Quiz about Quick Check on Chem Reaction Vocab and Evidence of Change

Question 1

What is a chemical reaction?

Accepted Answer

A process where substances are transformed into new substances with different properties.

Answer

A process where substances are mixed but not changed.

Answer

A process where substances are physically altered but not chemically changed.

Answer

A process where substances are dissolved in water.

Question 2

Which of the following best describes a chemical change?

Accepted Answer

A change that results in the formation of one or more new substances with new chemical properties.

Answer

A change in the state of matter, such as melting or freezing.

Answer

A change in the size or shape of a substance.

Answer

A change in the temperature of a substance without altering its chemical structure.

Question 3

What are reactants in a chemical reaction?

Accepted Answer

The starting substances in a chemical reaction that undergo change.

Answer

The substances that are formed as a result of a chemical reaction.

Answer

The substances that speed up a chemical reaction.

Answer

The substances that remain unchanged in a chemical reaction.

Question 4

What are products in a chemical reaction?

Accepted Answer

The substances formed as a result of a chemical reaction.

Answer

The starting substances in a chemical reaction.

Answer

The substances that speed up a chemical reaction.

Answer

The substances that remain unchanged in a chemical reaction.

Question 5

What does the Law of Conservation of Mass state?

Accepted Answer

Matter cannot be created or destroyed during a chemical reaction; the mass of reactants equals the mass of products.

Answer

Matter can be created or destroyed during a chemical reaction.

Answer

The mass of reactants is always greater than the mass of products.

Answer

The mass of products is always greater than the mass of reactants.

Question 6

Which of the following is an exothermic reaction?

Accepted Answer

A reaction that releases heat energy into its surroundings.

Answer

A reaction that absorbs heat energy from its surroundings.

Answer

A reaction that neither absorbs nor releases heat energy.

Answer

A reaction that only occurs at low temperatures.

Question 7

Which of the following is an endothermic reaction?

Accepted Answer

A reaction that absorbs heat energy from its surroundings.

Answer

A reaction that releases heat energy into its surroundings.

Answer

A reaction that neither absorbs nor releases heat energy.

Answer

A reaction that only occurs at high temperatures.

Question 8

What is a synthesis reaction?

Accepted Answer

A reaction in which two or more substances combine to form a single product.

Answer

A reaction in which a compound breaks down into simpler substances.

Answer

A reaction that involves the exchange of ions between two compounds.

Answer

A reaction that occurs without the presence of a catalyst.

Question 9

What is a decomposition reaction?

Accepted Answer

A reaction in which a compound breaks down into simpler substances.

Answer

A reaction in which two or more substances combine to form a single product.

Answer

A reaction that involves the exchange of ions between two compounds.

Answer

A reaction that occurs without the presence of a catalyst.

Question 10

What is the role of a catalyst in a chemical reaction?

Accepted Answer

It speeds up a chemical reaction without being consumed or altered during the process.

Answer

It is consumed during the reaction and alters the products.

Answer

It slows down a chemical reaction and is consumed in the process.

Answer

It has no effect on the rate of a chemical reaction.

Question 11

You mix vinegar and baking soda in a beaker, and bubbles immediately form. What evidence of a chemical reaction is observed?

Accepted Answer

Formation of a gas

Answer

Change in temperature

Answer

Formation of a precipitate

Question 12

A piece of iron is left outside, and it begins to rust over time. What evidence shows that a chemical reaction occurred?

Accepted Answer

Change in color

Answer

Formation of a gas

Answer

Dissolving of the iron

Question 13

A strip of magnesium metal is burned, producing a bright white light. What evidence of a chemical reaction is observed?

Accepted Answer

Emission of light and heat

Answer

Change in state

Answer

Melting of the magnesium

Question 14

When two clear solutions are mixed, a yellow solid forms and settles at the bottom of the container. What evidence of a chemical reaction is shown?

Accepted Answer

Formation of a precipitate

Answer

Formation of a gas

Answer

Change in temperature

Question 15

During a lab experiment, a thermometer shows a decrease in temperature after two liquids are mixed. What evidence of a chemical reaction is this?

Accepted Answer

Endothermic reaction (absorption of heat)

Answer

Formation of a gas

Answer

No evidence of a reaction

Question 16

A candle is burned, producing heat, light, and smoke. What is the evidence of a chemical reaction?

Accepted Answer

Formation of a gas and emission of heat and light

Answer

Change in state only

Answer

No evidence; this is a physical change

Question 17

A silver spoon turns black over time when exposed to air. What evidence of a chemical reaction is observed?

Accepted Answer

Change in color

Answer

Formation of a precipitate

Answer

Release of energy

Question 18

When an effervescent tablet is dropped into water, bubbles form, and the water gets slightly warmer. What evidence suggests a chemical reaction?

Accepted Answer

Formation of a gas and release of heat

Answer

Change in color

Answer

Dissolution of the tablet

Question 19

Two solutions are mixed, and a dramatic temperature increase occurs. What evidence of a chemical reaction is shown?

Accepted Answer

Exothermic reaction

Answer

Endothermic reaction

Answer

No reaction occurs

Question 20

A slice of apple turns brown when left exposed to air. What evidence of a chemical reaction is observed?

Accepted Answer

Change in color

Answer

Change in shape

Answer

No evidence of a reaction

Question 21

When an electric current passes through water, bubbles of gas form at the electrodes. What evidence shows a chemical reaction?

Accepted Answer

Formation of a gas

Answer

Dissolution of water

Answer

Change in state

Question 22

A teacher adds a small amount of acid to a base, and the solution becomes hot. What evidence of a chemical reaction is this?

Accepted Answer

Release of heat (exothermic)

Answer

Emission of light

Answer

Formation of a precipitate

Question 23

Mixing hydrogen peroxide with a catalyst produces a rapid release of oxygen bubbles. What evidence of a chemical reaction is observed?

Accepted Answer

Formation of a gas

Answer

No evidence; this is a physical change

Answer

Change in temperature

Question 24

An old copper coin turns green after prolonged exposure to air and moisture. What evidence suggests a chemical reaction?

Accepted Answer

Change in color

Answer

Formation of a precipitate

Answer

Evaporation of water

Question 25

A log burns in a fireplace, producing heat, light, and ash. What evidence of a chemical reaction is observed?

Accepted Answer

Emission of heat and light and formation of a new substance (ash)

Answer

Melting of the log

Answer

No evidence of a chemical reaction

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