What is the mass of wood required to raise the temperature of 1000 kg of water from 25.0 to 100.0 °C (in kg with at least 3 sig figs.) ? The specific heat of water is 4.184 J/g°C, and the lower heating value of dry wood is 16.72 MJ/kg.

Question

Chemistry

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2 January, 10:57

What is the mass of wood required to raise the temperature of 1000 kg of water from 25.0 to 100.0 °C (in kg with at least 3 sig figs.) ? The specific heat of water is 4.184 J/g°C, and the lower heating value of dry wood is 16.72 MJ/kg.

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Answers (1)

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Jaylee Ware · Answer 1

1.877 x 10⁷ kg

Explanation:

To solve this problem we first use the equation:

Q = m * c * ΔT

Where Q is the heat needed to increase the temperature of a substance, m is the mass, c is the specific heat and ΔT is the difference in temperature.

For this problem:

m = 1000 kg = 1000000 g J = 4.184 J/g°C ΔT = 100°C - 25°C = 75°C

We put the data in the equation and solve for Q:

Q = 1000000 g * 4.184 J/g°C * 75°C Q = 313.80 MJ

So that's the energy required to heat 1000 kg of water, now we calculate the mass of wood using the equation:

Q = m * b

Where b is the heating value of wood and m its mass:

313.80 MJ = m * 16.72 MJ/kg m = 1.877 x 10⁷ kg wood