Molecles And Matter Flashcards
Define density
Density is the mass of an object divided by its volume.
Density is often expressed in units such as kg/m³.
Write the equation for density
Density (ρ) = Mass (m) / Volume (V)
This formula is fundamental in understanding material properties.
How to test the density of a liquid?
Measure the mass of a known volume of the liquid and calculate density using the formula.
Common methods include using a hydrometer or volumetric flask.
How to test the density of an irregular shape?
Use the water displacement method to find the volume, then calculate density using mass.
This method involves submerging the object in water and measuring the displaced volume.
Define the term latent heat
Latent heat is the energy required to change the state of a substance without changing its temperature.
It is involved in phase changes such as melting and boiling.
Give the equations for latent heat of vaporization and fusion
Latent heat of fusion (Lf) and latent heat of vaporization (Lv) are given by Q = mLf and Q = mLv, respectively.
Q is the heat energy, m is the mass of the substance.
Define the terms boiling point and melting point
Boiling point is the temperature at which a liquid becomes a gas, while melting point is the temperature at which a solid becomes a liquid.
These points vary for different substances.
What happens to particle movement and energy when a substance boils?
Particles move faster and gain kinetic energy, while internal energy increases as they transition from liquid to gas.
This process requires energy input, overcoming intermolecular forces.
Calculate the specific latent heat of fusion of Naphthalene
Specific latent heat of fusion = 6x10 J / 4 kg = 1.5x10 J/kg
This calculation shows how much energy is needed to change the state per kilogram.
What happens to gas pressure with increasing temperature in a sealed container?
Gas pressure increases as temperature increases due to higher particle movement and collisions.
This relationship is described by Gay-Lussac’s Law.
Name the changes of state
- Solid -> Liquid
- Liquid -> Solid
- Liquid -> Gas
- Gas -> Liquid
- Solid -> Gas
These changes are also known as phase transitions.
Fill in the blank: Solid -> Liquid is called _______
melting
This process absorbs heat.
Fill in the blank: Liquid -> Solid is called _______
freezing
This process releases heat.
Fill in the blank: Liquid -> Gas is called _______
vaporization
This includes boiling and evaporation.
Fill in the blank: Gas -> Liquid is called _______
condensation
This process releases energy.
Fill in the blank: Solid -> Gas is called _______
sublimation
This process occurs without passing through a liquid state.
