F.3 Chemistry 唔明 pls help :D

Jenny

2011-11-14 4:50 am

1. Salmon steak is grilled on the barbecue 同 Slices of bread are toasted 係咪 chemical change?

2. Heating a mixture of iron and sulphur 係chemical change 因為有new substance formed (iron sulphide) ，但係點解alloy唔算chemical change? 都係融左佢地一齊wor.

3. Chemical formula 係咪通常寫C先，然後到H，之後係O?

4. 本書一時話body of aircraft係用aluminium做，一時又carbo-fibre0reinforced plastics，一時又duralumin，係咪種種都會用ga?

5. Water pipe通常用plastic, iron 定copper? 邊種最好?

Thanks a lot!!

回答 (1)

用戶9394

2011-11-15 2:34 am

✔ 最佳答案

1. There is a chemical change because the oil & carbohydrate are burned to form some carbon & some oil reacted to higher polymers or fused with the protein .
2. When 2 elements reacted to form a new cpd , this is chemical change . FeS is a new substance while an alloy is only a mixture of 2 or more metal elements .
3 . Yes , always in this way .
4. Different parts of the aircraft will have different substances to buld it up. They serve multi functions .
5 Durable plastic pile is mostly employed for water delivery because it is light , not rusting & cheaper too ,

👍 0 👎 0