Is flour and milk mixed a physical change or a chemical change?

Answer 1

It's a physical change. The various constituents of flour are all organic compounds, and water is usually a neutral medium with organic compounds (the only exceptions I know of are the various organic acids like acetic acid (vinegar)).

However, if you ask this because you want to use flour that got soaked, I don't really recommend it. Flour is a very good source of carbohydrates, which lots of things can very easily digest. Wet flour has basically everything necessary for a lot of simple life forms, so it has a decent chance of mouldering or getting infested with insects.

In general, chemical reactions are accompanied by one or more of:
Temperature change
Generation of light (though most of the reactions that do this are rather dangerous, like sodium and water, or TNT, or combustion (burning)
Generation of bubbles (though this is also caused by heating things to boiling)
Formation of a precipitate (seemingly clear water suddenly has small particles (like table salt) floating in it when something is added)
Color change (like rust - iron to iron oxide... and steel is just iron with a bit of carbon in it)
Source: answers.com question on indicators in chemical reactions.

I'd also like to add rapid changes of physical state (solid-liquid-gas-aqueous, the latter of which is when you have something dissolved in water to the point where it can't be removed) to that list, though it's hard to see in lots of cases. Being a student in a hydrometallurgy class, I'd be remiss not to add the key indicator of importance in hydrometallurgy.

Answer 2

flour mix with water is a physical change because when you will mix it ,flour will settle down at the bottom and we can separate it out by filteration.

Answer 3

This is a physical change