OCTOBER 16

Today we started chapter 3, The Mole.

One mole = 602 000 000 000 000 000 000 000
or also written as: 6.02 x 10^23 <-Avogadro's Number

2H2 + O2 --> 2H20

How big is Avogadro's number?

• distance from earth to the moon: 3.84 x 10^5 km
• distance from earth to pluto: 6 x 10^9 km

How gases combine:

1. John Dalton

• looked at the masses or gases:
  -11.1g of H2 reacts with 88.9g of O2
  -46.7g of N2 reacts with 53.3g of O2
  -42.9g of C reacts with 57.1g of O2
• *No pattern*

2. Joseph Gay-Lussac

• 1L of hydrogen reacts with 1L of Cl2 -> 2L of HCl
  1L of N2 reacts with 3L of H2 0> 2L NH3
  2L of CO reacts with 1L of O2 -> 2L of CO2
• reactions occur in simple rations

3. Avogadro's Hypothesis:

• Equal volumes of any gas at the same temperature and pressure contain equal numbers of molecules

H2 + O2 -> H2O

*Our homework for today is: numbers 1, 2, 3, and 5 on page 322*