Explanation:
The given reaction equation is as follows.
+ ___ 
As there is release of one hydrogen which shows that mass number has increase by 1 on the product side.
Therefore, particle 
must be added in order to balance the given reaction equation.
Hence, the complete reaction equation will be as follows.
I would say that descriptive investigations aren't repeatable because it means that you are only describing something - you ask certain question about something, but do not form a hypothesis at that point yet. So it would be a waste of time to simply ask the same questions over and over again with no hypothesis to prove, which is why these types of investigations cannot be repeated.
Answer:
A product in science is a substance that is formed when two or more chemicals react.
Explanation:
When a chemical reaction takes place, a new substance is often created from the atoms or molecules of the original substances. There are often multiple products formed in a reaction.
Answer: 3
Explanation: You may not always get feedback that would be helpful and requesting the answer would be cheating
