Is SO3 polar or non polar? A correct, detailed explanation would be greatly appreciated. Thanks!

An atom of sodium-23 (atomic number = 11) has a positive charge of +1. give this information, how many electrons does it have? how many proteins and neutrons does this atom have

Calculate the number of kilojoules to warm 125 g of iron from 23.5°c to 78.0°c.

Suppose you mix one mole of sulfuric acid (h2so4) with 1 mole of sodium hydroxide(naoh). why does the ph of the solution remain below 7? ( explain so i can get better understanding! )