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Assigments 2 (Chapters 3-4): Stoichiomery and Chemical Reactions
2.1 Most combustion reactions occur in excess O2, that is, more than enough O2 to burn the
substance completely. Calculate the mass of CO2, in grams, that can be produced by burning
6.00 mol of CH4 in excess O2.
2.2 A sample of commercial sulfuric acid is 96.4% H2SO4 by mass, and its specific gravity
is 1.84. Calculate the molarity of this sulfuric acid solution.
2.3 Calculate (a) the number of moles of H2SO4 and (b) the number of grams of H2SO4 in
500. mL of 0.324 M H2SO4 solution.
2.4 Calculate the volume in liters and in milliliters of a 0.324 M solution of sulfuric acid
required to react completely with 2.792 grams of Na2CO3 according to the equation
H2SO4 + Na2CO3 --- > Na2SO4 + CO2 + H2O
2.5 Find the volume in liters and in milliliters of a 0.505 M NaOH solution required to react
with 40.0 mL of 0.505 M H2SO4 solution according to the reaction
H2SO4 + NaOH --- > Na2SO4 + H2O
2.6 We find that 22.3 mL of 0.240 M NaOH is required to react with a 50.0 mL sample of
vinegar. Calculate the concentration of acetic acid in the vinegar.
2.7 a/ If it requires 50. ml of 0.030 M HCI to titrate a 1 00. ml sample of potassium
hydroxide to the equivalence point, how many moles of potassium hydroxide are in the
sample?
b/ What was the original concentration of the potassium hydroxide?
c/ What is the concentration of the potassium chloride salt at the equivalence point?
2.8 A solution of 37.12 ml of 0.1 1 51 M NaOH is required to neutralize a 20.00 ml sample
of citric acid (H3C6H5O7)·
H3C6H5O7 + NaOH ------ > H2O + Na3C6H5O3
What is the molarity of the citric acid solution?
Nguyen Tien Thao, Faculty of Chemistry, Hanoi College of Science, VNU
19 -Le Thanh Tong, Hanoi, Vietnam. Email:


2.9 Copper metal reacts with concentrated nitric acid to produce nitric oxide and copper
nitrate. Calculate the mass of nitric oxide produced when 5.00 9 of copper is consumed. The

unbalanced reaction is:
Cu(s) + HNO3(aq) --- > Cu2+(aq) + NO3-(aq) + NO(g) + H2O
2.10 How many milliliters of a 0.10 Mpotassium dichromate solution are required to titrate
50. mL of an acidic 0.1 0 M iron(lI) chloride solution? The unbalanced chemical reaction is:
Fe2+ + H+ + Cr2O72- -Æ Cr3+ + Fe3+ + H2O
Chemistry, Seventh Edition, Steven S. Zumdahl
University of Illinois

Susan A. Zumdahl
University of Illinois

Chapter 4, Exercises:
45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 89, 81, 83, 85, 87, 89

Nguyen Tien Thao, Faculty of Chemistry, Hanoi College of Science, VNU
19 -Le Thanh Tong, Hanoi, Vietnam. Email: