May 7, 2012

HONORS CHEMISTRY

Brain Teaser

Turn in Titration Lab Describe the characteristics or

properties of solid, liquid and gases

Agenda

Brain Teaser Unit 9 Acid/Base Test Result Notes: Introduction to Gases and Gas Laws Homework

Charles and Boyles Law Worksheet

Introduction to GasesIntroduction to Gases

Earth is surrounded by a layer of gaseous molecules - the atmosphere - extending out to about 50 km.

Characteristics of GasesCharacteristics of Gases

Gases low density; compressible volume = shape of container expand when heated large distance between particles

Model of a gas: rapidly moving particles: vol. & shape of container no attraction between particles moving about freely large space between particles: low density & high

compressibility

12m05vd112m05vd1

12m05vd1.mov.lnk

gas_particle_motion.exe.lnk

Liquids and SolidsLiquids and Solids

Liquids higher density, lower compressibility characteristic volume; shape of container particles closer together; moving about;

experience attractive forces Solids

high density; low compressibility particles are close together; little empty

space; strong attractive forces characteristic volume and shape

Atomic View of the States of MatterAtomic View of the States of Matter

Note distance between particles and order of arrangement of particles

Figure 9.101m07an101m07an1

01m07an1.mov.lnk

atomdemo.exe.pif

A10-1-19.mov.lnk

States of MatterStates of Matter

change_of_state.exe.lnk

PressurePressure

Pressure = force/area Units: lb/ft2

Pa = N/m2 = kg/ms2

torr = mm Hgatm

1 atm = 760 torr= 760 mm Hg1 atm = 29.9 in Hg = 14.7 lb/in2

1 atm = 101.3 kPa Measure pressure with barometer or U-

tube or manometer

gas_pressure.exe.lnk

Charles’ Law- Relationship between:_________ and __________

Variables/Units

Held Constant

Relationship (direct or inverse)

In words

T = K V = L P = atm n = moles

Direct

As temperature increases, volume increases

Charles’ Law

Graph of Relationship

Charles’ Law

Charles’ Law Formula

How to convert

C to K

F to C to K

V/T = m m= constant V1/T1 = V2/T2

K = C + 273

C = 5/9(F-32) K = C + 273

Charles’ Law

Temperature

Conversion Practice

Practice Problem

Convert 212 degrees F to K

Convert 50 degrees C to K

The volume of a sample of gas is 2.50L at 45K. What is the volume when it is heated to 125K at a constant pressure.

Pressure

Why does a pin hurt?

Why don’t snowshoes sink?

Boyle’s Law: The relationship between _______ & ________

Variables/Units

Held Constant

Volume (L) Pressure (atm)

Temperature (K) Moles (n)

Boyle’s Law:

Relationship (direct or inverse)

Relationship in words

Inverse

As pressure increases volume decreases.

Boyle’s Law

Sketch Graph

Pressure vs. Volume

Boyle’s Law

Sketch Graph

Pressure vs. 1/ V

Boyle’s Law Formula

Boyle’s Law Formula

Pressure Units

PV = m m = constant P1V1 = P2V2

atm = atmospheres mmHg = millimeters of mercury torr Pa = Pascals psi = pounds per square inch 1 atm = 101,325Pa = 760 mmHg

= 760 torr = 14.70psi

Boyle’s Law Formula

Pressure Unit Conversions

1 atm = 101,325Pa = 760 mmHg = 760 torr = 14.70psi

Boyle’s Law

How to convert from pressure units to atm

(use dimensional analysis)

Convert 458mmHg to atm

Convert 96.5 psi to atm

Convert 485kPa to atm

Boyle’s Law

Boyle’s Law Practice Problem

The pressure on 2.5L of anesthetic gas is changed from 760mmHg to 304mmHg. What will be the new volume of the gas?

STP: Standard Temperature and Pressure

0 oC (273 K) , 1 atm

HONORS CHEMISTRY (5/6)

Open Note Quiz (5/6) Place Homework on your desk

Textbook Notes Charles and Boyles’ Laws Worksheet

Time – 10 minutes

Unit Conversion for Gas Laws Calculations

Convert to the following unitsP = atm

V = Liters

T = Kelvin (oC + 273)

Agenda

Open Note Quiz Grade Homework

Charles & Boyles’ Laws Worksheet Exploring Gas Behavior

Exploring Gas Behavior Activity

Refer to Handout

HONORS CHEMISTRY

May 11, 2012

Brain Teaser

The pressure on 5.5 L gas is changed from 3 atm to 5 atm. What will be the new volume of the gas?

The volume of a sample of gas is 4 mL at 40oC. What is the volume when it is heated to 60 oC at a constant pressure?

