You have 10.0 g each of Na, C, Pb, Cu and Ne. Which contains the smallest number of moles?
To determine which element contains the smallest number of moles, we first need to calculate the number of moles for each element.
To calculate the number of moles, we use the formula:
Moles = Mass / Molar mass
Let's calculate the number of moles for each element:
1. Sodium (Na):
Molar mass of Na = 22.99 g/mol
Moles of Na = 10.0 g / 22.99 g/mol ≈ 0.435 mol
2. Carbon (C):
Molar mass of C = 12.01 g/mol
Moles of C = 10.0 g / 12.01 g/mol ≈ 0.832 mol
3. Lead (Pb):
Molar mass of Pb = 207.2 g/mol
Moles of Pb = 10.0 g / 207.2 g/mol ≈ 0.048 mol
4. Copper (Cu):
Molar mass of Cu = 63.55 g/mol
Moles of Cu = 10.0 g / 63.55 g/mol ≈ 0.157 mol
5. Neon (Ne):
Molar mass of Ne = 20.18 g/mol
Moles of Ne = 10.0 g / 20.18 g/mol ≈ 0.495 mol
Comparing the results, we see that lead (Pb) contains the smallest number of moles, with approximately 0.048 moles.
To determine which element contains the smallest number of moles, we need to calculate the moles of each element using their molar masses.
The molar mass is the mass of one mole of a substance, and it is given in grams per mole (g/mol). The molar mass of an element is equal to its atomic mass, which can be found on the periodic table.
The atomic masses of the elements you provided are:
- Na (sodium) - 22.99 g/mol
- C (carbon) - 12.01 g/mol
- Pb (lead) - 207.2 g/mol
- Cu (copper) - 63.55 g/mol
- Ne (neon) - 20.18 g/mol
To calculate the number of moles for each element:
- Moles of Na = mass of Na (in grams) / molar mass of Na
- Moles of C = mass of C (in grams) / molar mass of C
- Moles of Pb = mass of Pb (in grams) / molar mass of Pb
- Moles of Cu = mass of Cu (in grams) / molar mass of Cu
- Moles of Ne = mass of Ne (in grams) / molar mass of Ne
Now let's calculate the number of moles for each element:
Moles of Na = 10.0 g / 22.99 g/mol = 0.4351 mol
Moles of C = 10.0 g / 12.01 g/mol = 0.831 mol
Moles of Pb = 10.0 g / 207.2 g/mol = 0.0482 mol
Moles of Cu = 10.0 g / 63.55 g/mol = 0.1574 mol
Moles of Ne = 10.0 g / 20.18 g/mol = 0.4956 mol
From the calculations, we can see that the element with the smallest number of moles is Pb (lead), which has 0.0482 moles.
moles = mass/Molar mass
the mass is given and the molar mass can be obtained from the periodic table.