How many bromine molecules, Br2, have a mass equal to 31.8 g?
The molecular weight of Br2 is 159.8. 31.8 g is 31.8/159.8 = 0.199 moles
Multiply that by Avogadro's number for the number of molecules.
Well, you're in luck! I happen to know that the molar mass of bromine, Br2, is approximately 159.808 g/mol. So, to find the number of bromine molecules that have a mass equal to 31.8 g, we can use some math.
First, we divide the given mass by the molar mass:
31.8 g / 159.808 g/mol = 0.199 mol
Then, we'll have to use Avogadro's number, which is approximately 6.022 x 10^23 molecules/mol, to find the number of bromine molecules in 0.199 mol:
0.199 mol x 6.022 x 10^23 molecules/mol ≈ 1.198 x 10^23 molecules
So, it looks like there are approximately 1.198 x 10^23 bromine molecules with a mass equal to 31.8 g. That's quite a lot of bromine, isn't it?
To find out the number of bromine molecules that have a mass equal to 31.8 g, we need to use the concept of moles.
1. Start by finding the molar mass of bromine (Br). The molar mass of bromine (Br) is 79.90 g/mol (rounded to two decimal places).
2. Next, calculate the number of moles of bromine by dividing the given mass (31.8 g) by the molar mass of bromine.
Number of moles = Mass / Molar mass
Number of moles = 31.8 g / 79.90 g/mol
Number of moles ≈ 0.3982 mol (rounded to four decimal places).
3. Now, use Avogadro's number to convert moles to molecules. Avogadro's number is approximately 6.022 x 10^23 molecules/mol.
Number of molecules = Number of moles x Avogadro's number
Number of molecules = 0.3982 mol x 6.022 x 10^23 molecules/mol
Number of molecules ≈ 2.3967 x 10^23 molecules (rounded to four decimal places).
Therefore, approximately 2.3967 x 10^23 bromine molecules (Br2) have a mass equal to 31.8 g.
To determine the number of bromine molecules that have a mass equal to 31.8 g, you need to use the concept of Avogadro's number and the molar mass of bromine.
1. Find the molar mass of bromine (Br2):
The molar mass of bromine (Br2) is calculated by adding up the atomic masses of two bromine atoms.
The atomic mass of bromine (Br) is approximately 79.904 g/mol.
So, the molar mass of bromine (Br2) = 2 x atomic mass of bromine (Br) = 2 x 79.904 g/mol = 159.808 g/mol.
2. Calculate the number of moles:
The number of moles can be obtained by dividing the given mass of bromine (31.8 g) by its molar mass.
Number of moles = mass ÷ molar mass = 31.8 g ÷ 159.808 g/mol = 0.199 mol (rounded to three decimal places).
3. Use Avogadro's number to find the number of molecules:
Avogadro's number, denoted as NA, is approximately 6.022 x 10^23 molecules/mol.
To determine the number of molecules, multiply the number of moles by Avogadro's number.
Number of molecules = number of moles x Avogadro's number = 0.199 mol x (6.022 x 10^23 molecules/mol) ≈ 1.198 x 10^23 molecules.
Therefore, approximately 1.198 x 10^23 bromine molecules (Br2) have a mass equal to 31.8 g.