Question 1

A person left a bottle of distilled water and a bottle of a sugary drink outside overnight. In the morning, one liquid was frozen but the other was not. Which liquid was frozen and why did it freeze?

Accepted Answer

The distilled water froze because pure substances have a higher freezing point than solutions. Adding sugar to water lowers its freezing point, so the sugary drink would have a lower freezing point than the distilled water, making the distilled water freeze first under the same conditions.

Question 2

Which of the following characteristics of an element can be determined precisely by considering only the element's specificposition on the periodic table?

Accepted Answer

The number of protons in each atom of an element is directly determined by its position on the periodic table, as the elements are arranged in order of increasing atomic number, which equals the number of protons.

Question 3

The pH of four different solutions of common materials is measured. Which of the following lists the solutions in order from most acidic to most basic?

Accepted Answer

Battery acid is highly acidic, typically around pH 0-1. Lemon juice, also acidic, has a pH around 2-3. Blood is slightly alkaline with a pH close to 7.4. Laundry detergent is basic, often having a pH of 9-11. Therefore, the correct order from most acidic to most basic is battery acid, lemon juice, blood, laundry detergent.

Question 4

Which of the following statements explains why the bond in hydrogen chloride (HCl) is polar covalent?

Accepted Answer

The bond in hydrogen chloride (HCl) is polar covalent because chlorine has a higher electronegativity than hydrogen, meaning chlorine attracts the shared electron pair more strongly than hydrogen does, creating a dipole with a partial negative charge on the chlorine atom and a partial positive charge on the hydrogen atom.

Question 5

Which of the following samples of sugar will dissolve fastest in a pitcher of lemonade?

Accepted Answer

Granulated sugar has a larger surface area compared to cubed sugar, allowing it to dissolve faster. Additionally, higher temperatures increase the solubility of sugar in liquid, making 20°C lemonade more conducive to dissolving sugar quickly than 5°C lemonade.

Question 6

Which of the following comparisons correctly describes subatomic particles?

Accepted Answer

Neutrons have a neutral charge and are significantly more massive than electrons, which are negatively charged and have a very small mass.

Question 7

One way that mixtures differ from pure substances is in the methods that can be used to separate them into their components.Which of the following is a method used to separate the components of some mixtures?

Accepted Answer

Filtration is a physical process used to separate solids from liquids or gases by passing the mixture through a filter, which allows only certain components to pass through. This method is commonly used for mixtures, not for separating components of pure substances.

Question 8

Which of the following describes the separation of the components of a mixture?

Accepted Answer

B) Salt is isolated from seawater through evaporation. This process describes the separation of components of a mixture (salt and water) without changing their chemical identities, which is a key characteristic of physical separation methods.

Question 9

Which of the following statements accurately describes alpha particles in terms of charge and mass?

Accepted Answer

Alpha particles are positively charged (they consist of two protons and two neutrons, similar to a helium nucleus) and are more massive than beta particles (which are high-energy, high-speed electrons or positrons).

Question 10

A gas enters a compressor where it is converted to a liquid. Which of the following happens to the gas as it becomes a liquid?

Accepted Answer

When a gas is compressed and converted into a liquid, it undergoes an exothermic process, meaning it releases heat. The mass and number of protons of the substance remain unchanged, and electricity is not inherently released in this process.

Question 11

Which of the following examples is evidence of a physical change?

Accepted Answer

Melting ice cream is a physical change because it involves a change in state from solid to liquid without altering the chemical composition of the ice cream.

Question 12

Which of the following statements describes properties of most metals?

Accepted Answer

Most metals have high melting and boiling points due to the strong metallic bonds between the atoms.

Question 13

Which of the following statements explains how a buffer maintains pH when small amounts of a strong base are added?

Accepted Answer

The weak acid in the buffer reacts with the added strong base to form a salt and water, thereby neutralizing the base and minimizing changes in the pH. This is how a buffer maintains its pH when small amounts of a strong base are added.

Question 14

Which of the following correctly describes molecules of two different gases if they are at the same temperature and pressure?

Accepted Answer

At the same temperature, all gases have the same average kinetic energy according to the kinetic theory of gases. This is because temperature is a measure of the average kinetic energy of the particles in a substance. Pressure does not directly affect the average kinetic energy of gas molecules; it is the temperature that determines this.

Question 15

Which of the following is not true of a sample of gas as it is heated in a rigid, closed container?

Accepted Answer

When a gas is heated in a rigid, closed container, the volume of the container does not change, meaning the average distance between molecules remains constant. The increase in temperature causes the molecules to move faster, leading to increased pressure and more frequent collisions, but it does not change the spacing between the molecules in a rigid container.

Question 16

The density of a gas is 1.35 g/L at standard temperature and pressure (STP). What is the molar mass of the gas at STP?

Accepted Answer

At STP, 1 mole of any gas occupies 22.4 L. The density of the gas is given as 1.35 g/L. To find the molar mass, multiply the density by the volume occupied by 1 mole at STP: 1.35 g/L * 22.4 L = 30.24 g/mol, which is approximately 30.2 g/mol.

Question 17

The three main types of nuclear radiation are alpha, beta, and gamma. Which of the following lists these types of radiation from highest penetrating power to lowest penetrating power?

Accepted Answer

Gamma rays have the highest penetrating power, followed by beta particles, and alpha particles have the lowest penetrating power.

Question 18

Water cools from 2°C to -2°C. During this time, what happens to the motion of the molecules?

Accepted Answer

As temperature decreases, the kinetic energy of the molecules decreases, leading to a reduction in their motion.

Question 19

Which of the following explains why saltwater is considered a mixture?

Accepted Answer

Saltwater is considered a mixture because it consists of water (H2O) and dissolved salts (primarily sodium chloride, NaCl), where both components retain their original chemical properties. This means that the water and salt in saltwater do not chemically combine to form a new substance; instead, they physically mix, allowing each component to maintain its chemical identity.

Question 20

When stirred in 30°C water, 5 g of powdered potassium bromide, KBr, dissolves faster than 5 g of large crystals of potassium bromide. Which of the following best explains why the powdered KBr dissolves faster?

Accepted Answer

Powdered potassium bromide exposes more surface area to water molecules than large crystals, allowing more water molecules to interact with the solute at once, thus speeding up the dissolution process.

Quiz 2: Chemistry