$$A_r = \frac{\text{mass of isotope 1} \times \text{abundance 1}}{100} + \frac{\text{mass of isotope 2} \times \text{abundance 2}}{100}$$

Question 1

Which of the following statements best explains why solids have a fixed shape and volume?

Accepted Answer

Particles in solids are packed closely together and vibrate in fixed positions due to strong intermolecular forces.

Question 2

During which change of state do particles gain enough energy to overcome intermolecular forces and move freely?

Accepted Answer

Boiling/Evaporation

Question 3

Refer to the heating curve of water. What does the flat portion of the curve between solid and liquid represent?

Accepted Answer

The substance is undergoing a phase change (melting) and energy is used to break intermolecular forces.

Question 4

Which property is unique to gases compared to solids and liquids?

Accepted Answer

Gases can be compressed easily due to large spaces between particles.

Question 5

A sealed syringe contains a gas. If the plunger is pushed in, what happens to the gas particles?

Accepted Answer

The particles are compressed closer together, decreasing the volume.

Question 6

Which of the following best describes diffusion in gases?

Accepted Answer

Particles move randomly and spread from areas of higher concentration to lower concentration.

Question 7

How does the relative molecular mass of a gas affect its rate of diffusion?

Accepted Answer

Gases with higher relative molecular mass diffuse slower.

Question 8

Which statement correctly distinguishes a compound from a mixture?

Accepted Answer

A compound is formed by chemically bonding elements in fixed ratios, while a mixture is a physical combination of substances.

Question 9

Which of the following is true about the atomic structure of a carbon atom?

Accepted Answer

Carbon has 6 protons, 6 neutrons, and 6 electrons.

Question 10

What is the electronic configuration of a carbon atom?

Accepted Answer

$$2, 4$$

Question 11

Which formula is used to calculate the relative atomic mass $$(A_r) of an $$element from its isotopes?

Accepted Answer

$$A_r = \frac{	ext{mass of isotope 1} 	imes 	ext{abundance 1}}{100} + \frac{	ext{mass of isotope 2} 	imes 	ext{abundance 2}}{100}$$

Question 12

Which statement about ions is correct?

Accepted Answer

Ions are atoms or molecules with a charge due to the gain or loss of electrons.

Question 13

A student mixes two colorless solutions and observes a white precipitate. Which type of change has occurred?

Accepted Answer

Chemical change

Question 14

Which of the following is NOT a property of elements?

Accepted Answer

Elements can be broken down into simpler substances by chemical means.

Question 15

Which process describes the change from gas to liquid?

Accepted Answer

Condensation

Question 16

If a liquid is cooled, what happens to the movement of its particles?

Accepted Answer

Particles slow down and intermolecular forces hold them closer together.

Question 17

Which of the following best explains why liquids have an indefinite shape but a fixed volume?

Accepted Answer

Particles in liquids are close together but can move past each other, allowing the liquid to take the shape of its container.

Question 18

Which of the following is a correct statement about mixtures?

Accepted Answer

Mixtures can be separated by physical methods without breaking chemical bonds.

Question 19

Which of the following is the correct definition of atomic number?

Accepted Answer

The number of protons in one atom of an element.

Fundamental Concepts in General Chemistry: States of Matter, Atomic Structure, and Chemical Substances

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