Question

If the heat of combustion of gasoline is 47 kJ/g, how many grams of gasoline are required to heat 2500.0 mL of water in a bomb calorimeter from an initial temperature of 21.9°C to a final temperature of 67.8°C?

a. 14.0 g
b. 10.2 g
c. 2.44 g
d. No right answer.

Answer 1

10,2 grams of gasoline are required to heat 2500.0 mL of water in a bomb calorimeter (option b.)

Step-by-step explanation:

1 g of gasoline has 47 kJ as heat of combustion, so let's calculate our heat with the data the excersie give us.

First of all we should know water density which is 1 g/ml, so we assume that 2500 mL are been occuped by 2500 g.

Q = m . C . ΔT

Q = 2500 g . 4,186 J / g ºC (Tfinal - Tinitial)

Q= 2500 g . 4,186 J / g ºC ( 67,8ºC - 21,9 ºC)

Q = 480343,5 J

Now, we convert the J to kJ to make the rule of three

480343,5 J / 1000 = 480,3 kJ

By the end:

47 kJ _______ 1 g

480,3 kJ ______ (480,3 kJ . 1g) / 47 kJ = 10,2 g