3A-1 Flashcards
Machine
Is defined as a device that receives energy and uses this energy to do work
Simple Machine
receives energy from a single input force and then does work by producing a single output force.
What is Effort?
Is is synonymous with force (newtons)
What is required to achieve a Mechanical Advantage?
The effort or input energy must be applied over a greater distance than the load actually moves.
Ideal Machine
A machine that has no losses to friction. Has an efficiency of 100%. Not possible in real world
Wheel
Effort part of wheel and axle system. The diameter or radius can represent the effort distance
Axle
Load carrying part of wheel and axle system. The diameter or radius can represent the loads distance
Velocity Ratio for Pulley System
When effort is applied downwards VR = Number of Pulleys
When effort is applied upwards VR = Number of Pulleys + 1
Mass Desnity
Mass Density = Mass (kg) / Volume (m^3)
Density of Fresh Water
1000 kg/m^3
Relative Density
Relative Density = Density of Substance / 1000
What is a Beam?
It is a structural member that is subjected to loads perpendicular to its longitudinal axis.
Stress
The internal resistance to an external force is called stress
Linear Strain
When a material is subjected to sufficient external force it will become deformed in some way. When tensile or compressive stresses cause deformation this is known as linear strain.
Reaction Force
A reaction force is a force that acts in the opposite direction to an action force. Friction is the reaction force resulting from surface interaction and adhesion during sliding. Reaction forces and reaction moment are usually the result of the actions of applied forces.
Space Diagram
is a signal diagram which shows a number of different vectors all originating from a single point
Coplanar Vectors
Vectors all in the same plane
Concurrent Vectors
Vectors whose lines of action meet at one point
Regular Pyramid
A pyramid in which the base is a regular polygon and all sides are equal and all angles are equal
Quadrilateral
is any plane (two-dimensional figure) that is bounded by four straight lines. Square/Rhomboid/Rhombus/Trapezium/Rectangle
Obtuse Triangle
One angle is greater then 90 degrees but less then 180
Straight Angle
Is an angle that is exactly 180 degrees
Reflex Angle
An angle greater then 180 degrees
Radian
is illustrated by an arc of equal distance of one radius of the circle.
Absolute Pressure
A pressure scale that begins at zero, which can be defined as the pressure at which a perfect vacuum exists.
Atmospheric Pressure
The pressure of the outside at a certain location on earth. Generally calculated at 101.3 Kpa but can vary depending on elevation. The higher up you go the less atmospheric pressure is present.
Perfect Vacuum Versus Partial Vacuum
Anything below atmospheric pressure (101.3 Kpa) is considered a partial vacuum. Only when absolute pressure reaches 0Kpa is a perfect vacuum reached.
Gauge Pressure
Pressure Gauges start at atmospheric pressure. So zero on their scale is equal to 101.3 Kpa. For instance, when a gauge reads 200 Kpa the absolute pressure is actually 301.3 Kpa.
Internal Energy
Is known as the sum of kinetic energy and potential energy present in all substances due to the vibration of the molecules.
Latent Heat of Fusion
The heat required to change a unit mass of a solid to a liquid
Latent Heat of Evaporation
The heat required to change a unit mass of liquid into a gas at the same temperature and pressure
Calorimetry
is a scientific process that involves the determination of the heating values of fuels or the specific heats of substances.
Thermal Expansion
The increase or decrease in dimension of atmos due to the addition or loss of heat is known as thermal expansion or contraction.
Thermal Expansion of Solids
Linear Expansion
Superficial (Surface Area)
Volumetric
Thermal Expansion of Liquids
Liquids can only expand by volume since they conform to the shape of their container
Thermal Conductivity
Refers to the ability of a material to conduct heat. This means how fast heat can transfer through materials. Generally, metals will conduct heat much more readily than other materials.
Enthalpy
is defined as the total heat energy in KJ contained in a substance at a given pressure and temperature. Enthalpy is measured from a standard starting point of zero degrees C. For instance, the amount of heat energy that is present in a kilogram of steam includes all the sensible heat and latent heat it required to produce that steam.
Specific Enthalpy
Specific Enthalpy is the heat energy contained in 1 Kg of a substance at a given pressure and temperature.
Perfect Gases
Are defined as gases that remain in a gaseous state even during changes in conditions of temperature/volume/pressure. Or put simply they tend not to condense easily. Examples of perfect gases include nitrogen, oxygen and dry air.
Isothermal Compression/Expansion
If compression or expansion occurs with a gas with no change in temperature of the gas then the process is called isothermal and Boyles Law is applied. This can only occur if any additional heat is removed during compression or expansion to maintain a constant temperature.
Adiabatic Compression/Expansion
Can only occur when a gas is totally insulated from external heat transfer. Since no heat transfer can occur the temperature of an expanding gas will decrease. While during the compression of an insulated gas the temperature will increase.
Polytrophic Compression & Expansion
Polytrophic Compression & Expansion takes into account that some heat or cooling is inevitable. Isothermal and Adiabatic are both theoretical ways of calculating at expansion or compression
Difference Between Coagulation and Flocculation?
Coagulation is the removal or neutralization of charges of small particles so they don’t repel one another.
While Flocculation is simply the gathering together of smaller particles into larger ones.
What type of thermal expansion does a hollow object experience?
They expand through volumetric thermal expansion or 3 times the coefficient of linear expansion
Water Equivalent
Is the equivalent mass of water that would require the same amount of heat transfer as the substance in questions to produce the same temperature change.
