Which of the following samples contains the smallest number of molecules?
A. 1g of phosphorus, P4
B. 1g of chlorine, Cl2
C. 1g of nitrogen, N2
D. 1g of sulfur, S8
Here is what you do. I'll use Cl2 as an example.
mols Cl2 = grams/molar mass = 1/71 = ? whatever.
Then you know 1 mol Cl2 contains 6.02E23 x whatever above = number of molecules.
Now you do the same for P4, N2, and S8 along with completing Cl2, then compare to which number of molecules is the smallest.
In order to determine which sample contains the smallest number of molecules, we need to calculate the number of molecules in each sample.
To calculate the number of molecules, we can use Avogadro's number and the molar mass of each substance.
Avogadro's number is approximately 6.022 x 10^23 molecules/mol.
The molar mass of phosphorus (P4) is 123.88 g/mol.
The molar mass of chlorine (Cl2) is 70.9 g/mol.
The molar mass of nitrogen (N2) is 28.02 g/mol.
The molar mass of sulfur (S8) is 256.52 g/mol.
Let's calculate the number of molecules in each sample:
A. 1g of phosphorus, P4:
Number of moles of P4 = 1g / 123.88 g/mol ≈ 0.008 mol
Number of molecules of P4 = Number of moles x Avogadro's number
≈ 0.008 mol x 6.022 x 10^23 molecules/mol
≈ 4.8176 x 10^21 molecules
B. 1g of chlorine, Cl2:
Number of moles of Cl2 = 1g / 70.9 g/mol ≈ 0.014 mol
Number of molecules of Cl2 = Number of moles x Avogadro's number
≈ 0.014 mol x 6.022 x 10^23 molecules/mol
≈ 8.4528 x 10^21 molecules
C. 1g of nitrogen, N2:
Number of moles of N2 = 1g / 28.02 g/mol ≈ 0.036 mol
Number of molecules of N2 = Number of moles x Avogadro's number
≈ 0.036 mol x 6.022 x 10^23 molecules/mol
≈ 2.1712 x 10^22 molecules
D. 1g of sulfur, S8:
Number of moles of S8 = 1g / 256.52 g/mol ≈ 0.004 mol
Number of molecules of S8 = Number of moles x Avogadro's number
≈ 0.004 mol x 6.022 x 10^23 molecules/mol
≈ 2.4088 x 10^21 molecules
Comparing the results, we can conclude that the sample with the smallest number of molecules is sample D, which is 1g of sulfur, S8, with approximately 2.4088 x 10^21 molecules.
To determine which sample contains the smallest number of molecules, we need to compare the amount of substance in each sample. In chemistry, the amount of substance is often measured in moles.
A mole is a unit that represents 6.022 x 10^23 particles, which is known as Avogadro's number. One mole of any substance contains Avogadro's number of molecules, atoms, ions, or other particles.
To find the number of moles for each sample, we need to use the molar mass of the substance. The molar mass is the mass of one mole of a substance and is expressed in grams.
Let's calculate the number of moles for each sample:
A. 1g of phosphorus, P4
The molar mass of phosphorus (P) is 31.0 g/mol. Since the sample contains P4, the molar mass of P4 is 4 * 31.0 g/mol = 124 g/mol.
To find the number of moles, we divide the mass of the sample by the molar mass:
Number of moles = 1g / 124 g/mol ≈ 0.00806 mol
B. 1g of chlorine, Cl2
The molar mass of chlorine (Cl) is 35.5 g/mol. Since the sample contains Cl2, the molar mass of Cl2 is 2 * 35.5 g/mol = 71 g/mol.
Number of moles = 1g / 71 g/mol ≈ 0.0141 mol
C. 1g of nitrogen, N2
The molar mass of nitrogen (N) is 14.0 g/mol. Since the sample contains N2, the molar mass of N2 is 2 * 14.0 g/mol = 28 g/mol.
Number of moles = 1g / 28 g/mol ≈ 0.0357 mol
D. 1g of sulfur, S8
The molar mass of sulfur (S) is 32.1 g/mol. Since the sample contains S8, the molar mass of S8 is 8 * 32.1 g/mol = 256.8 g/mol.
Number of moles = 1g / 256.8 g/mol ≈ 0.00389 mol
Comparing the number of moles for each sample:
A. 0.00806 mol
B. 0.0141 mol
C. 0.0357 mol
D. 0.00389 mol
From the calculations, we can see that sample D, 1g of sulfur (S8), contains the smallest number of molecules since it has the lowest number of moles.