Q: How many molecules are present in 2.00 moles of $$\mathrm{CO_2$}$$? (Avogadro's number $$= 6.022 \times 10$$^{23}$$ molecules/mol)

$$1.20 \times 10$$^{24}$$ molecules

Question 1

Which of the following best describes the difference between ionic and covalent compounds?

Accepted Answer

Ionic compounds are formed by transferring electrons between a metal and a nonmetal, while covalent compounds are formed by sharing electrons between nonmetals.

Question 2

What is the correct chemical formula for a compound formed from aluminum ions ($$\mathrm{Al$$^{3+}$$}) $$and oxide ions ($$\mathrm{O$$^{2-}$$}$$)?

Accepted Answer

$$\mathrm{Al_2O_3}$$

Question 3

Which of the following is the correct name for the compound $$\mathrm{Mg_3$(PO_4$)_2}$$?

Accepted Answer

Magnesium phosphate

Question 4

How many covalent bonds does nitrogen typically form to complete its octet?

Accepted Answer

Three

Question 5

Which of the following compounds is a covalent compound?

Accepted Answer

$$\mathrm{CO_2$}$$

Question 6

What is the correct name for the compound $$\mathrm{N_2O_5}$$?

Accepted Answer

Dinitrogen pentoxide

Question 7

Which of the following is the correct Lewis structure for methane ($$\mathrm{CH_4$}$$)?

Accepted Answer

A central carbon atom with four single bonds to four hydrogen atoms.

Question 8

What is the molar mass of $$\mathrm{$$NaClO_3$$}$$? (Atomic masses: Na = 22.99, Cl = 35.45, O = 16.00)

Accepted Answer

$$106.44\ \mathrm{g/mol}$$

Question 9

How many molecules are present in 2.00 moles of $$\mathrm{CO_2$}$$? (Avogadro's number $$= 6.022 	imes 10$$^{23}$$ molecules/mol)

Accepted Answer

$$1.20 	imes 10$$^{24}$$ molecules

Question 10

Which of the following best explains why the formula for calcium chloride is $$\mathrm{$$CaCl_2$$}$$?

Accepted Answer

Calcium forms $$\mathrm{Ca$$^{2+}$$}$$ ions and chlorine forms $$\mathrm{Cl^-}$$ ions, so two chloride ions are needed to balance the charge of one calcium ion.

Question 11

Which of the following is the correct name for $$\mathrm{Fe(NO_3$)_3}$$?

Accepted Answer

Iron(III) nitrate

Question 12

A sample contains $$3.01 	imes 10$$^{23}$$ molecules of $$\mathrm{H_2O}$$. How many moles of water are present?

Accepted Answer

$$0.500$$ moles

Question 13

Which of the following is the correct formula for barium sulfate?

Accepted Answer

$$\mathrm{$$BaSO_4$$}$$

Question 14

What is the total number of atoms in one molecule of glucose ($$\mathrm{C_6H_{12}O_6$}$$)?

Accepted Answer

24

Question 15

Which of the following is the correct name for $$\mathrm{$$PBr_5$$}$$?

Accepted Answer

Phosphorus pentabromide

Question 16

Which of the following statements about molecular formulas is correct?

Accepted Answer

Molecular formulas for covalent compounds show the actual number of each atom in a molecule and are not reduced to the lowest ratio.

Question 17

Which of the following is the correct formula for the ionic compound formed from $$\mathrm{Mg$$^{2+}$$}$$ and $$\mathrm{PO_4$^{3-}}$$?

Accepted Answer

$$\mathrm{Mg_3$(PO_4$)_2}$$

Question 18

A compound has a molar mass of $$180.16\ \mathrm{g/mol}$$ and the molecular formula $$\mathrm{C_6H_{12}O_6$}. $$How many moles are present in a $$90.08\ \mathrm{g}$$ sample?

Accepted Answer

$$0.500$$ moles

Chapter 3: Covalent and Ionic Compounds – Structure, Naming, and Counting Atoms

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