calculate the number of formula units of 0.0067 g of lithium carbonate, Li2CO3?
0.0067 g x (1 mol/formula mass Li2CO3) x (6.022E23 formula units/mol) = ??
To calculate the number of formula units of lithium carbonate (Li2CO3) from a given mass, you need to use the formula:
Number of formula units = (Mass in grams / Molar mass) * Avogadro's number
1. Determine the molar mass of Li2CO3:
- The molar mass of lithium (Li) is approximately 6.94 g/mol.
- The molar mass of carbon (C) is approximately 12.01 g/mol.
- The molar mass of oxygen (O) is approximately 16.00 g/mol.
- Since there are two lithium atoms, one carbon atom, and three oxygen atoms in a formula unit of Li2CO3, the molar mass of Li2CO3 is:
Molar mass of Li2CO3 = (2 * Li) + C + (3 * O) = (2 * 6.94) + 12.01 + (3 * 16.00) g/mol
2. Substitute the given mass into the formula:
Number of formula units = (0.0067 g / Molar mass of Li2CO3) * Avogadro's number
Note: Avogadro's number is approximately 6.022 x 10^23 formula units/mol.
3. Calculate the number of formula units:
Number of formula units = (0.0067 g / Molar mass of Li2CO3) * Avogadro's number
Using the given molar masses and Avogadro's number, you can substitute the values into the formula to calculate the number of formula units.
To calculate the number of formula units of lithium carbonate (Li2CO3) from the given mass of 0.0067 g, we need to use the concept of moles and Avogadro's number.
1. Determine the molar mass of lithium carbonate (Li2CO3):
- Lithium (Li) has a molar mass of 6.941 g/mol. Since there are two lithium atoms in lithium carbonate, the molar mass of lithium is 6.941 g/mol * 2 = 13.882 g/mol.
- Carbon (C) has a molar mass of 12.011 g/mol.
- Oxygen (O) has a molar mass of 16.00 g/mol. Since there are three oxygen atoms in lithium carbonate, the molar mass of oxygen is 16.00 g/mol * 3 = 48.00 g/mol.
Now, add the molar masses of the individual elements together to get the molar mass of lithium carbonate:
13.882 g/mol (Li) + 12.011 g/mol (C) + 48.00 g/mol (O) = 73.893 g/mol.
2. Calculate the number of moles of lithium carbonate:
Divide the given mass by the molar mass:
0.0067 g / 73.893 g/mol ≈ 9.07 x 10^-5 moles (rounded to 3 decimal places).
3. Determine the number of formula units:
Since there are two lithium ions (Li^+) in each formula unit of lithium carbonate, we need to multiply the number of moles by Avogadro's number (6.022 x 10^23 formula units/mol):
9.07 x 10^-5 moles * 6.022 x 10^23 formula units/mol ≈ 5.47 x 10^19 formula units (rounded to 3 significant figures).
Therefore, there are approximately 5.47 x 10^19 formula units of lithium carbonate (Li2CO3) in 0.0067 g.