Answer:
1. Molarity (M) = moles of solute / liters of solution
2. To find the number of moles of solute when the mass of the solute is known, you can use the formula:
moles of solute = mass of solute / molar mass of solute.
Where the molar mass of the solute is the mass of one mole of the substance and is expressed in g/mol.
3. To find the number of moles if molarity is known, you can use the formula:
moles = molarity x volume (in liters)
where the volume is the amount of solution in liters. Rearranging the formula, you can also calculate the molarity if you know the number of moles and the volume:
molarity = moles / volume (in liters)
4. The molar concentration of a liter of solution with 0.5 M solute is 0.5 moles/L.
A. Given:
- mass of solute (NaCl) = 90.0 g
- volume of solution = 3.5 L
To find:
- concentration in Molarity (M)
Formula for Molarity:
M = moles of solute / volume of solution (in L)
Molar mass of NaCl = 58.44 g/mol
Number of moles of NaCl = mass of NaCl / molar mass of NaCl
= 90.0 g / 58.44 g/mol
= 1.539 mol
Molarity = number of moles of solute / volume of solution
= 1.539 mol / 3.5 L
= 0.44 M
Therefore, the concentration in Molarity of the NaCl solution is 0.44 M.
B. The given information can be summarized as follows:
- Solute: glucose (C6H12O6)
- Solvent: water (H2O)
- Mass of solute: not given
- Volume of solution: 1000 mL = 1 L
- Chemical formula of solute: C6H12O6
- Molar mass of solute: 6(12.01 g/mol) + 12(1.01 g/mol) + 6(16.00 g/mol) = 180.18 g/mol
Since the mass of solute is not given, we cannot calculate the number of moles or the molarity of the solution.