k456456

How to do a,b ???
Help

edogawaconan

a）because excess towngas is burnt there
b）when the solid turns from orange to silvery grey because Pb is formed from the reaction between PbO and H2 and CO.(i think the anwser should be something like this)

k456456

但係a 個度,個set-up仲未有heating....

唔明

edogawaconan

Well then I am not so sure about that... Because normally a fire should not be ignited without heating the town gas... Solely referring to the diagram, heating and combustion of excess town gas should exist simultaneously...

helloeveryone

引用:

原帖由 k456456 於 2014-2-23 06:43 PM 發表
但係a 個度,個set-up仲未有heating....

唔明

town gas starts to pass through Lead oxide before heating starts, and during that time no town gas is used, so some town gas will exit at the end of the delivery tube,
However, town gas in flammable, it is dangeous to release it directly into the lab, so we must burn them in order to consume excess gas.

edogawaconan

but the point is that, without heating, towngas itself should not burn . Now that in this question, the town gas combusts before it is heated.

helloeveryone

引用:

原帖由 edogawaconan 於 2014-2-23 08:02 PM 發表
but the point is that, without heating, towngas itself should not burn . Now that in this question, the town gas combusts before it is heated.

I believe the heating in the chamber does not ingite the town gas because there is no oxygen inside the chamber
Besides, if the heating ignite the town gas, combustion should occur inside the chamber and ruin the lead oxide.
I believe the town gas's ignition has nothing to do with the reaction itself, we ignite town gas at the end of the tube on purpose, which is to consume the excess gas.
May be they ignite the gas using a lighter or a burning split, but the heating of the chamber does not ignite the gas

[ 本帖最後由 helloeveryone 於 2014-2-23 08:16 PM 編輯 ]

edogawaconan

o i c yr point. Yes, you re correct. The excess towngas which escapes from the hole has to be ignited first before the tube is heated.

Abbichiu

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