What is molar mass of metal with BCC structure having density 10 g cm$$^{-3}$$ and edge length 200 pm?

Calculate difference between $$\Delta \mathrm{H}$$ and $$\Delta \mathrm{U}$$ for following reaction at $$25^{\circ} \mathrm{C}$$ ?

$$\mathrm{C}_2 \mathrm{H}_{6(\mathrm{~g})}+3.5 \mathrm{O}_2 \rightarrow 2 \mathrm{CO}_{2(\mathrm{~g})}+3 \mathrm{H}_2 \mathrm{O}_{(l)}\left(\mathrm{R}=8.314 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\right)$$

What is cryoscopic constant of water if $$5 \mathrm{~g}$$ of glucose in $$100 \mathrm{~g}$$ of water has depression in freezing point $$2.15 \mathrm{~K}$$ ? (Molar mass of glucose $$=180$$ )

Which of the following pairs of alkenes is an example of position isomers?