C. Ninhydrin is used to detect prints on a non-porous surface
Answer:
Excess Reagent = oxygen
Explanation:
Limiting reagent: The substance that is totally consumed when the reaction is completed.
Excess reagent: The substance left after the limiting reagent is consumed completely
The balanced chemical equation for formation of water is as follow:

This means when 2 moles of hydrogen reacts with 1 mole of oxygen, 2 moles of water is produced.
Hence the ratio in which hydrogen and oxygen gas reacts is 2:1
Now if 2 mole hydrogen require 1 mole of oxygen ,then 4 mole hydrogen need 2 mole of oxygen.

or

Here 5 mole of oxygen is reacting but only 2 mole is required .
Oxygen is in excess.
Answer:
Explanation:
Chemically, we can have a reaction between chlorine gas and solid sodium
This reaction is actually explosive and would produce fine powder of sodium chloride
We have the reaction as follows:

Essentally, what we can deduce from here is that we do not need to add water to the flask. Except for the reason that we would want the sodium chloride solid in the solution form, there is absolutely no reason to add water to the flask as the reaction would proceed normally
Answer is: because they were using simple chemical reactions to transform elements, but that is possible only with nuclear reactions, which in that time were not possible to conduct.
Nuclear reactions can produce new elements, because number of protons and neutrons is changed, lead and gold have different atomic and mass numbers.
The electrons of an atom participates in a chemical reaction, chemical reactions involve the rearrangement of electrons, because there is transfer, loss, gain and sharing of electrons in chemical reactions, new elements are not formed.
Answer:
5.17 × 10^-1
Explanation:
move the decimal to the right one space.
when you move the decimal to the right its exponent becomes a negative.