Calculate the mass of Na2S2O3•5H2O needed to prepare 250.0 ml of 0.2000 M solution. Note, include the 5 waters in your calculation of the formula mass.
How many moles do you need? That's moles = M x L = 0.2000 x 0.2500 = ?
Then grams Na2S2O3.5H2O = moles x formula mass
To calculate the mass of Na2S2O3•5H2O needed to prepare a 0.2000 M solution in 250.0 ml, you need to follow these steps:
Step 1: Find the molar mass of Na2S2O3•5H2O.
The molar mass of Na (sodium) is 22.99 g/mol, the molar mass of S (sulfur) is 32.07 g/mol, and the molar mass of O (oxygen) is 16.00 g/mol. For H2O (water), the molar mass is 18.02 g/mol.
Using this information, you can calculate the molar mass of Na2S2O3•5H2O as follows:
(2 × Na) + (2 × S) + (3 × O) + (5 × H2O)
= (2 × 22.99 g/mol) + (2 × 32.07 g/mol) + (3 × 16.00 g/mol) + (5 × 18.02 g/mol)
= 45.98 g/mol + 64.14 g/mol + 48.00 g/mol + 90.10 g/mol
= 248.22 g/mol
So, the molar mass of Na2S2O3•5H2O is 248.22 g/mol.
Step 2: Determine the number of moles of Na2S2O3•5H2O required.
To calculate the number of moles, you can use the formula:
moles = molarity × volume (in liters)
Given that the volume is 250.0 ml (or 0.2500 L) and the concentration is 0.2000 M, plug these values into the formula:
moles = 0.2000 M × 0.2500 L
= 0.0500 moles
So, you need 0.0500 moles of Na2S2O3•5H2O for the solution.
Step 3: Calculate the mass of Na2S2O3•5H2O needed.
To find the mass, you can use the formula:
mass = moles × molar mass
Plug in the values:
mass = 0.0500 moles × 248.22 g/mol
= 12.41 g
Therefore, you would need 12.41 grams of Na2S2O3•5H2O to prepare the 0.2000 M solution in 250.0 ml.
To calculate the mass of Na2S2O3•5H2O needed, we need to follow these steps:
Step 1: Calculate the molar mass of Na2S2O3•5H2O.
The molecular formula Na2S2O3•5H2O indicates that there are two sodium atoms (Na), two sulfur atoms (S), three oxygen atoms (O), and ten hydrogen atoms (H) in each formula unit. The molar mass of each element is as follows:
- Sodium (Na): 22.99 g/mol
- Sulfur (S): 32.07 g/mol
- Oxygen (O): 16.00 g/mol
- Hydrogen (H): 1.01 g/mol
To calculate the molar mass of Na2S2O3•5H2O, we sum up the molar masses of each element, taking into account the number of atoms:
Molar mass (Na2S2O3•5H2O) = (2 × Na) + (2 × S) + (3 × O) + (10 × H) + (5 × H2O)
Step 2: Convert the volume of the solution to moles.
We are given that the volume of the solution is 250.0 mL (milliliters) and the concentration (molarity) is 0.2000 M (moles per liter).
To calculate the number of moles, we use the formula: moles = concentration × volume (in liters)
Moles = 0.2000 M × 0.250 L
Step 3: Calculate the mass of Na2S2O3•5H2O.
To find the mass of Na2S2O3•5H2O, we multiply the number of moles by the molar mass determined in Step 1:
Mass = Moles × Molar mass (Na2S2O3•5H2O)
Now, we can proceed with the calculations:
Step 1: Calculate the molar mass of Na2S2O3•5H2O:
Molar mass (Na2S2O3•5H2O) = (2 × 22.99 g/mol) + (2 × 32.07 g/mol) + (3 × 16.00 g/mol) + (10 × 1.01 g/mol) + (5 × (2 × 1.01 g/mol + 16.00 g/mol))
= 46.00 g/mol + 64.14 g/mol + 48.00 g/mol + 10.10 g/mol + 90.10 g/mol
= 258.34 g/mol
Step 2: Convert the volume of the solution to moles:
Moles = 0.2000 M × 0.250 L
= 0.050 mol
Step 3: Calculate the mass of Na2S2O3•5H2O:
Mass = Moles × Molar mass (Na2S2O3•5H2O)
= 0.050 mol × 258.34 g/mol
= 12.92 g
Therefore, to prepare 250.0 mL of a 0.2000 M Na2S2O3•5H2O solution, you would need approximately 12.92 grams of Na2S2O3•5H2O.