EXO ENDO FUEL

Question 1

fuel

Answer 1

a substance that gives large amount of usable energy upon combustion

Question 2

characteristics of an efficient fuel

Answer 2

• high calorific value
• moderate ignition temperature
• no harmful byproducts
• easy to store, transport, and handle
• low handling cost

Question 3

fire triangle? (elements needed for a fire to start and burn)

Answer 3

1. fuel = the actual combustible material
2. enough heat to reach the ignition temperature of the fuel
   - can be in the form of a spark, arc, hot surface, or friction.
3. oxygen to sustain combustion (around 16%)

Question 4

give example of fuel

Answer 4

can be (l), (s), (g)
ex.
diesel, kerosene, ethanol, methanol
wood, wax, coal, paper
butane, propane

Question 5

fuel A is burnt for 20 minutes and temp rose from 500C to 1000C

fuel B is burnt for 20 minutes and temp rose from 400C to 600C

which is fuel is&raquo_space;

Answer 5

fuel A&raquo_space;

• this is what calorific value basically is

Question 6

bond breaking

Answer 6

• endothermic
• ∆H = +ve

Question 7

bond formation

Answer 7

• exothermic
• ∆H = -ve

Question 8

what is exothermic reaction

Answer 8

energy released
* products have lower energy than reactants

Question 9

endothermic reaction

Answer 9

energy absorbed
* products have higher energy than reactants

Question 10

exampes of exothermic reactions

Answer 10

• combustion
• respiration

Question 11

examples of endothermic reactions

Answer 11

• photosynthesis
• decomposition
• electorlysis

Question 12

∆H calculation in enthalpy diagram (graph)

Answer 12

products-reactants

Question 13

∆H calculation using bond energies

Answer 13

reactants-products