Unit 9: States of Matter

Lesson 1 – Intermolecular Forces, States of Matter & Phase Diagrams

Intermolecular Forces Forces that occur ____________ molecules (________ compounds)

Intramolecular (ionic and covalent) bonds are ___________ a compound. They are stronger than intermolecular forces.

Dipole When there is a ___________ (δ+) and a _____________ (δ-) side to an atom or molecule

______________________ - forms when electrons momentarily shift to one side of an atom at random

_______________________ - occurs when a neighboring molecule moves past one with a temporary dipole

_______________________ - the result of a polar bond in the molecular structure

There are three types of Intermolecular Forces (IMFs)

1. _____________________________ AKA ___________________________

* ____________________ of the IMFs * the only IMF found in ________________________ molecules

While the electrons in the 1s orbital of helium would _______________________

(and, therefore, tend to stay far away from each other), it does happen that they

occasionally wind up on the _________________________________________.

At that instant, then, the helium atom is _____________, with an

excess of _______________ on the left side and a shortage on

the right side.

Another helium nearby, then, would have a dipole _____________

in it, as the electrons on the left side of helium atom 2 __________

the electrons in the cloud on helium atom 1.

London dispersion forces are attractions between an ________

dipole and an ________________dipole. These forces are present

in ________ molecules, whether they are polar or nonpolar.

2. ______________________________________

* __________________ than dispersion forces

* occur between molecules with ___________________________________

3. _____________________________________

* _____________________ of the IMFs

* Very strong dipole-dipole interactions that occur when __________________ in one molecule is attracted

to a ____________________________________ in another molecule. This is due to the _____________

_______________________________ of N, O and F.

* Hydrogen bonds are what make _____________________ have so many unique ___________________.

IMFS affect physical properties

Viscosity - _______________________________

* Increases with _______________intermolecular forces and _______________ with higher temperatures.

Surface Tension - __________________________________________________________________________

Melting & __________________ Points –-> Stronger IMFs equal ______________ melting and boiling points.

States of Matter

The fundamental difference between

states of matter is the

______________________________.

Solid

Strong cohesive forces

Particles in fixed lattice positions

________________ shape

________________volume

_______________ compressibility

Liquid

Particles are close together

Not held in fixed positions

_________________of container

Have ________________ volume

_________________compressability

Gas

Particles are _____________

Completely fill container

____________ compressed

The state a substance is in at a particular ________________________ and __________________________ depends on two things:

1. The ____________________________ of the particles (kinetic =movement)

2. The strength of the attractions between the _______________________________________________

The IMFs between particles become

_________________ as particles are packed

_______________________________ and

move ___________ rapidly (less ____)

Phase Changes

Require Energy Release Energy

* *

* *

* *

Remember: all ______________ changes are __________________ changes!

Phase Diagrams

Phase diagrams display

the _________________

of a substance at various _____________________

and ________________

and the places where

_______________exist between phases.

The AB line is the ____________________________ interface.

It starts at the ______________________ (A), the point at which all ______________states are in equilibrium.

It ends at the ________________ _________________ (B); above this critical _____________________ and critical __________________ the liquid and vapor are ________________________ from each other.

Each point along this line is the _________________________of the substance at that pressure.

The AD line is the interface between ___________________ and _______________.

The _______________ ______________ at each pressure can be found along this line.

Below A the substance cannot exist in the ___________________state.

Along the AC line the _________________ and _______________ phases are in equilibrium; the ___________________ __________ at each pressure is along this line.

Phase Diagram of Water

Note the high ______________

__________________ and ______________

_________________. These are due to the

_______________ van der Waals forces between

water molecules.

Phase Diagram of Carbon Dioxide

Carbon dioxide cannot exist in the

________________ state at pressures

below 5.11 atm;

CO2 __________________ at normal

pressures.

Lesson 2 – Kinetic Molecular Theory & Dalton’s Law

KMT operates under 5 assumptions:

1. Gas particles are in _______________________________________.

2. Particles are separated by great _________________.

3. Collisions are ___________ and___________

4. No _____________ of attraction between particles.

5. Total energy remains _____________.

Average kinetic energy is _____________ proportional to temperature!! As temp goes ________, so does kinetic energy.

Kinetic-Molecular Theory

• A gas consists of very small particles, each of which has a__________.

• A gas spreads out and takes on the _____________ of its container. The volume of the gas particles is assumed to be ____________because it is negligible compared with the total volume of the gas.

• Gas particles are in________,___________ and __________ motion. They move in _______________lines, until they bump into something.

