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1 The compound 2-methyl-2-pentene Select one: a. has no structural or geometric

ID: 835402 • Letter: 1

Question

1 The compound 2-methyl-2-pentene Select one:

a. has no structural or geometric isomers

b. has 2 structural alkene isomers, each of which has an E isomer and a Z isomer form.

c. has 5 structural isomers

d. has 3 structural isomers

e. exists as E and Z isomers

2 A mixture consisting of 0.150 M N2(g) and 0.515 M H2(g) reacts and then reaches equilibrium according to the equation:
N2(g) + 3H2(g) ? 2NH3(g)
At equilibrium, the concentration of ammonia is 0.147 M. Calculate the concentration (molarity) of H2(g) at equilibrium to 3 decimal places. Do NOT enter any units.

3   

The system H2(g) + X2(g) ? 2HX(g) has a value of 24.4 for the equilibrium constant Kc.


A system being tried in a 3.00 L reactor was charged with 0.150 mol H2, 0.150 mol X2 and 0.600 mol HX.

The catalyst was introduced using a remote unit and the system was allowed to come to equilibrium. Which statement below describes the system coming to equilibrium?

(Note: in the answers, Q refers to the reaction quotient, K refers to the equilibrium constant).

Select one:

a. The reaction goes to the right, as Q < K

b. The reaction goes to the left, as Q < K

c. The reaction goes to the right, as Q > K

d. The reaction goes to the left, as Q > K

e. It is not possible to predict in which direction the system will travel to arrive at equilibrium.

4

Consider the following reaction (assume an ideal gas mixture):
2NOBr(g) ? 2 NO(g) + Br2(g)
A 1.0 L vessel was initially filled with pure NOBr, at a pressure of 4.0 bar, at 300 K. After equilibrium was established the partial pressure of NOBr was 2.5 bar.

p

Explanation / Answer

1. d

Has three structural isomers if you write the structure in newman projection by taking the ethyl groups as a point of view.

2. 0.294

you have to write first the initial (I), change(c), equillibrium(e) table:

            N2       3H2      2NH3

I           0.150   0.515    0

c            -x        -3x        2x

e         0.150-x 0.515-3x 2x=0.147

x= 0.0735

[H2]= 0.515-(3*0.0735)=0.294

3. a

first you need to find the molarity for each species

[H2]= 0.150/3 =0.05

[X2]= 0.150/3= 0.05

[HX]=0.60/3= 0.2

Then find rection quotient Q

Q=[HX]^2/[H2][X2]

Q=(0.2)^2/(0.5*0.5)

Q= 16

since, Q<K reaction will shift to right

4. e

Like in question 2 you have to draw ICE table

    2NOBr   2NO Br2

I   4            0      0

c -x           2x   x

e 4-x        2x   x

The quillibrium conc is found in the following way

4-x=2.5 ===> x=1.5

Kp=(2x)^2*x/(4-x)

=2.16

5. b

Weight of solute /100 g of solvent =wt%

6. e

first you need to find mol fraction of CaCl2

no of mol of water = 100ml =100g/18=5.556

mol fraction of CaCl2= 0.040/(5.556+0.040)=0.007

then use Raoult's law of relative lowering of vapour pressure

(pi-p)/pi=x2

(2.320-p)/2.320=0.007

p= 2.31

7.a

First you need to find molality of ethylene glycol

m= 20*1000/(62.07*85)= 3.791

Then

delTf= Kf Cm

=1.86*3.791

=7.05

Tf= 0-7.05

=-7.06