Agenda

Brain Teaser Grade Worksheet: Charles and Boyles’

Law Worksheet Notes: Combined Gas law, Avogadro’s

Law and Ideal Gas Law Homework

Ideal Gas Law and Combined Gas Law Worksheet

Combined Gas Law

2

22

1

11

2

2

1

1

2211

T

VP

T

VP

T

V

T

V

VPVP

Boyle’s Law

Charles’s

Combined

Avogadro’s Law

How can we change the volume of a gas in a balloon?

Avogadro’s Law

Why did the blimp deflate?

2

2

1

1

0

)(

n

V

n

V

mn

V

b

bnmV

Avogadro’s Law If the pressure and temperature are held

constant, the volume of a gas is directly proportional to the number of moles (n).

V

n

Gas Laws Part 2: Work on Gas Notes Sheet instead of Brain Teaser

Avogadro’s Law

O2 O3

Suppose we have a 12.2 L sample containing 0.50 mol oxygen gas at a pressure of 1 atm and a temperature of 25 ºC.

1) Balance the equation2) If all this oxygen is converted to ozone at the same

temperature and pressure, what would be the volume

of the ozone?

• The total pressure is the sum of the partial pressures.

• Ptotal = P1 + P2 + P3 + …..

Dalton’s Law Practice

A mixture of oxygen, carbon dioxide, and nitrogen has a total pressure of 0.97atm. What is the partial pressure of Oxygen, if the partial pressure of carbon dioxide is 0.70atm and the partial pressure of nitrogen is 0.12atm?

The Gas LawsThe Gas Laws

Variables: V, P, T, n (or m and MM or d)

Ideal Gas: properties are independent of the identity of the gas

What is the relationship between the variables for an ideal gas?

Basketball Bike Tire

5.3 Ideal Gas Law

PV = nRT P= pressure V = volume n = number of moles R = ideal gas constant

0.08206 L·atm/mol·K T = temperature

STP

Standard Temperature and Pressure 0ºC and 1 atm

Use the Ideal Gas Law to calculate the volume of 1.00 mol of gas at STP

Molar Volume at STP

We can show that 22.414 L of any gas at 0C and 1 atm contain 6.02 1023 gas molecules.

Example

A sample of Hydrogen gas has a volume of 8.56 L at 0ºC and a pressure of 1.5 atm. Calculate the moles H2 molecules present in this gas sample.

Practice ProblemPractice Problem

The volume of an oxygen cylinder is 1.85 L. What mass of oxygen gas remains in the cylinder when it is “empty” if the pressure is 755 torr and the temperature is 18.1oC?

Answer: 2.46 g

Gas Law Stoichiometry

Quicklime (CaO) is produced by the thermal decomposition of calcium carbonate. Calculate the volume of CO2 at STP produced from the decomposition of 152 g of CaCO3 by the reaction

CaCO3 (s) CaO (s) + CO2 (g)

Molar Mass and the Ideal Gas Law

If 0.126 g of a gas are contained in a 25mL tank at 25ºC and 3.25 atm, what is the molar mass of the gas? What is the gas?

Kinetic Molecular Theory A model that attempts to explain the behavior of an

ideal gas. The particles are so small that compared with the

distances between them that the volume of the individual particles can be assumed to be negligible (zero).

The particles are in constant motion. The collisions of the particles with the walls of the container are the cause of the pressure exerted by the gas.

Kinetic Molecular Theory

The particles are assumed to exert no forces on each other; they are assumed to neither attract nor repel each other.

The average kinetic energy of a collection of gas particles is assumed to be directly proportional to the Kelvin temperature of the gas.

When does the Kinetic Molecular Theory break down?

What conditions would cause our assumptions to become in valid?

Derivations from the Ideal gas law:

Derivations occur in non-ideal conditions such as low temperature or high pressure:

At high density the volume of the particles themselves become important.

Gas particles do attract each other when they are close together.

BarometerBarometer

What is in a vacuum? What is the weight of the atmosphere?

Figure 9.3

atmospheric_pressure.exe.lnk

Pressure

Lab: soft drink can 13m18vd1.mov.lnk

Charles’ Law As x increases, y stays

the same, no relationship. y = b y is constant

As x increases, y increases

Y = mx + b

As x increases, y decreases

Y = m(1/x) + b

Team

A sample of nitrogen occupies a volume of 250 mL at 25ºC. What volume will it occupy at 95ºC.

Fluorine gas at 300 K occupies a volume of 500 mL. To what temperature should it be lowered to bring the volume to 300 mL?

Boyle’s Law by the Book

Lab investigation

Pop Quiz: Boyle’s Law

Sulfur dioxide, a gas that plays a central role in the formation of acid rain, is found in the exhaust of automobiles and power plants. Consider a 1.53 L sample of gaseous sulfur dioxide at a pressure of 5.6 x 103 Pa. If the pressure changed to 0.148 atm at a constant temperature, what will be the new volume of gas?

GROUP WORK

Charles and Boyle’s Law Worksheet