Question

How many moles of each B and D are present before the reaction occurs?

a. 0.1 moles of B, 0.1 moles of D
b. 0.2 moles of B, 0.2 moles of D
c. 0.1 moles of B, 0.2 moles of D
d. 0.2 moles of B, 0.1 moles of D

Answer 1

To calculate the number of moles for each sample, divide the mass of each element by its molar mass. For boron (B), there are 2 moles. For manganese (Mn), there is 1 mole. For mercury (Hg), there are 0.5 moles. For barium (Ba), there are 0.364 moles. For lead (Pb), there are 0.193 moles.

Step-by-step explanation:

To calculate the number of moles for each sample, we use the equation:

Moles = mass / molar mass

a. For boron (B), we have:
Moles = 21.6 g / 10.81 g/mol = 2 moles

b. For manganese (Mn), we have:
Moles = 54.9 g / 54.94 g/mol = 1 mole

c. For mercury (Hg), we have:
Moles = 100.3 g / 200.59 g/mol = 0.5 moles

d. For barium (Ba), we have:
Moles = 50 g / 137.32 g/mol = 0.364 moles

e. For lead (Pb), we have:
Moles = 40 g / 207.2 g/mol = 0.193 moles