How much paraffin oil would be needed to heat the same volume of water?
• Heat capacity of water = 4200 j kg-1 K-1
• Mass of 1 litre of water = 1kg
• Heat value of paraffin = 45M J kg-1
• Density of paraffin = 800kg m -3
• 1 cubic centimetre (1cm3 = 10-6 m3)
• Water Temperature of 20oC
To heat 1 litre of water from 200C to boiling point 1000C
= 80x4200 J = 336KJ
• Energy released from burning 1cm3 of paraffin
=45x800 x 10-6 MJ =36KJ
• Volume of wood needed
=336/36 = 9.33cm3
Just need this checked
To heat 1 liter (1 kg) of water from 20°C to its boiling point at 100°C, you need to calculate the amount of energy required.
The heat capacity of water, given as 4200 J kg^-1 K^-1, means that it takes 4200 J of energy to raise the temperature of 1 kg of water by 1 K (or 1°C).
The temperature change you need is 100°C - 20°C = 80°C.
So, to heat the water, you would need:
Energy = mass × heat capacity × temperature change
= 1 kg × 4200 J kg^-1 K^-1 × 80 K
= 336,000 J (or 336 kJ)
Now, let's calculate the energy released from burning 1 cm^3 of paraffin oil.
Given that the heat value of paraffin is 45 MJ kg^-1, and the density is 800 kg m^-3, we can calculate the energy released from burning 1 cm^3 of paraffin oil.
First, convert the heat value of paraffin from MJ to J by multiplying by 10^6:
Heat value of paraffin = 45 MJ kg^-1 = 45 × 10^6 J kg^-1
Now, let's calculate the energy released from burning 1 cm^3 of paraffin oil:
Energy released = heat value of paraffin × density of paraffin × volume
= 45 × 10^6 J kg^-1 × 800 kg m^-3 × 10^-6 m^3
= 36,000 J (or 36 kJ)
To find out how much paraffin oil is needed, divide the energy required to heat the water (336 kJ) by the energy released from burning 1 cm^3 of paraffin oil (36 kJ):
Volume of paraffin oil needed = energy required / energy released
= 336 kJ / 36 kJ
≈ 9.33 cm^3
Therefore, approximately 9.33 cm^3 of paraffin oil would be needed to heat the same volume of water.
To calculate the amount of paraffin oil needed to heat the same volume of water, we need to consider the heat capacity of water, the mass of water, the heat value of paraffin oil, and the density of paraffin oil.
Given:
- Heat capacity of water = 4200 J/(kg * K)
- Mass of 1 liter of water = 1 kg
- Heat value of paraffin oil = 45 MJ/kg
- Density of paraffin oil = 800 kg/m³
To heat 1 liter (1 kg) of water from 20°C to boiling point (100°C), we first need to calculate the amount of energy required.
Energy required (Q) = Mass * Specific Heat Capacity * Temperature change
Q = 1 kg * 4200 J/(kg * K) * (100 - 20) K
Q = 1 kg * 4200 J/K * 80 K
Q = 336,000 J
Now, let's calculate the energy released from burning 1 cm³ of paraffin oil.
Energy released = Heat value of paraffin oil * Density of paraffin oil * Volume
Volume = (Mass of 1 cm³ * Density of paraffin oil) = (10⁻⁶ m³ * 800 kg/m³) = 0.0008 kg
Energy released = 45 MJ/kg * 0.0008 kg
Energy released = 36,000 J
To find the volume of paraffin oil needed, we divide the energy required to heat the water by the energy released from burning 1 cm³ of paraffin oil.
Volume of paraffin oil needed = Energy required / Energy released
Volume of paraffin oil needed = 336,000 J / 36,000 J
Volume of paraffin oil needed = 9.33 cm³
So, to heat the same volume of water, approximately 9.33 cm³ of paraffin oil would be needed.