When and why are machines considered powerful

What is the nature of the ca-cl bond in a molecule of calcium chloride (cacl2) if the electronegativity value of calcium is 1.0 and that of chlorine is 3.16?

Why is the vapor pressure of a warm lake higher than the vapor pressure of a cold lake? o a. warm water has a greater heat of vaporization. ob. warm water evaporates more quickly. cool water evaporates more quickly. od. cool water has a greater heat of vaporization.

Chemistry worksheet - i am not sure what they are asking for exactly?