The Basics

Reminders about simple terms

and concepts.

Zumdahl Chapter 3

Equations

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)

EquationsZn(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.

Moles and Molar MassesThe ‘bunch’ I alluded to earlier is the number of atomscontained in exactly 0.0120000 kg of carbon which containsonly the 12C isotope. ( 6 protons + 6 neutrons in thenucleus.)

We call this unit the MOLE.

1 mole is 6.023 x 1023 particles

Avogado Number.

Moles and Molar MassesThus the MOLAR MASS is just the mass of a mole of anyparticular substance. May also be referred to as the atomicor 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 calculaterelative amounts of material.

Stochiometry

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

one mole of zinc metal reacts with two mole of hydrogenchloride to produce one mole of zinc ions two moles ofchloride 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 GASES

Zumdahl, Chapter 5

Basic Definitions

• Amount in moles ( mol )

• Pressure in Pascals ( N m-2 )

• Volume in metre3 ( m3 )

• Temperature in Kelvin ( K )

Pressure

Pressure = force / area

= Newtons / metre2 = Pascals.

Pressure

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 thatwill support a column of mercury 760 mm tall in abarometer.

Volume

Measured in metre3 which may not be convenient.

More common to use litres but :

1 L = 0.001 m3

Temperature

We need an absolute temperature scale. i.e. one forwhich zero means something.

We use the Kelvin scale on which ice melts at 273.2 Kor 0K is -273.2 oC.

Boyle’s Law

volume is proportional to 1 / pressure

P1V1 = P2V2

For a fixed amount of gas at constant temperature.

Charles’ Law

Volume is proportional to absolute temperature

V1 / V2 = T1 / T2

For a fixed amount of gas at constant pressure.

V

T o C-273 0

He

N2

Equation of state

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??????????