Question

1. The goose has a mass of 22.2 lb (pounds) and is flying at 9.80 miles/h (miles per hour). What is the kinetic energy of the goose in joules?

2. A piston has an external pressure of 8.00 atm. How much work has been done in joules if the cylinder goes from a volume of 0.120 liters to 0.520 liters?

3. The combustion of toluene has a ΔErxn of –3.91×103 kJ/mol. When 1.55 g of toluene (C7H8) undergoes combustion in a bomb calorimeter, the temperature rises from 23.12∘C to 37.57∘C. Find the heat capacity of the bomb calorimeter.

Answer 1

1)

m = 22.2 lb or 10.08 kg

V = 9.8 mi/h --> 4.38 m/s

Find Ek

Ek = 1/2*m*v^2 = 1/2*10.08*4.38^2 = 38.4 J

2)

P = 8 atm = 8*101325 Pa =810600 Pa

W = ?

dV = Vf-Vi = 0.52-0.12 = 0.4 liter or 0.4*10^-3 m3

W = P*dV = 810600*(0.4*10^-3) =324.24 J

3

Erxn = –3.91×103 kJ/mol

m = 1.55 g

MW toluene= 92 g/mol

n = 1.55/92 = 0.0168 mol

dT = 37.57 - 23.12 = 14.15 °C

a) Find heat capacity of calorimeter (J/C)

Q/dT

Q = HRXN * n =  (–3.91×10^3)*0.0168 = -65.688 kJ

Cap = Q/dT =  +65.688 kJ /  14.15 °C= 4.64 kJ/C

Cap =  4.64 kJ/C