Answer:
0.034 mol (4dp)
Explanation:
Use the formula n = m/M where n= number of moles, m=mass in grams and M=molar mass in g/mol.
Therefore to find how many moles, divide the mass in grams (2) by the molar mass of sodium chloride which is 22.99+35.45
Answer:
B) K2X
Explanation:
In an uncharged compound, the total oxidation state must be zero. The oxidation state of the calcium is +2, thus we get the following formula, where x is the oxidation state of the polyatomic ion X:

Also, it is known that potassium has an oxidation state of +1. Since the new compound also has a total oxidation state equal to zero, we get the following equation, where k is the number of K atoms:

That's how it is found that the compumd consists of 2 K+ ions and one X ion.
Answer:
CO
Explanation:
the rest are elements. CO is made up of one carbon atom and one oxygen atom