I have to make these solutions in lab and I need to show the calculations for th
ID: 571567 • Letter: I
Question
I have to make these solutions in lab and I need to show the calculations for them please help and show all work neatly, please.
Note: For number 4, the volume needed is 5mL.
Solutions: 100 ml of 20 mg/ml thymine in 10% NaOH (MW of thymine = 1261, CAS 65-71-4 and for NaOH MW-40 and CAS 1310-73-2) 100 ml of 0.04% l-napthol in 95% ethanol (MW of napthol = 144.2 and CAS is 90-1 5-3) 100 ml of 2% sodium thiosulfate (MW=158.1 and CAS is l 0102-17-73) 1:5 solution of bleach which must be prepared fresh daily 1. 2. 3. 4. arginine is 174.20 and CAS is 74-79-3)Explanation / Answer
So prepare 10 % NaOH (i.e. 10% solute in 90% of solvent)
10% solution of NaOH. = (wt of solute / wt of solution ) x 100
10% solution of NaOH. = (10 / 100 ) x 100 =10 %w/w
Weight of solvent = 100 –weight of solute = 100-10 = 90 gm
Take 10gm NaOH in 90 gm of solvent (i.e. in water).
We prepare 20 mg/ml of thymine
So 1 ml = 20 mg then 100ml = X mg of thymine
X = 100 x 20 = 2000 mg of thymine
Take 2000 mg of thymine in 100 ml volumetric flask and dilute upto mark with 10% NaOH solution.
solution prepare in mg/ ml
2. 100 ml of 0.04 % 1-naphthol in 95 % ethanol
Wt of solute =0.04 gm in 100 gm of solution calculate wt of solvent
Wt of solvent =wt of solution –wt of solute = 100-0.04 =99.96%
So add 0.04 gm of 1-naphthol in 99.96 gm of 95% ethanol
3. 100 ml of 2% sodium thiosulphate
As above calculate wt of solvent
wt of solvent =100-2 =98 %
take 2 gm of sodium thiosulphate in 98 gm of water
4. 1 : 5 bleach solution to 5 ml
In this solution take 1 part of bleach solution and 5 part of water
Take 0.8 ml bleach solution and add 4.2 ml of water to make 5 ml
5.
C1 = 1mM V1 =100 ml C2=100mM & V2= ? given volume of 100mM is 50 ml out of this how much is used to make 1 mM of 100 ml
So we find here how much amount of 100mM used to prepapre 1 mM of 100 ml
C1V1 = C2V2
1 x 100 = 100 x V2 i.e. V 2 = 1 ml
So take 1 ml of 100mM of arginine solution in 100 ml volumetric flask and dilute upto mark to make 1 mMsolution.