Question

The balanced combustion reaction for C6H6 is 2C6H6 + 15O2 = 12CO2 + 6H2O + 6542 kJ. If 8.20 g of C6H6 is burned and the heat produced is added to 569.1 g of water at 21°C, what is the final temperature of the water?

a) 55.6°C
b) 67.2°C
c) 39.1°C
d) 42.3°C
e) 50.8°C

Answer 1

To calculate the final temperature of water after burning benzene, use the heat transfer formula with the specific heat capacity of water and the heat released during combustion, based on the mass and molar mass of benzene.

Step-by-step explanation:

The question involves calculating the final temperature of water after combusting benzene (C6H6) and adding the heat produced to the water. To find the final temperature (Tfinal), we use the provided enthalpy change for the combustion of benzene and apply the specific heat capacity formula: q = mc∆T, where q is the heat transferred, m is the mass of the water, c is the specific heat capacity of water (4.184 J/g°C), and ∆T is the change in temperature.

To solve the problem, first we need to determine the amount of heat released by burning 8.20 g of C6H6. Since the enthalpy change for the combustion of 2 moles of C6H6 is 6542 kJ, we can find the heat released from 8.20 g by using its molar mass (78.11 g/mol) to convert grams to moles, then multiply by the given ∆H (enthalpy change) per mole.

The heat absorbed by the water (q = mc∆T) must equal the heat released from the combustion of benzene. Rearrange the formula to solve for the final temperature (Tfinal = Tinitial + q/mc), using the initial temperature of 21°C and m as 569.1 g. Through calculations, we can determine the correct option for the final temperature of the water.