Matter and Particles Flashcards
What is the equation that defines density?
Density = Mass / Volume
What is the unit of mass?
Kilogram
What is the unit of volume?
m^3
What is the unit of density?
kg/m^3
What are the three observations of the Geiger-Marsden experiment?
Most particles pass straight through the gold foil.Some particles are deflected by small angles.Very few particles are backscattered.
What are the consequences of the Geiger-Marsden experiment?
The nucleus is mostly empty space.The nucleus is positively charged.The nucleus is small and dense.
What observation in the Geiger-Marsden experiment implies that the nucleus is mostly empty space?
Most particles pass straight through the gold foil.
What observation in the Geiger-Marsden experiment implies that the nucleus is positively charged?
Some particles are deflected by small angles.
What observation in the Geiger-Marsden experiment implies that the nucleus is small and dense?
Very few of the particles are backscattered.
What is the implication of the observation that most particles pass straight through the gold foil in the Geiger-Marsden experiment?
The nucleus is mostly empty space.
What is the implication of the observation that some particles are deflected by small angles in the Geiger-Marsden experiment?
The nucleus is positively charged.
What is the implication of the observation that very few particles are backscattered in the Geiger-Marsden experiment?
The nucleus is small and dense.
Describe Rutherford’s Nuclear Model.
A small, dense positive nucleus surrounding by a cloud of negative electrons. Mostly empty space.
What is the name of the model of the atom that was developed in the wake of the Geiger-Marsden experiment?
Rutherford’s nuclear model.
Describe the particles in a solid.
Strong bonds, vibrating around fixed positions, slow speeds, small distances between them.
Describe the particles in a liquid.
Weak bonds, free to move around within the confines of the liquid, moderate speeds, moderate distances between them.
Describe the particles in a gas.
Very weak/non-existant bonds, free to move around the container, fast speeds, large distances between them.
What is the phase transition from a solid to a liquid?
Melting
What is the phase transition from a gas to a liquid?
Condensation
What is the phase transition from a liquid to a gas?
Boiling
What is the phase transition from a liquid to a solid?
Freezing
What charge does a proton have?
+1
What charge does an electron have?
-1
What charge does a neutron have?
0
What is the mass number of an atom?
The number of protons plus the number of neutrons in the nucleus.
What particles are in the nucleus of an atom?
Protons and neutrons
What is the proton number of an atom?
The number of protons in the nucleus.
What is an isotope?
An atom that has the same number of protons, but different numbers of neutrons.
Describe the motion of particles in a gas.
Rapid and random
What is temperature?
A measure of the average kinetic energy of an object.
How does Brownian motion provide evidence that the motion of gas/liquid particles is random?
Larger particles (e.g. pollen) suspending in a sea of smaller particles (e.g. water) appear to “jitter” and move randomly…… this occurs due to collisions of large number of smaller particles with the larger particle……which suggests that, as the motion of the large particle is random, the motion of the smaller particles are random.
What happens to the average speed of particles as I increase the temperature?
Increases
In a fixed container, what happens to the pressure of a gas when I increase temperature?
Increases
Explain how gases exert pressure.
The particles have kinetic energy and move around. The particles collide with the walls and change direction. In doing so, they exerted a force on the wall. When you add up all these forces and divide by the area, because P=F/A you get a pressure.
Explain, in terms of particles, why increasing temperature increases the pressure?
The particles move faster which means they collide more often with the wall and they collide harder with the wall, which means the force is greater. P=F/A, so if you increase the force, you increase the pressure.
