Ahypothetical substance has a melting point of −10°c and a boiling point of 155°c. if this substance is heated from 2°c to the gas at 155°c, which of the following would be used in the calculation: 1. specific heat capacity of the solid2. heat of fusion3. specific heat capacity of the liquid4. heat of vaporization5. specific heat capacity of the gas

The specific heat capacity of liquid and the het of vaporization is used.

.

Explanation:

Step 1: Data given

A substance at temperature 2°C.

The substance has a melting point of −10°C and a boiling point of 155°C.

The initial temperature is 2°C which is between the melting point (-10°C) and the boiling point (155°C). At 2°C, the substance is liquid.

At 155°C, the substance changes from liquid to gas.

To calculate the heat gained for the change of 2°C liquid to 155°C liquid, specific heat capacity of the liquid (C) is needed.

To calculate the heat gained for the change of liquid to 155°C gas, heat of vaporization (D) is needed.

The specific heat of the solid is not used because the substance is changed from liquid to gas. it doesn't come in the state of solid.

Heat of fusion is not used, because it's used when there is a change from its state from a solid to a liquid,

The specific heat capacity of the gas is not used, because the substance only formes gas after reaching 155 °C

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"