An oxygen tank kept at 20^{$\omicron $}C contains 28.0 moles of oxygen and the gauge reads 31.0 atm .After two weeks,The gauge reads 10.5 atm .How many moles of oxygen were used during the two-week period?

Question

Quizplus · Accepted Answer

We can use the ideal gas law to solve for the number of moles of oxygen used during the two-week period:

PV = nRT

where P is the pressure (in atm), V is the volume (in L), n is the number of moles, R is the gas constant (0.082 L·atm/mol·K), and T is the temperature (in K).

We know that the initial pressure was 31.0 atm and the initial volume was not given. However, we can assume that the volume stayed constant, so we don't need to worry about it. We also know that the temperature was -6.67°C, which is 266.48 K.

We can solve for the initial number of moles of oxygen:

n = PV/RT = (31.0 atm)(V)/(0.082 L·atm/mol·K)(266.48 K) = 28.0 mol

Now we can use the same equation to solve for the final number of moles of oxygen:

n = PV/RT = (10.5 atm)(V)/(0.082 L·atm/mol·K)(266.48 K) = ?

Solving for n gives:

n = 9.48 mol

Therefore, the number of moles of oxygen used during the two-week period is:

Δn = n_initial - n_final = 28.0 mol - 9.48 mol = 18.5 mol

The answer is D.

An Oxygen Tank Kept at 20 ο\omicron ο C Contains 28

An Oxygen Tank Kept at 20^$\omicron$C Contains 28