- 86 Views
- Uploaded on
- Presentation posted in: General

The Mole , Ch. 10 You need a calculator from this chapter on.

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

The Mole, Ch. 10You need a calculator from this chapter on.

- *The mole was invented as a way to describe number of atoms.

- *1 mole = 6.02 x 1023 things.
- 602,000,000,000,000,000,000,000 things.

- In a mole of water, there are 6.02 x 1023 molecules of H2O.
- Pass around 1 mole of water.

- Convert 3 moles of aluminum to number of atoms of aluminum.
- Convert 7 moles of methane to molecules of methane.

- One mole of an atom will weigh ___ grams (shown on the periodic table).

- Mg. 1 mole ? grams
- 6.94 grams

- 3 moles Be ? grams
- 27 grams.

- 2.5 x 1022 atoms of Na grams Na?
- .96 grams

- 3 moles of CH4 to grams?
- 48 grams.

- 4 moles of HF to grams?
- 80 grams

- 6 moles of H2O to grams.
- 126 g of NaF to moles.
- 108 grams, 3 moles

- Molar mass of Uranium a ball of uranium with a radius of 1.3 inches weighs a pound.

- *A mole of any gas takes up 22.4 L (at STP). This is Avogadro’s Hypothesis.
- This is like a cube with sides of 28.2 cm.

- One mole of He, H, O, N, etc. will all take up 22.4 L.
- Question: How many He atoms are there in 22.4 L?
- Question: How many H2 molecules are there in 22.4 L?

- How many moles of O2 in 44.8 liters of O2?

- How many L in 4 moles of N2?
- 89.6 L

- STP 0 C, pressure = 1 atm (101.3 kPa)

- Often is measured in g/L.
- What is the density of H2 gas at STP?
- .089 g/L

- Gas density

- Page 303, roadmap.
- Try: 55 E23 particles of He to volume of gas. Try: 55 E23 particles of He to grams of gas.

- Be able to solve mole problems.
- Compare a mole of eggs to a dozen eggs.
- What is a mole useful for?

- *Gas density to molar mass.
- Exp: 2.86 g/L.

- Is the percent by mass of each element in the compound.

- *Percent Composition from mass data:
- 5.4 g of oxygen and 8.2 g of magnesium in a 13.6 gram compound.
- 60.3% Mg, 39.7% O

- *Percent composition from the chemical formula Find the amount of grams of each element in 1 mole of the compound, then find the %.
- C3H8
- 81.8% C, 18% H

- How many grams of O are present in 36 grams of H2O?
- 32 grams O

- *Empirical formula: Expresses the atoms in their lowest ratio.
- *Molecular formula: Expresses the atoms in their actual abundance.
- Exp: H2O2 HO

- 25.9% N
- 74.1 % O
- Assume 100 g of the compound, find the # of moles, then find the whole number ratio.
- Answer = 2 mol N, 5 mol O

- The molecular formula is always a whole number multiple of the empirical formula.

- Empirical formula to Molecular formula If the empirical formula is CH4N and the molecular molar mass is 60 g/mol, what is the molecular formula?
- C2H8N2

- Draw and explain with words:
- If you could have a mole of anything, what would you want and why?
- Can be creative and funny.