Chemistry exam qs that I didn't get full marks

Question 1

Explain why the use of a catalyst reduces energy demand and benefits the environment

Answer 1

• the reaction uses less thermal energy as the catalyst allows the reaction to be finished at lower temperatures so co2 emissions are reduced due to less fossil fuels being used

Question 2

The rate of reaction between Zinc and HCL can be increased by using a solution of copper (II) sulfate as a catalyst

ii) why is it difficult to classify the solution of copper (ii) sulfate as homogeneous or heterogeneous

Answer 2

As copper sulfate can be the same state of one of the reactants e.g. zinc and a different state for another HCL

Question 3

State an example of a catalyst used by the chemical industry and write the equation for the reaction that is catalysed.

catalyst:
Reaction:

Answer 3

there is a number of different ones but im going to use Fe in the harbour process
Catalyst: Fe
Reaction: N2 + 3H2 —-> 2NH3
<——

Question 4

Explain how increasing temperature increases the rate of reaction, include a labelled sketch of the boltzmann distribution curve (4)

Answer 4

(1) labelled axis
(1) 2 curves correctly drawn
(1) labelled which one is temp
(1) increasing temperature means more molecules above activation energy so rOR is increased

Question 6

How many P orbitals are occupied by electrons in a sulfur atom
A) 2
B)4
c)6
D)10

Answer 6

c

Question 7

Magnesium nitrate decomposes when heated :
Mg(no3)2 -> Mg0 + 2NO2+0.5o2
0.00250 mol of magnesium nitrate is decomposed what’s the volume of gas produced at RTP
a0 30cm
B) 60cm
c) 120
d) 150

Answer 7

d

Question 8

Zinc reacts with aqueous silver nitrate as shown in the equation
Zn + 2AgNO3 -> 2AG + Zn(no3)2
0.10g zinc is added to 15cm3 of o.250 mol dm agNo3
what is mass of silver nitrate
0.16
0.20
0.33
0.40

Answer 8

0.33g

Question 9

A sample of gas has a volume of 0.60m3 under a pressure of 200Kpa and at 300k , how many moles of molecules are there?

a) 0.021
b) ).048
21
D) 48

Answer 9

D PV=NRT

Question 10

what would be the reason that an equation would be at homogenous equilibrium

Answer 10

as the catalyst was the same state as reactants and the products