Question 1

Which of the following best describes the unified atomic mass unit (u)?

Accepted Answer

It is defined as 1/12 of the mass of a carbon-12 atom.

Question 2

Given the isotopic masses and abundances for chlorine: $$^{35}\mathrm{Cl} (34.969 u$$, 75.76%) and $$^{37}\mathrm{Cl} (36.969 u$$, 24.24%), what is the weighted average atomic mass of chlorine?

Accepted Answer

$$35.45\ \mathrm{u}$$

Question 3

A sample contains $$5.291 	imes 10$$^{24}$$ atoms of silver (Ag). How many moles of silver are present? (1$$\ \mathrm{mol} = 6.022 	imes $$10^{23}$$ atoms)

Accepted Answer

$$8.78\ \mathrm{mol}$$

Question 4

Which of the following best describes the difference between a compound and a mixture, according to the classification of matter diagram?

Accepted Answer

A compound has a constant composition and can be chemically separated into elements, while a mixture does not have a constant composition.

Question 5

Which of the following statements about covalent and ionic bonds is correct?

Accepted Answer

Covalent bonds involve the sharing of electrons between atoms, while ionic bonds involve the transfer of electrons.

Question 6

What is the correct formula for a compound formed between $$\mathrm{Ca}^{2+}$$ and $$\mathrm{N}^{3-}$$ ions?

Accepted Answer

$$\mathrm{Ca}_3\mathrm{N}_2$$

Question 7

Which of the following is the correct name for the compound $$\mathrm{Fe}_2\mathrm{O}_3$$?

Accepted Answer

Iron(III) oxide

Question 8

Which of the following is a polyatomic ion with a $$2-$$ charge?

Accepted Answer

Sulfate ($$\mathrm{SO}_4$$^{2-}$$)

Question 9

What is the systematic name for the compound $$\mathrm{N}_2\mathrm{O}_3$$?

Accepted Answer

Dinitrogen trioxide

Question 10

A balloon contains 36.064 g of sulfur. How many moles of sulfur are present? (Molar mass of S = 32.064 g/mol)

Accepted Answer

$$1.125\ \mathrm{mol}$$

Question 11

Which of the following best describes the arrangement of ions in a sodium chloride crystal?

Accepted Answer

Alternating layers of sodium and chloride ions in a cubic lattice

Question 12

Which of the following ions is most likely to be formed by an element in Group 2 of the periodic table?

Accepted Answer

$$\mathrm{M}^{2+}$$

Question 13

What is the correct formula for ammonium sulfate?

Accepted Answer

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

Question 14

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

Accepted Answer

Phosphorus trichloride

Question 15

Which of the following best describes the trend in metallic character across the periodic table?

Accepted Answer

Metallic character increases from top to bottom within a group.

Question 16

Which of the following is the correct formula for the compound formed between $$\mathrm{Ni}^+$$ and $$\mathrm{CO}_3$$^{2-}$$?

Accepted Answer

$$\mathrm{Ni}_2\mathrm{CO}_3$$

Question 17

Which of the following is the correct name for $$\mathrm{Mn(HCO}_3)_4$$?

Accepted Answer

Manganese(IV) hydrogen carbonate

Question 18

Which prefix is used to indicate five atoms of an element in a molecular compound?

Accepted Answer

Penta-

Question 19

Which of the following is the correct formula for aluminum phosphate?

Accepted Answer

$$\mathrm{AlPO}_4$$

Question 20

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

Accepted Answer

Bromine trifluoride

Atomic Mass, The Mole, and Chemical Bonding: Foundations of General Chemistry

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