PHYSICAL AND CHEMICAL CHANGES

Physical and chemical changes

by: C. McClammey

Poll

How would you rate your understanding of Physical and Chemical Changes?

• I know everything!

• I know a little about the topic.

• I don't know anything.

Multiple Choice

Select the answer that is NOT a physical change.

• baking bread

• ripping paper

• painting a picture

• mixing coffee

Multiple Choice

Mixing peas and carrots for dinner.

• Chemical Change

• Physical Change

• Neither Physical nor Chemical

• Both Physical and Chemical

Multiple Select

Select ALL Chemical Change examples.

• Melting ice

• Burning wood

• Smashing a pumpkin

• Digesting food

• Plants going through photosynthesis.

Multiple Select

Select ALL examples of Physical Changes.

• cutting a sheet of paper

• burning propane

• melting ice cream

• digesting French fries

• boiling water

​Physical Changes

The difference between a physical change and a chemical change is composition. In a chemical reaction, there is a change in the composition of the substances in question; in a physical change there is a difference in the appearance, smell, or simple display of a sample of matter without a change in composition.

​Examples of Physical Changes

• ​Physical changes are limited to changes that result in a difference in display without changing the composition. Some common changes (but not limited to) are:

  • ​Texture

  • ​Color

  • ​Temperature

  • ​​Shape

  • ​​Change of State (freezing, melting)

Open Ended

What is a physical change?

​Chemical Change

• ​In a chemical change, there is a change in the composition of the substances in question.

​Signs of a Chemical Change

• ​Change in Temperature

• ​Change in Color

• ​Noticeable Odor

• ​Formation of a Precipitate

• ​Formation of Bubbles

Multiple Choice

Is "boiling an egg" a Physical Change or a Chemical Change?

• Physical Change

• Chemical Change

Multiple Choice

Burning a candle ______________ change.

• physical

• chemical

• internal

• external

​Change in Temperature

• ​A change in temperature is characteristic of a chemical change. During an experiment, one could dip a thermometer into a beaker or Erlenmeyer Flask to verify a temperature change. If temperature increases, as it does in most reactions, a chemical change is likely to be occurring. This is different from the physical temperature change.

Multiple Choice

Exploding Fireworks

• Physical Change

• Chemical Change

• Neither Physical nor Chemical

Multiple Choice

Mixing sugar and powdered drink mix.

• Physical Change

• Chemical Change

• Neither Physical nor Chemical

• Both Physical and Chemical

Multiple Choice

Flammability means that the matter has the ability to ____________.

• explode

• react

• burn

• spill

​Change in Color

​A change in color is also another characteristic of a chemical reaction taking place. For example, if one were to observe the rusting of metal over time, one would realized that the metal has changed color and turned orange. This change in color is evidence of a chemical reaction. However, one must be careful; sometimes a change in color is simply the mixing of two colors, but no real change in the composition of the substances in question.

Multiple Choice

A saw cuts a log and creates sawdust.

• Physical Change

• Chemical Change

• Both Physical and Chemical 

• Neither Physical nor Chemical