Express each quantity as a mass in grams.
a) 3.70mol of H2O
b) 8.43 x 10^23 molecules of PbO2
a) Each mole weighs 18.0 g. Do the numbers
b) That is 8.43/6.023 = 1.400 moles. Multiply that by the molecular weight of PbO2: 207.3 + (2 x 16.0)= ? . The answer will be in grams.
To express each quantity as a mass in grams, we need to use the molar mass of each substance.
a) 3.70 mol of H2O:
The molar mass of H2O is:
(2 x 1.008 g/mol) + (1 x 16.00 g/mol) = 18.02 g/mol
To find the mass, multiply the number of moles by the molar mass:
Mass = 3.70 mol x 18.02 g/mol = 66.574 g
Therefore, 3.70 mol of H2O is equal to 66.574 grams.
b) 8.43 x 10^23 molecules of PbO2:
To convert from molecules to grams, we need to use Avogadro's number and the molar mass of PbO2.
The molar mass of PbO2 is:
207.2 g/mol (lead) + 2 * (16.00 g/mol) = 239.2 g/mol
First, convert the number of molecules to moles:
Moles = 8.43 x 10^23 molecules / (6.022 x 10^23 molecules/mol) = 0.1399 mol
Then, multiply the number of moles by the molar mass:
Mass = 0.1399 mol x 239.2 g/mol ≈ 33.41 g
Therefore, 8.43 x 10^23 molecules of PbO2 is equal to approximately 33.41 grams.
To express each quantity as a mass in grams, we need to use the molar mass of the substance.
a) To find the mass of 3.70 mol of H2O, we need to know the molar mass of water (H2O). The molar mass of water is calculated by adding up the atomic masses of the atoms in one molecule of water.
The atomic mass of hydrogen (H) is 1.01 g/mol, and the atomic mass of oxygen (O) is 16.00 g/mol. Since water (H2O) has two hydrogen atoms, the total atomic mass contribution from hydrogen is 2 x 1.01 g/mol = 2.02 g/mol. The atomic mass contribution from oxygen is 16.00 g/mol.
Adding up these contributions, we get the molar mass of water: 2.02 g/mol + 16.00 g/mol = 18.02 g/mol.
Therefore, to find the mass of 3.70 mol of H2O, we multiply the number of moles by the molar mass:
3.70 mol x 18.02 g/mol = 66.67 g.
So, 3.70 mol of H2O is equal to 66.67 grams.
b) To find the mass of 8.43 x 10^23 molecules of PbO2, we first need to convert the number of molecules to moles. Since 1 mole contains 6.022 x 10^23 molecules (Avogadro's number), we divide the given number of molecules by Avogadro's number:
8.43 x 10^23 molecules / 6.022 x 10^23 molecules/mol = 1.40 mol.
Next, we need to find the molar mass of PbO2. The atomic mass of lead (Pb) is 207.2 g/mol, and the atomic mass of oxygen (O) is 16.00 g/mol. Since PbO2 has one lead atom and two oxygen atoms, the total atomic mass contribution from lead is 207.2 g/mol, and the total atomic mass contribution from oxygen is 2 x 16.00 g/mol = 32.00 g/mol.
Adding up these contributions, we get the molar mass of PbO2: 207.2 g/mol + 32.00 g/mol = 239.2 g/mol.
Therefore, to find the mass of 1.40 mol of PbO2, we multiply the number of moles by the molar mass:
1.40 mol x 239.2 g/mol = 334.88 g.
So, 8.43 x 10^23 molecules of PbO2 is equal to 334.88 grams.