physics topic 3
- Created by: olivia15555
- Created on: 12-11-18 08:27
density of materials
comapctness of a substance-mass per unit volume
DENSITY=MASS DIVIDED BY VOLUME
a dense materila has partcles packed together
less dense partcles are more spread out
IF YOU COMPRESS PARTICLES MOVE CLOSER TOGETHER BECOMING MORE DENSE
VOLUME WOULD DECREASE BYT MASS WOULDNT CHANGE
3 STATES OF MATTER
SOLIDS,LIQUIDS, AND GASES
SOLIDS LIQUIDS AND GASES
SOLIDS STRONG FORCES OF ATTRACTION PARTCLE CLOSE TOGETHER FIXED REGULAR ARRANGEMENTSO ONLY VIBRATE
DENSITY HIGHEST THIS STATE AS PARTCLES CLOSESTS TOGETHER
LIQUIDS WEAKER FORCES OF ATTRTACTION PARTCLES CLOSE TOEGETHER BUT MOVE AND FORM IRREGULAR ARRANGEMENTSMORE ENERGY
LESS DENSE THAN SOLIDS
GASES ALMOST NO FORCES OF ATTRTACTION BETWEEN PARTCLES HAVE MORE ENERGGY AND TRAVEL HIGH SPEEDS RANDOM DIRECTIONS
LESS DENSE THAN LIQUIDS AND SOLIDS
how to measure density-practical
to find density of solid object-
use a BALANCE to meausre mass
is regular solid-measure length widht and height and calculate volume
irregular solid SUBMERGE IT IN EUREKA CAN FILLED WITH WATER-water displced by object place in measuring cylinder
record volume of water there
put mass and volume in formula to fimnd out density
practical
to find density of liquid-
place measuring cylinder on a balance and zero the balance
pour 10ml of liquid in and record liquids mass
pour another 10ml and repeat untill full-record mass and total volume each time
for each meausrement use formula find density
take an average
internal energy and changes of state
internal energy is TOTAL ENERGY STPRED BY PARTCLES THAT MAKE UP A SYSTEM
PARTCLES VIBRATE OR MOVE AROUND so have energy in kinetioc energy stores
energy is stored in partcles
when heating a system the energy is transfered to its particles -so gain energy in kinetic energy stores causing them to move faster- INCREASING INTERNAL ENERGY
LEADING TO CHANGE IN TEMP OR STATE
SIZE OF CHANGGE DEPENDS ON MASS AND ENERGY INPUT
THE ENERGY BREAKS BONDS HOLDING PARTCLES TOGETHER
conservation of mass
changes of state-
SOLIDS-
MELTING-liquid
SUBLIMATION-gas
LIQUIDS-
FREEZING-solids
BOILING AND EVAPORATING-GAS
GAS-
CONDENSING-liquid
changes of state
physical chnage not chemical MEANS DONT END UP WITH NEW SUBSTANCE
REVERSING A CH AGE IN STATE SUBSTANCE WILL RETURN TO ORIGINAL STATE
MASS IS CONSERVED AS NUMBER OF PARTCILES DONT CHNAGE ONLY ARRANGEMENT OF PARTCLES
SPECIFIC LATENT HEAT
CHANGING STATE REQUIRES ENERGY
WHEN MELTING OR BOILING A SUBSTANCE YOU ARE OUTTING ENERGY IN WHICH IS INCREASINGG THE INTERNAL ENERGY
ENERGY IS USED FOR BREAKING INTERMOLECULAR BONDS NIOT RAISING TEMPERTAURE
WHEN CONDENSING OR FREEZING BONDS ARE FORMINGG BETWEEN PARTCLES WHICH RELEASES ENERGY
INTERNAL ENERGY THEREFORE DECREASES BUT TEMP DOESNT GO DOWN UNTIILL ALL SUBSTANCE GOES TO LOIQUID
THE ENERGY NEEDED CHANGE STATE OF SUBSTANCE IS LATENT HEAT
specific latent heat
energy needs to chnage state of 1kg mass
from one state to another without changing tempertaure
when coolingg slh is the energy released
SPECIFIC LATENT HEAT OF FUSION IS FOR CHNAGE BETWEEN SOLIDS AND LIQUIDS-MELTINGG AND FREEZING-
SPECIFIC HEAT OF EVAPORISATION IS SLH FOR CHANGING A LIQUID AND GAS-EVAPORATING CONDENSING OR BOILING
FORMULA
ENERGY=MASSXSLH
energgy joules, mass kg and slh j/kg
particle motion in gases
average energy in kinetic stores reaktes to tempertaure
GAS-
particles constantly moving around random directions and speeds
if increase temp, transfer energy into kinetic energy stpres of its partcles
higher temp higher average energy
COLLIDING AS PARTCLES CREATES PRESSURE -exert a force
in a sealed conatiner, outward gas pressure is total force exerted by particles on unit area of container
increase un net force if increase in temperature
IF TEMP CONSTANT AND INCREASE THE VOLUME OF GAS PARTCLES GET MORE SPREDA OUT HIT WALLS LESS PRESSURE DECREASES
pressure
pressure and volume are inversely proportional-as VOLUME GOES UP PRESSURE GOES DOWN
PRESSURE-PASCALS-xVOLUME=CONSTANT
volume
change is presuure cause change in volume
because pressure of partcles cause net oitwards force on container at right angles
also presuure on outside of conatiner due to pressure of gas around it
if a conatiner can easily chnage its size then then chmahe in pressure will casue container to compress of expand
EXAMPLE HELIUM BALLOON
WHEN RELEASED ATMOSPHERIC PRESSURE DECREAZES WITH HEIGHT SO PRESSURE OUTISDE BALLOO DECREASES CAUSING BALLOON TO EXPAND UNTILL PRESSURE INSIDE DROPS TO SAME AS OUTSIDE
doing work on a gas
is you transfer energy by applying a force your doing work
this increases internal energy which increases temp
EXAMPLE-BIKE PUMP
GAS APPLIES PRESSURE TO PLUNGER OF PUMP AND EXERTS A FORCE ON IT
WORK HAS TO BE DONE AGAINST THIS FORCE TO PUSH DOWN PLUNGE
THIS TRANSFERS ENERGY TO KINETIC ENERGY STORES OF GAS PARTICLES INCREASING TEMP
Related discussions on The Student Room
- A-Level Physics »
- is this enough for revision »
- A level options »
- My GCSE journey!! 🦞 »
- GYG - GCSEs in a month »
- Taking a gap year to retake a levels, tips for getting A/A*? »
- Please help me how do i learn most of chemistry for alevel in less than two weeks »
- Mocks day after Holidays - Panicking No revision »
- GCSE Exam Discussions 2024 »
- Should I swap alevel further maths for physics? »
Comments
No comments have yet been made