Question 15
Question 15 of 40
Question image for Q15
Periodic Table
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No letter options?
Older MCQs might not have the typical A, B, C, D choices. They have choices 1, 2, 3, and a combination of them is the answer. Below is the key that maps such combinations to the answer.
A 1, 2 and 3 are correct
B 1 and 2 only are correct
C 2 and 3 only are correct
D 1 only is correct
Topics Tested
9. Metals
9.6. Extraction of metals

State the symbol equations for the extraction of iron from hematite (a) ( C + O_2 ightarrow CO_2 ) (b) ( C + CO_2 ightarrow 2CO ) (c) ( Fe_2O_3 + 3CO ightarrow 2Fe + 3CO_2 ) (d) ( CaCO_3 ightarrow CaO + CO_2 ) (e) ( CaO + SiO_2 ightarrow CaSiO_3 )

6. Chemical reactions
6.4. Redox

Identify redox reactions by changes in oxidation number using: (a) the oxidation number of elements in their uncombined state is zero (b) the oxidation number of a monatomic ion is the same as the charge on the ion (c) the sum of the oxidation numbers in a compound is zero (d) the sum of the oxidation numbers in an ion is equal to the charge on the ion