Iron is the most commonly used metal iron is extracted in a blast fumace from iron oxide using carbon monoxide.
Fe:03
Fe 300
A sample of the ore haematite contains 70% iron oxide.
Calculate the amount of iron oxide in 2000 tonnes of haematite.
tonnes
Amount of iron oxide =

70/100 X 2000 = 1400 tonnes of iron.

Explanation:

take the percentage of iron oxide and divide with overall amount of iron oxide using 2000 tonnes of hematite ore. 1400 tonnes of iron will be produced. this is not the percentage. if you want the percentage of iron produced just divide.

70/100 x 200 = 1400 tonnes of iron

percentage of iron produced = 70/1400 x 100 = 5 % of iron produced from 70% of iron oxide in 2000 tones of hematite ore

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.

the answer is a and have a great day