Answer:
is this the question?please
Answer: 0.462 moles
Explanation: 13C indicates an isotope of carbon and its mass number is 13. It means the mass of 1 mol of 13C is 13 gram.
The question asks to calculate the number of atoms present in 6.00 grams of 13C.
To calculate the number of moles we divide the given grams by the mass of 1 mol of the element. The set could be shown easily using dimensional analysis as:

= 0.462 moles
So, there will be 0.462 moles of atoms in 6.00 grams of 13C.
Answer:
c) more OH⁻ ions than H₃O⁺ ions
Explanation:
A substance with a PH of 9 implies that it has more OH⁻ ions than H₃O⁺ ions.
Such substances are said to be an alkaline or a base.
A base is a substance the produces excess hydroxyl ion in aqueous solutions.
An acid will produce excess hydroxonium ions in a solution.
So, the pH scale is used to indicate whether a substance is an acid or base or non of them.
Acids have pH of less than 7
Bases have pH of > 7
<span>From the above given choices :
melting is an endothermic process</span>