If a few drops of acetone will be placed in a watch glass and be set aside for a few minutes, what type of change is evaporation?
How if about 2mL of acetone will be placed in an evaporating dish and ignite the acetone with a lighted matchstick? What type of change is the burning of a combustible matter?
If a pinch of sugar will be heated in a test tube very strongly, what type of change will take place?
Will there be any change if a few grains of clean sand will be heated?
Please I need your help.
Thank you.
2006-12-15 22:28:52 · 2 answers · asked by jann kyle_upvcc 1 in Science & Mathematics ➔ Chemistry
1. Evaporation of Acetone that takes place is a PHYSICAL CHANGE (change of phase) .
2. Combustion of Acetone that takes place is a CHEMICAL CHANGE
Reaction:
CH3COCH3 + 3O2------------3CO2+ 3H2O
3. Charring of sugar takes place on strong heating. It decomposes and you get a black layer of Carbon.
Its a CHEMICAL CHANGE.
4.No CHANGE takes place when few grains of clean sand are heated .
If heated too strongly till sand melts ,glass is formed. This takes place in furnace.
2006-12-15 23:44:17 · answer #1 · answered by Som™ 6 · 0⤊ 0⤋
The first one is ambiguous, but it's a phase change.
The second one is a phase change too, but it is the result of an oxidation-reduction reaction. That's what combustion is.
Heat it and it will liquify. (Phase Change) Heat it long enough and it will carmelize. Not sure what carmelization would be classified as.
It will become glass.
2006-12-16 06:33:59 · answer #2 · answered by jhedlind22 3 · 0⤊ 1⤋