which of the following is a physical change?

Question

a. milk becomes sour
b. an iron nail rusts
c. all the water in a solution of salt water evaporates leaving a lot of crystals of salt in the bottom of the dish
d. A wooden log is burned leaving ash in the fireplace

Answer 1

a. milk becomes sour due to microbial action causing a chemical change that leads to the formation of sour tasting chemicals.

b. iron reacts with the oxygen and moisture of the atmosphere forming rust i.e., hydrated iron (III) oxide Fe 2 O3.nH2O . So, this is a chemical change too.

d. a wooden log undergoes combustion using oxygen and forms ash which is mainly carbon. This is chemical change too.

so, c is the right answer as water evaporates and forms vapor, leaving behind crystals of salt. The change of state of water is a physical change, as there is no change in its chemical composition, and the process can easily be reversed.

Answer 2

I guess all of them are physical change ocurring due to chemical reactions.
Milk becomes sour - the bectrial growth will change the physical properties of milk like viscousity.
Iron Nail rust - the chemical recation will transform iron to iron oxide and thus reducing the weight of iron nail
Salty water solution - is obvious as mentioned in all other ans.
Wooden Log is burned - again the burning process changes the physical properties of the remains so its again a physical change.

Answer 3

A) experience Burning - Chemical. The reaction between the experience head and the friction (warmth) motives a chemical reaction (particularly burning, an extremely hardship-loose chemical substitute indicator). B) Glass Breaks - actual. The glass nevertheless exists, it relatively is outward visual attraction has only been replaced - breaking is a hardship-loose actual substitute indicator. C) Rubber Band Being Stretched - actual. The rubber band remains a rubber band. that's only a sprint elongated. besides, whilst released, it assumes its unique variety. no longer something replaced. D) Iron Rusts - Chemical. The chemical composition of the iron is being replaced. The rust replaces the iron. Rusting is yet another hardship-loose indicator of a chemical substitute going on. E) Ice Melts - actual. Water, water vapor, and ice all have a similar chemical composition - the all too established H2O. only because of the fact it relatively is melted does no longer recommend it relatively is replaced chemically. a similar is going for all melted gadgets. F) Sugar cube overwhelmed - actual. it relatively is comparable to the glass breaking in that the sole ingredient it relatively is replaced is its outward length. besides the shown fact that, dissolving in water could be a chemical substitute.

Answer 4

c..Only, is a physical change.
As the water simply changes to vapour it's still water in a different form.
The salt in solution comes out as crystals when the water evaporates. It is however, still salt in solid form..

Answer 5

Is this a trick question?

a) which is an organic transformation.
b) is an oxidation reduction reaction
c) is evaporation, the salt is unchanged
d) is a chemical metemorphis leaving a residue.

I guess C)

Answer 6

'Which' of the following is a physical change?mm... Actually there is no which in that following. Then, how can you say that 'which' is a physical change. You are hear only to ask questions in this section and not to state your own laws! Anyway, for your ultimate satisfaction,........ C!!!

Answer 7

c. change of state from liquid to gas is a physical change that is easily reversible. The others changes listed are all chemical and exhibit a color change.

Answer 8

C. because it is not completly changing it inot something new. It's still the same, just in a different form. Hope this helps

Answer 9

only c is a physical change

Answer 10

answer c

Others are chemical changes