Chemical Reactions Quiz

Label the following as a physical change (P) or a chemical change (C). a. Folding clothes

• P

• C

• Both

• None

Answer explanation

Folding clothes is a physical change (P) because it alters the shape and arrangement of the fabric without changing its chemical composition.

Label the following as a physical change (P) or a chemical change (C). b. Clipping your fingernails

• P

• C

• Both

• None

Answer explanation

Clipping your fingernails is a physical change (P) because it alters the shape and length of the nails without changing their chemical composition.

Label the following as a physical change (P) or a chemical change (C). c. Cooking an egg

• C

• P

• Both

• Neither

Answer explanation

Cooking an egg is a chemical change (C) because it involves the transformation of proteins through heat, resulting in new substances. This process cannot be reversed, distinguishing it from a physical change.

Label the following as a physical change (P) or a chemical change (C). d. Melting ice

• P

• C

• Both

• None

Answer explanation

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

Label the following as a physical change (P) or a chemical change (C). e. Digesting food

• C

• P

• Both (P and C)

• Neither

Answer explanation

Digesting food is a chemical change (C) because it involves breaking down food into simpler substances, resulting in new chemical compositions, unlike physical changes that do not alter the substance's chemical structure.

Label the following as exothermic (EX) or endothermic (EN). a. Your hands absorbing the heat from a heating pack

• EN

• EX

• None of the above

• Not applicable

Answer explanation

Your hands absorbing heat from a heating pack indicates that heat is being taken in, which characterizes an endothermic process (EN). Thus, the correct label is EN.

Label the following as exothermic (EX) or endothermic (EN). b. Flower absorbing sunlight

• EN

• EX

• Neither

• Both

Answer explanation

The process of a flower absorbing sunlight is part of photosynthesis, which requires energy from sunlight. This makes it an endothermic (EN) reaction, as it absorbs energy rather than releasing it.

Label the following as exothermic (EX) or endothermic (EN). c. Sitting around a campfire

• EX

• EN

• Neither

• Both

Answer explanation

Sitting around a campfire is an exothermic process because the fire releases heat and light energy into the surroundings, warming up the area and the people nearby. Thus, it is labeled as exothermic (EX).

Label the following as exothermic (EX) or endothermic (EN). d. Melting ice

• EN

• EX

• NEITHER

• BOTH

Answer explanation

Melting ice is an endothermic process because it absorbs heat from the surroundings to change from solid to liquid. Therefore, the correct label is EN.

Label the types of reactions as: Synthesis (S), Decomposition (D), Single Replacement (SR), and Double Replacement (DR). a. 2AgI → 2Ag + I₂

• Decomposition (D)

• Synthesis (S)

• Single Replacement (SR)

• Double Replacement (DR)

Answer explanation

The reaction 2AgI → 2Ag + I₂ involves the breakdown of a compound (AgI) into simpler substances (Ag and I₂), which is characteristic of a decomposition reaction. Therefore, the correct label is Decomposition (D).