Question

Какое кол-во в-ва содержат 140 г оксида бора (3)

Answer 1

 n(B2O3)=m/M=140/70=2

Answer 2

Calculating the Amount of Boron Oxide (B2O3) in 140g

To calculate the amount of boron oxide (B2O3) in 140g, we can use the molar mass of B2O3 to convert the mass to moles and then determine the amount of substance.

The molar mass of B2O3 can be calculated as follows: - Boron (B) has a molar mass of approximately 10.81 g/mol. - Oxygen (O) has a molar mass of approximately 16.00 g/mol.

Using these values, the molar mass of B2O3 can be calculated as: - 2(B) + 3(O) = 2(10.81) + 3(16.00) = 21.62 + 48.00 = 69.62 g/mol.

Now, we can calculate the amount of B2O3 in 140g using the molar mass.

Calculations: - Number of moles = Mass / Molar mass - Number of moles = 140g / 69.62 g/mol - Number of moles ≈ 2.01 moles

Therefore, 140g of boron oxide (B2O3) contains approximately 2.01 moles of the compound.