Chemistry - Chapter 2 Full*

Which of the following is an example of a physical change?

• a metal being hammered into a sheet

• a chemical reacting violently with water

• a compound exploding

• a metal corroding in the presence of an acid

Answer explanation

A metal being hammered into a sheet is a physical change because it alters the shape without changing the metal's chemical composition. The other options involve chemical reactions, which result in new substances.

A rock weighs more than a piece of foam, even if the foam is twice the volume of the rock. What property of matter does this illustrate?

• conductivity

• malleability

• density

• ductility

Answer explanation

This illustrates density, which is the mass per unit volume. The rock, despite being smaller in volume, has a greater mass than the foam, indicating it has a higher density.

Match the term to the definition.

• ability to conduct electricity

• malleability

• amount of matter in a given volume

• ductility

• ability to be stretched into a wire

• density

• ability to be hammered into thin sheets

• conductivity

How many atoms of sulfur are present in Al₂(SO₄)₃?

• 2

• 3

• 4

• 6

Answer explanation

In Al₂(SO₄)₃, there are 3 sulfate (SO₄) groups. Each sulfate contains 1 sulfur atom, so 3 sulfate groups contribute 3 sulfur atoms in total. Thus, the correct answer is 3.

Tags

NGSS.MS-PS1-1

A mixture that consists of two or more materials in distinct phases is called __________.

• heterogeneous

• homogeneous

• pure substance

• compound

Answer explanation

A mixture with distinct phases, where components are not uniformly distributed, is termed heterogeneous. In contrast, homogeneous mixtures have a uniform composition, while pure substances and compounds consist of a single type of material.

The measure of the dispersal of energy in a system is known as ___________.

• conservation of energy

• entropy

• enthalpy

• none of these

Answer explanation

The measure of the dispersal of energy in a system is known as entropy. It quantifies the amount of disorder or randomness, making it the correct choice among the options provided.

Tags

NGSS.HS-PS3-4

Heat is the term used for the movement of ___________ energy.

• thermal

• kinetic

• potential

• increased

Answer explanation

Heat refers to the transfer of thermal energy, which is the energy associated with the temperature of an object. Therefore, the correct answer is 'thermal'.

Tags

NGSS.MS-PS3-3

Temperature measures the total kinetic energy in a sample.

• True

• False

Answer explanation

The statement is false because temperature measures the average kinetic energy of particles in a sample, not the total kinetic energy. Total kinetic energy depends on the number of particles and their individual energies.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Reactions that absorb energy are exothermic.

• True

• False

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Which of the following is not a characteristic of solids?

• fixed volume

• particles rigidly held in a fixed volume

• ease of compressibility

• relatively little kinetic energy

Tags

NGSS.MS-PS3-1