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Density |\left( \rho \right)|
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|\rho = \displaystyle \frac {{m}}{{V}}| |
Density is the ratio between the mass and volume of an object. |
| Concentration in g/L |\left( {C} \right)| | |{C} = \displaystyle \frac {{m}}{{V}}| |
Concentration is the ratio between the amount of solute and the volume of solution. |
| Molar Concentration (or molarity) |\left( {C} \right)| | | {C}=\displaystyle \frac{{n}}{{V} }| |
The molar concentration is the number of moles of solute per litre of solution. |{C}| : molar concentration |\text {(mol/L)}| |{n}| : number of moles |\text {(mol)}| |{V}| : volume of solution |\text {(L)}| |
| Concentration and volume before and after dilution | | {C} _{1}\cdot{V} _{1} = {C} _{2}\cdot {V} _{2}| |
The product of the initial volume |({V}_1)| and the initial concentration |({C}_1)| is equal to the product of the final volume |({V}_2)| and the final concentration |({C}_2)|. It is important to use the same units of volume and concentration for the initial and final situations. |{C}_1|: initial concentration |{V}_1|: initial volume |{C}_2|: final concentration |{V}_2|: final volume |
| Number of moles |\left( {n} \right)| | | {n} = \displaystyle \frac{{m} }{ {M} }| |
The number of moles is equal to the ratio between the mass of a substance and the molar mass. |{n}|: number of moles |\text {(mol)}| |{m}|: mass |\text {(g)}| |{M}|: molar mass |\text {(g/mol)}| |
| Energy efficiency |\left( \text {R.E.} \right)| | |\text {E.E.}=\displaystyle \frac{\text {Useful energy}}{\text {Consumed energy}}\times 100| |
Energy efficiency is the percentage of the energy consumed by a system that will actually be transformed into useful energy. |\text {E.E.}| : Energy efficiency |\text {(%)}| |\text {Useful energy}| : Energy used by the device to perform its main function |\text {(J)}| |\text {Energy consumed}| : Total energy used by the device |\text {(J)}| |
| Thermal energy (heat) |\left( {Q} \right)| | | {Q} = {m} \cdot {c} \cdot \Delta {T} | |
Thermal energy is the amount of energy a substance possesses as a function of the amount of particles it contains (its mass) and its temperature. |{m}|: mass of the substance |\text {(g)}| |{c}|: specific heat capacity |\text {(J/(g}\cdot ^{\circ}\text{C))}| |\Delta {T}|: temperature variation |\text {(ºC)}| |
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Gravitational potential energy |\left( {E}_{{p} _{{g}}} \right)| |
| {E} _{ {p_{g}} } = {m} \cdot {g} \cdot {h} | or | {E} _{ {p_{g}} } = {m} \cdot {g} \cdot {y} | |
Potential energy is defined as the stored energy that an object contains due to its position or shape. |{E}_{{p_{g}}}|: gravitational potential energy |\text {(J)}| |{m}|: mass |\text {(kg)}| |{g}|: intensity of the gravitational field |(\text {9.8 m/s}^2 |{h}| or |{y}|: vertical position (height) of the object |\text {(m)}| |
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Kinetic energy |\left( {E}_{{k}} \right)| |
| {E} _{ {k} } = \displaystyle \frac {1}{2} \cdot {m} \cdot {v} ^{2}| |
Kinetic energy is defined as the energy that a body possesses due to its motion. |
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Mechanical energy |\left( {E}_{{m}} \right)| |
| {E} _ {{m} } = {E} _{ {k} } + {E} _ {{p}} | |
Mechanical energy refers to the energy of a system stored in the form of kinetic energy and potential energy. |
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Speed |\left( {v} \right)|
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|{v} = \displaystyle \frac {{d}}{\Delta {t}}| |
Speed is the ratio between the distance an object travels and the time it takes to travel that distance. |
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Gravitational force (weight) |\left( {F}_{{g}} \right)| |
| {F} _{ {g} } = {m} \cdot {g} | |
Gravitational force is a force of attraction between two bodies. |{m}|: mass |\text {(kg)}| |{g}|: gravitational acceleration |\text {(9,8 N/kg)}| |
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Work |\left( {W} \right)| |
| {W} = {F} \cdot \triangle {x} | |
Work is defined as a transfer of energy. |{W}|: work |\text {(J)}| |
