Gases Flashcards
(42 cards)
Gas
A substance that has no well defined boundaries but DIFFUSES rapidly to fill any container it’s places in
How can temp be converted to a kelvin from Celsius?
By adding 273
What us the standard temp, I.e the freezing point of water?
273K
Boyle’s Law
At constant temp. the volume of a fixed mass of gas is inversely proportional to its pressure
Charles’ Law
At constant pressure, the volume of a fixed mass of gas is directly proportional to its temp, measured on the Kelvin scale
Gay-Lussac’s Law of Combining Volumes
In a reaction between gases, the volumes of the reacting gases and the volumes of any gaseous products are in the ratio of small whole numbers, provided the volumes are measured at the same temp and pressure
Avogadro’s Law
Equal volumes of gases contain equal numbers of molecules under the same conditions of temp and pressure
An ideal gas
A gas that perfectly obeys all the assumptions of the kinetic theory of gases under all conditions of temp and pressure
How do Real gases differ from Ideal gases?
- Forces of attraction and repulsion do exist between the molecules
- the volume of the molecules isn’t negligible
When subbing into the equation PV=nRT
What are the units of pressure, volume and temperature?
Pressure= pascals Volume= cubic metres Temperature= Kelvins
What is the equation of state for an ideal gas?
pV=nRT
-this tells us how the 4 variables change (V,P,T,n) going from one set of conditions to another
What is the pressure of a gas?
The pressure is the force that a gas exerts on a unit area of its container, measured in pascal (Pa)
What is a volatile liquid?
A liquid that has a low boiling point, and evaporates easily
Diffusion
The spreading of gases, e.g. smoke spreading around a room
Define matter
A scientific term for substances/materials
What are the three states of matter?
Solids, liquids, gases
What differentiates a gas from a solid or liquid?
Gas particles have more freedom of movement and will fill any container it’s placed in, they don’t have a fixed volume
What are the particles of solids, liquids and gases?
Atoms, molecules or ions
What two factors does the volume of a sample of gas depend on?
Temp. and pressure
What is temperature?
A measure of the degree of hotness of an object (e.g. Celcius scale & Kelvin scale)
What are the two fixed points of the Celsius scale?
Freezing point of water: 0 degrees
Boiling point of water: 100 degrees
What temperature scale is also known as the absolute scale?
Kelvin scale (absolute zero -273 degrees Celsius)
What is the volume of a gas?
Vol. of a sample of gas is the same as the vol. of the container it’s held in
Why do we normally measure volume in cubic centimetres or Litres instead of cubic metres?
Cubic metres are too large for lab work
