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# Applied Phys-unit 1

### Resp Therapy-Applied Physics Unit I

Question | Answer |
---|---|

What are solids? | They have a high degree of internal order. Their atoms or molecules are limited to back and forth motion about a central position. They maintain their shape because their atoms are kept in place by strong mutual attractive forces. |

What are liquids? | They have weaker mutual attraction forces than in solids and liquid molecules can move about freely. They are dense and cannot be easily compressed (just like solids aren't that way) |

What are gasses? | Their molecular attractive forces are very weak. Their molecules exhibit rapid, random motion w/ frequent collisions. They have no inherent boundaries and are easily compressed and expanded. |

What is kinetic energy? | The energy of motion. 1) All matter has some since atoms of all matter are in motion at ordinary temps 2) This makes up most of the energy for gases since their attractive forces are so weak. |

What is potential energy? | Energy of position. 1) This makes up the energy in solids and liquids due to the strong attractive forces between molecules |

point 1 of kinetic molecular theory- gases are composed of: | discrete molecules |

point 2 of kinetic molecular theory- the molecules are in: | random motion, traveling in a straight line or path |

point 3 of kinetic molecular theory- all molecular collisions are: | elastic, causing no energy transfer between molecules |

point 4 of kinetic molecular theory- the molecular activity is directly dependent on: | the temperature |

point 5 of kinetic molecular theory- there is no physical attraction between: | the molecules composing the gas |

brownian motion | random motion of the larger particles in a gas |

the temperature of a gas is directly proportional to | its kinetic energy |

What is absolute zero? | temperature at which there is no kinetic energy. No one has been able to achieve this, this is a purely conceptual. |

In Celsius units, kinetic molecular energy stops at | -273 degrees celsius. This is "absolute zero" for celsius. |

0 ° K = | -273° C |

0°C | 273°K |

To convert degrees celsius into degrees kelvin, | K= C + 273 |

In fahrenheit scale, absolute zero is | -460°F |

To convert degrees fahrenheit to celsius and vice versa: | °C = (5/9) (°F-32) |

How are gases like liquids? | They are both capable of exerting pressure, capable of flow and exhibit the property of viscosity (force opposing a fluid's flow). |

How are gases not like liquids? | Gases are readily compressed and expanded and fill the spaces available to them through diffusion. |

Quick overview of kinetic activity of gases: | i. Weak forces of attraction, most internal energy is kinetic energy ii. Gas molecules travel about randomly at high speeds and w/ frequent collisions iii. Velocity of gas molecules is directly proportional to its temperature |

What is Avogadro's law? | This states equal volumes of gases under the same conditions must contain the same no of molecules, atoms or ions. Therefore, 1 mole of gas, at a constant temp and pressure, should occupy same volume as 1 mole of any other gas. |

What is Avogadro's constant? | 6.023 x 10^23 (one mole) |

In SI units, quantity of matter is | 1 mole |

Ideal volume is called | molar volume |

At standard temp and pressure, dry (STPD), the ideal molar volume of any gas is | 22.4 L |

What is density? | the ratio of a substance's mass to its volume |

A dense substance has | heavy (high atomic weight) particles packed closely together (Denser gas will be drawn to the lighter gas) |

density (gr/L) is calculated by | =gmw/22.4 L |

For density of a gas mix to be calculated | (percentage of gas X * gmw of X) + (percentage of gas Y * gmw of Y) / 22.4L |

What is grahams' law? | rate of diffusion of a gas (D) is inversely proportional to the square foot of its gmw D gas = 1/ (square root of gmw) (Lighter gases diffuse rapidly, whereas heavy gases diffuse more slowly.) |

Pressure is | measure of force per unit area. Unit is N/m^2 , dynes/cm^2, PSI or lbs/in^2 |

Pressure can be measured indirectly | as the height of a column of liquid, as is commonly done to determine atmospheric pressure |

Pressure = | height x density |

1 atmosphere of pressure is equivalent | 1034 g/cm^2 and 14.7 lb/in^2 |

Dalton's law | The pressure exerted by a gas mixture must equal the sum of the kinetic activity of all its component gases. |

the pressure exerted by a single gas in a mixture is called its | partial pressure |

