Posted by **Rachel** on Saturday, January 22, 2011 at 1:55pm.

Can someone please check my work?

Calculate the mass of (NH4)2S2O8 needed to prepare 250mL of a 0.100M solution.

I got 5.705 g.

Calculate the volume of 2.00M KI needed to prepare 250mL of a 0.200M solution.

I got 0.025L or 25mL.

Calculate the volume of 0.100M Na2S2O3 needed to prepare 250mL of a 0.0100M solution.

I got 0.025L or 25mL.

- Chemistry -
**DrBob222**, Saturday, January 22, 2011 at 2:14pm
5.705 is a correct number for the first one; however, you can't have that many significant figures. You are allowed three; therefore, I would round to 5.70 g. Your prof may not round a 5 the same way and could round to 5.71 g.

The second one is correct also; however, you are allowed 3 s.f. and I would give the answer as 25.0 mL.

Same thing for the third one. 25.0 mL.

## Answer This Question

## Related Questions

- Chemistry - You are a work study student in our chemistry department. Amy, your ...
- Chem - Calculate the volume of .300 M NaOH needed to prepare a pH=3.50 buffer ...
- chemistry - Calculate the number of grams of h2c2o4.2h2o needed to prepare ...
- chemistry - 5.85g of sodium chloride is dissolved in 250mL of solution. ...
- chemistry - a 500ml stock solution of NAOH has a purity of 70% and a density of ...
- chemistry - How many grams of NH2OH are needed to prepare 250mL of a solution ...
- Chemistry - 1. In order to make 250mL of a 0.100 M HNO3 solution from a 15.9 M ...
- Chemistry - Urgent... Someone please help!! Can someone please check to see if I...
- chemistry - how wold you prepare 2.00L of 1.00M HCl solution using 6.00 M HCl? i...
- chemistry - Calculate the mass of salt needed to prepare 100 cm3 of 0.05 M ...

More Related Questions