Flame test

Tom

2007-09-15 2:44 am

我知道flame test 是test certain metal in metallic compounds，那我想問如果我heat CaCO3的話，它是不是應該有brick-red flame嗎?
By the equation:
CaCO3＝＝＝＞CaO + CO2
如果keep on heating，即是CaO被heat啦，即是不是應該亦有brick-red flame啦?但是我們知道CaO＝＝＝＞CaO，即是沒有反應啦，那flame是不是一直是brick-red in colour?

回答 (1)

Steve

2007-09-15 5:48 am

✔ 最佳答案

BURN (燒) 唔同 HEAT (加熱)
Burning that is the substance react with oxygen
In flame test, it is burning
burning calcium ion will give brick red falme color

But the equation you stated is decomposition of calcium caebonate by heating
We put the sample in a test tube and heat the test tube (the sample) by Bunsen burner
This is heating, only increases its temperature until the temperature is high enough for the decomposition to occur

So they are actually different actions

Similarly, if you burn CoCO3, there will not be CO2 given out

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