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28 Cards in this Set
- Front
- Back
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Thermodynamics |
study of the transfer and behaviour of heat energy |
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Heat energy can be transferred from... |
A hotter to a cooler object |
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Thermal equilibrium |
heat transfer will continue until the two subjects are the same temp. |
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heat energy is measured in |
Joules |
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Internal energy (U) is... |
The total of the different types of energies 'inside' a substance (all kinetic and potential energy) |
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Temperature SI (heat energy) |
Kelvin (K)
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Kinetic energy =Temperature |
The faster the particles are moving the higher the temperature of the substance |
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potential energy= Bonding |
Solids have relatively strong bonds, gases relatively weak, different substances have different bonds. |
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temperature is a measure of... |
motions of particles (the average kenetic energy of the particle) |
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Heat can be transferred from... |
a higher temp to a cooler temp |
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Conduction |
Transfer of heat by contact.- from particle to particle. |
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Convection |
Heat transfer in a gas or liquid by the circulation of currents from one region to another. (particles carry heat from a hotter place to a cooler place). |
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Radiation |
heat waves, infrared waves, 'carry' heat energy from a hotter place to a cooler place. |
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Vapour pressure |
the pressure of a vapour in contact with its liquid or solid form. |
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Partial pressure |
The pressure of a single gas in a mixture of gasses. i.e air has a PP of oxygen of 21 % Daltons law (P total= p1 + p2 + p3...) |
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Evaporation |
Occurs when the kinetic energy of particles is great enough to allow them to break free of the intermolecular bonds holding them together in a liquid and become gas. |
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Humidity |
The amount of water in the air. |
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Absolute humidity |
Measure of water vapour in the air regardless of the temp. (the mass of water vapour divided by the volume of air and water mixture at a given temperature and pressure.) |
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Specific humidity |
The ratio of water vapour content of the mixture to total air content on a mass basis. (the mass of water vapour in air divided by the mass of dry air for the sample of air.) |
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Relative humidity |
how much water vapour there is in air compared to the maximum air can hold as water vapour. as a percentage. (relative humidity=vapour density/saturation vapour density x 100%) |
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Water vapour will condense into droplets depending on... |
temperature. |
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The temperature at which droplets form (condensation) is called... |
dew point |
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The greater the relative humidity the... |
-More likely it is to rain (or form fog) -less likely evaporation will occur. -Higher the ambient temp seems. |
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The lower the relative humidity the... |
-drier the air seems -more likely mucuos membranes will dry out as evaporation will occur -cooler the ambient tep seems. |
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Specific heat capacity |
The amount of heat (Q) required to raise the temp of a mass of a substance by one degree kelvin. SI = J/KgK C=Q/mT or Q=mCT Where C= specific heat , Q= heat, M=mass, T= temp. |
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Latent heat |
the amount of heat energy required to change the state of a substance.
As these changes of phase occur, there is no temp change until the phase/state has changed. |
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latent heat of fusion |
solid to liquid |
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latent heat of vaporisation |
liquid to gas |
