Suppose you had a balloon containing 1 mole of helium at stp and a balloon containing 1 mole of oxygen at stp. which statement(s) is(are) true?

(a) the balloons will have the same volume.
(b) the balloons will have the same mass.
c) (both a) and b) are true.
(d) neither a) nor b) are true.
(e) not enough information

The true statement  is option A.

Explanation:

Using ideal gas equation:

PV = nRT

where,

P = Pressure of gas =  1 atm

V = Volume of gas = ?

n = number of moles of gas = 1 mol

R = Gas constant = 0.0821 L.atm/mol.K

T = Temperature of gas = 273.15 K

V = 22.42 L

This means that 1 mole of an ideal gas at STP occupies 22.42 liters of volume.

So, 1 mole of helium gas and 1 mole of oxygen gas will have same value of volume in their respective balloons at STP.