calculate the weight in grams far a given solution of sodium thiosulphate crystals of strength 2.0M
this makes no sense to me.
I meant to find mass in grams of sodium thio sulphate of strength .0M
You still don't have it Sonia. Of course you meant 2.0 M BUT you have no volume of solution. Since M = mols/L, you have M and you want mols but L must be in thee somewhere.
To calculate the weight in grams for a given solution of sodium thiosulphate crystals of strength 2.0M, you will need to know the desired volume of the solution. The formula you can use is:
Weight (in grams) = Volume (in liters) × Concentration (in moles per liter) × Molecular Weight (in grams per mole)
Step 1: Find the molecular weight of sodium thiosulphate. The molecular formula of sodium thiosulphate is Na2S2O3. To calculate the molecular weight, you need to find the atomic weights of each element in the compound.
Atomic weights:
Na (sodium) = 22.99 g/mol
S (sulfur) = 32.07 g/mol
O (oxygen) = 16.00 g/mol
Molecular weight of Na2S2O3:
2 × Na + 2 × S + 3 × O = (2 × 22.99) + (2 × 32.07) + (3 × 16.00) = 158.11 g/mol
Step 2: Determine the volume of the solution. Let's assume you want to prepare 500 mL (0.5 L) of the 2.0M sodium thiosulphate solution.
Volume = 0.5 L
Step 3: Now, we can use the formula mentioned earlier to calculate the weight in grams.
Weight (in grams) = Volume (in liters) × Concentration (in moles per liter) × Molecular Weight (in grams per mole)
Weight = 0.5 L × 2.0 mol/L × 158.11 g/mol
Weight = 158.11 g
Therefore, for a given solution of sodium thiosulphate crystals with a strength of 2.0M and a volume of 0.5 L, the weight of the crystals needed is 158.11 grams.