 5 molecules of a product.

Which equation is the correct representation of the reaction?

• 2A+3B→5C
• 2A+5B→3C
• A2+B3→C3
• 3A2+B3→C5

2. A sample of nitrogen gas (N2)contains 3.0×10^24atoms of nitrogen.

About how many moles of nitrogen gas are in the sample?

• 1.0
• 2.5
• 3.0
• 5.0

3. Approximately how many particles are in a mole?

• 2.4×10^24
• 6.0×10^23
• 1.2×10^24
• 1.8×10^24

4. A chemical reaction yields 3 moles of lithium hydroxide (LiOH).

How many grams of lithium hydroxide are present?

• 3 g
• 24 g
• 48 g
• 72 g

5. What is the formula mass of calcium sulfate dihydrate [CaSO4·2H2O]?

Be sure to add the water of hydration, which is the 2H2O part (water surrounding the calcium sulfate).

• 136 g/mol
• 154 g/mol
• 164 g/mol
• 172 g/mol

6. In a spacecraft, this reaction occurs:CO2(g)+2LiOH(s)→LiCO3(s)+H2O(l)

How many liters of carbon dioxide will 4 moles of lithium hydroxide (LiOH) absorb? (One mole of any gas occupies 22.4 L under certain conditions of temperature and pressure. Assume those conditions for this question.)

• 3.0 L
• 6.0 L
• 34 L
• 45 L

7. Which statement is true about 22.4 L each of hydrogen, ammonia, and uranium dioxide gas assuming that the temperature and pressure are the same for all the gases?

• The gases have the same number of molecules.
• Oxygen gas has the most number of molecules.
• Uranium dioxide gas has the most number of molecules.
• Hydrogen gas has the least number of molecules.