Topic 6 - Molecules and Matter Flashcards
What equation links density, mass and volume?
Density (kg/m3) = mass (kg) / volume (m3) or p = m/v.
If a box has a mass of 56kg and a volume of 0.5 m3, what density does it have?
112 kg/m3
What is boiling point?
The temperature at which a liquid boils into a gas or condenses back into a liquid.
What is a freezing point?
The temperature at which a liquid freezes to become a solid.
What is internal energy?
The energy of particles in a substances due to their individual motion and positions.
What is latent heat?
The amount of energy need to change the state of 1kg of a substance without change their temperature.
What is melting point?
The temperature at which a pure substance melts or solidifies.
What is a physical change in a substance?
A change in which no new substances are produced but the appearance of an object may change.
What is the pressure of a substance?
The force applied per unit of cross-sectional area, measured in Pa (Pascals).
What is the specific latent heat of fusion?
The energy needed to melt 1 kg of a solid with no change in temperature.
What is the specific latent heat of vaporisation?
The energy needed to boil away 1 kg of a liquid with no change in temperature.
______ can be poured. What state of matter fits the sentence?
Liquids.
_____ particles are closely packed together and vibrate about fixed positions. What state of matter fits the sentence?
Solid.
_____ particles are very far apart and move around quickly, what state of matter fits best?
Gas.
What is the law of conservation of mass in changes of state?
The mass of the products is the same as the mass of the reactants.
What is internal energy the sum of?
Internal energy is the sum of all KE and PE (kinetic and potential energy).
If particles are further apart they have more?
Potential energy.
If particles are faster they have more?
Kinetic energy.
What is a plateau?
A flat part of a graph.
When heading steric acid from room temperature to above 50 degrees, why does the temperature stop increasing at 32 degrees for a minute and restart increasing again?
The energy is transferred to break the bonds in the steric acid and not to increase its temperature as it has reached its boiling point.
What is the equation for specific latent heat?
Energy (J) = mass (kg) x specific latent heat (J/kg) or E = m x lf or lv. Lf is used with specific latent heat of fusion and lv is used in specific latent heat of vaporisation.
What is absolute zero?
The coldest possible temperature in the universe.
Why is absolute zero the lowest possible temperature in the universe?
It is the point where pressure reaches zero if you continue a graph relating pressure and temperature.
What is the Kelvin scale?
The temperature scale that starts at absolute zero, where absolute zero is 0 degrees compared with -273.3 degrees Celsius.
How do you convert from kelvin to Celsius?
By adding 273 to your Celsius value.
What is Brownian motion?
The idea that particles move randomly, caused by other particles bouncing off of them.
What is pascals?
The unit of pressure.
What is Boyle’s law?
Pressure (Pa) x Volume (m3) = constant.
What is the relationship between pressure and volume?
They are inversely proportional, so as pressure increases, volume decreases.
What is the defintion for internal energy?
The sum of kinetic and potential energy of all particles in a system.
What is sublimation?
Where a solid can directly turn into a gas.
What kind of force is applied by a gas on walls of a container?
A force at right angles, which is called gas pressure.
What is the result of carrying out work on a gas?
We transfer energy to gas particles, increasing the internal energy of the gas. This also increases temperature as kinetic energy of particles has increased.
