Q: Calculate the formula mass of glucose (C$$_6H$_{12}O$_6) $$using the following atomic masses: C = 12.01 amu, H = 1.008 amu, O = 16.00 amu.

$$6 \times 12.01 + 12 \times 1.008 + 6 \times 16.00 = 180.16$$ amu

Q: A 325 mg aspirin tablet contains acetylsalicylic acid (C$$_9H$_8O$_4). $$How many molecules of acetylsalicylic acid does it contain? (Molar mass = 180.15 g/mol, Avogadro's number = $$6.022 \times 10$$^{23}$$)

$$1.09 \times 10$$^{21}$$ molecules

Q: What is the mass percent of chlorine in Freon-112 (C$$_2Cl$_4F$_2$$)? (Atomic masses: C = 12.01, Cl = 35.45, F = 19.00)

$$\frac{4 \times 35.45}{203.8} \times 100\% = 69.7\%$$

Question 1

Which of the following best explains why water (H$$_2O) $$has very different properties from its constituent elements, hydrogen and oxygen?

Accepted Answer

Water is a compound with a fixed ratio of hydrogen to oxygen, resulting in new chemical properties.

Question 2

According to the law of definite proportions, which statement is true about water (H$$_2O$$)?

Accepted Answer

Water always contains hydrogen and oxygen in a 2:1 atom ratio.

Question 3

Which of the following compounds is held together by ionic bonds?

Accepted Answer

NaCl

Question 4

What is the empirical formula for a compound with the molecular formula C$$_4H$_8$$?

Accepted Answer

CH$$_2$$

Question 5

Which of the following best describes the difference between an ionic compound and a molecular compound?

Accepted Answer

Ionic compounds are composed of ions held together by electrostatic forces; molecular compounds are composed of molecules held together by covalent bonds.

Question 6

A sample of a compound is decomposed in the laboratory and produces 24.5 g nitrogen and 70.0 g oxygen. What is the empirical formula of the compound?

Accepted Answer

N$$_2O$_5$$

Question 7

Which of the following is the correct name for the compound FeCl$$_3$$?

Accepted Answer

Iron(III) chloride

Question 8

What is the formula for the ionic compound formed between magnesium and nitrogen?

Accepted Answer

Mg$$_3N$_2$$

Question 9

Which of the following is the correct name for the compound P$$_4S$_{10}$$?

Accepted Answer

Tetraphosphorus decasulfide

Question 10

Calculate the formula mass of glucose (C$$_6H$_{12}O$_6) $$using the following atomic masses: C = 12.01 amu, H = 1.008 amu, O = 16.00 amu.

Accepted Answer

$$6 	imes 12.01 + 12 	imes 1.008 + 6 	imes 16.00 = 180.16$$ amu

Question 11

A 325 mg aspirin tablet contains acetylsalicylic acid (C$$_9H$_8O$_4). $$How many molecules of acetylsalicylic acid does it contain? (Molar mass = 180.15 g/mol, Avogadro's number = $$6.022 	imes 10$$^{23}$$)

Accepted Answer

$$1.09 	imes 10$$^{21}$$ molecules

Question 12

Which of the following is the correct name for NaNO$$_2$$?

Accepted Answer

Sodium nitrite

Question 13

What is the mass percent of chlorine in Freon-112 (C$$_2Cl$_4F$_2$$)? (Atomic masses: C = 12.01, Cl = 35.45, F = 19.00)

Accepted Answer

$$\frac{4 	imes 35.45}{203.8} 	imes 100\% = 69.7\%$$

Question 14

Which of the following is a property of ionic solids such as NaCl?

Accepted Answer

They are brittle and shatter when struck.

Question 15

Which of the following best describes the octet rule?

Accepted Answer

Atoms tend to gain, lose, or share electrons to achieve eight valence electrons.

Question 16

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

Accepted Answer

Al$$_3N$_2$$

Question 17

A compound has the empirical formula CH and a molar mass of 78.11 g/mol. What is its molecular formula?

Accepted Answer

C$$_6H$_6$$

Question 18

Upon combustion, a compound containing only carbon and hydrogen produces 1.83 g CO$$_2$$ and 0.901 g H$$_2O. $$What is the empirical formula of the compound?

Accepted Answer

C$$_5H$_{12}$$

Molecules and Compounds: Structure, Bonding, and Formulas

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