Calculate the radius of an atom of metal if it forms simple cubic unit cell with edge length 380 pm.

Identify dispersed phase and dispersion medium in cheese.

How many moles of carbon atoms are present in 3.6 kg of carbon?

Calculate enthalpy change for following reaction.

$$\mathrm{H}_2 \mathrm{C}=\mathrm{CH}_{2(\mathrm{~g})}+\mathrm{H}_{2(\mathrm{~g})} \longrightarrow \mathrm{H}_3 \mathrm{C}-\mathrm{CH}_{3(\mathrm{~g})}$$

[The bond energy of $\mathrm{C}-\mathrm{H}, \mathrm{C}-\mathrm{C}, \mathrm{C}=\mathrm{C}$ and $\mathrm{H}-\mathrm{H}$ is $414,347,615$ and 435 kJ respectively]