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Flashcards

density

Ellaine Wahome Physics gcse GCSE English 36 cards

Cards in this deck (36)

  1. 1densitymeasure of compactness of a substance
    (mass of a substance and how much space it takes up)
  2. 2units for densityg/cm3 or kg/m3
  3. 3density depends on the spacing of atoms in mattersolids and liquids - have similar densities (space between atoms doesn't change significantly)
    liquids have a lower density than solids (main exception is ice and water)
  4. 4gasses have a far lower densityspacing between atoms increase x10 (particles have lots of energy to move so volume increases greatly and therefore density decreases greatly compared to solid/liquids)
  5. 5if questions involve a change in state and ask for new volume/pressurethe mass is the same
  6. 6*particles of a substance in each state are the same *only the arrangement and energy of the particles are different
    (if you REVERSE a state - the particles go back to how they were before)
  7. 7solidsstrong forces of attraction hold the particles together in a fixed regular arrangement
    - particles don't have much energy in their kinetic stores (can only vibrate about their fixed positions)
  8. 8liquidsforce of attraction between the particles are weaker (particles are close together , but can move past each other and form irregular arrangements)
    *has more energy in their kinetic stores than particles in a solid (move randomly at low speeds)
  9. 9Gasalmost no forces of attraction between particles
    Particles have more energy in their kinetic energy stores than those in liquids
    (free to move- travels in random directions at high speeds)
  10. 10when you heat a liquidextra energy is transferred into the particles kinetic energy stores making it move faster
    (when enough of the particles have enough energy to overcome their attraction to each other, big bubbles of gas form in the liquid) - boiling
  11. 11heating a solidextra energy makes particles vibrate faster until eventually the forces between them are partly overcome and the particles start to move around (melting)
  12. 12finding densities of solids or liquids- measure its mass and volume
    ---------------------------------
    easiest way to FIND DENSITY - use a measuring cylinder
    - use a mass balance to measure the mass of the empty measuring cylinder
    pour in the liquid you are investigating ( measure mass of the cylinder again and the difference in mass = mass of liquid)
    (or press 0 to reset it after placing the cylinder on the balance and pour in the water)
    ------------------------------
    Finding VOLUME OF A LIQUID - read it from cylinder scale
    VOLUME OF A PRISM- - area of base x height (cube = length x width x height)
  13. 13if your object isn't a regular shape you can find its volume by...use a eureka can filled with water and an empty measuring cylinder - oulet on the side will allow water to flow out and be collected in the cylinder
    (object submerged in water will displace the volume of the water equal to its own volume)
  14. 14the larger the volume measured the more accurate the densityminimise affects on the uncertainty in taking the measurements
    Multiple measurements - identify anomalies and also calculate a mean
  15. 15strong forces of attraction between particlessolid
  16. 16weak forces of attraction between particlesliquid
  17. 17very weak forces of attraction between particlesgas
  18. 18when a gas is heatedif the container is expandable the volume will increase
    - fixed container - pressure will increase
  19. 19in a closed system changes in state won't change the mass at allnumber of particles remains the same
  20. 20condensationwhen heat is lost, particles won't have enough energy to overcome the force of attraction (bonds start to form between the particles)
  21. 21specific latent heatamount of energy needed to change 1kg of the substance with no change in temp
    - substance needs to be at the right temp to change state first
    -SLH of fusion - energy to freeze/melt
    SLH of vaporisation - energy to boil/condense
  22. 22energy is absorbed when melting and evaporatingreleased - when freezing and condensing
  23. 23specific heat capacityamount of energy required to raise the temp of 1kg of the substance by 1c
  24. 24specific heat capacity of water experiment1. use a mass balance to measure the mass of the insulating container
    2. fill with water and measure again (difference in mass is the mass of the water)
    3. set up the experiment (add thermometer and an electric immersion heater inside the water connecting the immersion heater to a power supply)
    4. set the joulemeter to read 0 and place a lid on the container if you have one
    5. measure the temp of the water and turn on the power
    6. KEEP AN EYE ON THE THERMOMETER (when temp has increased eg by 10 degrees stop the experiment and record the energy on the joulemeter and the increase in the temp)
    6. calculate SHC of h20 by rearranging the equation and plugging in your equations
    7. repeat the whole experiment at least 3 times (calculate average of the SHC)
  25. 25you need to put in energy to break intermolecular bondswhen you heat a solid, liquid - you are transferring energy to the kinetic energy stores of the particles in the substance making the particles vibrate or move faster
  26. 26when a substance is boiling or meltingyou are still putting in energy but the energy is used for breaking the intermolecular bonds rather than rising temp
  27. 27when a substance is condensing or freezingbonds are forming between particles which releases energy - means temp doesn't go down until all the substance has turned to liquid or solid
  28. 28particle motion in gases...
  29. 29motion of particles in a gasmove randomly in every direction
  30. 30increased temperature means more energy given to particlesthermal energy is transferred to kinetic
    - particles move faster
    - collisions occur more often
    - particles hit the wall with a greater impact
    - SO PRESSURE INCREASES
  31. 31gas pressure varies with volume and tempspeed of gas particles- depends on the temp of the gas
    (higher temp=particles move faster and collide more often)
    - increasing temp of a fixed volume of gas increases its pressure
  32. 32if temp is constant , Increasing VOLUME of gas means...particles get more spread out and hit walls of containers less often (pressure decreases)
  33. 33pressure and volume are INVERASELY proportionalwhen volume goes up , pressure goes down
    gas of fixed mass at a constant temp the relationship is p1v1=p2v2
  34. 34absolute zero-273degrees celsius - the COLDEST anything can get (pretty much STILL)
    (particles have as little energy in their kinetic energy store as its possible to get )
  35. 35absolute 0 is the start of the kelvin scale temptemp change of 1 degrees is also a change of 1 kelvin
    (2 scales are similar - only difference is where 0 occurs)
  36. 36to convert from degrees celcius to kelvinsjust add 273
    kelvin ---> celcius (take away 273)

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GCSE Physics gcse (paper 2) Flashcards on density, created by Ellaine Wahome on 20/06/2022.
Created by
Ellaine Wahome · Jun 2022
Updated
Jun 22, 2022
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