Particles Flashcards
What are the three states of matter?
The three states of matter are solid, liquid, and gas. Each has different arrangements and movement of particles.
How are particles arranged in a solid?
In a solid, particles are tightly packed in a fixed, regular pattern. They vibrate around fixed positions.
How are particles arranged in a liquid?
In a liquid, particles are close together but can move past each other, allowing the liquid to flow.
How are particles arranged in a gas?
In a gas, particles are far apart and move randomly and quickly in all directions.
What is the internal energy of a substance?
Internal energy is the total energy stored in the particles of a substance due to their motion and positions.
What happens to internal energy when a substance is heated?
Heating increases the internal energy. This may cause a temperature rise or a change of state if enough energy is supplied.
What is a change of state?
A change of state is a physical change between solid, liquid, and gas. The substance remains the same but the arrangement and energy of particles change.
What happens to temperature during a change of state?
The temperature stays constant during a change of state because energy is used to break or form bonds between particles.
What is density?
Density is how much mass is in a given volume. It tells you how compact the particles in a substance are.
How does the arrangement of particles affect density?
Solids usually have the highest density because particles are tightly packed. Gases have the lowest because particles are spread out.
What is the difference between physical and chemical changes?
Physical changes, like changes of state, are reversible and do not create new substances. Chemical changes form new substances and are not easily reversible.
What happens to mass during a change of state?
Mass is conserved during a change of state. No particles are added or removed.
Why does a substance cool when it evaporates?
Particles with the most energy leave the liquid, lowering the average energy and temperature of the remaining particles.
What causes pressure in a gas?
Gas pressure is caused by particles colliding with the walls of the container, exerting a force.
What happens to gas pressure if temperature increases?
If temperature increases, particles move faster, collide more often and with more force, increasing the pressure (if volume is fixed).
What happens to gas pressure if volume increases?
If volume increases (and temperature is constant), particles have more space, collide less often, and pressure decreases.
What does compressing a gas do to its particles?
Compressing a gas forces the particles closer together, increasing the pressure and density.
What is the particle model used for?
The particle model helps explain the properties of solids, liquids, and gases by looking at particle movement and arrangement.
What do flat sections on a heating or cooling graph represent?
Flat sections show where the substance is changing state. Energy is being used to break or form bonds, not to change temperature.
Why is energy still transferred even if temperature doesn’t change?
During a change of state, energy goes into changing the particle arrangements rather than increasing kinetic energy, so temperature stays the same.
