Chapter 6

Question 1

What are the primary states of matter ?

Answer 1

Solid, liquid, gas, and plasma

Solid: have a fixed volume or shape. Solids have a high degree of internal order, their atoms or molecules are limited to back and forth motion. Solids maintain their shape because their atoms are kept in place by strong mutual attractive forces called Van der Waals forces.

Liquid : have a fixed volume but adapt to the shape of their container. Liquids are dense and cannot be compressed easily.

Gas: in a gas molecular attractive forces are very weak. Gas molecules lack restriction to their movement and exhibit rapid random motion with frequent collisions.

Plasma : a combination of neutral atoms, free electrons, and atomic nuclei

Question 2

Internal Energy of Matter

Answer 2

Potential energy : is referred to as the energy of position. It’s the energy posed by an object balanced on a shelf.

Kinetic Energy : energy of motion such as that of a falling object.

Question 3

Laws of Thermodynamics

Answer 3

Thermodynamics can refer to either the science of studying the properties of matter at various temperatures or the kinetics or reactions of matter at various temperatures.

The laws of thermodynamics, these laws describe how fundamentals physical quantities like temperature and energy behave under various circumstances

The increase in internal energy can be observed as an increase in heat.

Question 4

Heat transfer

Answer 4

When two objects exist at two different temperatures the first law of thermodynamics tells us that heat will move from the hotter objects to the cooler objects until both object temperatures are equal.

Heat can be transferred in 4 ways
1. Conduction - is a transfer of energy by direct contact between hot and cold molecules. Heat transfer between objects is quantified by using a measure called thermo conductivity.

2. Convection - Involves the mixing of fluid molecules at different temperatures, heat transfers in liquids and gases occur mainly by convection.
3. Radiant - is another mechanism for heat transfer, radiant heat transfer occurs without direct physical contact. Heat transfer by radiantion occurs even in a vacuum as when the sun warms the earth.
4. Evaporation and condensation - vaporization is the change of state from liquid to gas, vaporization requires heat energy. One form of vaporization called evaporation is when heat is taken from the air surrounding the liquid cooling the air. Condensation is the opposite of evaporation. In condensation gases becomes liquids, because vaporization takes heat from the air around the liquid condensation must give heat back to the surrounding.

Question 5

Temperature

Answer 5

Temperature is a measurement of heat

Question 6

Absolute zero

Answer 6

Is the lowest possible temperature achieved, The temperature at which there is no kinetic energy. Because there is no energy the molecules seize to vibrate and the object has no heat that can be measured.

Question 7

Temperature scales

Answer 7

Fahrenheit and Celsius scales are based on properties of water and are most commonly used in the US.

The Kelvin scale is mostly used internationally.

The formula to convert Fahrenheit to Celsius is C = (F-32)/1.8

The formula to convert Celsius to Fahrenheit is F = ( 1.8xC) + 32

The formula for Celsius to Kelvin is K = C + 273

Question 8

Melting

Answer 8

Is the change from solid to a liquid state. The temperature at which the change occurs is the melting point. The extra heat needed to change a solid to a liquid is the latent heat of fusion.

Question 9

Freezing

Answer 9

Is the opposite of melting, because melting requires large amounts of externally applied energy, you would expect freezing to return its energy to its surroundings.

During freezing heat energy is trans feed from a liquid back to the environment usually exposed to cold.

Sublimation is the term used for the phase transition from a solid to a vapor without becoming a liquid.

For Example : Dry Ice

Question 10

Pressure in liquids

Answer 10

Liquids exert pressure which has the dimensions of force per unit area. The pressure exerted by liquid depends on height and weight density. The pressure of a given liquid is the same at any specific depth, regardless of the container shape. This is because the pressure of a liquid acts equally in all directions, that concept is called pascals principle.

Question 11

Bouyancy

Answer 11

An object merged in water appears to weigh less than it did in air, because the pressure below a submerged object, always exceed the pressure above it.

Question 12

Viscosity

Answer 12

Is the force opposing the fluids flow and is similar to friction and solids.

Laminar flow is viewed as concentric layers of fluid flowing parallel to the tube wall.

The difference of velocity in the concentric layers is called shear rate. It is simply a measure of how easily these layers separate.

The heart must perform even more work when blood viscosity increases, as it occurs in polycythemia ( and an increase in red blood cells concentration in the blood. )

Question 13

Cohesion and adhesion

Answer 13

The attractive force between like molecules is called cohesion

The attractive force between unlike molecules is called adhesion

Question 14

Surface tension

Answer 14

Is a force per unit length and is exerted by like molecules at the surface of a liquid.

