What is the mass of 2.64 moles of water

Determine the number o moles of ions/atoms/particle in the following: 2.50 miles of k2s (let me know how to do)

What does the symbol (–hfus) indicate in a phase change?

An alloy contains 66 g of pure zinc. what is the percentage of zinc in the alloy? express your answer to two significant figures and include the appropriate units.