A balloon has 0.3 moles of air inside and a volume of 7 liters after 0.2 more moles of air were blown into this balloon what is the volume

11.67L

Explanation:

From the ideal gas equation

PV = nRT

If all the variables ( i.e P and T) are kept constant, then the volume is directly proportional to n as shown below

V = nRT/P

RT/P ==> constant

V1/n1 = V2/n2

Data obtained from the question include:

n1 = 0.3mol

V1 = 7L

n2 = 0.3 + 0.2 = 0.5mol

V2=?

V1/n1 = V2/n2

7 /0.3 = V2 /0.5

Cross multiply to express in linear form

V2 x 0.3 = 7 x 0.5

Divide both side by 0.3

V2 = ( 7 x 0.5) /0.3

V2 = 11.67L

The new volume is 11.67L