Unit 3 Chemical Reactions Test

Unit 3 Chemical Reactions Test

GRADED A+ (ACTUAL TEST ) Questions and Answers (Solved)

• Type of chemical reaction that absorbs energy in order to take

place. Sign of a chemical reaction.

Answer: Endothermic

• Type of chemical reaction that releases energy as it takes place.

Sign of a chemical reaction.

Answer: Exothermic

• Solid compound produced from 2 liquids during a chemical

reaction. Sign of a chemical reaction.

Answer: Precipitate

• Gas given off during a chemical reaction; may or may not have

an odor. Sign of a chemical reaction.

Answer: Bubbles

• light, heat, color change, new substance exists

Answer: Other Signs of a Chemical Reaction

• Mass cannot be created nor destroyed; Mass can only change

forms. The total mass of products equals the total mass of the reactants.

Answer: Law of Conservation of Mass

• / 2

• Number in front of a compound's chemical formula telling you

how many molecules of that compound are needed.

Answer: Coefficient

• Number written after and BELOW an element in a chemical

formula telling you how many of the preceding element are needed for that compound or molecule.

Answer: Subscript

• Chemical equation where the total mass of the reactants equals

the total mass of the products. Produced by changing the coefficients of the com- pounds.

Answer: Balanced Equation

• Chemical change; when substances interact with each other.

Original substances are used up. New substance created.

Answer: Chemical Reaction

• Written representation of a chemical reaction/chemical change;

shows all the reactants and products. Always in the form of:

Reactants Yield (arrow) Products.

Answer: Chemical Equation

• A change that occurs when one or more substances change into

entirely new substances with different properties.

Answer: Chemical Change

• When a substance changes its phase (changes to a solid, liquid ,

gas, or plasma) or is modified (size, shape, etc) but remains the same substance.

• / 2