Question 1

Which of the following statements best summarizes a key conclusion from Rutherford’s gold foil experiment?

Accepted Answer

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

Question 2

Which of the following elements is a metalloid and is located along the zigzag line of the periodic table?

Accepted Answer

Silicon (Si)

Question 3

A neutral atom of magnesium has an atomic number of 12 and a mass number of 24. How many neutrons does it contain?

Accepted Answer

12

Question 4

Which of the following correctly represents the formula for ammonium sulfate?

Accepted Answer

$$ (NH_4$)_2SO_4 $$

Question 5

Which of the following is the correct name for the compound $$ $$FeCl_3$$ $$?

Accepted Answer

Iron(III) chloride

Question 6

A sample contains 3.01 × $$ 10$$^{23}$$ $$ molecules of $$ CO_2$ . $$What is the mass of this sample? (Molar mass of $$ CO_2$  = 44.0 g/$$mol)

Accepted Answer

22.0 g

Question 7

Which of the following best describes the law of constant composition?

Accepted Answer

A given compound always contains the same proportion of elements by mass.

Question 8

Which of the following is the empirical formula for a compound with the molecular formula $$ C_6H_{12}O_6$ $$?

Accepted Answer

$$ CH_2O $$

Question 9

Which of the following ions is most likely formed by a main group element in Group 2A?

Accepted Answer

$$ Mg$$^{2+}$$ $$

Question 10

A sample of chlorine contains 75.8% $$ ^{35}Cl  ($$mass = 34.97 u) and 24.2% $$ ^{37}Cl  ($$mass = 36.97 u). What is the average atomic mass of chlorine?

Accepted Answer

$$ 35.5 \ 	ext{u} $$

Question 11

Which of the following is the correct name for $$ H_2SO_4 $$?

Accepted Answer

Sulfuric acid

Question 12

Which of the following is a molecular compound?

Accepted Answer

$$ CO_2$ $$

Question 13

What is the formula mass of $$ Ca(OH)_2 $$? (Atomic masses: Ca = 40.1, O = 16.0, H = 1.01)

Accepted Answer

$$ 74.1 $$

Question 14

Which of the following is the correct name for $$ N_2O_5 $$?

Accepted Answer

Dinitrogen pentoxide

Question 15

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

Accepted Answer

$$ CH_2O $$

Question 16

Which of the following best describes a cation?

Accepted Answer

An atom or group of atoms with a positive charge

Question 17

How many moles are in 25.0 g of $$ NaCl $$? (Molar mass of $$ NaCl  = 58.5 g/$$mol)

Accepted Answer

$$ 0.427 $$

Question 18

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

Accepted Answer

$$ Al_2$(SO_4$)_3 $$

Question 19

A sample contains 0.500 mol of $$ H_2O . $$How many molecules of water are present?

Accepted Answer

$$ 3.01 	imes 10$$^{23}$$ $$

Question 20

Which of the following is the correct name for $$ $$HClO_3$$ $$?

Accepted Answer

Chloric acid

Atoms, Elements, Compounds, and Chemical Composition: Study Guide

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