Mole Concept (Assignment) - Shailendra Kumar Chemistry

PHYSICAL CHEMISTRY By: Shailendra Kumar
74) Sodium borohydride, NaBH , a substance used in the synthesis of many pharma ceutical
4
agents, can be prepared by reaction of NaH with B H according to the equation
2 6
2 NaH + B H 2 NaBH . How many grams of NaBH can be prepared by reaction
2 6 4 4
between 8.55 g of NaH and 6.75 g of B H ? Which reactant is limiting, and how many grams of
2 6
the excess reactant will be left over ?
Ans : 13.5 g NaBH produced, NaH is the limiting reactant, B H left over =1.82 g
4 2 6
75) What is the molarity of each ion in a solution perpared by dissolving 0.550 g of Na SO , 1.188 g
2 4
of Na PO , and 0.223 g of Li SO in water and diluting to a volume of 100.00 mL ?
3 4 2 4
Ans : Na + = 0.295 M, Li + –2 –3 = 0.0406 M, SO = 0.059 M, PO4 = 0.0725 M
4
76) When eaten, dietary carbohydrates are digested to yield glucose (C H O ), which is then
6 12 6
metabolized to yield carbon dioxide and water :
C H O + O 6 12 6 2 CO + H O 2 2
Heat
Unbalanced
Ans :
Balance the equation, and calculate both the mass in grams and the volume in liters of the CO2 produced from 66.3 g of glucose, assuming that 1 mole of CO has a volume of 25.4 L at
2
normal body temperature.
97.2 g CO , 56.1 L CO 2 2
77) Aluminum and elemental oxygen will react to form aluminum oxide, Al O . The chemical equation
2 3
is; 4Al(s) + 3O (g) 2Al O (s)
2 2 3
How many moles of oxygen are required to react with 1.86 mole of aluminum ?
Ans : 1.4 mole
78) Ethanol, C H OH, is a component of the fuel called gasohol. The unbalanced
2 5
chemical equation for the combustion of ethanol is
C H OH(g) + O (g) 2 5 2 CO (g) + H O(g)
2 2
Ans :
How many moles of oxygen will be required with 8.24 moles of ethanol ?
24.7 mole
79) Aluminum will react with iodine to form aluminum iodide. The chenical equation is
2Al(s) + 3I (s) 2 2AlI (s) 3
Ans :
How many moles of aluminum iodide can be obtained from 5.6 mole of iodine and the required
amount of aluminum ?
3.7 mole
80) Sodium hydroxide reacts with sulfuric acid to form sodium sulfate an water. The chemical
equation is; 2NaOH(aq) + H SO (aq) 2 4 Na SO (aq) + 2H O(l)
2 4 2
Ans : 1.5 mole
81) Nitric acid, HNO , is manufactured by a process that allows nitrogen dioxide to react with water.
3
The chemical equation is; 3NO (g) + H O(l) 2HNO (aq) + NO(g)
2 2 3
How many moles of nitrogen dioxide are required to produce 3.56 mole of nitric acid ?
Ans : 5.34 mole
82) Sodium hydrogen carbonate is the chemical name for baking soda. This substance can be
prepared by dissolving gaseous carbon dioxide in an aqueous solution of sodium carbonate.
The chemical equation is;
Na CO (aq) + CO (g) + H O(l) 2 3 2 2 2NaHCO (aq) 3
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