The Chemical Industry

Question 1

Give the systematic names of the following compounds:
a) NO2
b) Cu(NO2)2
c) HNO3
d) NO2-
e) NO
f) N2O

Answer 1

a) Nitrogen (IV) oxide
b) Copper (II) nitrate (III)
c) Nitric (V) acid
d) Nitrate (III) ion
e) Nitrogen (II) oxide
f) Nitrogen (I) oxide

Question 2

What Nitrogen Oxide gas is coloured and what colour is it?

Answer 2

NO2 (Nitrogen Dioxide), Brown

Question 3

Describe the 4 step method of ascertaining the reaction between two nitrogen compounds

Answer 3

• Write the formula of the two species and balance any elements other than O and H
• Include enough H2O to balance the oxygens
• Include enough H+ ions to balance the hydrogens
• Include enough e- (electrons) to balance the charge

Question 4

Describe the test for the presence of ammonium ions

Answer 4

•Add NaOH solution and heat gently
• If ammonium ions are present, ammonia gas will be evolved, which can be tested for with a strip of damp red litmus paper (red -> blue)

Question 5

Describe the test for nitrate (V) ions

Answer 5

• Add NaOH solution and Dervarda’s alloy/aluminum foil and heat gently
• If NO3- ions are present, they will react to form ammonia gas, which can be tested for with a damp strip of red litmus paper (red -> blue)

Question 6

What are the units for Kc of the following reaction?
N2 + 3H2 ⇌ 2NH3

Answer 6

mol-²dm⁶

Question 7

For the following reaction (forward = exothermic), determine the pros and cons of:
• Decreasing temperature
• Increasing pressure
• Adding a catalyst

2SO2(g) + O2(g) ⇌ 2SO3(g)

Answer 7

Temperature: Higher yield as equation shifts to the right (products) to minimise the change in conditions AND cheaper to keep lower heat, but rate is reduced as less frequent collisions, of which more occur under the activation energy

Pressure: Higher yield as equation shifted to the right (products) as it has less gaseous moles (tmtcic) AND increased rate as more collisions because particles are closer together, but more expensive and dangerous for workers

Catalyst: Speeds up the rate of both reactions equally

Question 8

Give the expression for the rate constant for a reaction, with a zero order, first order, and second order reactants in that order

Answer 8

Kc = [m][n]^2
(Letters are interchangable)

Question 9

Give the rate against concentration graph for a reactant which is:
• Zero order
• First order
• Second order

Answer 9

• Horizontal line across the graph
• Directly proportional line (y=x)
• Exponentially proportional line (y=x^2)

Question 10

Give the concentration against time graphs of a reactant that is:
• Zero order
• First order
• Second order;
and state the unique feature all first order graphs share

Answer 10

• Straight line coming down from the y axis to the x axis
• Curves down from the y to x axis AND has a constant half life
• Curves down even quicker/steeper from the x to y axis

Question 11

When plotting a graph for the arrhenius equation, what variables go on the y and x axis? Give units where appropriate

Answer 11

Y axis: ln(k)
X axis: 1/T /Kelvin

Question 12

Describe the formula that links Ea to the arrhenius equation

Answer 12

Ea = -(Gradient×R (Gas constant 8.314))

Question 13

Describe how the rate constant, K, varies with temperature

Answer 13

K increases as temperature increases

Question 14

State the difference between Co-product and By-product

Answer 14

Co-product is useful/can be sold/used in industry whereas By-product is not useful/waste

Question 15

Give the formula of ammonium sulfate (VI)

Answer 15

(NH4)2SO4