4.4

Question 1

Characteristics of a chemical change

Answer 1

1) gas (bubbles)
2) change in temp
3) color
4) odor
5) precipitate

Question 2

What is considered a physical or chemical change?

Answer 2

Dissolution: is reversible but bonds are broken

Question 3

Chemical reactions

Answer 3

1) combustion (always creates water and CO2)
2) single replacement
3) double replacement
4) synthesis
5) decomposition (when CO3 2- decomposes, it’s creates CO2 and a metal oxide: Na2CO3 —> CO2 + Na2O)