Question

A balloon contains 10.0 g of helium gas. If the initial volume is V, and the temperature

and pressure are held constant, what is the final volume (in terms of V) after 10.0 g
of neon is added?

Answer 1

1.2 V

Step-by-step explanation:

10 g helium = 2.5 moles He

10 g Neon = ~ .5 mole neon

2.5 is to V as (2.5 + .5) is to x

2.5 / V = 3/x

2.5 x = 3 V

x = 3/2.5 V = 1 1/5 V

Answer 2

Avogadro's Law (P,T constant)

`\tt (V_1)/(n_1)=(V_2)/(n_2)`

n = mol

V = volume

AM He = 4 u, mol = 10 : 4 = 2.5

AM Ne = 20 u, mol = 10 : 20 = 0.5

`\tt (V)/(2.5)=(V_2)/(2.5+0.5)\\\\V_2=\boxed{\bold{1.2V}}`