Physical vs Chemical Changes

What is the difference between a physical and a chemical change?

• In a physical change, the molecules stay the same. In a chemical change, the molecules are different.

• In a chemical change, the molecules stay the same. In a physical change, the molecules are different.

• A physical change is something you can see. A chemical change cannot be seen.

• They are both the same.

Which of these examples shows a physical change? (Select all that apply)

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Which of these examples shows a chemical change? (Select all that apply)

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Does this formula show a physical or a chemical change? Why?

H2O -> H2O

• Physical change because the molecules change into something new.

• Chemical change because the molecules change into something new.

• Physical change because the molecules stay the same.

• Chemical change because the molecules stay the same.

Does this formula show a physical or a chemical change? Why?

NH3 -> N2 + H2

• Chemical change because the molecules stay the same.

• Chemical change because the molecules change into something new.

• Physical change because the molecules stay the same.

• Physical change because the molecules change into something new.

Does this model show a physical change or a chemical change?

• Physical change because the molecules stay the same.

• Physical change because the molecules are different before and after.

• Chemical change because the molecules stay the same.

• Chemical change because the molecules are different before and after.

Does this model show a physical change or a chemical change?

• Physical change because the molecules stay the same.

• Physical change because the molecules are different before and after.

• Chemical change because the molecules stay the same.

• Chemical change because the molecules are different before and after.