Q: What is the formula mass of calcium carbonate ($$\mathrm{$$CaCO_3$$}$$)? (Atomic masses: Ca = 40.08 amu, C = 12.01 amu, O = 16.00 amu)

$$40.08\ \mathrm{amu} + 12.01\ \mathrm{amu} + 3 \times 16.00\ \mathrm{amu} = 100.10\ \mathrm{amu}$$

Question 1

Which of the following best describes the difference between a molecular formula and an empirical formula?

Accepted Answer

A molecular formula shows the actual number of atoms of each element in a molecule, while an empirical formula shows the simplest whole-number ratio of atoms.

Question 2

What is the formula mass of calcium carbonate ($$\mathrm{$$CaCO_3$$}$$)? (Atomic masses: Ca = 40.08 amu, C = 12.01 amu, O = 16.00 amu)

Accepted Answer

$$40.08\ \mathrm{amu} + 12.01\ \mathrm{amu} + 3 	imes 16.00\ \mathrm{amu} = 100.10\ \mathrm{amu}$$

Question 3

According to the law of constant composition, which statement is true for all samples of water?

Accepted Answer

All samples of water contain the same proportion by mass of hydrogen and oxygen.

Question 4

Which of the following elements exists naturally as a diatomic molecule?

Accepted Answer

Nitrogen ($$\mathrm{N_2$})$$

Question 5

What is the correct name for the ion $$\mathrm{Fe$$^{3+}$$}$$?

Accepted Answer

Iron(III) ion

Question 6

Which compound is an example of an ionic compound?

Accepted Answer

Sodium chloride ($$\mathrm{NaCl})$$

Question 7

What is the correct formula for aluminum bromate?

Accepted Answer

$$\mathrm{Al($$BrO_3$$)_3}$$

Question 8

Which of the following is the correct systematic name for $$\mathrm{K_2O}$$?

Accepted Answer

Potassium oxide

Question 9

What is the correct formula for sulfur hexafluoride?

Accepted Answer

$$\mathrm{SF_6$}$$

Question 10

Which of the following ions is a polyatomic ion?

Accepted Answer

$$\mathrm{SO_4$^{2-}}$$

Question 11

What is the correct name for $$\mathrm{$$MgBrO_3$$ \cdot 6H_2O}$$?

Accepted Answer

Magnesium bromate hexahydrate

Question 12

Which of the following acids is named correctly according to its anion?

Accepted Answer

HClO is hypochlorous acid

Question 13

What is the empirical formula for glucose ($$\mathrm{C_6H_{12}O_6$}$$)?

Accepted Answer

$$\mathrm{CH_2O}$$

Question 14

Which of the following is the correct formula for dinitrogen pentoxide?

Accepted Answer

$$\mathrm{N_2O_5}$$

Question 15

A compound contains 40.0 g of calcium and 60.0 g of chlorine. What is the mass ratio of chlorine to calcium?

Accepted Answer

$$\frac{60.0\ \mathrm{g}}{40.0\ \mathrm{g}} = 1.5:1$$

Question 16

Which of the following is the correct formula for cobalt(III) nitride?

Accepted Answer

$$\mathrm{CoN}$$

Question 17

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

Accepted Answer

Covalent compounds are formed by sharing electrons between atoms.

Question 18

What is the correct name for $$\mathrm{Pb(CO_3$)_2}$$?

Accepted Answer

Lead(IV) carbonate

Question 19

Which of the following is the correct formula for phosphorous acid?

Accepted Answer

$$\mathrm{H_3PO_3}$$

Molecules and Compounds: Chemical Formulas, Nomenclature, and Types of Compounds

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