Is mixing sodium chloride sand and water a chemical or physical change?

Answer 1

It depends on how the mixing is performed. If you take the two solids and mix them then it is a physical change as you get a heterogeneous mixture of solids. If you dissolve and them and mix the solutions- then a chemical change may occur- as different compounds are formed.

Na2CO3 + CaCl2---> 2NaCl + CaCO3

Answer 2

Mixing the two results in a chemical change via the reaction.

NaHCO3(s) + CH3COOH(l) → CO2(g) + H2O(l) + Na+(aq) + CH3COO-(aq)

with s = solid, l = liquid, g = gas, aq = aqueous or in water solution

Another common way to write this reaction is:

NaHCO3 + HC2H3O2 → NaC2H3O2 + H2O + CO2

The above reaction, while technically correct, does not account for the dissociation of the sodium acetate in water. The chemical reaction actually occurs in two steps. First, there is double displacement reaction in which acetic acid in vinegar reacts with sodium bicarbonate to form sodium acetate and carbonic acid:

NaHCO3 + HC2H3O2 → NaC2H3O2 + H2CO3

Carbonic acid is unstable and undergoes a decomposition reaction to produce the carbon dioxide gas:

H2CO3 → H2O + CO2

The carbon dioxide escapes the solution as bubbles. The bubbles are heavier than air, so the carbon dioxide collects at the surface of the container or overflows it. A dilute sodium acetate solution remains after the reaction. Although you certainly see some physical phenomena as a result of the chemical change, it doesn't qualify as a physical change because the actual compounds are changing. In a purely physical change, you still have all the same compounds but they have changed in some physical way such as melting, freezing, evaporating, condensing, getting hotter or colder, expanding or contracting, dissolving or precipitating out of solution, being broken into pieces or coalescing, etc.

Answer 3

This a physical change because when you let the mixture dry, the sand and salt are the same and have not chemically changed. They are still sand, salt and water (evaporated). If they had been chemically changed, you would not be able to change them back.

Answer 4

No. It is a chemical change as sodium chloride, water and carbon dioxide are the product.

Answer 5

chemical change

Answer 6

This is a physical change.

Answer 7

Mixing is a physical process.

Answer 8

It is a physical change.

Answer 9

Chemical