How would i calculate the density of Li2S in grams per cubic centimeter?
I have to use the equation :
density= mass/ volume:
But i don't know how to find out the volume using the edge length of the unit cell which is 5.88* 10^2 pm.
1.50g/cm^3
If the edge length is 5.88 x 10^2 pm, first convert that to cm, then cube that to find the volume in cc.
The mass of a unit cell is (4 x molar mass)/6.022 x 10^23.
and how can i find out the mass m in grams of a unit cell of Li2S.
when the formula units in the unit cell for Li2S is 4.
My answer for mass is for 4 atoms to the unit cell. I don't know if that's the same as 4 formula units per unit cell or not.
To calculate the density of Li2S in grams per cubic centimeter, you need to find the mass and volume of the substance.
1. Finding the mass:
To determine the mass, you will need to know the molar mass of Li2S, which is the sum of the atomic masses of lithium (Li) and sulfur (S).
The atomic mass of lithium (Li) is approximately 6.94 grams/mol, and the atomic mass of sulfur (S) is approximately 32.07 grams/mol.
The molar mass of Li2S is:
(2 * atomic mass of Li) + atomic mass of S
= (2 * 6.94 g/mol) + 32.07 g/mol
= 13.88 g/mol + 32.07 g/mol
= 45.95 g/mol
2. Finding the volume:
The volume of the unit cell can be calculated using the given edge length of the unit cell (5.88 * 10^2 pm). However, you need to convert picometers (pm) to centimeters (cm).
1 pm = 10^-12 m = (10^-12 m) * (100 cm/1 m) = 10^-10 cm
So the edge length in centimeters is:
5.88 * 10^2 pm * 10^-10 cm/pm = 5.88 * 10^2 * 10^-10 cm
Now that you have the edge length in centimeters, you can calculate the volume of the unit cell. The unit cell of Li2S is a cubic cell, so the volume is the cube of the edge length.
volume = (edge length)^3
= (5.88 * 10^2 * 10^-10 cm)^3
= (5.88 * 10^-8 cm)^3
= 1.307 * 10^-22 cm^3
3. Calculating the density:
Now that you have the mass and volume, you can use the density equation to find the density.
density = mass / volume
= 45.95 g/mol / 1.307 * 10^-22 cm^3
= (45.95 g/mol) / (1.307 * 10^-22 cm^3)
= 3.515 * 10^22 g/cm^3
So the density of Li2S is approximately 3.515 * 10^22 grams per cubic centimeter.