- ____________ is a measurement of the average kinetic energy (speed) of the particles

– _______________is a measurement of the number and force of the collisions of the particles with the walls of the container

The collisions of gas particles with each other and with the container are totally __________.

Gas particles exert ________________________because their attractions are so weak they are assumed to be zero.

• Gas Properties Relating to the Kinetic-Molecular Theory

Diffusion ____________________________________________________________.

Effusion_____________________________________________________________.

Graham’s Law

Molecules __________________ through holes in a rubber balloon and deflate

This occurs at a rate equal to_______________________:

• proportional to _________

• inversely proportional to ____________ ____________

Therefore, He gas effuses ________ __________than O2 at the same T.

Rate of effusion

This also applies to________________, as ___________particles diffuse more _______________.

Example:Ammonia has a molar Mass of 17.0 g/mol; hydrogen chloride has a molar mass of 36.5 g/mol. What is the ratio of their diffusion rates?

What does this mean? __________________________________________________________________________________________________________________________.

Example on your own:Carbon Monoxide is less massive than Carbon Dioxide. How much faster will CO diffuse compared to CO2?

Dalton’s Law of Partial Pressures

¿

Dalton’s Law:

the __________ pressure exerted by a mixture of gases is

the ____________of all the ___________ _____________.

PTotal =

• Example

A mixture of oxygen, carbon dioxide and nitrogen (this mix is known as “air”) has a total pressure of 0.97 atm. What is the partial pressure of O2 if the partial pressure of N2 is 0.12 atm and CO2 is 0.70 atm?

Lesson 3 – Gas Laws

Real Gases

An _____________gas adheres to the Kinetic Theory exactly in all situations.

_________gases deviate from ideal behavior at ____________ pressures and ________ temperatures.

When the pressure is __________, it becomes more difficult to ___________ a gas because the particles actually have a ____________ of their own.

When the temperature is ____________, gas particles slow down and attractions between them become _____________________ as they clump together and form _____________.

Gas law terms:

n = ____________of gas particles

V = ______________ (of the container)

T = _______________ (must be in ___________________)

P = _________________

Temperature

______________ is the only temperature scale that measures absolute ___________ of particles.

All temperatures in gas law problems need to be in ____________________.

Pressure

1 atm =____________kPa= _____________torr=___________mmHg

1atm is the normal atmospheric pressure at _________ ___________

Pressure changes with _____________

Air pressure is measured with a _________________.

Standard Temperature and Pressure (STP)

Standard temperature =Standard pressure =

Pressure, Volume, & Temperature

Boyle’s Law

__________________and __________________are __________________ proportional if the temperature remains constant

Charles’ Law

____________________ and _____________________ are _________________ proportional if pressure remains constant. Temperature must be in _____________.

Gay-Lussac’s Law

___________________ and _____________________ are _____________ proportional if volume remains constant. Temperature must be in ________________.

Avogadro’s Law

For a gas at constant __________________ and ___________________, the _______________ is directly proportional to the ______________________________ of gas (at low pressures).

V = volume of the gas n = number of moles of gas

Avogadro’s Principle: At STP, ____________ gas is equal to ________________.

Combined Gas Law

Temperature must be in _____________. Cross out any _____________.

Sample Problem

At conditions of 785 torr of pressure and 15.0 oC temperature, a gas occupies a volume of 45.5 mL. What will be the volume of the same gas at 745 torr and 30.0oC?

Example

On a cold morning (10.0 oC) a group of hot-air balloonists start filling their balloon with air, using a large fan. After the balloon is three-fourths filled, they turn on the propane burner to heat the air. At what Celsius temperature will the air completely fill the envelope to its maximum capacity of 1700. m3?

Ideal Gas Law

R is the __________________ ________ ______________. An “R” value is picked based upon the unit being used to measure_________________________.

(R = 0.08206 atm L/mol K)(R = 8.314 kPa L/mol K)(R = 62.4 mmHg L/mol K)

Example

How many moles of a gas at 100oC does it take to fill a 1.00-L flask to a pressure of 1.50 atm?

Example

What is the volume occupied by 9.45 g of C2H2 at STP?

Gas Stoichiometry

Only gas volumes at __________ (Avogadro’s Principle: 1 mol = 22.4 L) can be entered into a stoichiometry equation

If gas is at a different __________________ and _______________, use PV=nRT to convert ____________ to ____________ and then continue with the stoichiometry.

Sample Problem

3 H2 + N2 2 NH3

A chemist might commonly perform this reaction (______________ process) in a chamber at 327oC under a pressure of 900. mm Hg. How many grams of ammonia would be produced from 166.3 liters of hydrogen at the above conditions?