Question

How many moles of boron are in 37.8 (B, 10.81 g/mol) grams of boron?

a) 1.5 moles
b) 2.5 moles
c) 3.50 moles
d) 4.0 moles

Answer 1

To find the number of moles in 37.8 grams of boron, divide the mass by the molar mass of boron (10.81 g/mol). The result is 3.50 moles, corresponding to option (c).

Step-by-step explanation:

To calculate the number of moles of boron in 37.8 grams of boron, you can use the molar mass of boron. First, let's restate the question: How many moles of boron are in 37.8 grams (given that the molar mass of boron is 10.81 g/mol)? The solution involves dividing the mass of the boron sample by its molar mass. Here is the calculation:

Number of moles = mass of substance (g) / molar mass (g/mol)

Number of moles = 37.8 g / 10.81 g/mol

Number of moles = 3.50 moles

Therefore, the answer is that there are 3.50 moles of boron in 37.8 grams of boron, which corresponds to option (c).