Dear Ifrah,

Yes, you are correct. For construction standard curve you have to use different dilutions as specified in the method being adopted by you.

P. C. Srivastava

interested& followed

On predicting the pH of pure ammonium sulfate aq. sol.; see: https://www.researchgate.net/post/What-is-the-difference-between-using-ammonium-sulfate-and-using-sodium-sulphate-in-protein-ppt-and-seperation

Need 0.1 moles Na2SO4 per 1l solution, or 0.05 moles per 200 ml. Since the molar mass is 142 g/mol, 0.05 moles is 2.84 g. So, weight 2.84 g of Na2SO4, transfer to a measuring cylinder, and add water to make up the total volume of 200 ml. If you dissolve 58.44g of NaCl in a final volume of 1 litre, you have made a 1M NaCl solution. To make a 0.1M NaCl solution, you could weigh 5.844g of NaCl and dissolve it in 1 litre of water; OR 0.5844g of NaCl in 100mL of water OR make a 1:10 dilution of a 1M sample.

Hi,

You may use the web tool to calculate

https://www.alfa-chemistry.com/solution-dilution-calculator.htm

https://www.alfa-chemistry.com/mass-molarity-calculator.htm

Dr Chen Jingwen thank you for your contribution to the discussion

To prepare a 1 M solution, dissolve 1.3 g of solid (NH4)2SO4 in a final volume of 10 mL of H2O. Filter-sterilize the solution and store the solution at room temperature. To prepare 1000 mL of a 0.1 mol/L solution of Sodium sulfate we have to dissolve 32.2193 g of Na2SO4×10H2O (100 % purity) in deionized or distilled water. Prepare a 0.1 ppm ammonia standard by measuring 100 mL of the 1 ppm ammonia standard from Step 2 using a graduated cylinder. Add the 100 mL measured into a 1000 mL volumetric flask. Add 900 mL DI water, diluting to the mark indicated on the flask. Mix the solution well. There's just one sulfur atom in ammonium sulfate. If we multiply and add everything up, we'll find the molar mass of ammonium sulfate is 132 grams per mole.