$$1 \text{ in.} = 2.54 \text{ cm}$$

$$\text{Mass number} = \text{number of protons} + \text{number of neutrons}$$

Question 1

Which of the following best describes water (H$$_2O) as $$shown in the images above?

Accepted Answer

A compound consisting of hydrogen and oxygen atoms chemically bonded in a fixed ratio

Question 2

Which of the following statements about the periodic table is correct?

Accepted Answer

Elements in the same group (column) have similar chemical properties.

Question 3

A sample contains only C$$_{12}H$_{22}O$_{11}$$ molecules. How would you classify this sample?

Accepted Answer

Compound

Question 4

Which of the following is the correct scientific notation for 0.0000278?

Accepted Answer

$$2.78 	imes 10$$^{-5}$$

Question 5

How many significant figures are in the measurement 0.00560?

Accepted Answer

3

Question 6

A doctor prescribes 7.5 mg of a drug per kg of body weight. How many mg should be given to a patient weighing 60 kg?

Accepted Answer

450 mg

Question 7

Which of the following is the correct molar mass of H$$_2O$$?

Accepted Answer

$$18.0152 g/$$mol

Question 8

What is the total number of valence electrons in a molecule of CH$$_4$$?

Accepted Answer

8

Question 9

Which of the following molecules has a bent molecular geometry according to VSEPR theory?

Accepted Answer

H$$_2O$$

Question 10

Which of the following intermolecular forces is the strongest?

Accepted Answer

Hydrogen bonding

Question 11

Which of the following molecules can form hydrogen bonds with itself?

Accepted Answer

NH$$_3$$

Question 12

A gas sample has an initial volume of 2.0 L at 1.0 atm. If the pressure is increased to 4.0 atm at constant temperature, what is the final volume?

Accepted Answer

0.5 L

Question 13

Which of the following best explains why CO$$_2 is a $$nonpolar molecule even though it contains polar bonds?

Accepted Answer

The molecule is linear and the bond dipoles cancel each other out.

Question 14

Which of the following is a correct conversion factor for converting inches to centimeters?

Accepted Answer

$$1 	ext{ in.} = 2.54 	ext{ cm}$$

Question 15

Which of the following best describes a heterogeneous mixture?

Accepted Answer

A mixture with a variable composition throughout

Question 16

How many moles are present in 36.0 g of water (H$$_2O$$)? (Molar mass of H$$_2O = 18.0152 g/$$mol)

Accepted Answer

2.00 mol

Question 17

Which of the following is the correct Lewis structure for methane (CH$$_4$$)?

Accepted Answer

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

Question 18

Which of the following molecules is polar due to its molecular geometry?

Accepted Answer

NH$$_3$$

Question 19

Which of the following best describes the relationship between pressure and volume for a gas at constant temperature (Boyle’s Law)?

Accepted Answer

$$P \propto \frac{1}{V}$$

Question 20

Which of the following is the correct formula for calculating the mass number of an atom?

Accepted Answer

$$	ext{Mass number} = 	ext{number of protons} + 	ext{number of neutrons}$$

Chemistry Basics: Matter, Measurement, and Atomic Structure

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