According to the aplace law the pressure inside the bubble varies directly with the surface tension of the liquid and inversely with its radius.

Question 15

Capillary action

Answer 15

Is a phenomenon in which a liquid and a small tube moves upward against gravity, capillary action involve both adhesive and surface tension forces.

Question 16

Boiling

Answer 16

All the boiling is associated with high temperatures, the boiling point of most liquified gases are very low.

At 1 atm, oxygen boils at -183 Celsius.

Energy is also needed to vaporize liquids. The energy required to vaporize a liquid is the latent heat of vaporization.

Question 17

Humidity

Answer 17

Absolute humidity can be measured by weighing the water vapor extracted from air using a drying agent.

Absolute humidity is 43.8 mg/L

Water vapor is 47mm

When a gas is not fully saturated its water vapor content can be fully expressed in relative terms using a measure called relative humidity.

Hygrometer allows measurements of RH using a wide variety of mechanisms based on the effects of humidity.

When the water vapor content of a volume of gas equals its capacity the RH is 100%

If air that is RH of 90% is cooled its capacity to hold water vapor decreases.

Because RH never exceeds 100% any further decrease in temperature causes condensation that is also called the Due Point.

In clinical practice 2 additional measures of humidity are used percent body humidity and humidity deficit.

Humidity deficit is associated with a BH of less than 100% and represents the amount of water vapor the body must add to the inspired gas to achieve saturation at body temperature.

Question 18

Molar volume and gas density

Answer 18

Molar volume : the idea molar volumes of any gas is 22.4 L

Density is the ratio of the mass of a substance to its volume.

Question 19

Gaseous diffusion

Answer 19

Diffusion is the process of where molecules move from areas of high concentration to areas of low concentration, kinetic energy is the driving force behind diffusion.

Question 20

Gas pressure

Answer 20

Wether free in the atmosphere or closed a container or dissolve in a liquid like blood.

all gases exert pressure the pressure or tension of gas depends mainly on its kinetic.

In addition gravity effects gas pressure.

Pressure is a measure of force per unit.

Question 21

Measuring atmospheric pressure

Answer 21

A barometer of an evacuated glass tube, approximately 1m long, the tube is closed at the top with the bottom open, emerged in mercury reservoir.

Question 22

Partial pressure ( Dalton’s law )

Answer 22

Dalton’s law describes the relationship between the partial and the total pressure in a gas mixture, according to this law the total pressure of a mixture of gases must equal the sum of the partial pressures of all component gases.

A gas making up 25% of mixture would exert 25% of the total pressure.

Question 23

Solubility of gases in liquids ( the Henry’s law )

Answer 23

Henrys law states that at a constant temperature the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas and equilibrium with that liquid.

Question 24

Gas laws

Answer 24

The boules law states that with constant temperature the volume and pressure are indirectly proportional as the pressure is increased the volume will decrease.

The Charles law states that with pressure constant the volume of a gas is directly proportional to its temperature

The Gay-Lussac’s law assumes that gas volume is constant and pressure and temperature are directly proportional to one another.

If the 3 laws are combined they are referred to as the gas laws.

Question 25

Correction factors

Answer 25

Correction factors can be used to convert gas volumes from one set of conditions to another

Ambient temperatures and pressure dry (ATPD)

Body temperature and pressure saturated ( BTPS )

Question 26

Critical temperature and pressure

Answer 26

For every liquid thee 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 critical temperature.

The pressure needed to maintain equilibrium between the liquid and gas phases of a substance at this critical temperature is the critical pressure.

Question 27

Laminar flow and turbulent flow

Answer 27

The difference in pressure requires to produce a given flow, under conditions of laminar flow through a smooth tube of fixed size, is defined by the poiseuille’s law

Turbulent flow under certain conditions the pattern of flow through a tube changes significantly with a loss of regular stream line instead fluid molecules from irregular currents in a chaotic pattern.

The change from laminar to turbulent flow depends on the fluid density, viscosity, linear velocity and tube radius, these factors determine a Reynolds’s number.

Question 28

Transitional flow

Answer 28

Is a mixture of laminar and turbulent flow

Question 29

Bernoulli’s Principle

Answer 29

Bernoulli’s Principle States that as the flow increases the pressure will decrease along with its potential energy.