chemistry

[sbi17111995]

1.the gas obtained om the reduction of iron with carbon is:
2.a black substance that behaves both as an oxidising agent and a catalyst is

[Mrs Y]

1. Carbon Dioxide. The reduction of iron is a two-stage process; during the first stage, Carbon is added which reacts with Oxygen to produce Carbon Monoxide (CO). During the second stage, the CO reduces the iron ore (FE2O3) to become pure iron (FE), and Carbon Dioxide (CO2).

2. Could it be Carbon?

[theprof]

Hmm, blast-furnace reduction. Let's have a look at number one again.

The first thing that happens is that carbon reacts with oxygen (from hot-air) to produce carbon dioxide

C + O2 = CO2

Excess carbon reacts with the carbon dioxide to form carbon monoxide

CO2 + C = 2CO

The carbon monoxide then reacts with the iron (iii) oxide (haematite) in the blast furnace to form carbon dioxide. The reason this happens is that the CO reacts with the oxygen in the haematite to form carbon dioxide.

Fe2O3 + 3CO = 2Fe + 3CO2

I'll leave the deduction of which gas is the answer to you.

[theprof]

Think of laboratory oxygen production involving potassium chlorate and manganese dioxide. One of these two substances is black,an oxidising agent and a catalyst

[Teddio]

A very poor and incomplete question! Iron is not reduced by carbon. Why do we have to assume the question is about the reduction of iron oxide in a blast furnace, thus adding oxygen to the process? I'm not being pedantic either.

[Mrs Y]

I apologise for making assumptions; just using my (very) limited knowledge to try and help.

Do you have any idea what the answer should be, Teddio? And could you explain it to me?

[Teddio]

Mrs Y, your answer is fine! I was just criticising the question for being incomplete and vague.
The question is probably asking about the Blast Furnace. iron oxide (with Fe in oxidation state +2 or +3) is reduced to Iron (oxidation state zero) by carbon monoxide gas.
The CO gas is produced in the two-step process you describe.
The CO is oxidised by the iron oxide to carbon dioxide.

[Mrs Y]

I wasn't being funny, just genuinely interested. Really didn't know that there were different types of iron reduction; only ever heard of blast furnace. Thanks for that x

[theprof]

Teddio, you are correct in that the question is incomplete and vague. Furthermore, I acknowledge that at face-value it might not be correct to assume that the question was about blast-furnace reduction. It was a mere off the cuff remark about a typical practical application of the reaction.

Nevertheless, you have to concede that each of the compounds and gases mentioned are formed in the correct sequence during blast-furnace production, so as far as the reaction is concerned, yes, blast furnace reduction might be said to be a process during which these sequence of reactions occur. Offhand, I know of no other and I'm pleased that you acknowledge that the reaction is probably about the blast furnace reaction in your last post. I merely used the reaction to outline a typical process during which such a sequence occurred.

As you are aware, oxygen is needed for the reaction stages to occur. the fact that this oxygen is sourced from air is incidental and it would work equally well with pure oxygen when cost was left aside.

I added my contribution as Mrs Y omitted to mention that carbon dioxide is the first gas produced rather than carbon monoxide.

The thing that baffled me for a few moments was the randomness of the two questions. I then realised that they might be taken from a class workbook that merely required short answers. I've never been a fan of these books and this is just another example about how kids nowadays often fail to appreciate the finer points of the sciences.