High School

Calculate the amount of heat needed to melt 36.6 g of solid hexane (C6H14) and bring it to a temperature of 30.2°C. Round your answer to 3 significant digits.

Answer :

Final answer:

The amount of heat needed to melt 36.6g of solid hexane (C6H14) and bring it to a temperature of 30.2°C is approximately 6.84 kJ.

Explanation:

To calculate the amount of heat needed to melt 36.6g of solid hexane (C6H14) and bring it to a temperature of 30.2°C, we need to consider two steps: melting the hexane and raising its temperature.

First, let's calculate the heat required to melt the hexane. We can use the formula q = m * ΔHf, where q is the heat, m is the mass of the substance, and ΔHf is the heat of fusion.

The molar mass of hexane (C6H14) is 86.18 g/mol. To convert the mass of hexane to moles, we divide the given mass by the molar mass:

moles = mass / molar mass = 36.6g / 86.18 g/mol = 0.424 mol

Now, we can calculate the heat required to melt the hexane:

q = moles * ΔHf = 0.424 mol * 9.96 kJ/mol = 4.23 kJ

Next, let's calculate the heat required to raise the temperature of the melted hexane to 30.2°C. We can use the formula q = m * c * ΔT, where q is the heat, m is the mass of the substance, c is the specific heat capacity, and ΔT is the change in temperature.

The specific heat capacity of hexane is 2.22 J/g°C. To convert the mass of hexane to grams, we multiply the given mass by 1000:

mass = 36.6g

Now, we can calculate the heat required to raise the temperature:

q = mass * c * ΔT = 36.6g * 2.22 J/g°C * (30.2°C - 0°C) = 2,607 J

Finally, we can calculate the total heat required by adding the heat required to melt the hexane and the heat required to raise its temperature:

total heat = heat to melt + heat to raise temperature = 4.23 kJ + 2,607 J = 4.23 kJ + 2.61 kJ = 6.84 kJ

Learn more about calculating heat required to melt a substance and raise its temperature here:

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