Question

PCl3 is a compound used to manufacture pesticides. A reaction requires that 95 g of PCl3 be raised from 30°C to 70°C. How much energy will this require given that the specific heat of PCl3 is 0.874 J/g°C.

Answer 1

In this question, we have a situation in which we have to use the Calorimetry formula, which is how much heat was released or absorbed (in Joules), after we had a change in temperature of a compound. The formula for this Calorimetry question is:

Q = mcΔT

Where:

Q = is energy as Heat

m = mass in grams, 95g

c = is the specific heat capacity, 0.874 J/g°C

ΔT = the change in temperature, calculated as Final Temperature - Initial T

70 - 30 = 40°C

Now we add these values into the formula:

Q = 95 * 0.874 * 40

Q = 3,321 Joules or 3.3 kJ is the energy required