Thermal Expansion
When a solid is cooled, does it expand or contract?
contract
Name 2 insulators and 2 conductors of thermal energy.
wool, cardboard, plastic
aluminum, metal, transition metals
What is the formula for pressure with units?
Pressure (Pa) = Force (N) / Area (m2)
Which method of heat transfer occurs mainly in solids?
conduction
What are lipids composed of?
glycerol and fatty acids
Draw 3 boxes showing particles in a solid, liquid, and gas
boxes
State what is meant by the specific heat capacity of a substance
energy/heat required to increase temperature
If I increase the temperature tell me EACH thing that will also increase.
more temp = more collision = greater force = greater force exerted
Why are metals good conductors of heat?
They have free electrons that transfer energy quickly.
What is the name of Ms Jess cat?
Bliss
Magnitude of the force to particles affects what?
relative distance
What sport does Ms Jess compete in?
Equestrian (Horse Back riding)
In one experiment, the gas particles push on one wall of the container with a total force of 240 N. The area of that wall is 0.80 m².
Calculate the pressure exerted by the gas on the wall of the container.
300 Pa
Describe what happens to warm water in a container of cooler water.
Warm water rises, cool water sinks, forming convection currents
A student measures the weight of a metal object using a force meter.
The force meter reads 3.84 N.
The mass of the object is recorded as 420 g. What is the gravity?
4.0 N/kg
A steel bridge is 120 m long on a cold morning when the temperature is 5 °C.
By midday, the temperature of the steel has increased to 35 °C.
-Describe what happens to the particles in the steel as its temperature increases.
-Explain why the bridge increases in length rather than mass.
Particles gain kinetic energy and vibrate more
Average separation between particles increases
Mass remains constant; only volume/length changes
Cold water flows into the copper tubes, which are heated by solar radiation. Hot water flows out of the tubes and is stored in a tank. (i) Explain why the tubes are made of copper and are painted black.
Copper is a good conductor of thermal energy / heat Black surface is a good / the best absorber of radiation/ infra red
A circular metal plate seals a pressurised gas tank.
The plate has a radius of 85 mm and experiences a force of 7 500 N from the gas inside. Calculate the pressure and convert your answer to kPa.
Radius = 85 mm = 0.085 m
Area = π(0.085)² ≈ 0.0227 m²
Pressure = 7500 ÷ 0.0227 ≈ 3.30 × 10⁵ Pa
Pressure = 330 kPa
The melting ice floats on top of the lemonade. Explain the process by which the lemonade at the bottom of the drink becomes cold
cold water denser AND sinks convection (current) OR circulation OR warmer water rises
The area of a leaf of the tomato plant is measured to be 45cm2 twenty-five days after the seed has been planted. One month later, the leaf has tripled in size. What is the area of the leaf in dm2?
1.35 dm2
Two solid rods, one made of aluminium and one made of glass, have the same length at 20 °C.
Both rods are heated to 80 °C.
Which will expand more? Why do solids expand less then liquids? Why will the repeated heating cooling cause the rods to fail?
Aluminium expands more than glass
Stronger IMFs and fixed positions in solids limit expansion
Repeated stress leads to fatigue and fracture
Explain why the bottom of a pot of water heats first and how the heat spreads.
Heat conducts through the pot and convection currents form in the water.
A circular piston is used to compress a gas inside a sealed container.
The piston has a diameter of 12 cm. A force of 3.6 kN is applied evenly to the piston
Force = 3.6 kN = 3600 N
Radius = 6 cm = 0.06 m
Area = πr² = π(0.06)² = 0.0113 m²
Pressure = 3600 ÷ 0.0113 ≈ 3.19 × 10⁵ Pa
What is the other word for waves that transfers thermal energy in conduction
phonons
what are the three characteristics of ionic bonds?
High melting and boiling points
Good conductor of electricity
Generally soluble in water