Hello! Could someone help me with this? I'm confused on what to do. Thanks!!

Question

The mole fraction of carbon dioxide (CO2) in water is 0.25. Determine the molarity of CO2. The density of the solution is 1.0 g/mL.

Answer 1

Molarity=molesSolute/litersolution
= molesSolute/molesSolution *molesSolution/1liter

= .25*1000/18= 250/18=14

Answer 2

mole fraction means .25 moles of CO2 for each mole of solution (along with
.75 moles of H2O)

molarity means moles of CO2 per LITER of solution

so, how many moles of water in a liter?

Answer 3

XCO2 = 0.25
Therefore, XH2O = 1.0 - 0.25 = 0.75
Take enough sample to have 1.0 mol total. You will have
0.25 mol CO2 and
0.75 mol H2O.
g CO2 = 0.25 x 44g/mol = 11 g CO2
gH2O = 0.75 x (18 g/mol = 13.5 g.
Total mass is 24.5 g.
Density is 1.0 g/mL; therefore, volume = g/density = 24.5/1.0 = 24.5 mL.
Now M = mols/L = 0.25/0.0245 = ?

Answer 4

55.6 moles of H2O per liter

x / (55.6 + x) = .25

x is the CO2 molarity

Answer 5

my proof:
10.2 M means 10.2 mols/L solution.
10.2 mols x 44g/mol = 448.8 g CO2
density solution is 1.0 g/mL so mass = volume x density or 1000 mL x 1.0 = 1000 g.
Then mass H2O = mass solution-mass CO2 = 1000-448.8 = 551.2 g H2O.

mols CO2 = 10.2
mol H2O = 551.2/18 = 30.62
Total mols = 10.2+30.62=40.82
XCO2 = 10.2/40.82 = 0.25
XH2O = 30.62/40.82 = 0.75
That matches the problem.

Answer 6

But you don't have 55.55 mols H2O because you don't have 1000 g H2O. You have a total of 1000 mL solution which has a mass of 1000 g since the density is 1.0 g/mL. So the total mass is mass H2O + mass CO2 and that weighs 1000 g. The amount of H2O is <1000g and <55.55 mols.