1. Agenda: Friday, March 22nd
1) Warm-up – 10 min
2) Coefficients review – 20 min
3) Chemical Change Review – 20 min
4) Open-Note Quiz – 30 min
2. Answer the 3 CST questions the same way we
did on Tuesday: Write down your answer, key
words, and reason you chose the answer.
3. Sometimes a change seems irreversible when it
is.
For example, when dry ice sublimates, can we
reverse it?
4. Yes we can!
Dry ice undergoes deposition at -78 degrees
Celsius. If we decrease the temperature below
that, Carbon Dioxide gas will re-form into dry ice
5. If we recycle a can and it gets crushed in order to
make something else.. is it a chemical change
because it changed into something else?
6. No! Because even though the can gets changed
into something else, the aluminum molecules in
the can do not get changed.
7. What is an example of a chemical change to a
table?
8. In a chemical change the molecules in the table
would react and form other molecules, such as
carbon dioxide gas and ash (made of carbon).
9. Chemical and Physical Changes
Definition of a Chemical change:
1) Substance changes its identity
2) Irreversible
3) New molecules are formed
Definition of a Physical change:
1) Substance changes appearance, not identity
2) Reversible
3) Same molecules after change as before
4) All phase transitions
Draw 2 examples of each type of change – 20 pts
10. Mini poster
With a sheet of paper, create a mini foldable for a
chemical and physical change. Mr. Lee will
demonstrate.
