How do you calculate the number of g of solute that would be needed to make the following?
2.50X10^2mL of 0.100M NaCl?
You want how many moles? That's M x L.
0.250 L x 0.100 M = 0.0250 moles
moles NaCl = grams NaCl/molar mass NaCl. solve for grams.
To calculate the number of grams (g) of solute needed to make a given solution, you need to follow a few steps. Here's how you can solve this problem:
Step 1: Gather the required information
In this case, you have been given the volume of the solution (2.50 × 10^2 mL) and the molarity (0.100 M) of the solute (NaCl).
Step 2: Convert the given volume to liters
Since the molarity is expressed in moles per liter (M), it is necessary to convert the given volume from milliliters (mL) to liters (L). To do this, divide the given volume by 1000:
2.50 × 10^2 mL ÷ 1000 = 2.50 × 10^2 L
Step 3: Apply the formula relating moles, molarity, and volume
The formula to calculate the number of moles (n) is:
n = Molarity × Volume (in liters)
Applying this formula, you get:
n = 0.100 M × 2.50 × 10^2 L = 2.50 × 10^1 moles
Step 4: Convert moles to grams
To convert moles to grams, you need to know the molar mass of the solute. In this case, the solute is NaCl. The molar mass of Na is approximately 22.9 g/mol, and the molar mass of Cl is approximately 35.4 g/mol. Adding these values together, you get:
Molar mass of NaCl = 22.9 g/mol + 35.4 g/mol = 58.3 g/mol
To calculate the mass of NaCl required, multiply the number of moles (2.50 × 10^1 moles) by the molar mass (58.3 g/mol):
Mass of NaCl = 2.50 × 10^1 moles × 58.3 g/mol
So, the final answer will be the product of these values:
Mass of NaCl = 2.50 × 10^1 moles × 58.3 g/mol = 1.46 × 10^3 g
Therefore, you would need 1.46 × 10^3 grams of NaCl to make a 2.50 × 10^2 mL solution with a molarity of 0.100 M.