Calculate the molarity of a 295 mL solution contain 45 g of ethanol (C2H5OH)
moles ethanol = grams/molar mass
M = moles/0.295L = ?
To calculate the molarity of a solution, we need to use the formula:
Molarity (M) = moles of solute / volume of solution (in liters)
First, let's convert the mass of ethanol (C2H5OH) to moles. To do this, we need to know the molar mass of ethanol:
C2H5OH:
C = 12.01 g/mol * 2 = 24.02 g/mol
H = 1.01 g/mol * 6 = 6.06 g/mol
O = 16.00 g/mol * 1 = 16.00 g/mol
Adding these values together, the molar mass of ethanol (C2H5OH) is:
24.02 g/mol + 6.06 g/mol + 16.00 g/mol = 46.08 g/mol
Now, we can calculate the number of moles using the formula:
moles = mass / molar mass
moles of ethanol (C2H5OH) = 45 g / 46.08 g/mol = 0.975 moles
Next, we need to convert the volume of the solution from milliliters to liters. Since there are 1000 mL in a liter, we divide the volume by 1000:
volume of solution = 295 mL / 1000 mL/L = 0.295 L
Finally, we can apply the molarity formula to find the molarity of the solution:
Molarity (M) = moles of solute / volume of solution
Molarity (M) = 0.975 moles / 0.295 L
Using a calculator, the molarity of the solution is approximately 3.305 M.
So, the molarity of the 295 mL solution containing 45 g of ethanol (C2H5OH) is approximately 3.305 M.