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Q: What is the % of magnesium in magnesium sulfate? ( Answered 5 out of 5 stars,   1 Comment )
Subject: What is the % of magnesium in magnesium sulfate?
Category: Science > Chemistry
Asked by: karon-ga
List Price: $10.00
Posted: 23 Apr 2004 01:08 PDT
Expires: 23 May 2004 01:08 PDT
Question ID: 334746
The whole question is, weight by weight, what is the % of:

magnesium in magnesium sulfate?
iron in iron sulphate?
potassium in potassium sulfate?
zinc in zinc sulphate?
manganese in manganese sulfate?

Thank you.
Subject: Re: What is the % of magnesium in magnesium sulfate?
Answered By: eiffel-ga on 23 Apr 2004 13:08 PDT
Rated:5 out of 5 stars
Hi karon,

A sulfate (or sulphate) is a compound in which the hydrogen of
sulfuric acid is replaced by a metal.

Let's start by noting the atomic weights for the elements related to your question:

      sulfur: 32.1
      oxygen: 16.0
   magnesium: 24.3
        iron: 55.8
   potassium: 39.1
        zinc: 65.4
   manganese: 54.9

We will then calculate the molecular mass for each of the sulfates,
and work out the proportion that the metal forms of the total. These
calculations assume that you are interested in anhydrous forms. If you
are interested in hydrated forms, let me know which hydrated forms you
wish me to use.

According to the Sargent-Welch website
the relevant formulae are:

   magnesium sulfate: MgSO4.
        iron sulfate: FeSO4
   potassium sulfate: K2SO4
        zinc sulfate: ZnSO4
   manganese sulfate: MnSO4

Therefore, the proportion of magnesium in magnesium sulfate, weight for weight, is

   24.3 / (24.3 + 32.1 + 64) = 20.2%

The proportion of iron in iron sulfate, weight for weight, is

   55.8 / (55.8 + 32.1 + 64) = 36.7%

The proportion of potassium in potassium sulfate, weight for weight, is

   (39.1 * 2) / ( (39.1 * 2) + 32.1 + 64) = 44.9%

The proportion of zinc in zinc sulfate, weight for weight is

   65.4 / (65.4 + 32.1 + 64) = 40.5%

The proportion of manganese in manganese sulfate, weight for weight, is

   54.9 / (54.9 + 32.1 + 64) = 36.4%

Please request clarification if this answer does not yet meet your needs.


Periodic Table - WebElements
(for the atomic weights)

Google Search Strategy:

define: sulfate

"magnesium in magnesium sulfate OR sulphate"

"magnesium sulfate OR sulphate" forumula

"iron sulphate OR sulfate"

"atomic weight" magnesium

"potassium sulfate OR sulphate" chemistry formula


Request for Answer Clarification by karon-ga on 26 Apr 2004 05:13 PDT
Thank you, Weiffel-ga.

For a $5 tip, could you please confirm to me the weight of each
sulfate needed to produce:

78.1 mg of magnesium
131 mg of potassium
9.1 mg of iron
10.2 mg of zinc
9.1 mg of managanese

Many thanks

Clarification of Answer by eiffel-ga on 26 Apr 2004 08:20 PDT
Hi karon,

78.1 mg of magnesium is contained in 387 mg of MgSO4

131 mg of potassium is contained in 292 mg of K2SO4

9.1 mg of iron is contained in 24.8 mg of FeSO4

10.2 mg of zinc is contained in 25.2 mg of ZnSO4

9.1 mg of managanese is contained in 25.0 mg of MnSO4

Thanks for an interesting question!

karon-ga rated this answer:5 out of 5 stars and gave an additional tip of: $5.00
Thank you, Eiffel.

Subject: Re: What is the % of magnesium in magnesium sulfate?
From: eiffel-ga on 27 Apr 2004 03:30 PDT
Thaks, karon, for the kind comments and tip.


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