What charge must the alpha particles have based on it's interaction with a positive nucleus? Explain how you can tell.

What is the density of the black hole

Once similarity and one difference between a mixture of elements and a mixture of compounds

Need what is special about water as a compound? how does water regulate climate? what drives water evaporation?   why is the water vapor fresh water when it rises from the ocean? why might freshwater in the form of snow take longer to enter the water cycle again than liquid precipitation?   what is an aquifer? what role do people play in the water cycle? plz just answer as many as you can ! thx if you !