Pre-test: Chemical Reactions

When a scientist mixed two chemicals, an exothermic reaction takes place. Which of the following would be proof that the reaction was exothermic?

• a change of color
• a change of state
• a temperature decrease
• a temperature increase

Which of the following is a chemical change?

• water freezes to form ice
• sugar dissolves in water
• gasoline burns in a car engine
• a piece of metal expands when it is heated

Tags

NGSS.MS-PS1-2

In the reaction methane + oxygen turns into carbon dioxide + water, the methane and oxygen are called _______________.

• reactants
• products
• neutrals
• energizers

A change in the shape of an object is an example of _________________.

• a chemical change
• energy
• an endothermic change
• a physical change

What type of change occurs when a new substance is formed that has different properties from the original substances?

• chemical change
• nuclear change
• physical change
• mutation

In any chemical reaction, the mass of the products is always:

• slightly less than the mass of the reactants
• much less than the mass of the reactants
• the same as the mass of the reactants
• greater than the mass of the reactants

How do chemical reactions turn substances into new substances?

• with burning acid
• the molecules mix together and create new substances
• the atoms break apart and combine back together in new ways
• the ionic compounds mix in water to form solutions

How many Hydrogens are on the product side of this chemical equation?

• 1

• 2

• 3

• 4

Why are chemical equations always balanced? Select ALL that apply.

• Matter cannot be created.

• Matter cannot be destroyed.

• Matter can only be rearranged/conserved.

• Matter doesn't matter.

Which is the correct word equation for photosynthesis?

• water + glucose + oxygen ---> energy + carbon dioxide

• energy + oxygen + carbon dioxide ---> water + glucose

• water + carbon dioxide + energy ---> glucose + oxygen

• glucose + oxygen ---> water + carbon dioxide + energy