A chemical equation is the symbolic representation of a chemical reaction in the form of symbols and formulae, wherein the reactant entities are given on the left-hand side and the product entities on the right-hand side
A chemical symbol is a notation of one or two letters representing a chemical element
A chemical formula identifies each constituent element by its chemical symbol and indicates the proportionate number of atoms of each element.
Answer:
39g
Explanation:
Details of the solution is shown below. From the information provided regarding the N2 produced, we could calculate the amount of N2 produced and use that to find the mass of sodium azide reacted.
Answer:
4.525% is the percentage by volume of oxygen in the gas mixture.
Explanation:
Total pressure of the mixture = p = 4.42 atm
Partial pressure of the oxygen = 
Partial pressure of the helium = 
(Dalton law of partial pressure)





According Avogadro law:
(At temperature and pressure)
Volume occupied by oxygen gas =
Total moles of gases = n = 1 mol
Total Volume of the gases = V


Percent by volume of oxygen in the gas mixture:

Answer: Event 1 is an example of a physical change and Event 2 is an example of a chemical change.
Explanation: Physical change is one in which there is no change in chemical composition of the substance. There is only a change in phase change.
Chemical change is a change in which there is a change in chemical composition and there might or might not be a phase change.
On Boiling, the water molecules remain bonded in the same form and only covert from liquid to gaseous form, thus is a physical change.
On Rusting of iron nail, the iron changes to iron oxide by combining with oxygen, there is a rearrangement of atoms and thus is a chemical change.

The tilt of the Earth on its axis is what causes the seasons.