A 300mL solution was made by dissolving 5.0g of MgCl2 in water. What is its molarity?
mols MgCl2 = grams/molar mass
Then M = mols/L solution
300ml solution equals to 0.5 g mgcl2
1ml " " "0.5/300 "
1000ml " " " (0.5*1000)/300g "
1.667M (ans.)
What you have posted is pure blarney.
First error: 300 mL solution equals 5 g MgCl2 and not 0.5. The problem says 300 mL solution and 5.0 g MgCl2.
Second error: you are trying to base molarity on solution/grams and it should be mols/L solution.
The correct solution is as follows:
300 mL contains 5.0 MgCl2 (molar mass 95.2).
mols MgCl2 = 5.0/95.2 = approx 0.0525
M = mols/L = 0.0525/0.300 = 0.175M
i'm sorry. I didn't understand the question properly. Thank u for showing my mistakes.
To find the molarity of a solution, we need to know the amount of solute (in moles) and the volume of the solution (in liters).
Step 1: Convert the mass of MgCl2 to moles.
The molar mass of MgCl2 is calculated by adding the atomic masses of magnesium (24.31 g/mol) and chlorine (35.45 g/mol) multiplied by 2 (as there are 2 chlorine atoms in MgCl2). So the molar mass of MgCl2 is 95.21 g/mol.
To convert grams to moles, we divide the mass (in grams) by the molar mass.
molar mass of MgCl2 = 95.21 g/mol
mass of MgCl2 = 5.0 g
moles of MgCl2 = mass / molar mass
= 5.0 g / 95.21 g/mol
= 0.0525 mol
Step 2: Convert the volume of the solution to liters.
The volume given is in milliliters (mL), but we need to convert it to liters.
1 L = 1000 mL
volume of the solution = 300 mL = 300/1000 L
= 0.3 L
Step 3: Calculate the molarity.
Molarity (M) is defined as moles of solute divided by the volume of the solution in liters.
Molarity (M) = moles of solute / volume of solution (in liters)
Molarity = 0.0525 mol / 0.3 L
= 0.175 M
Therefore, the molarity of the 300 mL solution made by dissolving 5.0 g of MgCl2 in water is 0.175 M.