Chemical and Physical Changes

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Questions and Answers

What fundamental process occurs during a chemical change?

A substance is transformed into an entirely new substance through the breaking or forming of chemical bonds. (correct)
The substance's state of matter transitions without altering its chemical identity.
The substance undergoes temporary changes in color but maintains the same chemical structure.
A substance solely alters its physical form without changing its elemental composition.

Which observation is the MOST indicative of a chemical change?

Formation of a gas. (correct)
A substance changing from solid to liquid.
A temporary alteration in color.
The tearing of paper.

Which of the following processes represents a physical change?

Burning wood.
Rusting of iron.
Cutting paper. (correct)
Boiling an egg.

Which of the following is an example of a substance changing state from solid to liquid?

Ice melting. (D) Signup and view all the answers

Wood burning is a chemical change. What is the best evidence of this?

The wood turns to ash and smoke. (C) Signup and view all the answers

Why is salt dissolving in water classified as a physical change?

Because the salt can be recovered by evaporating the water. (C) Signup and view all the answers

Why is freezing a popsicle considered a physical change?

Because it changes from a liquid to a solid, but the composition remains the same. (D) Signup and view all the answers

Why is shattering glass considered a physical change?

Because the glass only changes in shape and size. (A) Signup and view all the answers

Why is the combination of hydrogen and oxygen to form water considered a chemical change?

Because a new substance with new properties is formed. (C) Signup and view all the answers

Crushing a rock into smaller pieces is a physical change. Why?

The rock's chemical identity remains the same. (B) Signup and view all the answers

Why is burning paper classified as a chemical change?

Because new substances like ash and gases are produced. (A) Signup and view all the answers

Why is boiling an egg considered a chemical change?

The egg's proteins denature and its texture changes irreversibly. (D) Signup and view all the answers

The formation of rust on a nail is a chemical change. What is the key indicator of this?

A new substance (rust) forms on the nail. (D) Signup and view all the answers

Why is chewing food considered a physical change?

Because food is broken down into smaller pieces without changing its chemical composition. (D) Signup and view all the answers

Why is the digestion of food (saliva breaking down food molecules) considered a chemical change?

Because enzymes in saliva break chemical bonds, creating new molecules. (C) Signup and view all the answers

What eventually happens to a pot of water left on a hot stove?

It will eventually evaporate. (C) Signup and view all the answers

Which of the following correctly lists the three states of matter?

Solid, liquid, and gas. (A) Signup and view all the answers

Which of the following is NOT a fundamental property of matter?

Color (D) Signup and view all the answers

Which of the following describes a substance undergoing a change of state from a solid to a liquid?

Melting (C) Signup and view all the answers

Why might a rusty nail increase in measured mass, compared to its original mass?

The creation of rust deposits additional material. (C) Signup and view all the answers

Flashcards

Chemical Change

A change that happens when a substance changes to create an entirely new substance, breaking or forming chemical bonds.

Evidence of Chemical Change

Evidence can include gas formation, color change, and the production of a new substance.