is this physical change or chemical change?

Question

phisical or chemical-
1) metals tarnish in moist air
2)gasoline burns
3)paint fades

Answer 1

a physical change is a change the compound undergoes without changing its chemical property whereas a chemical change is one where a change takes place due to change in chemical property.

for the first.

metals are oxidised. like iron for example, becomes iron oxide.
thus this is chemical.

for the second.

burning of gasoline is combustion of hydrocarbons, producing heat, water and carbon dioxide. this too is a chemical change.

for the third.

paint fades due to light bleaching. as for this, the paint is oxidised. thus it is chemical as well.

i hope this has helped.

Answer 2

All three are chemical changes.

1 - Iron becomes Iron Oxide

2 - Hydrocarbons + O2 becomes CO2

3 - Paint oxidizes as it is exposed to O2 and UV rays over a long time

Answer 3

All three are chemical changes - even the paint fading. This can only be due to gradual chemical change. All three are examples of oxidation.

Answer 4

1. physical change
2. chemical change
3. physical change

A physical change in a substance doesn't change what the substance is.
In a chemical change where there is a chemical reaction, a new substance is formed and energy is either given off or absorbed.

Answer 5

If the change makes a different substance, it's a chemical change...

1) new one would be rust...so chemical
2) would form some kind of carbon (i think) ..chemical
3) faded paint is still paint...physical

Answer 6

All 3 are chemical changes.

Answer 7

first one is chemical
gasoline burning is chemical
third is physical

hows about a best answer vote?

Answer 8

Its