Question 429087
To prepare a 5% solution of baking soda in 500mls of water how much baking soda do I need and how would I mathmatically figure this?
<pre>

Baking soda is measured by weight, so we must consider the solution is by
weight, not by volume.  1 milliliter of water weighs 1 gram.  So let x be the
number of grams of baking soda to add.  Then the concoction would weigh 100+x
grams.

So we have the equation:

{{{x/(100+x)=.05}}}

{{{x = .05(100+x)}}}

{{{x = 5 +.05x}}}

{{{x - .05x = 5}}}

{{{1.00*x-.05*x = 5}}}

{{{.95x = 5}}}

{{{x = 5/.95}}}

{{{x = 5.263157895}}} grams of baking soda.

Edwin</pre>