FOS-P
Unit 4 Review
Topics to know: difference between physical and chemical change; 5 evidences of chemical
reaction (change); 3 parts of a chemical equation; balancing chemical equations; 5 types of
chemical equations; calculate the change in energy in a chemical equation (determine exo- or
endothermic); mole conversions (molar mass, mol to gram, mol to atoms or molecules);
stoichiometry calculations (mol to mol, g to mol, g to g)
1. Identify the type of reaction, then balance the equation.
a. __C7H16 + __O2  __CO2 + __ H2O
type ________________
b. __AgNO3 + __K2CrO4  __ Ag2CrO4 + __ KNO3
type ________________
c. __NaBr + __I2  __ NaI + __ Br2
type ________________
d. __Al + __O2  __ Al2O3
type ________________
2. Consider the following equation: __CaCO3 + __HCl  __CaCl2 + __CO2 + __H2O
a. Balance the equation.
b. What is the mole ratio of the products?
___ : ___ : ___
c. If 3 moles of CaCO3 are reacted, how many moles of HCl are needed?
d. If 4.5 grams of CO2 are produced, how many grams of CaCO3 were reacted?
3. What is the molar mass of NaOH?
FOS-P
Unit 4 Review
a. What is the mass of 2 moles of NaOH?
4. What is the difference between a physical change and chemical change?
a. Is boiling a physical change or chemical change? Why?
5. Calculate the change in energy for this reaction: C2H4 + 3 O2  2 CO2 + 2 H2O
a) Change in energy ________________ KJ/mol
b) Is the reaction endothermic or exothermic?
5. What is the molar mass of CH3Cl?
a. How many molecules of CH3Cl are in a 3.92 mole sample?
b. What is the mass in grams of 0.084 mole of CH3Cl?
FOS-P
Unit 4 Review
c. What is the mass in grams of 7.12 x 1024 molecules of CH3Cl?