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.
When you add salt to water, you lower to freezing point of the substance.
So for example, normal water freezes at 0°C. But water with salt in it won't freeze at 0°C, because its freezing point is lowered.
In answer to the question. It takes longer for water with salt in it to freeze because the substance requires a lower temperature than normal water to freeze.
The reaction equation represents the mole number ratio. So the hydrogen is 8/2=4 mol. Oxygen is 64/32=2 mol. So the water is 4 mol. The mass of water is 4*18=72 g. Or if it is confirmed that they are completely reacted. You can simply add them up.
Answer:
Sulfur has the same amount, like all the other elements in group 16, has six valence electrons.
Explanation:
