To calculate molarity, divide the number of moles of solute by the volume of the solution in liters. If you don't know the number of moles of solute but you know the mass, start by finding the molar mass of the solute, which is equal to all of the molar masses of each element in the solution added together.
When ice changes into liquid water it melts. The solidified ice in the frozen, would melt via the burning sun shooting its streaks down at the ice. Which causes the ice to melt, and turn into liquid water.
The nucleus is positively charged because it contains all of the protons however the charge of an atom is neutral because there is an equal amount of protons (positive) and electrons (negative) meaning the opposite charges cancel each other out therefore making the atoms overall charge neutral.