Help me with this it’s skeleton equations

Asmall amount of a solid is added to water. the observation made after fifteen minutes is shown in the figure. which of these solids has been probably added to water? a) oil b) sand c) sugar d) wood chips

There is a single path for electrons. the current decreases when additional resistors are added. the current will be the same in each resistor. these statements best describe a(n) circuit.

A50.0g sample of liquid water at 0.0 c ends up as ice at -20.0 c. how much energy is involved in this change?