Answer:
A is the answer. Chemical changes happen when atomic bonds are broken or created during chemical reactions. Hence, in this case, it involve changes to molecular structure.
- Change in states are physical changes.
- When salts are dissolved in water, you can use Distillation to separate them. Distillation is a physical change as well.
- Dissolving is just physical change.
Explanation:
The statement that is true of a chemical change among the statements given in the question is "It involves changes in the molecular structure". The correct option among all the options that are given in the question is the first option or option "A". I hope the answer has actually come to your help.
The atomic number is equal to number of protons present in the nucleus of an atom or vice-versa. For any atom, there is no change in number of protons either by adding or removal of electron.
Since, sodium is a metal, it has tendency to lose electron in the presence of non-metal i.e. chlorine. Thus, after lose of an electron, there is no change in the number of protons or number of protons will remain same.
Therefore, atomic number of metal is 11 which is also equal to the number of protons implies sodium will have 11 protons in its nucleus.
The characteristic being calculated here is the mean or the average of the data set.
To check:
(20.73 + 20.76 + 20.68 + 20.75)/4 [we divide it by 4 because there are 4 numbers]
= 82.92 / 4
= 20.73
That would be exothermic. Exothermic reactions are processes that release energy, usually in the form of heat or light. Energy is released because the total energy of the products is less than the total energy of the reactants.
