Boyles Law

Relate to Charles’ Law LabRelate to Charles’ Law Lab

Introduction Introduction

LabLab

Exit TicketExit Ticket

Graph of Charles’ Law Lab relating Temperature and Volume

http://www.grc.nasa.gov/WWW/K-12/airplane/glussac.html

2. Proportionality

• Inversely proportional relationship means Inversely proportional relationship means as one variable increase the other as one variable increase the other decreases. decreases.

• Proportional relationship means that as one Proportional relationship means that as one variable increases the other variable increases the other increases. increases.

3. Does the graph of Charles’ Law show an inversely proportional or

(directly) proportional relationship?

• Proportional, Why?Proportional, Why?• As temperature increases, volume also As temperature increases, volume also

increases increases • As temperature decreases, volume also As temperature decreases, volume also

decreasesdecreases

4. According to the Kinetic Molecular Theory of Gases, the

actual volume occupied by a gas is extremely small compared to the

volume it occupies?

• Real World: Yes, the actual gas molecule is Real World: Yes, the actual gas molecule is extremely small as compared to the volume extremely small as compared to the volume it occupies, but it does occupy a volume. it occupies, but it does occupy a volume.

• Calculation: Individual molecules are very Calculation: Individual molecules are very small and negligible to the calculation.small and negligible to the calculation.

Compressibility

• This is a crowding effect of gases when the This is a crowding effect of gases when the volume is decreasedvolume is decreased

Pressure • Pressure is not the same as force. Pressure is not the same as force.

• Pressure is a force over an area. Pressure is a force over an area.

• Example: psi = Pounds per inExample: psi = Pounds per in22

Photograph by : Larry MacDougal/CanWest News Service

http://hypertextbook.com/physics/thermal/pressure-temperature/

Measuring Pressure

• A A barometerbarometer measures measures atmospheric atmospheric pressure. pressure.

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Units of Pressure

• Kilopascals (Kilopascals (kPakPa),),• Atomospheres (Atomospheres (atmatm),),• Millimeters of Millimeters of

mercury (mercury (mm of Hgmm of Hg), ), • Torr (Torr (torrtorr))

• Helpful ConversionsHelpful Conversions• 1 atm = 1 atm = 760 760 mm Hgmm Hg• 1 atm = 1 atm = 760 760 torrtorr• 1 mm Hg = 1 mm Hg = 11 torr torr• 1 atm = 1 atm = 101.325101.325 kPa kPa

Volume

• Liters (Liters (LL),),• Milliliters (Milliliters (mLmL),),• Centimeters (Centimeters (cmcm33))

• Helpful conversions Helpful conversions – 1000 mL = 1000 mL = 11 L L

– 1 mL = 1 mL = 11 cm cm33

Boyle’s Law:

• PressurePressure and and volumevolume are inversely are inversely proportional proportional

• Formula: PFormula: P11VV11 = P = P22VV22

Boyle’s Law

http://www.grc.nasa.gov/WWW/K-12/airplane/boyle.html

Lab Overview

1.1. Pressure = Books of Uniform MassPressure = Books of Uniform Mass

2.2. Find the Average Volume for Each MassFind the Average Volume for Each Mass

3.3. Graph the Average Volume vs. Pressure Graph the Average Volume vs. Pressure

4.4. Exit Ticket Exit Ticket

Lab Parts

Draw up 35 mL (or cc) in

syringe and cap it—notice we will read the measurement

from the bottom of the plunger. What about sig

figs?

Be sure to put the cap in the bottom. Some kits have black caps and some

have orange caps.

Slide the other end of the syringe into the wooden platform.

The uniform masses are textbooks.

• You will add one book You will add one book at a time.at a time.

• Record the volume Record the volume (correct sig figs) after (correct sig figs) after each book is added.each book is added.

• When you have all 6 When you have all 6 books on the books on the apparatus, you will apparatus, you will then remove one book then remove one book at a time and record at a time and record the volume after each the volume after each book is removed.book is removed.

Lab Safety

• GogglesGoggles

• Lab ApronLab Apron

• Common Sense! Common Sense!

QUESTIONS??