Organic Chemistry Answers

Compute for the standard change in enthalpy of the following reactions:

(A) PbO_(s)+C_(s) -> CO_(g)+Pb_(s)

(B) Ca(OH)_2(s)+CO_2(g) -> CaCO_3(g)+H₂O_(g)

(C) 2H₂SO_4(l) -> 2H₂O_(g)+O_2(g)+2SO_2(s)

Given the following reactions, calculate the heat of formation of hydrazine in megajoules.

(A) H_2(g)+1/2 O_2(g) -> H₂O_(g) ΔH= -241.8 kJ

(B) N₂N_4(l)+O_2(g) -> N_2(g)+2H₂O_(g) ΔH= -534.2 kJ

Given the following thermochemical equations, calculate the change in enthalpy for the

formation of one mole of dinitrogen pentoxide from its elements in their stable state at

25°C and 1 atm.

(A) 2H_2(g)+O_2(g) -> 2H₂O_(l) ΔH= -571.6 kJ

(B) N₂O_5(g)+H₂O_2(l) -> 2HNO_3(l) ΔH= -73.7 kJ

(C) 1/2N_2(g)+3/2O_2(g)+1/2H_2(g) -> HNO_3(l) ΔH= -174.1 kJ

Calcium carbide, CaC₂, is the raw material used for the production of acetylene

, C₂H₂ ,(used in welding torches). Calcium carbide is produced by reacting calcium oxide with carbon, producing carbon monoxide, CO as a byproduct. When one mole of calcium

carbide is formed, 464.8 kJ of heat is absorbed,

CaO_(s)+ 3C_(s) -> CaC_2(s)+ CO_(g) H = 464.8 kJ

a. What is the change in enthalpy when 1.00 g of calcium carbide is formed?

b. If the enthalpy change for the reaction is 246.7 kJ, what mass of calcium carbide is

produced?

c. What is the enthalpy change if 46.7 g of carbon reacts with excess calcium oxide?

d. How many grams of carbon are used up when 20.00 kJ of heat are absorbed?

e. How many gigajoules of energy is required to consume 1.38x10⁵g calcium oxide?

When 2.35g of Magnesium (OH)2 is added to 250.0mL of water the temperature of water raises from 20.5°C to 36.0°C. What’s the molar enthalpy of the solution?

  A 5g carboxylic acid was neutralized by 30.10 mL of 0.1M NaOH, What is the percentage of carboxylic group (-COOH) in the given organic compound.                                    

How to write in complete structure

1.     You will be given an unknown compound for which you will need to find out the chemical structure of compound. This unknown gives positive tests for both N and S elements in their Lassaigne’s test and soluble in sodium bicarbonate solution with effervescence, it will also contain amine functional groups but may also contain other functional groups as well. The compound gives following chemical tests of the qualitative analysis.                              (02)

Table-1: Results for Functional Group Test

Functional Group Test

(+ve)/(-ve)

Functional Group Test

(+ve)/(-ve)

Bromine test

(+ve)

Fehling’s test

(-ve)

Baeyer’s test

(+ve)

Lucas Test

(-ve)

Bicarbonate test

(+ve)

Biuret test

(-ve)

Esterification test

(+ve)

Nitrous acid test 

(+ve) (an azo dye is formed)

Tollen’s test

(-ve)

Carbylamine test

(+ve)

1.     A 5g carboxylic acid was neutralized by 30.10 mL of 0.1M NaOH, What is the percentage of carboxylic group (-COOH) in the given organic compound.                                    (01)

Synthesize ethyl ethanoate from 70g of the ethanoic acid. Calculate theoretical yield and percentage yield of the ethyl ethanoate if actual yield is 30g.

1.Background

2.Reagents/ Apparatus

3.Procedure

4.Applications

5.Precautions

A.Reaction and Mechanism

B.Calculations

C.Observations

D.Conclusion