quiz r

What does exothermic mean?

• a chemical reaction that absorbs heat energy

• a chemical reaction that changes a substance

• a chemical reaction that releases heat energy

The substances that go into a reaction are called the……………………… .

• reactants

• chemicals

• questions

• products

The substances that go out of a reaction are called the…………………… .

• reactants

• chemicals

• products

A change of color is an evidence of a chemical reaction.

• True

• false

What does the arrow in a chemical equation represent?

• Addition

• Decomposition

• Yields or produces

What is the purpose of writing chemical equations?

• To balance the equation

• To describe the reactants and products in a reaction

• To show the temperature of the reaction

• To determine the speed of the reaction.

Which of the following is not a sign of a chemical reaction?

• Color changes

• Cutting into fourths

• Light is produced

What are the reactants in the chemical reaction: Na + cl → NaCl?

• Na

• Cl

• Na and cl

• Nacl

What is the product of the reaction between sodium (Na) and chlorine (Cl)?

• NaCl

• NaCl₂

• Na₂oH

The mass is …………………befor and after the chemical reaction?

• increases

• decreases

• the same