Which form of iron has the highest melting point?

What is obtained when a mixture of $Cu_2O$ and $Cu_2S$ is heated?

For the electrolytic production of aluminium,$(i)$ the cathode and $(ii)$ the anode are made of

Which of the following chemical equations represents the hydrometallurgical process for the extraction of copper from its ore?

Parke's process is used to extract

Tin is obtained from cassiterite by reduction with coke. Use the data given below to determine the minimum temperature (in $K$) at which the reduction of cassiterite by coke would take place.
At $298 \ K$: $\Delta_{f}H^{\circ}(SnO_{2(s)}) = -581.0 \ kJ \ mol^{-1}$,$\Delta_{f}H^{\circ}(CO_{2(g)}) = -394.0 \ kJ \ mol^{-1}$
$S^{\circ}(SnO_{2(s)}) = 56.0 \ J \ K^{-1} \ mol^{-1}$,$S^{\circ}(Sn_{(s)}) = 52.0 \ J \ K^{-1} \ mol^{-1}$
$S^{\circ}(C_{(s)}) = 6.0 \ J \ K^{-1} \ mol^{-1}$,$S^{\circ}(CO_{2(g)}) = 210.0 \ J \ K^{-1} \ mol^{-1}$
Assume that the enthalpies and the entropies are temperature independent.