Physical vs Chemical Changes
Cutting a piece of paper is an example of:
A. Chemical change
B. Phase change
C. Physical change
D. Mixture separation
✅C. Physical change
The smallest unit of matter is:
A. Element
B. Atom
C. Molecule
D. Proton
B. Atom
1. Boiling water is a:
A. Physical change
B. Chemical change
C. Nuclear change
D. New substance creation
A. Physical change
Which of the following is a chemical change?
A. Ice melting
B. Water boiling
C. Iron rusting
D. Sugar dissolving
C. Iron rusting
A molecule is:
A. One type of atom only
B. A group of uncombined atoms
C. Two or more atoms chemically bonded
D. Something that cannot be separated
C. Two or more atoms chemically bonded
In a chemical reaction, mass is:
A. Gained
B. Lost
C. Destroyed
D. Conserved
D. Conserved
Which is NOT a sign of a chemical change?
A. Temperature change
B. Color change
C. Formation of gas
D. Breaking into smaller pieces
D. Breaking into smaller pieces
What’s the difference between a compound and a mixture?
A. Compounds are physical combinations
B. Mixtures are chemically bonded
C. Mixtures can be separated physically; compounds cannot
D. Mixtures are always gases
C. Mixtures can be separated physically; compounds cannot
Which statement about energy and matter in ecosystems is true?
A. Both energy and matter are recycled
B. Energy flows and is lost; matter is recycled
C. Matter flows one way; energy cycles
D. Neither energy nor matter is reused
B. Energy flows and is lost; matter is recycled
What’s the key difference between physical and chemical changes?
A. Physical changes are always reversible
B. Physical changes form new substances
C. Chemical changes do not affect properties
D. Chemical changes form new substances
D. Chemical changes form new substances
Is butter an element, compound, or mixture? Why?
A. Element; it has only one atom
B. Compound; it has bonded elements
C. Mixture; it has various substances not chemically combined
D. None of the above
B. Compound; it has bonded elements
A balanced chemical equation shows:
A. Only products
B. More atoms on the product side
C. Equal atoms on both sides of the reaction
D. More atoms on the reactant side
C. Equal atoms on both sides of the reaction
Why is baking bread considered a chemical change?
A. The bread is still dough
B. It produces a new substance with a different texture and smell
C. It can be reversed easily
D. The bread just changes shape
B. It produces a new substance with a different texture and smell
Which statement describes the structure of an atom?
A. Neutrons orbit the nucleus
B. Protons and electrons are in the nucleus
C. Electrons orbit a nucleus with protons and neutrons inside
D. Atoms have only protons and electrons
C. Electrons orbit a nucleus with protons and neutrons inside
What happens to atoms in a chemical reaction like rusting?
A. Atoms disappear
B. Atoms are created
C. Atoms rearrange to form a new substance
D. Atoms lose energy and stop moving
C. Atoms rearrange to form a new substance