Which element contains the greatest number of moles?

 Which element contains the greatest number of moles?

A. 8g of Helium

B. 48 g of Carbon

C. 78 g of Potassium

D. 130 g of Zinc

E. 216g of Silver

The correct answer is B. 48 g of Carbon.

Explanation:

A mole is a unit of measurement that helps us count particles at the atomic level. It is defined as the amount of any substance that contains as many elementary particles as there are atoms in exactly 12 grams of pure carbon-12. This number is known as Avogadro's number, and it is approximately 

6.022×10'23 particles per mole.

In order to find out which element contains the greatest number of moles, you need to know the molar mass of each given element. 

The molar mass of an element (in g/mol) is numerically equal to the element's atomic weight. 

Given below are the molar masses of the elements:

 Helium (He) = 4 g/mol, 

Carbon (C) = 12 g/mol, 

Potassium (K) = 39 g/mol, Zinc (Zn) = 65 g/mol, and 

Silver (Ag) = 108 g/mol.

To calculate the number of moles of each element, you divide the given mass of the element by its molar mass.

Formula n=m/mm

For instance, for Helium, it would be 

8g÷4g/mol=2moles

For Carbon it would be 

48g÷12g/mol=4moles

For Potassium it would be

78g÷39g/mol=2moles

For Silver it would be

216g÷108g/mol=2moles

After this calculation for all the options, we find out that Carbon (48 g) contains the greatest number of moles, which is 4 moles making option B the chosen one.

SOURCE: NECO CHEMISTRY 2001 QUESTION 27