please solve this!!!!!!!!!

[pharmacyXYZ]

A patient is currently taking 220 mg of anhydrous zinc sulphate. To receive the equivalent amount of elemental zinc, how many milligrams of zinc sulphate heptahydrate (•7 H20) would the patient have to take? (Molecular weights: zinc 65, ZnSO4 161, H20 18)

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[daabc]

A patient is currently taking 220 mg of anhydrous zinc sulphate. To receive the equivalent amount of elemental zinc, how many milligrams of zinc sulphate heptahydrate (•7 H20) would the patient have to take? (Molecular weights: zinc 65, ZnSO4 161, H20 18)

It looks like the question wants 220mg of Zn in his body.

ZnSO4 + (7H20) ===> Zn +SO4 + 7H2O

work backwards and turn that 220mg of Zn into mol.
Given:
220mg of Zn = .220g
1mol Zn =65g Zn

mol of Zn = .220g x (1mol Zn/65g Zn)==> (this will give you mol of zn)


Since 1 mol of Zn = 1 mol ZnSO4(7H2O)===>this will tell you how many mols of ZnSO4(7H2O) there are

just convert that mol to mg.

 

[FredDurst]

It looks like the question wants 220mg of Zn in his body.

ZnSO4 + (7H20) ===> Zn +SO4 + 7H2O

work backwards and turn that 220mg of Zn into mol.
Given:
220mg of Zn = .220g
1mol Zn =65g Zn

mol of Zn = .220g x (1mol Zn/65g Zn)==> (this will give you mol of zn)


Since 1 mol of Zn = 1 mol ZnSO4(7H2O)===>this will tell you how many mols of ZnSO4(7H2O) there are

just convert that mol to mg.

Hmm, take the fact that I haven't started pharmacy school yet and am approaching this from my chemistry view, but it doesn't seem right to say you want 220mg of elemental zinc because:

mol ZnSO4 = mol Zn
mass ZnSO4 =/= mass Zn

So,
Mass of Zn in 220mg of ZnSO4 = (mol of ZnSO4)*(Mol. Weight of Zn)
= (0.220g / 161g/mol)*(65g/mol)
= X grams of Zn

Then you should be able to convert to moles of Zn that X grams make and then just follow what you said.

 

[motorx]

@daabc: I'm no pharmacy math expert but I'm sure the problem does not ask for 220mg of "elemental" zinc in this patient body. YOU R KILLING your pt's kidney. In fact he's only taking 220mg of zinc sulfate (MW 161g/mol or 161mg per milimol) and out of that 161mg he's actually having 65mg of elemental zinc. Now you tackle the problem base on the percentage of elemental zinc 65mg/161mg of zinc anhydrates as to Xmg zinc/220mg zinc anhydrate. Once you get the amt of zinc the pt are getting daily (in this case X= 88.8mg or 89mg daily)

@FredyDurst: Zinc Sulfate Heptahydrate (hepta = 7 hydrate = water) so it's simply means Zinc Anhydrate + 7 water molecules or 161mg + (18mgx7) = 287mg is the mw of ZnSO4.7H2O. As you know from above, the pt needs 89mg of elemental zinc while you only get 65mg of elemental zinc from 287mg of ZnSO4.7H2O you get set it up this way: 89mg Zn/ Xmg ZnSO4.7H2O = 65mg Zn/ 287mg ZnSO4.7H20 Solve for X: Pt needs about 390mg of ZnS04.7H20 a day to get the equivalent amt of elemental Zn that he's currently taking. PharmacyXYZ: That's the answer for you

 

[nextchallenge]

I agree with motorx..This ques doesn't require complicated step, Just take care of molecular weight of anhydrous znso4(161) versus hydrous znso4 (287gm)
looking at ques
161 gm of anhydrous Znso4 contains 65 gm of elemental zinc
220 gm -----------------------------65/161 X 220 =0.08881gm = 88.81 gm

now consider hydrous form
65 gm of elemental zinc is present in 287 gm of hydrous znso4
.08881 gm----------------------------287/65 x .08881 =
0.3921 gm or 392.1 mg - answer

 

[pharmacyXYZ]

Thank you nextchallenge for solving this calculation.