Linear Thermal Expansion
Refers to a change in one direction/dimension only
Superficial Thermal Expansion
Refers to a thermal expansion in the surface area of a solid. Or expansion in 2 dimensions
Coefficient of Thermal Conductivity
The Coefficient of Thermal Conductivity refers to the number of joules of heat that will be conducted/transferred in 1 second through 1 metre of material thickness and 1m^2 of area when the temperature difference between the two points is 1 C.
Degrees of Super Heat
The amount of Temperature above the saturation point of steam.
Entropy
Entropy is the amount of energy that is unavailable to perform useful work in a given amount of steam
Critical Point of Steam
Is the point at which the amount of latent heat required to produce a state change is zero Kj. A specially designed supercritical boiler must be used in order to operate at the given pressures and temperatures required to reach the critical point.
Positive Ion?
Cation
Negative Ion?
Anion
Electronegativity
Indicates the grabbing power of elements. A higher number will mean the element will take an electron from the lower numbered element. The lower numbered element donates its electron/s
Ionic Bonding
Occurs when valance electrons are transferred from one atom to another. Generally occurs between metals and non-metals.
Covalent Bonding
Occurs when atoms share their valance electrons. Generally occurs between non-mentals and non-metal elements and is the most common bonding of the two ways atoms can be held together. If the electronegativity difference between the elements is less then 1.7 then covalent bonding will occur.
Law of Conservation of Mass
States that the total mass on the left side of a chemical equation must equal the total mass on the right side of the equation
Kilomole
is defined as the quantity of a substance that has a mass in kilograms equal to its molecular mass. For instance Carbon has a molecular mass of 12 so 1 kilomole of Carbon is equal to 16 kg
What is organic chemistry?
It is the study of compounds containing carbon such as hydrocarbons. Almost all compounds that contain carbon are organic expect for carbon oxides, carbonates and cyanides. 95% of the known compounds are organic. They generally exist as gases or liquids at room temp and are flammable compared to inorganic compounds.
Difference between compounds and mixtures?
Compounds are substances which can be formed by chemically combining two or more elements. Mixtures are substances that are formed by physically mixing two or more substances.
What are Hydrocarbons?
Hydrocarbons are only made up of hydrogen and carbon atoms. The simplest hydrocarbon is Methane (CH4).
Primary Hydrogen Versus Secondary Hydrogen?
Primary Hydrogen is hydrogen atoms attached to carbon chains at the ends of a carbon chain. If a primary hydrogen is removed from a hydrocarbon it the result is called a propyl
Secondary Hydrogens are attached in the middle of carbon chains. If a secondary hydrogen is removed from a hydrocarbon it the result is called a isopropyl
Alkanes
Alkanes are hydrocarbons that consist of single-bonded carbon and hydrogen atoms. Single bonded hydrocarbons are considered to be saturated hydrocarbons as they have the most hydrogen bonds as possible. Any double or triple-bonded carbon atoms are considered to be unsaturated hydrocarbons as they do not contain as much hydrogen as they could have due to the carbon-to-carbon bonding.
Alkenes
Alkenes or Olefins are hydrocarbons that consist of double-bonded or unsaturated carbon and hydrogen atoms.
Alkynes
Alkynes are hydrocarbons that consist of triple-bonded (unsaturated hydrocarbons) carbon and hydrogen atoms. Any double or triple-bonded carbon atoms are considered to be unsaturated hydrocarbons as they do not contain as much hydrogen as they could have due to the carbon-to-carbon bonding.
Define Corrosion?
Corrosion may be defined as the destruction of a metal by a chemical or electrochemical reaction with its environment. Or the loss of mass or the breaking down of a material due to the loss of electrons.
What is Cracking? (Fuel Process: Conversion)
It is a type of fuel process used in conversion methods that breaks long hydrocarbon chains into smaller ones through either chemical (Catalytic cracking) or thermal reactions.
Types of Fuel Processes?
These methods are used to manipulate hydrocarbons in order to produce fuels for different reasons.
Separation: Physical separation of hydrocarbon mixtures
Conversion: Chemical conversion through isomerization or cracking of hydrocarbons
Alkylation: combining short chained hydrocarbons back into larger chains
Petrochemical Processes
is a polymerization reaction that involves the combination of small molecules into larger ones. Generally, very large molecules are created.
What is a copolymer?
refers to a polymer created by polymerization of two different substances
Oxidation Reaction
Refers to any reaction in which a chemicals substance loses one or more electrons. Corrosion occurs due to this loss of electrons
Reduction Reaction
Is a chemical reaction in which a chemical element gains one or more electrons
Redux Reaction
Occurs when both a oxidation and reduction reaction occur at the same time. Simply a transfer if electrons in both direction both a loss and a gain of electrons.
Cold Working
Is mechanical work applied to a metal while the temperature is below the recrystallization temperature. Since the internal crystalline structure is already formed it is physically changed by internal slippage. This internal slippage traps atoms more tightly in the new plane causing an increase in the tensile strength of the metal.
Hot Working
Is mechanical work applied to a metal while the temperature is above the recrystallization temperature.
Heat Treating
Is a process that involves heating a metal to modify its internal structure which adjust its mechanical properties. Heating causes recrystallization which causes small grains to come together as larger chains of crystals.
Electrolyte
Is simply a solution that contains free ions through which electric current can flow.
Types of Atmospheric Corrosion
Atmospheric Corrosion is simply corrosion that happens outside due to the air/humidity/pollution
Types:
Dry: very slow and can create passivating films that further slow corrosion
Damp: Produced a thing film of electrolyte on the metal which induces galvanic corrosion
Wet:
How does salt accelerate corrosion?
Salt is hydroscopic meaning it attracts water which will create a film of electrolyte as the salt mixes with the water on the metal.
