B. compound a material that contains three elements joined in a fixed proportion
Answer:- 0.00724 moles.
Solution:- Grams of salicylic acid are given and it asks to calculate the moles.
For the moles, we divide the grams by the molar mass.
Formula of salicylic acid is 
Molar mass = 7(12.01)+6(1.01)+3(16.00)
= 84.07+6.06+48.00
= 138.13 gram per mol
We could make the dimensional analysis set up for showing unit cancellation and have the moles.

= 0.00724 moles
So, there will be 0.00724 moles of salicylic acid in it's 1.00 gram.
Dark is just absence of light like if the re container a and container b u nee to pour hcl from a to so a has hcl while b has absence of hcl
tell me if u need more examples.hope it helps
Products. I’m not 100% sure because I don’t fully understand what your asking but if you are talking as in chemical reactions, the answer is a product.
Explanation:
Whenever we need to make a dilute solution of an acid then it is necessary to add water or non-acidic component into the acid first. This is because addition of water or non-acidic component directly into the acid could be highly exothermic in nature.
As a result, the acid can splutter and can cause burning of skin and other serious damage.
So, in order to avoid such type of damage the addition of water or non-acidic component into the acid actually helps to minimize the heat generated.
Thus, we can conclude that correct order of steps for making a more dilute solution of an acid is that either add all of the water or non-acid component first, or add a significant portion, before adding the acid to the mixture.