Answer:
Is the source an authority on the subject?
Explanation:
To figure out which source is accurate, you want to find out the source's authority on the subject. For example, if you wanted to learn how to play the piano, you wouldn't go to a dance teacher, you would go to someone who knows how to play the piano. The person who knows how to play the piano has more authority to teach the piano than a dance teacher.
The answer is c. number of protons and d. atomic number. The proton number can identify an element. And also the atomic number is equal to the number of protons.
Answer:- Mole ratio of D to A is 4:3.
Explanations:- Mole ratio for a chemical reaction is the ratio of the coefficients.
The given generic chemical reaction is:

The numbers written in front of each chemical species in the chemical reaction are their moles. For the given generic chemical reaction the coefficient of A is 3 and that of B is 1. So, the mole ratio of A to B is 3:1.
Similarly if we want to write the mole ratio of C to D then it is 1:4.
We are asked to write the mole ratio of D to A. So, like the other ratios, the mole ratio of D to A is 4:3 as the coefficient of D is 4 and A is 3.
Answer:
Wavelength, 
Explanation:
Given that,
Frequency, 
We need to find the wavelength of a photon of light. The relation between frequency and wavelength is as follows :

So, the wavelength of the light is
.
Answer:
CaO(s) + 2NH4Cl(aq) -------> CaCl2(aq) + H2O(l) + 2NH3(g)
Explanation:
The solvay process is an important process in the chemical industry. In this process, ammonia gas is first dissolved in concentrated brine to form a mixture known as ammoniacal brine. This solution is made to trickle down the tower. A counter stream of carbon dioxide is forced up the tower. The two substances react to form sodium hydrogen trioxocarbonate IV. This substance is only slightly soluble and separates out as a solid sludge. The product is now dried and heated to give sodium trioxocarbonate IV.
The overall reaction of the process can be given as;
CaO(s) + 2NH4Cl(aq) -------> CaCl2(aq) + H2O(l) + 2NH3(g)
Calcium chloride is merely a by-product.