When 7.5 g of ethane was completely burned, all the heat produced was used to heat 1.50
kg of water. If the temperature of water rose from 20EC to 80EC, the heat of
combustion of ethane is
To find the heat of combustion of ethane, we can use the principle of heat transfer:
Heat transferred = mass of substance × specific heat capacity × change in temperature
In this case, the substance is water.
Given:
Mass of water = 1.50 kg
Change in temperature = (80 °C - 20 °C) = 60 °C
Specific heat capacity of water = 4.18 J/g°C (or 4.18 J/gK)
First, we must convert the mass of water from kg to grams:
Mass of water = 1.50 kg × 1000 g/kg = 1500 g
Next, we can calculate the total heat transferred by the water:
Heat transferred = mass of water × specific heat capacity × change in temperature
Heat transferred = 1500 g × 4.18 J/g°C × 60 °C = 377,400 J
Now, we need to determine the heat of combustion of ethane. The heat transferred by the water is equal to the heat produced by the combustion of ethane:
Heat transferred = Heat of combustion of ethane
Therefore, the heat of combustion of ethane is 377,400 J.
It's important to note that the units of mass and specific heat capacity must be consistent throughout the calculation. In this example, the mass of water is given in kilograms, but it's converted to grams for the calculation. The specific heat capacity of water is given in J/g°C.