Chemists want to place 2 x 10^24 atoms of carbon in a chemical reaction. How would they obtain this amount?

Explanation:

To determine what is been asked in this question, firstly, the formula to determine the number of atoms present in a substance must be used. The formula is

number of atoms = n × 6.02 × 10²³

where n is the number of moles

6.02 × 10²³ is avogadro's number

The number of atoms needed (to be present) has already been provided in the question as 2 × 10²⁴

Thus;

2 × 10²⁴ = n × 6.02 × 10²³

n = 2 × 10²⁴ ÷ 6.02 × 10²³

n = 3.32

The number of moles of carbon that will be placed in the reaction will be 3.32 but to determine the amount/mass of carbon that will be used in the reaction, we will use the formula

n = mass/molar mass

The molar mass of carbon is 12 g/mol

Thus;

3.32 = mass/12

mass = 3.32 × 12

mass = 39.84 g

The mass of carbon that will be required for the reaction will be 39.84, the procedure above shows how to obtain this amount.

The correct option is B.
This question is testing your knowledge of the differences between solid and liquid particles. The particles of the solid vibrate around a fixed position, they can not move about while those of the liquid are able to move to some extent. The candy in Damien's pocket melted because it was heated up by the temperature of his body. Because the particles of the chocolate has been heated, they gain more kinetic energy and they vibrate faster compare to that of the solid chocolate.