What is the whole mass of air surrounding earth?

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! )

If e is the symbol for an element, which two of the following symbols represent isotopes of the same element? 1. e2. e3. ea.1 and 2c.1 and 4b.3 and 4d.2 and 3

4. propanol and isopropanol are isomers. this means that they have a) the same molecular formula but different chemical properties. b) different molecular formulas but the same chemical properties. c) the same molecular formula and the same chemical properties. d) the same molecular formula but represent different states of the compound