 

[daabc]

A patient is currently taking 220 mg of anhydrous zinc sulphate. To receive the equivalent amount of elemental zinc, how many milligrams of zinc sulphate heptahydrate (•7 H20) would the patient have to take? (Molecular weights: zinc 65, ZnSO4 161, H20 18)

You guys sure they don't want 220mg of elemental zinc in his body? I highlighted the part of the question that seem to indicate what they wanted.

When I read that, to me, they wanted to know how much anhydrous zinc sulphate + zinc sulphate hetahydrate = 220mg elemental zinc absorbed.

I thought they wanted you to use the MM given to calculate the amount of zinc already absorbed from anhydrous zinc sulphate, and to use the reaction, mol relationship and MM to calculate how much zinc sulphate hetahydrate is needed make the total equivalent to 220mg.

FredDurst: The MM is given. So once you have the mol relationships, you can convert it to mg.

 

[pharmacyXYZ]

Hi guys,
I am still confused about the %DV calculation. Can you please solve one more problem?
1. 14 g of sugar (Carbohydrate) per 30 gram serving size of cereal? how do you calculate %DV based on 2000-calorie diet?

 

[pharmacyXYZ]

Can anyone solve the above problem?? highly appreciated!!!!!!!!
thanks

 

[daabc]

Hi guys,
I am still confused about the %DV calculation. Can you please solve one more problem?
1. 14 g of sugar (Carbohydrate) per 30 gram serving size of cereal? how do you calculate %DV based on 2000-calorie diet?

It looks like they want you to figure out how many calories is in 1 serving of cereal (14grams of carbs), and then convert it to a % base on 2000.

Does the question in your book tell you how many calories is in 1 gram of carbohydrate/sugar? Is it in the book somewhere?

 

[daabc]

Ok I was looking up values online and comparing it to my biochem book. I am just gonna stick with this estimate given by this site, since it is used for nutrition.

http://www.nutristrategy.com/nutrition/calories.htm

1 gram of carbs = 4 calories

so 14 grams of carbs ====> 14 grams of carbs x (4 calories/1 gram carb)= 56 calories

56 calories x 100%/2000cal = 2.3%

does the answer make sense and does it match what is in your book?

 

[nextchallenge]

Hi ParamcyXYZ,

Could you please explian question in detail. I do not understand, if question asked for how many gm of cereal required to fullfil DV%?
As far as DV%, I think that 70 % of daily calories are from carbohydrates.
If you have exact question please post.

Thanks

 

[Music Man]

Carbs are 3.4 kcal/g, not 4 kcal/g. Don't make that mistake on the Naplex, you will miss the question for sure...and I can't imagine there would be any calculation problems as difficult as your first problem on the Naplex.

 

[killerpenguin21]

Carbs are 3.4 kcal/g, not 4 kcal/g. Don't make that mistake on the Naplex, you will miss the question for sure...and I can't imagine there would be any calculation problems as difficult as your first problem on the Naplex.

That is incorrect.

carbs are in fact 4 kcal/g except for dextrose which is 3.4 kcal/gm. thats the mistake you dont want to make on naplex.

 

[daabc]

Carbs are 3.4 kcal/g, not 4 kcal/g. Don't make that mistake on the Naplex, you will miss the question for sure...and I can't imagine there would be any calculation problems as difficult as your first problem on the Naplex.

When I was looking up the energy/calories of carbohydrates in my books and online, I was getting multiple values depending on how it is measured. Thats why I suggested the OP look up the value that is given in his book. It is probably given in a table/chart/appendix somewhere.

As for the first question, its just a bunch of conversions using mols. I think we are disagreeing on what is being presented and what the question is actually asking.

 

[motorx]

Thank you nextchallenge for solving this calculation.

I thouht I solved your math problem FIRST (Not only that I solved it, I even pointed out to you how to approach similar math problems in the future) but you ONLY thanks nextchallenge...Ouch that's hurt I'll never come to any of your thread again pharmacyXYZ

 

[pharmacyXYZ]

Hi motorx,
I am sorry for that. I highly appreciate for your help. I may need more help from you.