How many grams of NaC2H3O2 are needed to prepare 350. mL of a 2.75 M solution?
i got 79.0 ??
thanks
To calculate the amount of NaC2H3O2 needed to prepare a 2.75 M solution, we can use the formula:
Molarity = moles / volume
First, we need to convert the volume from milliliters to liters:
350 mL = 0.350 L
Next, rearrange the formula to solve for moles:
moles = Molarity x volume
moles = 2.75 M x 0.350 L
moles = 0.9625 moles
Finally, we can convert moles to grams using the molar mass of NaC2H3O2. The molar mass of NaC2H3O2 is calculated as follows:
Sodium (Na) = 22.99 g/mol
Carbon (C) = 12.01 g/mol
Hydrogen (H) = 1.008 g/mol
Oxygen (O) = 16.00 g/mol
Thus, the molar mass of NaC2H3O2 = 22.99 + (2 x 12.01) + (3 x 1.008) + (2 x 16.00)
molar mass of NaC2H3O2 = 82.03 g/mol
Now, calculate the grams needed:
grams = moles x molar mass
grams = 0.9625 moles x 82.03 g/mol
grams = 79.09 g
Thus, the correct answer is approximately 79.09 grams of NaC2H3O2 needed to prepare a 350 mL of a 2.75 M solution.
To determine the mass of NaC2H3O2 required to prepare the given solution, you need to follow these steps:
Step 1: Recall the formula for calculating the number of moles in a given solution:
Molarity (M) = moles (mol) / volume (L)
Step 2: Rearrange the formula to solve for moles:
moles (mol) = Molarity (M) x volume (L)
Step 3: Convert the given volume from milliliters (mL) to liters (L):
350 mL = 350 mL / 1000 mL/L = 0.350 L
Step 4: Substitute the values into the formula and calculate the number of moles:
moles (mol) = 2.75 M x 0.350 L = 0.9625 mol
Step 5: Use the molar mass of NaC2H3O2 to convert moles to grams. The molar mass of NaC2H3O2 can be calculated by adding the atomic masses of sodium (Na), carbon (C), hydrogen (H), and oxygen (O) based on the molecular formula:
Na: 23.00 g/mol
C: 12.01 g/mol
H: 1.008 g/mol
O: 16.00 g/mol
Molar mass of NaC2H3O2 = (23.00 g/mol) + (2 * 12.01 g/mol) + (3 * 1.008 g/mol) + (2 * 16.00 g/mol) = 82.03 g/mol
Step 6: Calculate the mass of NaC2H3O2 using the moles and molar mass:
mass (g) = moles (mol) x molar mass (g/mol) = 0.9625 mol x 82.03 g/mol = 79.026 g
Therefore, the correct answer is approximately 79.0 grams of NaC2H3O2.
If you have copied the problem right the answer is 78.9 g.
You have three significant figures i 3.75 and 350. mL has 3.
2.75 x 0.350 x 82.0 = 78.92 which rounds to 78.9 g to 3 s.f.