Polar and nonpolar substances do not dissolve in each other. Some ionic substances dissolve in polar liquids, but some do not. When ionic substances dissolve in water, the solution conducts electricity. But when polar substances dissolve, the solution does not conduct electricity. Elements do not decompose, but all compounds decompose at some temperature.
Some compounds are stable, while others decompose easily.
When heated, some compounds melt first then decompose at a higher temperature. Some compounds decompose before melting. Explain what happens.