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1. (a) What is the average translational kinetic energy of an oxygen molecule at STP?
(b) What is the total translational kinetic energy of `2.0\ mol` of `O_2` molecules at `20°C`?
1. (a) What is the average translational kinetic energy of an oxygen molecule at STP?
(b) What is the total translational kinetic energy of 2.0\ mol of O_2 molecules at 20°C? `overline(KE) = 3/2kT`
a) `overline(KE) = 5.65 times 10^(-21)\ J`
b) `sumKE = 7.3 times 10^3\ J`
Given:
`STP` => `T = 273\ K`
Known:
`k = 1.38 times 10^(-23)\ J/K`
Equation:
`overline(KE) = 3/2kT`
(a)
`overline(KE) = 3/2kT`
`overline(KE) = 3/2(1.38 times 10^(-23)\ J/K)(273\ K)`
`overline(KE) = 5.65 times 10^(-21)\ J`
(b)
Given:
`T = 20°C = 293\ K`
`N = 2.0\ mol`
known:
`1\ mol = 6.02 times 10^(23) ` molecules
`sumKE = N overline(KE) = N(3/2kT)`
`sumKE = (2.0\ mol)(6.02 times 10^(23)\ //mol)(3/2(1.38 times 10^(-23))(293\ K))`
`sumKE = 7.3 times 10^3\ J` |