Understanding Chemical Reactions

Multiple Choice

Spoiling food is an example of:

• chemical change

• physical change

• no change

Multiple Choice

Which is an example of a different substance being formed?

• glass breaking

• metal melting

• water freezing

• wood burning

Multiple Choice

A change in an objects appearance, shape, and size without changing its composition is known as

• Chemical change

• Physical change

• Physical-Chemical change

Multiple Select

Which of the following are signs of a chemical reaction?

• Formation of a gas

• A change in temperature

• A change in color

• A change in size

Multiple Choice

In a chemical reaction, the number of atoms in the reactants and the products...

• Must be the same

• Must be different

Multiple Choice

Which of these is NOT a sign of a chemical reaction?

• A phase change

• Formation of a precipitate

• A color change

• A temperature change

Multiple Choice

Evidence of a chemical reactions is anything that shows - 

• a new substance has formed
• a solid dissolved in a liquid
• interaction between 2 gases
• a change in the state of matter

Multiple Choice

One of the signs of a chemical reaction taking place is:

• Bubbles are produced 
• Reactants are not combining
• Products are not forming
• Color is not changing

Multiple Choice

Substances that form as the result of a chemical reaction

• products
• reactants
• coefficients
• subscripts

Multiple Choice

Coefficients in chemical formulas...

• Multiply just the first atom

• Add to the subscripts at the end of the molecule

• Multiply elements without subscripts

• Multiply EVERYTHING!

Multiple Choice

A ______ is a number written in front of a chemical formula.

• Coefficient

• Subscript

• Exponent

• Coordinator

Multiple Choice

The ______ are numbers found on the lower right-hand side of an element symbol.

• Coefficient

• Exponent

• Multiplier

• Subscript

Multiple Choice

Substances present at the start of a chemical reaction

• subscripts
• coefficients
• reactants
• products

Multiple Choice

When writing a chemical equation, reactants are on the _____________ while products are on the _________________.

• top, bottom

• right, left

• left, right

• bottom, top

Multiple Choice

The law of conservation of mass states

• chemical reactions create new atoms

• atoms cannot be created or destroyed

• reactants vanish once a reaction takes place

• products appear when a reaction takes place

Multiple Choice

Chemical equations

• give directions for naming compounds

• describe only biological changes

• describe chemical reactions

• show how to write formulas