Q: A sample contains 3.00 mol of carbon atoms. How many atoms are present in the sample? (Avogadro's number $$= 6.022 \times 10$$^{23}$$ mol$$^{-1}$$)

$$1.81 \times 10$$^{24}$$ atoms

Question 1

Which of the following best describes the difference between mass and weight?

Accepted Answer

Mass is the amount of matter in an object, while weight is the force exerted by gravity on that mass.

Question 2

A sample of gold has a mass of 19.3 g and occupies a volume of 1.00 cm$$^3. $$What is the density of gold in g/cm$$^3$$?

Accepted Answer

$$19.3 \ \mathrm{g/cm}^3$$

Question 3

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

Accepted Answer

Iron rusts when exposed to oxygen.

Question 4

Which statement about the law of conservation of matter is correct?

Accepted Answer

Matter cannot be created or destroyed in a chemical reaction.

Question 5

Which of the following is a heterogeneous mixture?

Accepted Answer

Salad dressing with oil and vinegar.

Question 6

Which of the following is an extensive property?

Accepted Answer

Mass

Question 7

A sample contains 3.00 mol of carbon atoms. How many atoms are present in the sample? (Avogadro's number $$= 6.022 	imes 10$$^{23}$$ mol$$^{-1}$$)

Accepted Answer

$$1.81 	imes 10$$^{24}$$ atoms

Question 8

Which of the following best represents a compound?

Accepted Answer

NaCl

Question 9

Which of the following is the correct symbol for an atom with 17 protons, 18 neutrons, and 17 electrons?

Accepted Answer

$$^{35}_{17}\mathrm{Cl}$$

Question 10

A naturally occurring element X has two isotopes: $$^{10}X (20$$% abundance, mass = 10.0 amu) and $$^{11}X (80$$% abundance, mass = 11.0 amu). What is the average atomic mass of X?

Accepted Answer

$$10.8$$ amu

Question 11

Which of the following best describes the symbolic domain in chemistry?

Accepted Answer

The use of chemical symbols, formulas, and equations to represent substances and processes.

Question 12

Which of the following is a physical change?

Accepted Answer

Ice melting to form liquid water.

Question 13

A 25.0 g sample of a substance occupies 5.00 cm$$^3. $$What is its density?

Accepted Answer

$$5.00 \ \mathrm{g/cm}^3$$

Question 14

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons.

Question 15

Which of the following is the correct formula for calculating density?

Accepted Answer

$$\mathrm{Density} = \frac{\mathrm{mass}}{\mathrm{volume}}$$

Question 16

A sample of chlorine contains 75.53% $$^{35}Cl ($$mass = 34.97 amu) and 24.47% $$^{37}Cl ($$mass = 36.97 amu). What is the average atomic mass of chlorine?

Accepted Answer

$$35.45$$ amu

Question 17

Which of the following best describes a pure substance?

Accepted Answer

A material with a constant composition that can be either an element or a compound.

Question 18

Which of the following is a correct statement about Avogadro's number?

Accepted Answer

It is the number of particles in one mole, $$6.022 	imes 10$$^{23}$$.

Question 19

Which of the following best describes the macroscopic domain in chemistry?

Accepted Answer

Observations and phenomena that can be seen and measured directly, such as color and density.

Question 20

A 10.0 g sample of a compound contains 4.0 g of hydrogen and 6.0 g of carbon. What is the percent by mass of hydrogen in the compound?

Accepted Answer

$$40\%$$

Question 21

Which of the following best describes the result of Rutherford's gold foil experiment?

Accepted Answer

Most alpha particles passed through, but some were deflected, indicating a small, dense, positively charged nucleus.

Foundations of General Chemistry: Matter, Measurement, and Atomic Structure

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