Q: Which of the following best describes Avogadro's Number?

The number of molecules in 1 mole of a substance, $$6.02 \times 10$$^{23}$$.

Question 1

Which of the following best describes Avogadro's Number?

Accepted Answer

The number of molecules in 1 mole of a substance, $$6.02 	imes 10$$^{23}$$.

Question 2

How many moles of oxygen atoms are present in one mole of iron(III) oxide, $$\mathrm{Fe_2O_3}$$?

Accepted Answer

3 moles

Question 3

A 0.50 mol sample of carbon tetrachloride, $$\mathrm{$$CCl_4$$}$$, contains how many moles of chlorine atoms?

Accepted Answer

2.0 moles

Question 4

What is the correct balanced equation for the combustion of fructose ($$\mathrm{C_6H_{12}O_6$}$$)?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$} + 6\ O_2$ \rightarrow 6\ CO_2$ + 6\ H_2O$$

Question 5

How many grams are present in 543 g of fructose ($$\mathrm{C_6H_{12}O_6$}$$)? (Molar mass = 180 g/mol)

Accepted Answer

3.02 mol

Question 6

If you have 2.50 moles of fructose ($$\mathrm{C_6H_{12}O_6$}$$), how many grams do you have? (Molar mass = 180 g/mol)

Accepted Answer

450 g

Question 7

Which of the following is a double displacement (metathesis) reaction?

Accepted Answer

$$\mathrm{$$BaCl_2$$} + \mathrm{Na_2SO_4} \rightarrow \mathrm{$$BaSO_4$$} + 2\mathrm{NaCl}$$

Question 8

A sample of gas at 1.0 atm and 250 mL is compressed to 500 mL at constant temperature. What is the new pressure?

Accepted Answer

0.50 atm

Question 9

Which of the following best describes what happens to the volume of a gas as the pressure increases at constant temperature (Boyle's Law)?

Accepted Answer

The volume decreases.

Question 10

A 250 mL sample of gas is heated from 300 K to 450 K at constant pressure. What is the final volume?

Accepted Answer

375 mL

Question 11

A gas mixture contains 2.5 g of $$\mathrm{CH_4$}$$ and 5.0 g of He. What is the total number of moles in the mixture? ($$M_{CH_4$} = 16\ \mathrm{g/mol}$$, $$M_{He} = 4\ \mathrm{g/mol})$$

Accepted Answer

2.06 mol

Question 12

A cyclopropane-oxygen mixture is used as an anesthetic. If the partial pressure of cyclopropane is 120 mmHg and the partial pressure of oxygen is 1.25 atm, what is the total pressure of the mixture in torr?

Accepted Answer

1070 torr

Question 13

Which of the following is the correct net ionic equation for the reaction between $$\mathrm{$$BaCl_2$$}$$ and $$\mathrm{Na_2SO_4}$$?

Accepted Answer

$$\mathrm{Ba$$^{2+}$$} + \mathrm{SO_4$^{2-}} \rightarrow \mathrm{$$BaSO_4$$(s)}$$

Question 14

Which of the following is a redox reaction?

Accepted Answer

$$\mathrm{Fe_2O_3} + 3\mathrm{CO} \rightarrow 2\mathrm{Fe} + 3\mathrm{CO_2$}$$

Question 15

Which of the following is the correct conversion factor needed to convert between Al and H$$_2 in $$the reaction $$2\mathrm{Al} + 3\mathrm{H_2SO_4} \rightarrow \mathrm{Al_2$(SO_4$)_3} + 3\mathrm{H_2$}$$?

Accepted Answer

$$\frac{3\ \mathrm{mol}\ H_2$}{2\ \mathrm{mol}\ Al}$$

Question 16

If a gas in the ocean releases a bubble with a volume of 500 mL at a pressure of 4.2 atm and a temperature of 12°C, what is the volume of the bubble when it reaches the surface where the pressure is 1.0 atm and the temperature is 27°C?

Accepted Answer

2200 mL

Question 17

Which of the following is NOT a unit that can be used to describe pressure?

Accepted Answer

Joule (J)

Question 18

Which of the following statements about the relationship between temperature and volume of a gas at constant pressure (Charles's Law) is correct?

Accepted Answer

As temperature increases, volume increases.

Question 19

Which of the following is the correct molar mass of iron(III) oxide, $$\mathrm{Fe_2O_3}$$?

Accepted Answer

159.7 g/mol

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