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question 7a
Question 7a

secondary 3 chevron_right A Maths chevron_right Singapore

pure chem thks

Date Posted: 2 months ago
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Eric Nicholas K
Eric Nicholas K's answer
5923 answers (Tutor Details)
A typical idea to solve mole concept questions is as follows.

1. Have a balanced chemical equation ready. In this case, it’s already given, but it’s not always the case.

2. Convert any non-mole quantity to mole. Here, we convert the mass of iron into the number of moles of iron. Note that the “3” in front of Fe is not used in the calculation of the number of moles of Fe as the coefficients are reserved for mole ratio comparisons.

3. Use the mole ratio comparison (ie comparing coefficients) to find the number of moles of the required substance formed/required. Here, we link Fe to Fe3O4 (for obvious reasons).

4. Convert the mole quantity into the quantity required. Here, we need to convert the number of moles of Fe3O4 into a mass figure.