HTML problems: Re: math problem

[Guest guest]

Dear ALL,

While whatever book 'spokane94' is using gives c. 1.0 L as a

possible answer, I just want to say this is an educator's nightmare

because we TEACH NEVER to use trailer zeros and ALWAYS use beginning

zeros, in order to avoid medication errors. So the answer should

read:

c. 1 L

By the way, Spokane 94 what book areyou using? The questions are

quite good.

Respectfully,

Jeanetta Mastron CPhT BS

Founder/Owner of this site

> >

> >

> > Math Tutorial From a Post - Given the Grams in a solution what is

> the

> > final volume?

> >

> > Posted by:

> > FROM: spokane94@

> > DATE: Sat, 20 Sep 2008 23:25:37 -0000

> > SUBJECT: math problem

> >

> >

> > How much 1/2NS solution can be made using 4.5g of NaCl?

> >

> > Possible answers are:

> > a. 0.25 L

> > b. 0.5 L

> > c. 1.0 L

> > d. 1.5 L

> >

> > Solution posted by Jeanetta Mastron CPhT BS :

> >

> >

> > First of all one must KNOW (commit to memory) and understand

> > (rationalize the math) the following conversion factors:

> >

> > 1 NS = 0.9 % NaCl

> > 1/2 NS = 0.45 % NaCl

> > 1/4 Ns = 0.2 % NaCl

> >

> > Worth repeating: 1/2 NS = 0.45 % NaCl

> >

> > Key Recall #1: The number of grams of a substance in 100 ml or

100

> > grams of a total is equal to the percentage of that substance:

> >

> > 1/2 NS = 0.45% NaCl, which is therefore equal to: 0.45grams NaCl

> in

> > 100 ml solutionof NaCl and water (H20).

> >

> >

> > Key Recall #2: The part over the whole divided multiplied by 100

=

> > percent

> >

> >

> > 0.45 grams NaCL.............= (the Part)

> > --------------------------- = (over/divided by) X 100 = 0.45% NaCl

> > 100 ml solution of NaCl+H20 = (the Whole)

> >

> >

> > So restate this in a ratio/proportion statement (here are four

ways

> > you may state it in English but they all mean/equate to the same

in

> > the universal language of math):

> >

> > IF 0.45 grams of NaCl are found in 100 ml of solution (of NaCl +

> > H20) , THEN how many ml (X ml) of H20/NaCl solution are made

when

> > using 4.5 grams NaCl?

> >

> > Or

> >

> > IF 100 ml of solution (of NaCl + H20) contains 0.45 grams of

NaCl,

> > THEN how many ml (X ml) of H20 + NaCl solution are made if you

use

> > 4.5 grams NaCl?

> >

> > IF 100 ml of solution (of NaCl + H20) contains 0.45 grams of

NaCl,

> > THEN how many ml (X ml) of H20 + NaCl solution will 4.5 grams

NaCl

> > make?

> >

> >

> > IF 100 ml of solution (of NaCl + H20) contains 0.45 grams of

NaCl,

> > THEN how many ml (X ml) of H20 + NaCl solution will be made if

the

> > solution contains 4.5 grams NaCl?

> >

> >

> > Set up:

> >

> >

> > 0.45 grams NaCl........4.5 gram NaCl

> > ------------------ = --------------------

> > 100 ml (H20+NaCl)......X ml (H20+NaCl)

> >

> >

> > Replace the following " (H20+NaCl) " with the word 'solution'

> or 'sol'

> > for short.

> >

> >

> >

> > Cross Multiply:

> >

> > 100 ml sol x 4.5gms NaCl

> > ------------------------ = Xml sol

> > 0.45 gm NaCl

> >

> >

> > Xml sol = 1000 ml sol or 1 L sol of NaCl + H20

> >

> > Answer to the problem:

> >

> > c. 1.0 L

> >

> >

> > Hope this helps,

> >

> > You can find this in the File, Folder Math Only Tutorials

inspired

> > by posts

> >

> > Jeanetta Mastron CPhT BS Chemistry

> > Pharm Tech Educator

> > Founder/Owner of

> > The above solution is copyrighted by Jeanetta Mastron CPhT BS on

> > September 20, 2008

> >