Q: What is the charge-to-mass ratio of the electron as determined by J.J. Thomson?

$$-1.76 \times 10$$^{8}$$ \ \mathrm{C/g}$$

Q: Which of the following is the correct formula for calculating the average atomic mass of an element with two isotopes?

$$\text{Average atomic mass} = (\text{fractional abundance}_1 \times \text{mass}_1) + (\text{fractional abundance}_2 \times \text{mass}_2)$$

Question 1

Which statement best describes Dalton's Atomic Theory as presented in the study materials?

Accepted Answer

Atoms of each element are identical in mass and other properties, and chemical compounds are formed by the combination of atoms in specific ratios.

Question 2

Which experiment led to the determination of the charge of the electron?

Accepted Answer

Millikan's oil drop experiment

Question 3

A neutral atom of carbon-12 has an atomic number of 6 and a mass number of 12. How many neutrons does it contain?

Accepted Answer

6

Question 4

Which of the following best describes a heterogeneous mixture?

Accepted Answer

A mixture in which the composition varies from one region to another

Question 5

What is the charge-to-mass ratio of the electron as determined by J.J. Thomson?

Accepted Answer

$$-1.76 	imes 10$$^{8}$$ \ \mathrm{C/g}$$

Question 6

Which statement about the structure of the atom according to Rutherford's nuclear theory is correct?

Accepted Answer

Most of the atom's mass and all of its positive charge are contained in a small core called the nucleus.

Question 7

A lithium atom loses one electron to form a cation. What is the resulting charge of the ion?

Accepted Answer

$$+1$$

Question 8

Which of the following is the correct formula for calculating the average atomic mass of an element with two isotopes?

Accepted Answer

$$	ext{Average atomic mass} = (	ext{fractional abundance}_1 	imes 	ext{mass}_1) + (	ext{fractional abundance}_2 	imes 	ext{mass}_2)$$

Question 9

If the density of air is $$1.19 \ \mathrm{g/L}$$, what is the mass of $$2.5 \ \mathrm{L} of $$air?

Accepted Answer

$$2.98 \ \mathrm{g}$$

Question 10

Which statement about scientific theories is supported by the study materials?

Accepted Answer

Theories are never proven because some new observation or experiment may reveal a flaw.

Question 11

Which of the following is NOT a subatomic particle found in the atom?

Accepted Answer

Photon

Question 12

A fluorine atom gains one electron to form an anion. What is the resulting charge of the ion?

Accepted Answer

$$-1$$

Question 13

Which of the following best describes the difference between a compound and a mixture?

Accepted Answer

A compound is composed of two or more elements chemically combined in fixed proportions, while a mixture is composed of two or more substances physically combined in variable proportions.

Question 14

What is the mass (in amu) of a single proton?

Accepted Answer

$$1.0073 \ \mathrm{amu}$$

Question 15

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 16

Which unit is used in the International System of Units (SI) to measure mass?

Accepted Answer

Kilogram ($$\mathrm{kg})$$

Question 17

A sample contains $$3.0 	imes 10$$^{23}$$ atoms of sodium. How many moles of sodium are present?

Accepted Answer

$$0.50 \ \mathrm{mol}$$

Question 18

Which of the following best explains why water ($$\mathrm{H_2O}) $$has a bent structure rather than a linear structure?

Accepted Answer

The oxygen atom has two lone pairs of electrons that repel the hydrogen atoms, resulting in a bent molecular geometry.

Question 19

Which of the following is the correct conversion factor to convert miles to kilometers?

Accepted Answer

$$1 \ \mathrm{mile} = 1.61 \ \mathrm{km}$$

Atoms, Matter, and Measurement: Foundations of General Chemistry

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