ch. 6

93問 • 2年前

問題一覧

Which of the following statements correctly describe gases? I. Gases exhibit the phenomenon of flow. II. Molecular forces of attraction are minimal. III. Gases are difficult to compress. IV. Gases expand to fill their container.

1, 2, and 4 only

At what temperature does all kinetic activity of matter cease?

0 K

A patient has a recorded body temperature of 106° F. What is this temperature in degrees Celsius? formula: ° C = 5/9  (° F – 32)

41° C

A near-drowning patient has a recorded body temperature of 30° C. What is the equivalent temperature in degrees Fahrenheit? formula: ° F = (9/5 x ° C) + 32

86° F

By which of the following means can the internal energy of a substance be increased? I. Cooling the substance II. Performing work on the substance III. Heating the substance

2 and 3 only

What term is used for the transfer of heat by the direct interaction of atoms or molecules in ahot area with atoms or molecules in a cooler area?

Conduction

Which of the following would be the worst heat conductor?

Air

What is the primary means by which heat transfer occurs in fluids?

Convection

Which of the following is a good clinical example of using the principle of convection to transfer heat?

Heated, enclosed infant incubators

Which of the following methods of heat transfer requires no direct contact between the warmer and cooler substances?

Radiation

Which of the following would help to decrease a patient’s loss of body heat? I. Increase the temperature of the room. II. Increase the exposed skin surface area. III. Move the patient away from cold windows.

1 and 3 only

Which of the following is false about evaporation?

The process of evaporation warms the surrounding air.

What is the physical process whereby the gaseous form of a substance is changed back into its liquid state?

Condensation

Which of the following are true of liquids? I. They are easy to compress. II. . They exert pressure. III. They exert buoyant force. IV. They conform to their containers.

2, 3, and 4 only

Which of the following equations can be used to calculate the pressure exerted by a liquid? equation form: PL =h x dw

Liquid pressure = liquid density x liquid depth

According to Pascal’s principle, the pressure exerted by a liquid in a container depends on which of the following? I. Depth of the liquid II. Density of the liquid III. Shape of the container

1 and 2

Archimedes’ principle is applied clinically in which of the following devices?

Hydrometer

What is the internal force that opposes the flow of fluids (equivalent to friction between solid substances)?

Viscosity

Which of the following is false about viscosity?

Viscosity is most important under conditions of turbulent flow.

After placing a liquid into a small-diameter glass tube, you observe the formation of a convex (upwardly curved) meniscus. What conclusion is correct?

Strong cohesive forces exist among the liquid molecules.

What force is responsible for the spherical shape of liquid droplets and their ability to keepthis shape when placed into an aerosol suspension?

Surface tension

The ratio of the density of one fluid when compared with the density of another reference substance, which is typically water, describes the fluid’s:

specific gravity

What is the phenomenon whereby a liquid in a small tube tends to move upward against the force of gravity?

Capillary action

Which of the following is/are good clinical example(s) of the principle of capillary action? I. Capillary stick blood samples II. Absorbent humidifier wicks III. Certain surgical dressings

1, 2, and 3

What is the temperature at which the vapor pressure of a liquid equals the pressure exerted onthe liquid by the surrounding atmosphere?

Boiling point

Which of the following are true about boiling? 1. Bowling a liquid requires more energy than does evaporating it 2. Liquids boiling point varies with the atmospheric pressure 3. The greater the ambient pressure, the lower is the boiling point

1 and 2 only

What is the change in state of a substance from liquid to gaseous form occurring below its boiling point?

Evaporation

Which of the following are true about molecular water vapor? I. Water vapor exhibits kinetic activity. II. Molecular water vapor can be seen. III. Water vapor exerts pressure.

1 and 3 only

What occurs during the evaporation of water?

The adjacent air is cooled.

What is the equilibrium condition in which a gas holds all the water vapor molecules that it can?

Saturation

Which of the following methods would increase the rate of evaporation of a container of water? I. Increase the temperature of the surrounding air. II. Decrease the pressure of the surrounding air. II. Increase the temperature of the water.

1, 2, and 3

Which of the following represents a direct measure of the kinetic activity of water vapor molecules?

Water vapor pressure

What is the term for the actual content or weight of water present in a given volume of air?

Absolute humidity

What is the absolute humidity (water vapor content) of saturated gas at normal body temperature (37° C)?

43.8 mg/L

What is the water vapor pressure of saturated gas at normal body temperature (37° C)?

47.0 mm Hg

What is the term for the ratio of the actual water vapor present in a gas compared with the capacity of that gas to hold the vapor at a given temperature?

