Answer: Option (3) is the correct answer.
Explanation:
A reaction due to which there occurs change in chemical composition of reactants is known as a chemical reaction.
For example, evolution of heat when two substances combine together shows a chemical reaction has taken place between the substances.
Whereas a reaction which does not bring any changes in chemical composition of the reactants is known as a physical reaction.
For example, boiling point, melting point, mass, volume etc are all physical properties.
Thus, we can conclude that out of the given options a substance melts when sitting in the Sun, is not an indication of a chemical reaction.
Answer:
One mole is defined as the amount of substance containing as many elementary entities (atoms, molecules, ions, electrons, radicals, etc.) as there are atoms in 12 grams of carbon-12 (6.023 x 1023). The mass of one mole of a substance equals its relative molecular mass expressed in grams. Also spelled as mol.
It's False.
Only metals can be conductors of heat and electricity.
Answer:
The Letter I
Explanation:
There are two flat horizontal lines. Those are phase changes. I is the solid state before the first phase change where the substance goes from a solid to a liquid.
So the answer is I
