Lecture 2.2: Physics of Gases Flashcards

1
Q

What is the Role of The Respiratory System?

A

• Serves to ensure that all tissues receive the oxygen they need
• And can dispose of the CO2 they produce
• Blood carries gases to and from tissues
• Lungs exchange with atmosphere

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2
Q

What is the Kinetic Theory of Gases?

A

• Gases are a collection of molecules moving around a space
• Pressure is generated by collisions of molecules with the walls
• The more frequent and harder the collisions the higher the pressure

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3
Q

How to calculate Pressure?

A

• Pressure = Force / per unit area
• i.e. 1 Newton (N) of force /square metre (m2) = 1 Pascal (Pa)

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4
Q

What other way can Pressure be expressed?

A

Pressure may also be expressed in mmHg (e.g. Blood Pressure of 120/80 mmHg),

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5
Q

How much is 1kPa in mmHg

A

7.5 mmHg

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6
Q

How much is 100mmHg in kPa?

A

13.3kPa

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7
Q

How much is 1 standard atmosphere in mmHg and kPa?

A

• 760 mmHg
• 101.1 KPa

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8
Q

What is Boyle’s Law?

A

• Pressure inversely proportional to volume
• If a given amount of gas is compressed into a smaller volume molecules will hit
the wall more often and pressure will rise

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9
Q

What is Charles’s Law?

A

• Kinetic energy of molecules increases with temperature
• As temperature increases molecules hit walls more often so pressure increases
• Pressure proportional to absolute temperature
• Scale starts at -273 deg C absolute zero

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10
Q

What is the Universal Gas Law?

A

• P.V=R.T
• Allows calculation of how volume will change as pressure and temperature
changes

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11
Q

What are Partial Pressures?

A

• In a mixture if gases molecules of each type behave independently
• They don’t chemically interact
• So each gas exerts a partial pressure
• Calculated as the same fraction of the total pressure as the volume fraction of
the gas in the mixture

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12
Q

What is Saturated Vapour Pressure?

A

• In biological systems gas mixtures always in contact with water
• So water molecules evaporate gas molecules dissolve
• Vapour pressure
• Depends only on temperature
• -6.28 kPa at 37 deg C

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13
Q

The amount of gas which enters the liquid to establish a particular
tension is determined by………..?

A

Solubility

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14
Q

What is the Equation to calculate Content?

A

Content = Solubility x Tension

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