Name: ______Per: _____

Ch. 8 Physical and Chemical Changes Review WKSHT

Counting Atoms - How many atoms of each element are present in the following chemical formulas? Write the amounts next to the formulas.

For example: PbCl2 Pb: 1 Cl: 2

Fe2O3 ______LiCl ______3 SH2 ______NaOH ______3 AlCl3 ______

Ca3P2 ______Ca(NO3)2 ______Si(OH)4 ______2 Si(OH)4 ______Co2(SO4)3 ______

Which Chemical Equation is balanced? Write a “B” for balanced and a “UB” for unbalanced. SHOW YOUR WORK for counting atoms underneath the equation.

AgNO3 + Li à LiNO3 + Ag ______

NaCN + CuCO3 à Na2CO3 + Cu(CN)2 ______

1 Li3PO4 + 3 NaBr à 1 Na3PO4 + 3 LiBr ______

2 CoBr3 + 3 CaSO4 à 2 CaBr2 + 1 Co2(SO4)3 ______

Balance the Chemical Equation – SHOW your work for balancing the equations.

____ Mn + ____ HI à ____ H2 + ____ MnI3

____ Si(OH)4 + ____ NaBr à ____ SiBr4 + ____ NaOH

____ CaF2 + ____ Li2SO4 à ____ CaSO4 + ____ LiF

(continue on the back!)

A Physical Change or a Chemical Change? Decide whether the descriptions below are physical or chemical changes. Write a “P” for physical change or a “C” for chemical change.

_____ Bubbles are made from bubble solution.

_____ An egg is cracked on the sidewalk.

_____ An egg is fried on a frying pan.

_____ A popcorn kernel pops in the microwave.

_____ Rust is formed on the metal chain of a bike.

_____ Chalk is used to write on a chalkboard.

_____ Soap is used to wash hands.

_____ Milk begins to spoil in the refrigerator.

_____ Salt dissolves in a cup of warm water.

_____ Water from the shower changes into steam.

Physical and Chemical Change – Answer the following questions with complete sentences.

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

______

How are physical and chemical changes similar? ______

______

Is a chemical change ALWAYS a physical change? Why? Give an example if you can. ______

______

______

Is a physical change ALWAYS a chemical change? Why? Give an example if you can. ______

______

______

A Physical Change or a Chemical Change? Decide whether the chemical equations below are describing physical or chemical changes. Write a “P” for physical change or a “C” for chemical change. * Note: Ignore the fact that some of these equations may be unbalanced.

_____ CuSO4 + H2O à H2O + CuSO4

_____ 2 H2O(1) à 2 H2 (g) + O2 (g)

_____ C12H22O11 (s) + H2O (l) à C12H22O11 (aq) + H2O (l)

_____ H2O(1) à H2O(g)

_____ K4Fe(CN)6 + KMnO4 + H2SO4 à KHSO4 + Fe2 (SO4)3 + MnSO4 + HNO3 + CO2 + H2O