Tuesday, October 27, 2009

OCTOBER 26, 2009 [JOANNE]

GASES AND MOLES:

The volume of a balloon occupied by a certain gas depends on the temperature & pressure.

Standard Ambient Temperature & Pressure (SATP)

  • 24.8L / 1mol
  • 25°C and 100kPa

*We will focusing much on SATP yet

STP:

The molar volume of any gas at STP is 22.4L

  • 22.4L / 1 mol
  • 1 mol / 22.4L

EXAMPLES:

Ø Find the volume occupied by 0.060 mol of c02 at STP
0.060mole x 22.4L/1mole = 1.3L

Ø Find the mass of a 200.0 mL sample of NO2 at SATP
STEPS:

o Note that the 200.0mL given is not in L

o Before we can convert it by SATP, we must change the mL to L.

o We divide 200.0mL by 1000 for our conversion factor from mL to L.

o Then we use SATP (22.4L / 1 mol )

o To finish the question in grams, we multiply by 46.0g because N = 14.0g + !6.0(2) O = 46.0g

o The Equation:

§ 200.0mL x 1L/1000mL x 1mol/22.4L x 46 g/ 1 mole = 9200/22400 =.41g

Ø Find the volume occupied by 22.0g of CO2(g)

o 22.0g x 1mol / 44.0g x 22.4L / 1mol = 11.2 L

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