Thursday

July 24, 2014

July 24, 2014

Posted by **Rachael** on Saturday, January 15, 2011 at 7:13am.

I got the answer of 18g with the following working:

9 ÷ 1000(ml) x 100 = 0.9

Therefore 9% of 1000ml (1L) is 9g

Multiply 9g by 2 because it is for 2L of water = 18g

Is this method of calculation suitable for a chemistry assignment or is there another way to do it?

Thanks.

- Chemistry -
**DrBob222**, Saturday, January 15, 2011 at 1:18pmThere is nothing wrong with your answer and your math appears ok but the reasoning is out of this world. You apparently picked 9 as a starting point (and it's good that you did); however, if you had picked any other number it wouldn't have given you the correct answer. Here is a (there are several) conventional way of doing it.

0.9% solution = 0.9g/100 g solution (which is the same as substituting into the percent equation as

%NaCl = (g NaCl/100 mL)*100 = (0.90 g NaCl/100 mL)*100 =0.9% NaCl. Now if we want 2.00 L, just multiply by the factor of what you want over what you have; i.e., (0.90g NaCl) x (2,000 mL/100 mL) = 18 g

**Related Questions**

chemistry - Isotonic saline is often given to patients intravenously to ...

chemistry - Isotonic saline and is often given to patients intravenously to ...

chemistry - Isotonic saline is a 0.9%(g/100ml) solution of salty water. You are ...

math - a pharmacist mixed some 10% saline solution with some 15% saline solution...

algebra - Nurse erika needs to prepare 12 liters of a 10% saline solution. The ...

algebra - Nurse erika needs to prepare 12 liters of a 10% saline solution. The ...

Math - A saline solution is 20% salt. How many gallons of water must be added to...

chemistry - the normal concentration of sodium chloride in blood is 0.9%(w/v). ...

chem 4 - How many grams of sodium chloride are needed to make 1 L of 0.9% (m/v...

chem engineering - Mass balance on an intravenous injection (IV) bag A nurse ...