1. Classify each of the following changes as chemical or physical:
A. Dissolving sugar in ice tea ______
B. Starting a car ______
C. Mixing baking soda and vinegar ______
D. Cutting your hair ______
E. Condensation forms on a cold glass ______
2. Balance the following equations:
A. ___CO(g) + ___H2(g) ® ___CH3OH(g)
B. ___Sb2S3(s) + ___HCl(aq) ® ___SbCl3(s) + ___H2S(g)
C. ___Al(s) + ___H2SO4(aq) ® ___Al2(SO4)3(aq) + ___H2(g)
3. Classify each of the following reactions as a combination, decomposition, single replacement, or double replacement.
A. 2Al(s) + 3Br2(g) ® 2AlBr3(s) ______
B. Pb(NO3)2(aq) + 2NaCl(aq) ® PbCl2(s) + 2NaNO3(aq) ______
C. Fe2O3(s) + 3C(s) ® 2Fe(s) + 3CO(g) ______
D. C6H12O6(aq) ® 2C2H6O(aq) + 2CO2(g) ______
E. CuO(s) + 2HCl(aq) ® CuCl2(aq) + H2O(l) ______
4. In the following reactions, identify what is oxidized, and what is reduced.
Extra Credit: Write out the half reactions.
A. Cl2(g) + 2KI(aq) ® 2KCl(aq) + I2(g) oxidized ______
reduced ______
B. Zn(g) + Cu2+(aq) ® Zn2+(aq) + Cu(s) oxidized ______
reduced ______
C. Fe(s) + CuSO4(aq) ® FeSO4(aq) + Cu(s) oxidized ______
reduced ______
5. Consider the following equation:
Show work.
Mg(s) + H3PO4(aq) ® Mg3(PO4)2(s) + H2(g)
A. How many molecules of Mg3(PO4)2 are present in 1.25 moles of Mg3(PO4)2?
B. How many moles of Mg are in 7.8 x 1021 atoms of Mg?
C. How many moles of H are in 0.175 moles of H3PO4?
D. How many grams of Mg are in 12.5 moles of Mg3(PO4)2?
6. Nitrogen gas reacts with hydrogen gas to produce ammonia by the following equation:
Show work.
N2(g) + 3H2(g) ® 2NH3(g)
A. How many moles of NH3 are produced when 1.4 moles H2 reacts?
B. If you have 1.80 moles H2, how many grams of NH3 can be produced?
C. How many grams of NH3 can be produced from 12.0 g H2?
D. How many molecules of N2 are needed to react with 0.250 mole H2?
7. How would each of the following change the rate of the reaction shown here?
i.e. increase, decrease, no change
2NO(g) + 2H2(g) ® N2(g) + 2H2O(g)
A. adding more NO ______
B. lowering the temperature ______
C. removing some H2 ______
D. adding a catalyst ______