Calculate the number of molecules present in .20 moles of h2o

Which element in the third period would you expect to have the larger atomic radius, sodium (na) or sulfur (s)? a. sodium, because it has a higher effective nuclear charge attracting electrons in fewer energy levels. b. sodium, because it has fewer protons attracting electrons in the same energy levels. c. sulfur, because it has more protons attracting electrons in more energy levels. d. sulfur, because it has a higher effective nuclear charge attracting electrons in the same energy levels.

Iwll give extra points to who gets this for ! what type of reaction is this? ?

What is the volume occupied by 10.0 dm3 of gas at standard pressure after it has been compressedat constant temputure to 500.0 kpa?