Properties of Matter Achieve Flashcards
Achieve Questions
Define specific heat capacity of a substance.
The amount of energy required to heat 1kg of a substance by 1 degree celcius.
Where would you find values for the specific heat capacity of different substances?
The data sheet
What are the units of specific heat capacity?
Jkg-1 C-1
A substance with a high specific heat capacitance is heated for the time as a substance with a low specific heat capacity. Which will have the largest change in temperature – the high or the low?
The substance with low specific heat capacity.
Write the equation to find the specific heat capacity of a substance.
E = cmΔT
Calculate the energy required to heat 1 kg of water by 1°C.
E = cmΔT
4180x1x1
4180Jkg-1 C-1
167200 J of energy is used to heat 4 kg of water. Calculate the temperature rise of the water.
E = cmΔT
167200=4180x4x?
167200/16720=?
10 degrees celcius
3 kg of iron has an initial temperature of 18°C. It is heated by 30 kJ of energy. Calculate the final temperature of the iron.
Change of temperature= 22
T final= 22+18= 40
What equipment is required to measure the specific heat capacity of a substance.?
Joule metre, scales, substance, heater, thermometer
List the measurements needed to find the specific heat capacity of a substance.
- Energy the heater uses
- Mass of the substance
- Temperature of the substance before the heater is on
- The temperature after the heater is switched off
State how to find the specific heat capacity of a substance using the following equipment. Wattmeter, timer, thermometer, substance, scales.
- Measure the mass of the substance.
- Measure the temperature of the substance before the heater is switched on.
- Time how long the heater is on for and the power it uses. Calculate the energy from the heater with E=Pt
- Measure the temperature when the heater is switched off and find the change in temperature.
Insert into the equation. E = cmΔT
A student measures the specific heat capacity of water to be lower than the value stated in the data sheet. Why might this be the case?
The heat could be lost to the surroundings.
How can you prevent heat being lost to the surroundings of the specific heat capacity practical?
Insulate the material.
Define the specific latent heat of a material.
The specific latent heat is the amount of energy required to change the state of a 1 kg substance.
Where would you find the specific latent heat of different substances?
In the data sheet.
What does vaporisation mean?
A substance changing from liquid to gas.
What does fusion mean?
A substance changing from solid to liquid
Two substances are heated – one with a large specific latent heat and one with a low specific latent heat. Which substance will take the least amount of energy to change state?
The substance with the small specific latent heat.
What are the units of specific latent heat?
Jkg-1
What is the equation to find the specific latent heat of a material?
E=ml
What happens to the temperature of a substance when it is changing state?
Temperature stays constant.
What kind of state change occurs when ice turns to water?
Fusion
Calculate the energy required to melt 0.5 kg of ice.
E = ml
E = 0.5 × 3.34 × 105
E = 1.67 × 105 J
(l is found in the data sheet)
It takes 40 kJ of energy to vaporise a mass of water. Calculate the mass of the water.
E = ml
40 × 103 = m × 22.6 × 105
m = 0.02 kg
It takes 1025 kJ of energy to melt a 5 kg substance. From this information, what material was melted?
E = ml
1025000 = 5 × l
l = 2.05 × 105 Jkg-1
l = copper
Define the term ‘pressure’ in physics.
Pressure is the force per unit area.
If the force is kept constant, what will happen to the pressure when the area is decreased?
Pressure increases.
If the area is kept constant, what will happen to the pressure if the force is decreased.
The pressure will decrease.
Force is…
Weight
Using the kinetic model describe what happens to the pressure of a gas when the temperature is increased and the volume is kept constant.
When the temperature increases the gas particles will again more kinetic energy. This means they move with a greater speed. As a result they hit the walls of the container more frequently and with a larger force. Therefore, because of P=F/A and the area/volume is **kept constant increasing **the force will increase the pressure.
Using the kinetic model describe what happens to the pressure of a gas when the volume is decreased and the temperature is kept constant.
When the volume decreases the gas particles will hit the container walls more frequently. This results in a larger pressure.
Using the kinetic model describe what happens to the volume of a gas when the temperature is increased and the pressure is kept constant.
When the temperature increases the gas particles will again more kinetic energy. This means they move with a greater speed. As a result they hit the walls of the container more frequently and with a larger force. Therefore, because of P=F/A and the pressure is kept constant increasing the force will increase the area which represents the volume of the container.
State absolute zero temperature in °C
-273 °C
Calculate 10°C in Kelvin.
283 K
Calculate the change in temperature in degrees Celsius between 278 K and 308 K.
30 °C
What happens to the volume of an ideal gas if the pressure is increased and the temperature is kept constant?
Increases
What happens to the volume of an ideal gas when the temperature is increased and the pressure is kept constant?
Increases
What happens to the pressure of an ideal gas when the temperature is decreases and the volume is kept constant?
Decreases
A syringe is connected to a pressure reader. How can this equipment be used to find the relationship between pressure and volume for an ideal gas?
Take measurements of the pressure at different volumes.
Multiply P1 and V1 together then P2 and V2 and so on with all the data. This should give a constant and therefore:
P1V1= constant
P1V1=P2V2
Describe an experiment to find the relationship between pressure and temperature when the volume of an ideal gas is kept constant.
Heat an ideal gas with a fixed volume. Take readings of the pressure and temperature of the ideal gas when the gas is being heated.
Divide P1 by T1 (temperature in Kelvin) then P2 by T2 and so on with all the data. This should give a constant and therefore:
P1/T1=P2/T2
Describe an experiment to find the relationship between volume and temperature of an ideal gas when the pressure is kept constant.
Heat an ideal gas with a fixed pressure. Take readings of the volume and temperature of the ideal gas when the gas is being heated.
Divide V1 by T1 (temperature in Kelvin) then V2 by T2 and so on with all the data. This should give a constant and therefore:
V1/T1=V2/T2
