Answer: 2) 0.21 mole H2O
3) 0.50 mole K2O
4) 123 g Ca( NO3)2
Explanation: solution attached.
For number 2 to find the number of moles of H2O just divide the given in molecules with the Avogadro's number.
For 3 convert grams of K2O to moles by using 1 mole of K2O is equal to the molar mass of K2O
For number 4 moles to grams. Same process with number 3
