# Blog

Calculating The Molar Mass Of An Unknown Compound From The Freezing Point Depression Problem: When 12.0g of an unknown nonelectrolyte compound are dissolved in 400.0g of benzene, the freezing point of the resulting solution is 3.90˚C. The freezing point of pure benzene is 5.44˚C. Calculate the molar mass of the unknown compound. (Kf for C6H6 […]

Calculating The Freezing Point Of A Solution From Freezing Point Depression ΔTf = i Kf m or ΔTf = i. Kf. w/M. 1000/W ΔTf – freezing point depression, i- Vont’ hoff factor, Kf – freezing point depression constant, m – molality (mole/kg), w- mass of solute (g), M- molar mass of non-volatile solute (g/mole), W- […]

Calculating The Freezing Point Depression Freezing-point depression is the process in which adding a note volatile salute to a solvent decreases the freezing point of the solvent. The freezing point of a solution is less than the freezing point of the pure solvent. ΔTf = i Kf m ΔTf – freezing point depression, i- Vont’ […]

How To Calculate The Number of Atoms In Specific Amount of Element: Problem: An element “X” having FCC structure has unit cell edge 500pm. Find the density of X and the number of unit cells for 20g of X. (atomic mass of X = 200g/mol) Solution: Follow the steps: 1-Calculate the volume of length of unit […]

How To Calculate The Radius Of An Ion Problem: A solid compound AB has NaCl structure. If the radius of the cation is 150nm, calculate the radius of anion B. Solution: Follow the steps: 1- Find out the structural arrangement of atoms in the solid compound 2- Find the radius ratio based on the structural […]

How To Calculate The Density Ratio Of Two Different Lattices Problem: A metal crystallizes into two cubic phases, body centred cubic (bcc) and face centred cubic (fcc) whose unit lengths are 4.0Å and 4.5Å respectively. Find the ratio of densities of b.c.c and f.c.c. (1 Å = 10-8cm). Solution: Follow the steps: 1- Calculate the […]

How To Calculate The Radius Of A Solid Crystal Element Problem: Iron which crystallizes as body centered cubic lattice has a density of 7.87 g/cm3 at 20˚C. Calculate the radius of iron atom. Solution: Follow the steps: 1- Calculate the length of the unit cell by applying the density formula 2- Find the relation between length […]

Calculating The % Of Empty Space Of A Solid Atom Question: The density of solid copper is 8.83 g/cm3 at 100.0°C. Assume that the copper atom is a sphere of radius 1.02×10-8 cm. Calculate the percentage of empty space of solid copper. (Atomic mass = 63.55) Solution: Follow the steps: 1- Calculate the volume of […]

How To Calculate Van’t Hoff Factor (i) Van’t Hoff Factor (i): It is a measure of degree of dissociation/association of a compound. i = [1 + (y-1)x] y is the number of dissociated ions, x is % value. If i >1, there is dissociation of solute. If i <1, there is association of solute If […]

Calculating The Edge Length of The Unit Cell density = Z x M / x Where Z – is the number of atoms per unit cell, Value for z: z = 1 for simple cubic cell (scc) z = 2 for body centered cubic structure (bcc) z = 4 for face centered cubic structure (fcc) […]