Ferrous sulphate heptahydrate is used to fortify foods with iron. The amount (in grams) of the salt required to
achieve 10 ppm of iron in 100 kg of wheat is _______.
Atomic weight : Fe = 55.85; S = 32.00;
O = 16.00
Answer (integer)
4
Solution
FeSO<sub>4</sub>.7H<sub>2</sub>O (M = 277.85)
<br><br>PPM = <span style="display: inline-block;vertical-align: middle;">
<div style="text-align: center;border-bottom: 1px solid black;">Mass of Iron</div>
<div style="text-align: center;">Mass of wheat</div>
</span> $\times$ 10<sup>6</sup>
<br><br>$\Rightarrow$ 10 = <span style="display: inline-block;vertical-align: middle;">
<div style="text-align: center;border-bottom: 1px solid black;">Mass of Iron</div>
<div style="text-align: center;">100 $\times$ 10<sup>3</sup></div>
</span>$\times$ 10<sup>6</sup>
<br><br>$\Rightarrow$ Mass of Iron = 1 gm
<br><br>Molecular mass of FeSO<sub>4</sub>.7H<sub>2</sub>O is 277.85
<br><br>55.85 gm iron is present in 277.85 gm of salt
<br><br>1 gm iron is present in = ${{277.85} \over {55.85}}$ = 4.97 gm of salt.
About this question
Subject: Chemistry · Chapter: Some Basic Concepts of Chemistry · Topic: Mole Concept
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