Calculate the mole fraction of acetic acid in vinegar, assuming that vinegar is 5.00% acetic acid(by mass) and that the density of vinegar is 1.05 g/mL

Let's call acetic acid HAc.

5.00% HAc by mass means 5.00 g HAc in 100 g solution.
moles in 5.00 g = 5.00/molar mass HAc. You can do the math.

The 100 g soln is made of 5.00 g HAc 95.0 g H2O. moles H2O in 95.0 g H2O = 95.0/molar mass H2O. You can do the math.

mole fraction HAc = moles HAc/total moles where total moles = moles HAc + moles H2O.

CH3COOH is acetic acid, always remember the formula or it will be wrong

And i don't get the question

The problem is to convert percent by mass to mole fraction.

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To calculate the mole fraction of acetic acid in vinegar, we need to know the molecular weight of acetic acid and the density of vinegar.

1. Determine the molecular weight of acetic acid (CH₃COOH).
Acetic acid consists of two carbon atoms, four hydrogen atoms, and two oxygen atoms.
Atomic weights: C = 12.01 g/mol, H = 1.008 g/mol, O = 16.00 g/mol
Molecular weight of acetic acid = (2 * C) + (4 * H) + (2 * O)
= (2 * 12.01) + (4 * 1.008) + (2 * 16.00)
= 60.05 g/mol

2. Determine the density of vinegar.
Given: Density of vinegar = 1.05 g/mL

3. Calculate the mass of 1000 mL (1 L) of vinegar.
Mass = Volume * Density
= 1000 mL * 1.05 g/mL
= 1050 g

4. Calculate the mass of acetic acid in 1000 mL of vinegar (assuming 5.00% by mass).
Mass of acetic acid = 5.00% * 1050 g
= 0.050 * 1050
= 52.5 g

5. Calculate the number of moles of acetic acid.
Moles = Mass / Molecular weight
= 52.5 g / 60.05 g/mol
≈ 0.8747 mol

6. Calculate the mole fraction of acetic acid in vinegar.
Mole fraction of acetic acid = Moles of acetic acid / Moles of vinegar
= 0.8747 mol / (0.8747 mol + 999.13 mol)
≈ 0.0008747

Therefore, the mole fraction of acetic acid in vinegar is approximately 0.0008747.