Question 1

Why does water evaporate faster from a wet surface on a hot, windy day compared to a cold, calm day?

Accepted Answer

Because higher temperature and wind increase the kinetic energy and remove vapor molecules quickly.

Question 2

Why does puddle water evaporate even when the temperature is below $$100^	ext{o}C$$? Choose the best explanation.

Accepted Answer

Because evaporation can occur at any temperature as long as some molecules have enough energy to escape.

Question 3

A mixture of sand and sugar is poured into water. Which method would best separate the two substances?

Accepted Answer

Filtration followed by evaporation.

Question 4

Which statement best explains why the boiling point of a liquid increases when a non-volatile solute is added?

Accepted Answer

The solute lowers the vapor pressure, requiring a higher temperature to reach atmospheric pressure.

Question 5

Which of the following is a chemical change?

Accepted Answer

Burning gasoline in a car engine.

Question 6

Which arrangement of electrons is most stable for an atom?

Accepted Answer

A full outer shell of electrons.

Question 7

Which of the following best describes the trend in atomic radius as you move down a group in the periodic table?

Accepted Answer

Atomic radius increases due to the addition of electron shells.

Question 8

Which statement correctly describes the trend in ionization energy across a period from left to right?

Accepted Answer

Ionization energy increases due to greater nuclear charge and smaller atomic radius.

Question 9

Which of the following materials is most likely to conduct electricity?

Accepted Answer

Copper metal.

Question 10

Which property distinguishes metals from non-metals?

Accepted Answer

Metals are malleable and conduct electricity; non-metals are brittle and insulators.

Question 11

Which of the following is a mixture rather than a pure substance?

Accepted Answer

Air.

Question 12

Which process is used to separate crude oil into useful fractions?

Accepted Answer

Fractional distillation.

Question 13

Which of the following is an alloy?

Accepted Answer

Brass.

Question 14

Which of the following is a reason why stainless steel is resistant to corrosion?

Accepted Answer

It contains chromium, which forms a protective oxide layer.

Question 15

Which of the following best explains why boiling occurs at a specific temperature for a pure liquid?

Accepted Answer

Boiling occurs when the vapor pressure equals atmospheric pressure.

Question 16

Which of the following is a physical property?

Accepted Answer

Melting point.

Question 17

Which of the following is a chemical property?

Accepted Answer

Ability to react with oxygen.

Question 18

Which of the following best describes the arrangement of electrons in a noble gas atom?

Accepted Answer

All electron shells are completely filled.

Question 19

Which of the following best explains why sodium reacts vigorously with water?

Accepted Answer

Sodium has a single electron in its outer shell, which is easily lost to form $$	ext{Na}^+.$$

Question 20

Which of the following best describes the process of corrosion?

Accepted Answer

A chemical reaction between a metal and oxygen, often accelerated by water.

General Chemistry: Properties of Matter, Phase Changes, and Periodic Trends – Study Notes

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