2C6H6(l) + 15O2(g) -> 12CO2(g) + 6H2O(l) + 6542 kJ
If the heat from burning 7.000 g of C6H6 is added to 5691 g of water at 21 degrees C what is the final temperature of the water?
How much energy do you obtain from the combustion of benzene?
That is 6542 x (7 g/2*78g) = about 293 kJ or 293,000 J.
Then 293,000 = mass H2O x specific heat H2O x (Tfinal-Tinitial).
Solve for Tfinal. Those numbers above are approximate; you should go through it with your calculator to obtain a more accurate reading.
your approximations are very accurate.. thanks!
is the final and intial temperature in kelvin or celcius my calculations seem off
To find the final temperature of the water, you need to calculate the heat gained by the water and equate it to the heat released by the combustion of C6H6.
Here are the steps to solve the problem:
Step 1: Calculate the heat gained by the water.
The heat gained by the water can be determined using the formula:
Q = mcΔT
Where:
Q is the heat gained (in joules)
m is the mass of the water (in grams)
c is the specific heat capacity of water (4.184 J/g°C)
ΔT is the change in temperature (final temperature minus initial temperature)
Given:
m = 5691 g
c = 4.184 J/g°C
ΔT = final temperature - 21°C
Step 2: Calculate the heat released by the combustion of C6H6.
The equation you provided shows that burning 2 moles of C6H6 releases 6542 kJ of heat. From this information, we can calculate the heat released for the given mass of C6H6.
Calculate the number of moles of C6H6:
molar mass of C6H6 = 6(12.01 g/mole) + 6(1.01 g/mole) = 78.11 g/mole
moles of C6H6 = mass of C6H6 / molar mass of C6H6
moles of C6H6 = 7.000 g / 78.11 g/mole
Calculate the heat released:
heat released = moles of C6H6 x heat released per mole
heat released = (moles of C6H6 / 2) x 6542 kJ
Step 3: Equate the heat gained by the water to the heat released by the combustion of C6H6:
Q = heat gained by the water
Q = heat released by the combustion of C6H6
Therefore:
mcΔT = (moles of C6H6 / 2) x 6542 kJ
Step 4: Solve for the final temperature of the water (ΔT):
ΔT = [(moles of C6H6 / 2) x 6542 kJ] / (mc)
Since we know the values for moles of C6H6, m, and c, we can substitute them into the equation to find ΔT.
After finding ΔT, add it to the initial temperature (21°C) to get the final temperature of the water.