To calculate partial pressure | multiply its fractional component by atmospheric pressure |

If the total pressure changes, what will change? | The pressures of the individual gases will change accordingly, but the concentration of the gas will not change. |

Henry's law formula | At a given temperature, the volume of a gas that dissolves in a liquid is equal to its solubility coefficient times its partial pressure V = α * (pp of gas x) |

What's the solubility coefficient? | solubility of gases in liquids is compared by using this measure, equals the volume of a gas that will dissolve in 1 ml of a given liquid at standard pressure and specified temperature |

Temp plays a role in gas solubility due to changes in kinetic activity. High temps ____ solubility and lower temps ____ it. | decrease, increase |

Boyle's law | If the temperature remains constant, the volume of a given mass of gas is inversely proportional to the absolute pressure. (Think of balloon example) |

What is the working formula for Boyle's law? | P1(V1) = P2(V2) |

Charles' law | The volume of gas varies directly with changes in its temperature (K°). In other words, as the temperature of a sample of gas at constant pressure increases, the volume increases. |

What is the working formula for Charles' law? | V1(T2) = V2 (T1) |

Gay-lussac's law | The pressure exerted by a gas varies directly w/ its absolute temperature. Simply put, if a gas's temperature increases then so does its pressure, if the mass and volume of the gas are held constant |

What is the working formula for Gay Lussac's law? | P1(T2) = P2(T1) |

What is the combined gas law? | combo of boyle's, charles' and gay-lussac's The pressure and volume of a gas are inversely proportional to each other, but volume is directly proportional to the temperature of that gas. |

What is the working formula for combined gas law? | P1(V1)/T1 = P2(V2)/T2 |

What is the ideal gas law? | If you increase your temperature, you are going to increase the volume, and pressure will increase |

What is the working formula for the ideal gas law? | PV = nRT |

What is the critical temperature? | This is the highest temperature at which a substance can exist as a liquid.The temperature above which the kinetic activity of its molecules is so great that the attractive forces cant keep them in liquid state (so it's just before it turns into a gas) |

What is critical pressure? | the pressure needed to maintain equilibrium btw the liquid and gas phases of a substance at this critical pressure; lowest pressure necessary at the critical temp of a substance to maintain it at a liquid stage |

What is fick's first law of diffusion? | the rate of diffusion of a gas into another gas is proportional to its concentration. That is, as the concentration gradient between gases increases, the rate of diffusion will increase. (think alveolar-capillary membrane) |

What is the formula for fick's first law? | Vgas= [(A x D) ÷ T ] (P1 - P2) |

What is electricity? | the flow of electrons. |

What are good conductors? | Most metals and salt water (body water) |

What are poor conductors? | Plastics, rubber and glass |

What is the energy source that allows electricity to flow called? | generators (or a battery) |

What do electrical energy sources do? | They pump electrons from the negative pole (cathode) to positive pole (anode) |

Voltage | This pushes electrons through a circuit. It is the power potential (the difference in ____ between point A and point B) behind the electrical energy. Measured in amps. Also called electromotive force (EMF) or potential difference (PD). |

The current that moves through an object is ______ related to the voltage diff between point A and point B and ________ related to the resistance offered by the makeup of the object | directly; inversely |

Resistance | a property of conductors, This opposes flow of electrons (current) in electrical current. |

Resistance is measured in: | ohms. |

How do you calculate resistance? | voltage (V) ÷ current |

What is the greatest danger to you or your patient when electrical shorts occur? | current |

What is Ohm's law? | The current in a circuit is directly proportional to the applied voltage and inversely proportional to the amount of resistance. This means that if the voltage goes up, the current flow will go up, and vice versa. |

How to calculate electromotive force (voltage)? | current x resistance |

What is Henry's law? | This states that the rate of a gas's diffusion into a liquid is proportional to the partial pressure of that gas at a given temperature. |

How to calculate Ranke? | R = F + 460 |