Chemical Reactions and Conservation of Matter Review

If a change in a substance produces heat or removes heat (feels cold), what type of change has happened?

• Physical change

• Chemical change

• Mechanical change

• Electrical change

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

One apple is allowed to rot in a closed jar and another apple rots in an open jar. Both apples clearly go through a chemical change, but the mass of the closed jar doesn’t change. Why does the mass of the open jar change?

• The apple absorbs air

• The apple releases gases

• The apple gains water

• The apple loses color

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

If a change occurs in a substance, but the substance is still made of the same thing at the end of the change, is this a physical or chemical change?

• Physical change

• Chemical change

• Nuclear change

• Biological change

Tags

NGSS.MS-PS1-5

4Fe + 3O₂ → 2Fe₂O₃. What are the reactants in this chemical reaction?

• Fe₂O₃

• 4Fe and 3O₂

• 2Fe₂O₃

• O₂ and Fe₂O₃

Tags

NGSS.MS-PS1-1

The properties of a substance are completely different after a change than before it. Was this a chemical or a physical change?

• Physical change

• Chemical change

• Thermal change

• Electrical change

Tags

NGSS.MS-PS1-2

When you dissolve salt in water, the water retains its properties and so does the salt. Is mixing salt in water a chemical or a physical change?

• Physical change

• Chemical change

• Biological change

• Nuclear change

Tags

NGSS.MS-PS1-5

When a chemical equation is written out, are the products of a chemical reaction written before or after the arrow?

• Before the arrow

• After the arrow

Cooking an egg is a chemical reaction because:

• The egg changes color and texture

• The egg remains the same

• The egg cools down

• The egg dissolves in water

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

Combining baking soda with vinegar produces bubbles and heat. Describe how this helps you know that a chemical change has occurred.

• The mixture becomes cold

• The mixture remains unchanged

• The production of bubbles and heat indicates a chemical reaction

• The mixture turns into a solid

Tags

NGSS.MS-PS1-2

Is the formation of a mixture a physical or a chemical change?

• Physical change

• Chemical change

• Both

• Neither