A ballon is filled with 30.0g of helium gas. What volume can be filled to a pressure of 1.15 atm if the temperature is 20.0°C?

156.7mL

Explanation:

First we need to find the number of mole of He. This can be achieved by doing the following:

Mass of He from the question = 30g

Molar Mass of He = 4g/mol

Number of mole = Mass /Molar Mass

Number of mole of He = 30/4

Number of mole of He = 7.5moles

Now, we can obtain the volume as follows:

P = 1.15 atm

T = 20°C = 20 + 273 = 293K

R = 0.082atm.L/Kmol

n = 7.5moles

V =?

Recall: PV = nRT

V = nRT/P

V = (7.5 x 0.082 x 293)/1.15

V = 156.7mL

Therefore, the volume that can be filled to that pressure is 156.7mL

your answer would be a. 12.5 kg

the ratio of the conjugate base to the acid required to attain the desired ph.