Question

1: Physical properties of ice, water, and steam are very different.
2: Chemical composition of water is different in all three states. Explain.
A.Only 1 is true
B.Only 2 is true
C.Both are true
D.Both are false

Answer 1

We know that physical properties are observed without any changes in composition of matter. Physical properties describe the intensive property (or) extensive property. Some of the physical properties include density, colour, conductivity etc. Chemical property is a feature where the characteristic could be determined by change in molecular structure of substance.

Complete answer: We know that ice is a solid, water is a liquid, and steam is gas. Physical properties of material depend on the strength of intermolecular force.
In solids, the energy of attraction between molecules is quite large compared with the average kinetic energy of the molecules and almost none of the molecules has enough energy to overcome the attractions. The molecules adopt an orderly arrangement that maximizes the energy of attraction, leading to the rigid characteristics of a solid.
The intermolecular forces in liquid are stronger enough to hold molecules close to each other but small enough that the molecules can move about. The attractive forces are not sufficiently strong to keep neighboring molecules in constant position and molecules are free and hit over each other.
In gases, the molecules are more separated and the absence of any important attractive force between molecules allows a gas to expand to occupy its container. The kinetic energy of the molecules is higher than any attractive forces present between the molecules.
So, statement 1 is true.
We know that the chemical composition of ice is ${H_2}O$, the chemical composition of water is ${H_2}O$ and chemical composition of gas is ${H_2}O$. The chemical composition of water is the same in all the three physical states. So statement 2 is false.
Therefore, the option (A) is correct because only statement 1 is true.

Note: We have to know that the strength of intermolecular attractions determines the stability of phases at a given temperature.
Example:
At room temperature, nitrogen is a gas, water is a liquid, and iodine is solid. The intermolecular forces present in nitrogen are weaker than those present in water that in turn is weaker than that of iodine. At higher temperature, both nitrogen and water are gases, but iodine remains as a solid. Therefore, the stability of phase of a substance is temperature dependent.