Q: What is the charge of an electron as determined by Millikan’s oil drop experiment?

$$-1.60 \times 10$$^{-19}$$ \ \mathrm{C}$$

Question 1

Which statement best describes a compound?

Accepted Answer

A substance composed of two or more elements that are chemically bonded in fixed proportions.

Question 2

Which of the following is an example of a heterogeneous mixture?

Accepted Answer

Sand and iron filings

Question 3

According to Dalton’s atomic theory, which statement is correct?

Accepted Answer

Atoms of different elements combine in simple whole-number ratios to form compounds.

Question 4

Which law states that in a chemical reaction, mass is neither created nor destroyed?

Accepted Answer

Law of Conservation of Mass

Question 5

A sample contains 2.5 g of hydrogen and 20.0 g of oxygen. What is the mass ratio of oxygen to hydrogen in this sample?

Accepted Answer

$$\frac{20.0}{2.5} = 8.0$$

Question 6

Which experiment provided evidence for the existence of the nucleus in the atom?

Accepted Answer

Rutherford’s gold foil experiment

Question 7

What is the charge of an electron as determined by Millikan’s oil drop experiment?

Accepted Answer

$$-1.60 	imes 10$$^{-19}$$ \ \mathrm{C}$$

Question 8

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 9

A neutral atom of neon-22 has how many neutrons?

Accepted Answer

12

Question 10

Which of the following best describes the plum pudding model of the atom?

Accepted Answer

Electrons embedded in a sphere of positive charge.

Question 11

Which statement about the scientific approach to knowledge is correct?

Accepted Answer

Observations are used to develop hypotheses and theories.

Question 12

A sample of chlorine contains 75.77% $$^{35}\mathrm{Cl} ($$mass = 34.97 amu) and 24.23% $$^{37}\mathrm{Cl} ($$mass = 36.97 amu). What is the atomic mass of chlorine?

Accepted Answer

$$35.45 \ \mathrm{amu}$$

Question 13

Which of the following is NOT a postulate of Dalton’s atomic theory?

Accepted Answer

Atoms can be converted into other elements by chemical reactions.

Question 14

Which law is illustrated when two elements combine to form more than one compound, and the masses of one element that combine with a fixed mass of the other are in a ratio of small whole numbers?

Accepted Answer

Law of Multiple Proportions

Question 15

Which subatomic particle is responsible for the chemical properties of an element?

Accepted Answer

Electron

Question 16

A certain element has atomic number 15 and mass number 31. How many neutrons does it have?

Accepted Answer

16

Question 17

Which statement about neutrons is correct?

Accepted Answer

Neutrons have no electrical charge.

Question 18

Which of the following is a chemical property?

Accepted Answer

Flammability

Question 19

Which of the following best explains why the gold foil experiment disproved the plum pudding model?

Accepted Answer

Most alpha particles passed through the foil, but some were deflected at large angles, indicating a dense nucleus.

Question 20

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

Accepted Answer

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

Foundations of General Chemistry: Matter, Atoms, and the Atomic Theory

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