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Gas Laws. We will cover. Boyle's Law Dalton's Law Henry's Law Charles' Law. Boyle’s Law. “At a constant temperature, the volume of a given mass of gas varies inversely with the absolute pressure”. Dalton's Law.
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We will cover • Boyle's Law • Dalton's Law • Henry's Law • Charles' Law
Boyle’s Law “At a constant temperature, the volume of a given mass of gas varies inversely with the absolute pressure”
Dalton's Law “In a mixture of gases, each constituent gas exerts a Partial Pressure in proportion to its percentage of the mixture”
Dalton's Law(Example) • Pure air at 1 bar pressure • Air consists 79% nitrogen and 21% oxygen • Partial pressure of nitrogen = 0.79 bar (ppN2 = 0.79 bar) • Partial pressure of oxygen = 0.21 bar (ppO2 = 0.21 bar)
Henry's Law "The amount of gas that dissolves in a liquid is proportional to the partial pressure of the gas in contact with the liquid" (Providing temperature is constant)
Henry's Law Cap sealed High pressure Excess gas dissolved in liquid
Gas Bubbling rushing out of liquid Henry's Law Cap removed Reduced pressure Reduced amount of gas can dissolve in liquid
Charles' Law "At constant pressure the volume of a gas varies directly with the absolute temperature" or "At constant volume the pressure of a gas varies directly with the absolute temperature"
Charles' Law(Example) • Cylinder pressure = 232 Bar (P1) • Original temperature = (20°C) 293 K (T1) • Temperature increase to (70°C) 343 K (T2)
P1 P2 = T1 T2 P2 = P1 x T2 T1 P2 = 232 x (273 + 70) (273 + 20) Charles' Law(Example) • If • New pressure in cylinder = 271 Bar = 271 Bar
Gas Laws Summary • Boyle's Law • Relates pressure and volume • Dalton's Law • Defines partial pressure exerted by individual gases in a mixture of gases • Henry's Law • Defines the solubility of gases in a liquid • Charles' Law • Relates change in pressure and volume of gases to changes in temperature
Pressure and volume are inter-related by: • Charles' Law? • Boyle's Law? • Henry's Law?
Pressure and volume are inter-related by: • Charles' Law? • Boyle's Law? • Henry's Law?
Dalton's Law deals with: • Pressure changes due to temperature increases? • Volume changes due to temperature increases? • Partial pressures of gases?
Dalton's Law deals with: • Pressure changes due to temperature increases? • Volume changes due to temperature increases? • Partial pressures of gases?
The Gas Law used to explain the Bends is: • Charles'? • Dalton's? • Henry's?
The Gas Law used to explain the Bends is: • Charles'? • Dalton's? • Henry's?
At a depth of 20 metres in sea water the partial pressure of nitrogen in the air supply will be _____ times the partial pressure which it is at the surface: • Two? • Three? • Four?
At a depth of 20 metres in sea water the partial pressure of nitrogen in the air supply will be _____ times the partial pressure which it is at the surface: • Two? • Three? • Four?
Exposing a full diving cylinder to excessive heat is not recommended because: • The paint may deteriorate and allow rust? • The rubber seals involved may perish and give rise to air leaks? • The internal air pressure may rise excessively?
Exposing a full diving cylinder to excessive heat is not recommended because: • The paint may deteriorate and allow rust? • The rubber seals involved may perish and give rise to air leaks? • The internal air pressure may rise excessively?
Serious diving ailments such as Nitrogen Narcosis are explained using: • Boyle's Law? • Charles' Law? • Dalton's Law?
Serious diving ailments such as Nitrogen Narcosis are explained using: • Boyle's Law? • Charles' Law? • Dalton's Law?
The analogy of the bubbles forming in a fizzy drink when the bottle is opened is used to explain: • The Bends? • Oxygen Starvation? • Nitrogen Narcosis?
The analogy of the bubbles forming in a fizzy drink when the bottle is opened is used to explain: • The Bends? • Oxygen Starvation? • Nitrogen Narcosis?