PLEASE ANSWER QUICKLY IT'S ON MY FINAL WILL GIVE BRAINLIEST FOR WHOEVER ANSWERS THE MOST QUESTIONS NEED COMPLETED BY 3:00 PM CENTRAL TIME

1) Most elements in the same column have similar physical and chemical properties, why?
2) What is the periodic trend for atomic size, and why?
3) How many grams are in each of the following?
- 3.6 x 10^24 molecules of FeCl2
- 6.02 x 10^23 molecules of CaO
- 15 moles of SO2
- .33 moles of NaCl
4) Balance the following equations
- __H2O__O2 + __H2
- __C6H6 + __ O2__H2O + __CO2
- __NH4PO4 + __Pb(NO3)4__PB3(PO4)4 + __NH4NO3
5) How many moles of water is produced when 100 grams of H2 reacts with excess O2
- 2H2 + O2 ⇒ 2H2O
6) Convert each of the following to moles
- 100 grams of Ca3(PO4)2
- 3.2 x 10^23 molecules of O2
- 1.87 x 10^25 molecules of NaCl
7) Given an irregular object has a mass of 51 grams and water displacement is used to find the volume, which goes from 17 ml to 24 ml., what is the density of the object?
8) A hydrate of Na2CO3 has a mass of 4.31 g before heating. After heating, the mass of the anhydrous compound is found to be 3.22 g. Determine the formula of the hydrate.

Thanks to anyone who helps, if you could explain any of the math done that would be amazing