| Electric field intensity |\left( {E} \right)| | |{E}=\displaystyle \frac{{k} \cdot {q}_{1}}{{r}^{2}}| |
The electric field is the region of space in which the electric force of a charged body acts on other charged bodies nearby. |{E} |: electric field intensity |\text{(N/C)}| | {k} |: Coulomb constant |\left( \text{9} \times \text{10}^{\text{9}} \displaystyle \frac{\text{N}\cdot \text{m}^{\text{2}}}{\text{C}^{\text{2}}}\right)| | {q} _{1}|: particle charge |(\text{C})| | {r} |: distance from the charged particle |(\text{m})| |
| Electric force |\left( {F}_{{e}} \right)| | |{F}_{{e}}=\displaystyle \frac{{k} \cdot {q}_{1} \cdot {q}_{2}}{{r}^{2}}| |
Electric force represents the force present between two electrically charged and stationary particles. | {F} _{ \text{e} }|: electric force |(\text{N})| | {k} |: Coulomb constant |\left( \text{9} \times \text{10}^{\text{9}} \displaystyle \frac{\text{N}\cdot \text{m}^{\text{2}}}{\text{C}^{\text{2}}} \right)| | {q} _{1}|: charge of the first particle |(\text{C})| |{q} _{2}|: charge of the second particle |(\text{C})| | {r} |: distance between the two particles |(\text{m})| |
| Current intensity |\left( {I} \right)| | |\displaystyle {I}=\frac{{q}}{\triangle {t}}| |
Current intensity is the quantity of charge that flowsflow at a precise point of the electrical circuit per second. |{I}|: current intensity |\text {(A)}| |{q}|: quantity of charges |\text {(C)}| |{\triangle {t}}|: time interval |\text {(s)}| |
| Potential difference |\left( {U} \right)| | |{U}=\displaystyle \frac{{E}}{{q}}| |
Voltage is the amount of energy transferred between two points in an electrical circuit. |{U}|: voltage |\text {(V)}| |{E}|: energy transferred |\text {(J)}| |{q}|: quantity of charges |\text {(C)}| |
| Ohm's law | |{U} = {R} \cdot {I}| |
Ohm's law represents the mathematical relationship between resistance, current intensity, and voltage. |{U}|: voltage |\text {(V)}| |{R}|: resistance |\left( \Omega \right)| |{I}|: current intensity |\text {(A)}| |
| Junction rule (Kirchhoff's first law) | Series: |{I}_{{t}} \: \text{or} \: {I}_{{s}} = {I}_{1} = {I}_{2} = {I}_{3} = ...| Parallel: |{I}_{{t}} \: \text{or} \: {I}_{{s}} = {I}_{1} + {I}_{2} + {I}_{3} + ...| |
The nodal rule states that the sum of the current intensity (I) flowing into a node must equal the sum of the current intensity flowing out of that node. |{I}_{{t}} \: \text{or} \: {I}_{{s}}|: Current intensity at the source |\text {(A)}| |{I}_{{1}}, {I}_{{2}}, ....|: Current intensity in each of the elements |\text {(A)}| |
| Kirchhoff's Loop Rule (Kirchhoff's second law) | Series: |{U}_{t} \: \text{or} \: {U}_{{s}} = {U}_{1} + {U}_{2} + {U}_{3} + ...| Parallel: |{U}_{{t}} \: \text{or} \: {U}_{{s}} = {U}_{1} = {U}_{2} = {U}_{3} = ...| |
The loop rule states that in an electrical circuit loop, the voltage at the terminal of the power source is equal to the sum of the voltages at the terminals of the other components. |{U}_{{t}} \: \text{or} \: {U}_{{s}}|: Voltage at the source |\text {(V)}|
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| Equivalent resistance |\left( {R}_{{eq}} \right)| | Series: |{R}_{{eq}} = {R}_{1} + {R}_{2} + {R}_{3} + ...| Parallel: |\displaystyle \frac {1}{{R}_{{eq}}} = \frac {1}{{R}_{1}} + \frac {1}{{R}_{2}} + \frac {1}{{R}_{3}} + ...| |
The equivalent resistance is the value of the resistance that would replace all the resistances in a circuit with a single one. |{R}_{{eq}}|: Equivalent resistance |(\Omega)| |{R}_{1} , {R}_{2}, ... |: Resistances of each of the elements |(\Omega)| |
| Electric power |\left( {P} \right)| | |{P}={U} \cdot {I}| |
Electric power indicates the amount of energy that a device can transform over a period of time. |{P}|: power |\text {(W)}| |{U}|: voltage |\text {(V)}| |{I}|: current intensity |\text {(A)}| |
| Electrical energy |\left( {E} \right)| | |{E} = {P} \cdot \triangle {t}| |
Electrical energy is the energy supplied in the form of current intensity. |{E}|: electric energy |\text {(J)}| |{P}|: power |\text {(W)}| |{\triangle {t}}|: time |\text {(s)}| or |{E}|: electrical energy |\text {(Wh)}| |{P}|: power |\text {(W)}| |{\triangle {t}}|: time |\text {(h)}| |