To calculate the molarity of a solution, we need to determine the number of moles of the solute (C6H12O6, glucose) and divide it by the volume of the solution in liters.
First, we need to convert the given mass of glucose (4.2 g) to moles. To do this, we divide the mass by the molar mass of glucose.
The molar mass of glucose (C6H12O6) can be calculated by adding up the atomic masses of its constituent elements:
C: 6 atoms × atomic mass of carbon (12.01 g/mol) = 72.06 g/mol H: 12 atoms × atomic mass of hydrogen (1.01 g/mol) = 12.12 g/mol O: 6 atoms × atomic mass of oxygen (16.00 g/mol) = 96.00 g/mol
Adding these values together gives the molar mass of glucose: 72.06 g/mol + 12.12 g/mol + 96.00 g/mol = 180.18 g/mol.
Now, we can calculate the number of moles of glucose:
moles = mass / molar mass moles = 4.2 g / 180.18 g/mol ≈ 0.0233 mol
Next, we need to convert the volume of the solution from milliliters (mL) to liters (L):
volume = 520 mL / 1000 mL/L = 0.520 L
Finally, we can calculate the molarity (M) using the formula:
Molarity = moles / volume Molarity = 0.0233 mol / 0.520 L ≈ 0.0448 M
Therefore, the molarity of the solution containing 4.2 g of C6H12O6 in 520 mL of H2O is approximately 0.0448 M.