Answer:
HEAT OF COMBUSTION PER GRAM OF OCTANE IS 1723.08 J OR 1.72 KJ/G OF HEAT
HEAT OFF COMBUSTION PER MOLE OF OCTANE IS 196.4 KJ/ MOL OF HEAT
Step-by-step explanation:
Mass of water = 100 g
Change in temperature = 28.78 °C - 21.36°C = 7.42 °C
Heat capcacity of water = 4.18 J/g°C
Mass of octane = 1.8 g
Molar mass of octane = C8H18 = (12 * 8 + 1 * 18) g/mol= 96 + 18 = 114 g/mol
First is to calculate the heat evolved when 100 g of water is used:
Heat = mass * specific heat capacity * change in temperature
Heat = 100 * 4.18 * 7.42
Heat = 3101.56 J
In other words, 3101.56 J of heat was evolved from the reaction of 1.8 g octane with water.
Heat of combustion of octane per gram:
1.8 g of octane produces 3101.56 J of heat
1 g of octane will produce ( 3101.56 * 1 / 1.8)
= 1723.08 J of heat
So, heat of combustion of octane per gram is 1723.08 J
Heat of combustion per mole:
1.8 g of octane produces 3101.56 J of heat
1 mole of octane will produce X J of heat
1 mole of octane = 114 g/ mol of octane
So we have:
1.8 g of octane = 3101.56 J
114 g of octane = (3101.56 * 114 / 1.8) J of heat
= 196 432.13 J
= 196. 4 kJ of heat
The heat of combustion of octane per mole is 196.4 kJ /mol.
Mass of water = 100 g
Change in temperature = 28.78 °C - 21.36°C = 7.42 °C
Heat capcacity of water = 4.18 J/g°C
Mass of octane = 1.8 g
Molar mass of octane = C8H18 = (12 * 8 + 1 * 18) g/mol= 96 + 18 = 114 g/mol
First is to calculate the heat evolved when 100 g of water is used:
Heat = mass * specific heat capacity * change in temperature
Heat = 100 * 4.18 * 7.42
Heat = 3101.56 J