What does a chemical change fundamentally alter?

• The physical state

• The molecular structure

• The volume

• The color

Answer explanation

A chemical change fundamentally alters the molecular structure of a substance, resulting in the formation of new substances with different properties, unlike physical changes that only affect the state, volume, or color.

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DOK Level 1: Recall

What is true about the movement of particles in matter?

• They are stationary in solids

• They move only in liquids and gases

• They are in constant motion

• They move in solids but not in liquids

Answer explanation

Particles in matter are always in constant motion, regardless of the state. In solids, they vibrate in place; in liquids, they move more freely; and in gases, they move rapidly and spread out. Thus, the correct choice is that they are in constant motion.

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DOK Level 1: Recall

In solids, _____________ remains constant.

• Volume

• Shape

• Temperature

• Mass

Answer explanation

In solids, the shape remains constant due to the fixed arrangement of particles. Unlike volume, which can change under pressure, or temperature and mass, shape is a defining characteristic of solid materials.

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DOK Level 1: Recall

When a liquid is transferred to a larger container, its _____________ remains the same.

• Volume

• Shape

• Temperature

• Mass

Answer explanation

When a liquid is transferred to a larger container, its volume remains the same because the amount of liquid does not change. The shape may change to fit the new container, but the mass and volume stay constant.

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DOK Level 1: Recall

Gases can expand to fill their container because of the _____________ between gas particles.

• Attraction

• Repulsion

• Space

• Pressure

Answer explanation

Gases can expand to fill their container due to the space between gas particles. Unlike solids and liquids, gas particles are far apart, allowing them to move freely and occupy the entire volume of their container.

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DOK Level 1: Recall

What is considered the most abundant state of matter in the universe?

• Solid

• Liquid

• Gas

• Plasma

Answer explanation

Plasma is the most abundant state of matter in the universe, making up about 99% of it. It consists of ionized gases found in stars, including our sun, and in interstellar space, unlike solids, liquids, and gases.

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DOK Level 1: Recall

Which statement about phase changes is false?

• Energy transfer is involved

• Particle speed remains constant during phase changes

• Particles have different energies in different states

• Phase changes are reversible

Answer explanation

The statement 'Particle speed remains constant during phase changes' is false. In reality, particle speed changes as energy is absorbed or released, affecting the temperature and state of the substance.

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DOK Level 1: Recall

What is the process called when a solid turns directly into a gas?

• Melting

• Freezing

• Sublimation

• Condensation

Answer explanation

The process when a solid turns directly into a gas is called sublimation. This occurs without passing through the liquid phase, unlike melting or freezing, which involve changes between solid and liquid states.

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DOK Level 1: Recall

Which of the following is a physical change?

• Rusting of iron

• Burning of wood

• Melting of ice

• Baking a cake

Answer explanation

The melting of ice is a physical change because it involves a change in state from solid to liquid without altering the chemical composition. In contrast, rusting, burning, and baking involve chemical changes.

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DOK Level 1: Recall

What is the term for the amount of space an object occupies?

• Mass

• Volume

• Density

• Weight

Answer explanation

The term for the amount of space an object occupies is 'Volume'. Mass refers to the amount of matter, density is mass per unit volume, and weight is the force of gravity on an object.

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DOK Level 1: Recall