Q: A sample of a compound contains 12.0 g of carbon and 32.0 g of oxygen. What is the percent composition of carbon in the compound?

$$ \frac{12.0}{44.0} \times 100 = 27.3\% $$

Q: Which of the following is a correct metric conversion using the factor-label method?

$$ 5.0\ \mathrm{kg} \times \frac{1000\ \mathrm{g}}{1\ \mathrm{kg}} = 5000\ \mathrm{g} $$

Q: A hydrate of magnesium sulfate has a mass of 13.52 g before heating and 6.60 g after heating. What is the percent by mass of water in the hydrate?

$$ \frac{13.52 - 6.60}{13.52} \times 100 = 51.2\% $$

Q: A sample contains $$ 3.01 \times 10$$^{23}$$ $$ molecules of $$ \mathrm{CO}_2 . $$What is the mass of the sample? (Molar mass of $$ \mathrm{CO}_2 = 44.0\ \mathrm{g/mol} )$$

$$ \frac{3.01 \times 10$$^{23}$$}{6.02 \times 10$$^{23}$$} \times 44.0 = 22.0\ \mathrm{g} $$

Question 1

Which of the following is an example of a chemical change?

Accepted Answer

Rusting of iron nails

Question 2

Which of the following statements about intensive and extensive properties is correct?

Accepted Answer

Boiling point is an intensive property because it does not depend on the amount of substance.

Question 3

A sample of a compound contains 12.0 g of carbon and 32.0 g of oxygen. What is the percent composition of carbon in the compound?

Accepted Answer

$$ \frac{12.0}{44.0} 	imes 100 = 27.3\% $$

Question 4

Which of the following is a correct metric conversion using the factor-label method?

Accepted Answer

$$ 5.0\ \mathrm{kg} 	imes \frac{1000\ \mathrm{g}}{1\ \mathrm{kg}} = 5000\ \mathrm{g} $$

Question 5

Which of the following best describes a homogeneous mixture?

Accepted Answer

A mixture in which the composition is uniform throughout, such as salt water.

Question 6

Which of the following is the correct formula for the compound formed between aluminum and sulfate?

Accepted Answer

$$ \mathrm{Al}_2(\mathrm{SO}_4)_3 $$

Question 7

A hydrate of magnesium sulfate has a mass of 13.52 g before heating and 6.60 g after heating. What is the percent by mass of water in the hydrate?

Accepted Answer

$$ \frac{13.52 - 6.60}{13.52} 	imes 100 = 51.2\% $$

Question 8

Which of the following is the correct electron configuration for a halogen in its ground state?

Accepted Answer

$$ [\mathrm{Ne}]\ 3s^2$\ 3p^5$ $$

Question 9

Which of the following is a correct statement about the periodic table?

Accepted Answer

Elements are currently arranged in order of increasing atomic number.

Question 10

A sample contains $$ 3.01 	imes 10$$^{23}$$ $$ molecules of $$ \mathrm{CO}_2 . $$What is the mass of the sample? (Molar mass of $$ \mathrm{CO}_2 = 44.0\ \mathrm{g/mol} )$$

Accepted Answer

$$ \frac{3.01 	imes 10$$^{23}$$}{6.02 	imes 10$$^{23}$$} 	imes 44.0 = 22.0\ \mathrm{g} $$

Question 11

Which of the following is the correct name for $$ \mathrm{FeCl}_3 $$?

Accepted Answer

Iron(III) chloride

Question 12

A student measures the temperature of a solution as $$ 25.0\ ^\circ\mathrm{C} . $$What is this temperature in Kelvin?

Accepted Answer

$$ 25.0 + 273.15 = 298.15\ \mathrm{K} $$

Question 13

Which of the following is a correct empirical formula for a compound with a molecular formula of $$ \mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 $$?

Accepted Answer

$$ \mathrm{CH}_2\mathrm{O} $$

Question 14

How many atoms are present in $$ 2.00\ \mathrm{mol}  of$$ $$ \mathrm{H}_2\mathrm{O} $$?

Accepted Answer

$$ 2.00 	imes 6.02 	imes 10$$^{23}$$ 	imes 3 = 3.61 	imes 10$$^{24}$$ $$ atoms

Question 15

Which of the following is a correct statement about the properties of metals?

Accepted Answer

Metals are good conductors of heat and electricity.

Question 16

A sample of ethanol has a density of $$ 0.789\ \mathrm{g/mL} . $$What is the mass of $$ 250.0\ \mathrm{mL}  of $$ethanol?

Accepted Answer

$$ 0.789 	imes 250.0 = 197.25\ \mathrm{g} $$

Question 17

Which of the following is the correct name for $$ \mathrm{Na}_2\mathrm{CO}_3 \cdot 10\mathrm{H}_2\mathrm{O} $$?

Accepted Answer

Sodium carbonate decahydrate

Question 18

Which of the following is a correct set of SI base units?

Accepted Answer

Meter, kilogram, second, ampere, kelvin, mole, candela

Question 19

A compound contains 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. What is its empirical formula?

Accepted Answer

$$ \mathrm{CH}_2\mathrm{O} $$

Question 20

Which of the following is the correct formula for ammonium sulfate?

Accepted Answer

$$ (\mathrm{NH}_4)_2\mathrm{SO}_4 $$

General Chemistry Study Guide: Matter, Measurement, and Chemical Quantities

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