Chemistry 9
posted by Seastone .
a) A 2.56 balloon contains 3.66 g of gas. Find the density
b) A 45.3 g sample placed in a graduated cylinder causes the water level to rise from 25.0 mL to 41.8 mL . Find the density

2.56 what. L?
b. density = mass/volume
mass = 45.3 g
volume = 41.8 mL  35.0 mL = ?
Substitute and solve for density. 
Yeah sorry for typing wrong its 2.56 L balloon contains 3.66 g of gas.

How do i do it?

2.56 L x (1 mol/22.4L) = ? mols.
mols = g/molar mass. You know mola and grams, solve for molar mass. 
Thank you so much:)