Relative humidity

At a room temperature of 22° C, air has the capacity to hold 19.4 mg/L of water vapor. If the absolute humidity in the air is 7.4 mg/L, then what is the relative humidity (RH)? %RH = absolute humidity ÷ air capacity x 100 = A %RH = A x100 = __ %

38%

When the water vapor content of a volume of gas equals its capacity, what is the relative humidity (RH) of this gas?

100%

A gas at 50° C with a relative humidity of 100% is cooled to 37° C. Which of the followingwill occur? I. Condensation on surfaces II. Visible droplet formation III. Warming of the adjacent air

1, 2, and 3

What is the term for the temperature at which the water vapor in a gas begins to condenseback into a liquid?

Dew point

What occurs when the temperature of a saturated gas drops down to its dew point?

Excess water vapor will condense as visible droplets.

The American National Standards Institute has set a water vapor content level of 30 mg/L asthe minimum absolute humidity required for patients whose upper airways have been bypassed. This equals what body humidity (BH)?

68%

If the absolute humidity in a medical gas being delivered to a patient is 14 mg/L, then what isthe body humidity (BH)?

32%

What is the term for the ratio of the amount of water vapor in a volume of gas compared to the amount of the water in gas saturated at a normal body temperature of 37° C?

Percent body humidity (BH)

Which of the following properties of gases distinguish them from liquids—that is, are uniqueto the gaseous phase of matter? I. Gases fill the available space. II. Gases exhibit viscosity. III. Gases exert pressure. IV. Gases are readily compressed.

1 and 4 only

Which of the following occurs when the temperature of a gas rises? I. The kinetic activity of the gas increases. II. The rate of molecular collisions increases. III. The pressure exerted by the gas rises.

1, 2, and 3

According to Avogadro’s law, which of the following is/are TRUE? I. One gram of any substance contains the same number of particles. II. Equal volumes of gases at standard temperature, standard pressure, dry (STPD) have the same number of molecules. III. Equal numbers of gas molecules at STPD occupy the same volume.

1 only

In International System (SI) units, what is any quantity of matter that contains 6.023 x 1023 atoms, molecules, or ions?

Mole (mol)

According to Avogadro’s law, under standard conditions of temperature and pressure (0° Cand 760 mm Hg), 1 mol of any gas occupies which of the following?

22.40L

What is the density of a mixture of 40% oxygen (O2) and 60% helium at STPD?

0.68 g/L

What is the physical process whereby atoms or molecules tend to move from an area of higher concentration or pressure to an area of lower concentration or pressure?

Diffusion

Which of the following best describes the physical concept of pressure?

Force ÷ unit area

What is the common British unit of pressure?

lb/in2 (psi)

One atmosphere (1 atm) of pressure is equivalent to which of the following? I. 29.9 in Hg2. II. 14.7 lb/in2 III. 1034.0 g/cm2 IV. 760.0 mm Hg

1, 2, 3, and 4

You obtain a mercury barometric reading of 760 mm Hg at 17° C. Using the following factor table, compute the corrected pressure.

757.8 mm Hg

The peak pressure on a ventilator reads 40 cm H2O. What is the equivalent pressure in mmHg?

29.6 mm Hg

The peak pressure on a ventilator reads 30 cm H2O. What is the equivalent pressure in kilopascals (kPa)?

2.9 kPa

From a bedside capnograph (CO2 measuring device), you obtain a “dry” gas reading of 5.3% CO2 in a patient’s exhaled gas. Given a barometric pressure of 765 mm Hg, what is the partial pressure of CO2 in this patient’s exhaled gas?

41 mm Hg

In the lung’s alveoli, there are four gases mixed together: O2, carbon dioxide, nitrogen, and water vapor. At a normal barometric pressure of 760 mm Hg, alveolar O2 exerts a partial pressure of 100 mm Hg, CO2 40 mm Hg, and water vapor 47 mm Hg. What is the alveolar partial pressure of nitrogen?

573 mm Hg

Which of the following factors determine how much of a given gas can dissolve in a liquid? I. Solubility coefficient of the gas II. Temperature of the liquid III. Gas pressure above the liquid

1, 2, and 3

At 37° C and 760 mm Hg pressure, 0.023 ml of O2 can be dissolved in 1 ml of plasma, whereas at the same temperature and pressure, 0.510 ml of CO2 will dissolve in 1 ml of plasma. What explains this difference?

CO2 is more soluble in plasma than O2.

Which of the following will occur when a gas undergoes expansion? I. The pressure of the gas increases. II. Molecular collisions decrease. III. The gas temperature increases.

