Worksheet-5
SI leader: Edward
09/23/13
1. Hydrazine, N2H4, a base like ammonia, can react with acid such as sulfuric acid
N2H4 (aq)+H2SO4 (aq)  N2H5+(aq)+SO4-2 (aq)
What mass of hydrazine can react with 250.mL 0.225 M H2SO4?
2. You are designing a process for a wastewater treatment facility inteneded to remove
aqueous HCl from the input water. Several bases are being considered for use, and their costs are
listed in the table below. If cost is the primary concern which base would you recommend using?
Use stoichiometric arguments to justiy your answer.
Cost:
CaCO3----$2.70×10-4/g
Ca(OH)2----$1.65×10-4/g
NH3----$2.55×10-4/g
NaOH----$3.15×10-4/g
3.Blood alcohol levels are usually reported in mass percent: a level of 0.1 means that 0.1
g of alcohol (C2H5OH) was present in 100g of blood. This is just one way of expressing the
concentration of alcohol dissolved in the blood. Other concentration unites could be used. Find
the molarity of alcohol in the blood of a person with a blood alcohol level of 0.12(the density of
blood is 1.2g/ml)
4. Calcium sulfate is the essential component of plasters and sheet rock. Waste calcium
sulfate can be converted into quicklime, CaO, by reaction with carbon at high temperatures. The
following two reactions represent a sequence of reactions that might take place:
CaSO4(s)+4C(s) CaS(l)+4CO(g)
CaS (s)+3CaSO4(s)4CaO(s)+4SO2(g)
What mass of sulfur dioxide (in grams) could be obtained from 1.250 kg of calcium sulfate?
5. If 24.6 g of H2S is mixed with 44.5 g of O2 and 26.8 g of SO2 forms, what is
percentage yield of the reaction? 2H2S + 3O2 2SO2 + 2H2O
(Molar masses are: H2S=34.08 g/mol; O2=32.00 g/mol; SO2=64.07 g/mol)
6. Aluminum hydroxide can be dissolved in hydrochloric acid a form aluminum chloride
and water. Write a balanced chemical equation for this reaction. How many mL of 2.37 M HCl is
needed to react with 10.0g of Al (OH) 3?