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The Basics

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The Basics

Reminders about simple terms

and concepts.

Zumdahl Chapter 3

Zn + H+ + Cl- ----> Zn2+ + Cl- + H2

Equations

Zn + 2H+ + Cl- ----> Zn2+ + Cl- + H2

Equations

Zn + 2H+ + 2Cl- ----> Zn2+ + 2Cl- + H2

Equations

Zn + 2H+ + 2Cl- ----> Zn2+ + 2Cl- + H2

Zn + 2(HCl) ----> Zn2+ + 2Cl- + H2

Equations

Zn + 2H+ + 2Cl- ----> Zn2+ + 2Cl- + H2

Zn + 2(HCl) ----> Zn2+ + 2Cl- + H2

Zn + 2H+ ----> Zn2+ + H2

Equations

Zn + 2H+ + 2Cl- ----> Zn2+ + 2Cl- + H2

Zn + 2(HCl) ----> Zn2+ + 2Cl- + H2

Zn + 2H+ ----> Zn2+ + H2

Zn(s) + 2H+(aq) ----> Zn2+(aq) + H2(gas)

Equations

Zn(s) + 2H+(aq) ----> Zn2+(aq) + H2(gas)

- means that on an atomic ratio, 1 Zn atom reacts with

2 H+ions to produce 1 Zn2+ ion and 1 hydrogen

diatomic molecule.

- we don’t work on an atomic scale very often so we

define a new unit which is a bunch of atoms or

molecules.

- we don’t count atoms very often so we work in the

mass of that bunch.

The ‘bunch’ I alluded to earlier is the number of atoms

contained in exactly 0.0120000 kg of carbon which contains

only the 12C isotope. ( 6 protons + 6 neutrons in the

nucleus.)

We call this unit the MOLE.

1 mole is 6.023 x 1023 particles

Avogado Number.

Moles and Molar Masses

Thus the MOLAR MASS is just the mass of a mole of any

particular substance. May also be referred to as the atomic

or molecular weight.

H = 1.0079 g / mol = 0.0010079 kg / mol

CO2 = 44.009 g / mol = 0.044009 kg /mol

Conceptually, this allows us to compare and calculate

relative amounts of material.

Zn + 2(HCl) ----> Zn2+ + 2Cl- + H2

one mole of zinc metal reacts with two mole of hydrogen

chloride to produce one mole of zinc ions two moles of

chloride ions and one mole of hydrogen gas.

65.39 g Zn + 72.92 g HCl ----> 65.39 g Zn2+ +

70.91 g of Cl- + 2.01 g of H2

IDEAL GASESZumdahl, Chapter 5

- Amount in moles ( mol )
- Pressure in Pascals ( N m-2 )
- Volume in metre3 ( m3 )
- Temperature in Kelvin ( K )

Pressure = force / area

= Newtons / metre2

= Pascals

.

Pressure = force / area

= Newtons / metre2

= Pascals

Standard atmospheric pressure = 101 325 Pascals

Pressure

Pressure = force / area

= Newtons / metre2

= Pascals

Standard atmospheric pressure = 101 325 Pascals

This is equivalent to 1.000 atm or a pressure that

will support a column of mercury 760 mm tall in a

barometer.

Measured in metre3 which may not be convenient.

More common to use litres but :

1 L = 0.001 m3

We need an absolute temperature scale. i.e. one for

which zero means something.

We use the Kelvin scale on which ice melts at 273.2 K

or 0K is -273.2 oC.

volume is proportional to 1 / pressure

P1V1 = P2V2

For a fixed amount of gas at constant temperature.

Volume is proportional to absolute temperature

V1 / V2 = T1 / T2

For a fixed amount of gas at constant pressure.

He

N2

V

-273

0

T o C

PV = n RT

R = 8.3145 Nm mol -1 K -1

= 8.3145 J mol-1 K -1

For an ideal gas.

Equation of state

PV = n RT

If you know any three of P, V, n, and T,

you can calculate the fourth.

What is the volume occupied by 2.30 moles

of helium at 313 K and 217 kPa?

What is the volume occupied by 2.30 moles

of helium at 313 K and 217 kPa?

V = n R T / P

V = 2.30 mol x 8.31 Nm mol-1 K-1 x 313 K / 217 x 103 Nm -2

V = 0.0276 m3

What is the volume occupied by 2.30 moles

of helium at 313 K and 217 kPa?

V = n R T / P

V = 2.30 mol x 8.31 Nm mol-1 K-1 x 313 K / 217 x 103 Nm -2

V = 0.0276 m3

DOES THIS MAKE SENSE??????????