The combustion of 0.1572 g benzoic acid increases the temperature of a bomb calorimeter by 2.52°C. Calculate the heat capacity of this calorimeter. (The energy released by combustion of benzoic acid is 26.42 kJ/g.)
What is the heat capacity in kJ/C? = 1.65 kJ/C
A 0.2197-g sample of vanillin (C8H8O3) is then burned in the same calorimeter, and the temperature increases by 3.28°C. What is the energy of combustion per gram of vanillin?
Energy in kJ/gram?
I know how to find the heat capacity, but I keep getting the energy incorrect.
are you certain about the mass of benzoic acid? .1572g is a very small amount.
heatenergy= grams*1.65kJ/g=.1572*26.42 kJ/g= = 4.153 kJ or 4153J
second one: energy=Heatcapacity*changetemp
energy= 1.65kJ/c*3.28C=5.41kJ or 5410J
energycomputstion= 5.41kJ/.2195g = ..
What would be the correct number of sig figs?
three sig figs, or course
To find the energy of combustion per gram of vanillin, you need to use the heat capacity of the calorimeter and the temperature change caused by the combustion.
First, calculate the heat released by the combustion of vanillin using the formula:
Heat released = mass of vanillin * temperature change * heat capacity of calorimeter
Given:
Mass of vanillin = 0.2197 g
Temperature change = 3.28°C
Heat capacity of calorimeter = 1.65 kJ/°C (from the previous question)
Substituting these values into the formula:
Heat released = 0.2197 g * 3.28°C * 1.65 kJ/°C
Calculate the value of heat released:
Heat released = 1.1582636 kJ
To find the energy of combustion per gram of vanillin, divide the heat released by the mass of vanillin:
Energy of combustion per gram of vanillin = Heat released / Mass of vanillin
Energy of combustion per gram of vanillin = 1.1582636 kJ / 0.2197 g
Calculate the value of energy of combustion per gram of vanillin:
Energy of combustion per gram of vanillin = 5.273 kJ/g
Therefore, the energy of combustion per gram of vanillin is approximately 5.273 kJ/g.