2 only

If a given mass of a gas is maintained at a constant temperature, what will decreasing its pressure do?

Increase its volume.

In what processes of gas compression or expansion does the temperature remain constant?

Isothermal

Both a compressed gas cylinder and its regulator are at room temperature with all valves inthe off position. After the cylinder is opened and gas begins flowing, you note that the regulator is extremely cold to touch. Which of the following principles best explains this observation?

Joule-Thompson effect

Respiratory therapists must ensure that any oil or dust is cleared from high-pressure medical-gas delivery systems before pressurization. Why is this action needed?

Adiabatic compression could ignite the oil or dust.

Which of the following occur(s) when water vapor is added to a dry gas at a constant pressure? I. The volume occupied by the gas mixture decreases. II. The relative humidity of the mixture increases. III. The partial pressure of the original gas is reduced.

1, 2 and 3

During some pulmonary function tests, saturated gas exhaled from a patient’s lungs is gathered at room temperature. Which of the following correction-factor tables would you useto determine what volume this gas occupied in the patient’s lungs?

Ambient temperature, ambient pressure, saturated (ATPS) to BTPS

A combination of neutral atoms, free electrons, and atomic nuclei describes:

plasma

For every liquid there is a temperature above which the kinetic activity of its molecules is so great that the attractive forces cannot keep them in a liquid state. This temperature is called the:

critical temperature.

Which of the following is a false statement about O2?

Its critical temperature is above normal room temperature.

Which of the following medical gases can be maintained in the liquid form at room temperature? I. Nitrous oxide II. Carbon dioxide III. O2 IV. Helium

1 and 2 only

What temperature is necessary to liquefy O2 at 1 atm pressure?

-183.0° C

With all else equal, under which of the following conditions would the drop in pressure occurring while a fluid flows through a tube be greatest?

D; Small; High

The resistance to flow of a fluid through a tube can be computed according to which of the following formulas? formula: R = (P1 - P2) ÷ V

Resistance = pressure ÷ flow

What is the pattern of flow in which a fluid moves in discrete cylindrical streamlines?

Laminar

According to Poiseuille’s law, the pressure needed to drive a fluid through a tube will increase under which of the following conditions? I. Increased fluid viscosity II. Decreased tube length III. Decreased rate of flow IV. Decreased tube radius

1 and 4

Under conditions of turbulent flow, what is the driving pressure? NR= v x d x 2r/h

Proportional to the square of the flow

Which of the following conditions tend to cause laminar flow to become turbulent (producinga high Reynold’s number)? I. High linear gas velocity II. High gas density III. Low gas viscosity IV. Smaller tube diameter

1, 2, and 3 only

Assuming a constant flow, what will happen to a fluid if the cross-sectional area of the tube in which its flows decrease?

Its velocity will decrease.

According to Bernoulli’s principle, as a fluid flows through a narrow passage or stricture, which of the following will occur? I. Fluid velocity will decrease. II. Lateral pressure will fall. III. Total energy will increase.

2 only

What is the most common application of Bernoulli’s principle in respiratory care equipment?

Air injector

Which of the following design components of an air injector would result in entraining the greatest amount of air? I. Small orifice jet II. Large entrainment ports III. Low-velocity gas flow

1 and 2 only

For which of the following purposes might a Venturi tube be used? I. To restore fluid pressure distal to a restricted orifice II. To help keep entrainment ratios constant with varying flows III. To make possible entrainment of large volumes of gas

1, 2, and 3

What physical principle underlies most fluidic circuitry?

Coanda effect

What are the forms of vaporization? I. Boiling II. Freezing III. Evaporation IV. Sublimation

1 and 3 only

What is the motion referred to when solid molecules travel until they collide?

Jiggle

Solids maintain their shape because their atoms are kept in place by strong mutual attractive forces, called:

van der Waals forces.

What is the ratio of the density of one fluid when compared with the density of another reference substance, which is typically water, This describes the fluid’s specific gravity.

True

A combination of neutral atoms, free electrons, and atomic nuclei describes plasma.

True

What is the behavior of gases at very low temperatures or very high pressures? I. The actual volume of the gas molecules becomes important. II. Intermolecular attractive forces have greater impact. III. Gases begin to deviate from their "ideal" behavior.

1, 2, and 3

A mercury barometer reads 770 mm Hg. What is the actual atmospheric pressure in g/cm2?

1047.0 g/cm2

Helium gases would diffuse most quickly and Graham’s law is known as X 0.543 gm/L.

True

ch. 2

Darya Rose · 83問 · 2年前

ch. 2