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a) Explain how a catalyst affects the activation energy during chemical reaction. (b)In an experiment to determine the heat of combustion of methanol. CH3OH, a student...

A) Explain how a catalyst affects the activation energy during chemical reaction.

B)In an experiment to determine the heat of combustion of methanol. CH3OH, a student was recorded the following requirement the following data
Volume of water =100cm3
Final temperature of water = 22.00c
Initial temperature of water = 36.00c
Final mass of lamp an methanol = 84.75g
Initial mass of lamp and methanol=85.10g
Density of water = 1 g/cm³
(S.H.C of water = 4.23 g-1K-1)

i)Write an equation for the combustion of methanol
(ii) Calculate:
(a) Number of moles of methanol used in this experiment
(b) The heat change for this experiment
(c) The heat of combustion per mole of methanol
(d) Explain why the molar heat of combustion for methanol obtained above is different from the theoretical value.
(e) State two factors to consider when choosing a fuel.
(f) Outline two disadvantages of using hydrogen as a source of fuel.

Answers

A.It lowers the activation energy

B.i)2CH₃OH(l) + 3 O₂ (g) ---------------------> 2CO₂(g) + 4H₂O(g)

ii)a.Mass of methanol = ( 85.10- 84.78) = 0.32 g
Moles = (0.32)/(32 )=0.01 moles

b) 100×4.2 ×14 = 5880 J OR 5.88 k J

c)
0.01= 5.88
1= ?
(1×5.88)/(0.01)=-588 Kj/mol

d)-Heat might be lost to the surrounding
-Heat absorption by the apparatus.

e)-Cost
-Heating value
-Availability
-Ease of transport and storage
-Environmental effect

f)-Not readily available
-Its explodes when ignited in air.

---

Githiari answered the question on September 14, 2017 at 19:42

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