Compound Z has a MW of 100. Your lab partner weighed 25 grams of compound Z and dissolved it in water to a final volume of 1 liter.
a) What is the concentration of the solution expressed as a percentage by weight (w/v)?
b) What is the concentration of the solution expressed as molarity?
b)moles = grams/molar mass. Solve for moles. Then M = moles/L.
a). %w/v = grams/100 mL = 25/1000 = 2.5/100 = 2.5 %w/v (but when I hear percentage by weight I think w/w.)
(a) to get the weight/volume percent, we just divide the mass of the compound to the volume, and multiply by 100:
25 g / 1000 mL * 100 = 2.5 % w/v
(b) recall that molarity is moles of solute per liter of solution. thus first get the number of moles of the compound by dividing the given mass by its molecular weight (MW):
25 g / 100 g/mol = 0.25 mol Z
Molarity = M = n/V = 0.25 mol / 1 L
Molarity = 0.25 M
hope this helps~ :)
a) The concentration of the solution expressed as a percentage by weight (w/v) can be calculated by dividing the weight of the compound by the volume of the solution and multiplying by 100. So, in this case, it would be (25 grams / 1000 mL) * 100 = 2.5% (w/v).
b) To calculate the concentration of the solution expressed as molarity, we need to convert the weight of the compound to moles using the molecular weight and then divide the number of moles by the volume of the solution in liters. Since we know the weight is 25 grams and the molecular weight (MW) is 100 g/mol, we can calculate the number of moles: 25 grams / 100 g/mol = 0.25 moles. Now, we divide this by the volume of the solution in liters (1 liter) to get the molarity: 0.25 moles / 1 liter = 0.25 M.
To calculate the concentration of the solution expressed as a percentage by weight (w/v), we need to divide the mass of the compound by the volume of the solution and multiply by 100.
a) Percentage by weight (w/v) = (mass of compound Z / volume of solution) x 100
Given that the mass of compound Z is 25 grams and the volume of the solution is 1 liter, we can calculate the percentage by weight (w/v) as follows:
Percentage by weight (w/v) = (25 grams / 1 liter) x 100
Percentage by weight (w/v) = 25%
Therefore, the concentration of the solution expressed as a percentage by weight (w/v) is 25%.
To calculate the concentration of the solution expressed as molarity, we need to know the number of moles of the compound and divide it by the volume of the solution in liters.
b) Molarity = moles of compound Z / volume of solution (in liters)
To find the number of moles of compound Z, we can use its molecular weight (MW) and the mass of the compound.
Number of moles of compound Z = mass of compound Z / molecular weight of compound Z
Given that the molecular weight of compound Z is 100 and the mass of the compound is 25 grams, we can calculate the number of moles as follows:
Number of moles of compound Z = 25 grams / 100 g/mol
Number of moles of compound Z = 0.25 moles
Now, we can calculate the molarity using the number of moles and the volume of the solution.
Molarity = 0.25 moles / 1 liter
Molarity = 0.25 M (mol/L)
Therefore, the concentration of the solution expressed as molarity is 0.25 M.
To answer these questions, we first need to calculate the amount of Compound Z in the solution in grams and in moles.
a) To find the weight/volume percentage (w/v), we need to calculate the weight of Compound Z in the solution. Given that 25 grams of Compound Z were dissolved in 1 liter of water, we can directly express this as a percentage:
Weight of Compound Z in Solution = 25 grams
Total weight of Solution = 25 grams + 1000 grams (mass of water in 1 liter)
Percentage by weight (w/v) = (Weight of Compound Z in Solution / Total weight of Solution) x 100
To calculate the Total weight of Solution, we need to convert liters to grams using the density of water, which is 1 g/mL:
Density of water = 1 g/mL
1 liter of water = 1000 mL of water
Total weight of Solution = 1000 mL x 1 g/mL = 1000 grams
Substituting the values:
Percentage by weight (w/v) = (25 grams / 1000 grams) x 100 = 2.5%
Therefore, the concentration of the solution expressed as a percentage by weight (w/v) is 2.5%.
b) To find the concentration of the solution expressed as molarity, we first need to calculate the number of moles of Compound Z in the solution.
Number of moles of Compound Z = Weight of Compound Z / Molar Mass of Compound Z
Given that the Molar Mass (MW) of Compound Z is 100 g/mol and 25 grams of Compound Z were used, we can calculate the number of moles:
Number of moles of Compound Z = 25 grams / 100 g/mol = 0.25 moles
Molarity (M) is defined as the number of moles of solute per liter of solution. In this case, we have 0.25 moles dissolved in 1 liter of solution, so the concentration expressed as molarity is:
Molarity = Number of moles / Volume of solution in liters
Molarity = 0.25 moles / 1 liter = 0.25 M
Therefore, the concentration of the solution expressed as molarity is 0.25 M.