Chemistry Answers

The hypothetical heats of hydrogenation for 1,3,5-cyclohexatriene is different from the heats of hydrogenation of benzene. Explain this in detail.

If 100mL of water contains 5 grams of NaCl molecular mass = 58.8g/mol what is the molarity of the solution in moles/L?

For the following reaction, 5.59 grams of oxygen gas are mixed with excess carbon (graphite). The reaction yields 7.10 grams of carbon dioxide.

carbon (graphite) ( s ) + oxygen ( g )  carbon dioxide ( g )

What is the theoretical yield of carbon dioxide? ____ grams

What is the percent yield for this reaction? ____ %

 In a biochemical assay, a chemist needs to add 2.93 g of glucose to a reaction mixture. Calculate the volume in mL of a 1.35M glucose solution she should use for the addition.

Iron produces from fe2o3 by reaction with carbon. The reaction products are

Fe, FeO and CO. If we mix 100 Kg of Fe2o3 and 24 Kg of C and produced 12 Kg of FeO, determine:

a) Limiting reaction and excess reaction.

b) % Excess reaction.

c) % Conversion of Fe2o3 and C.

d) The degree of completion of reaction.

e) Mass of Fe in Kg.

Fe2o3+ 2C / Fe+FeO+2CO

Mw;

Fe = 56

C=12.

O = 16

3. A 11.896-gram sample of metal shavings was lowered into a graduated cylinder containing 6.40mL of water; the water level rises to 7.53 mL. Calculate the density of the metal pieces.

2. A student experimentally measured the density of gold as 19.74g/cm3. A handbook reports a value of 19.02 g/cm3. Calculate the percent error in the student’s measurement.

1. Which has a greater volume, 10 grams of water or 10 grams of acetone? [density of acetone is 0.79g/mL]

How many liters of a stock solution of 2.50M KNO3 are needed to prepare 10 L of 0.78M KNO3?

Draw the Pressure v/s Volume graph for all the 4 steps of Carnot Cycle and state

which steps are isenthalpic (Involve no change entropy). Can a Carnot engine be 100

% efficient?