Chemistry - Individual Gas Laws

Question

At STP a gas occupies a 56.6 kiloliter balloon. How many mol of the gas must be in the balloon?

Answer 1

Hi Julia,

For Gas Laws, you may have seen the famous equation:

PV = nRT

P = pressure

V = volume

n = mol of gas

R = gas constant

T = temperature (K)

For this question, we are given two key points, the gas is at STP (Standard Temperature & Pressure) and the volume is 56.6 kL.

At STP, the temperature is 273 K and the pressure is 1 atm. The volume is 56.6 kL = 56,600 L. Our gas constant depends on the units of P, V, and T. In this case, R = 0.0821 (L x atm)/(mol x K)

Let us rearrange the formula to solve for n = moles.

PV = nRT

n = PV/RT <-- I divided RT into both sides to isolate n. Now substitute what we know, and include the units to help you!

n = (1 atm x 56,600 L)/(0.0821 (atm x L)/(mol x K) x 273 K)

Now with this, all the units would cancel each other, except for mol because we need to find the moles of this gas. Do the multiplication on the numerator and denominator and then divide to find the number of moles.

n = 2525.29 mol <--I rounded this answer to the nearest hundredths place, but I do not know whether the question asks for any solutions with the correct significant figures. But, nonetheless, this is your solution.

Hope this helps, and if you need more help, just reply to this response!