Midterm Flashcards
Properties of a Gas
A gas has fast moving particles that have no definite shape or volume
What happens to particles at higher temperatures
At higher temperatures, particles move faster
What is the reverse of condensation?
Evaporation
What is the reverse of freezing
Melting
What is the reverse of sublimation
Deposition
What do physical properties include?
Physical properties include density, boiling point, melting point, size, shape, etc.
What do chemical properties include?
Chemical properties include: reactivity with acids
Endothermic reaction
An Endothermic reaction is when heat is absorbed from the environment
Exothermic reaction
An Exothermic reaction is when heat is released to the environment
How is a compound formed?
A compound is formed when two or more elements join together chemically
What is the smallest particle which an element can be divided and still be the same substance?
An atom is the smallest particle which an element can be divided and still be the same substance. According to the ancient Greek definition of an atom, it is a particle that cannot be cut.
What has the least mass compared to other particles that make up an atom?
An electron has the least mass compared to other particles that make up an atom, such as protons and neutrons. In fact, protons and neutrons, which make up the nucleus of an atom, have about 1800 times the mass of an electron.
What is the nucleus?
The nucleus is the central region of the atom where most of the mass is concentrated.
What is an electron?
An electron is a negatively charged particle discovered by J.J. Thomson.
What is a neutron?
A neutron is a subatomic particle in the center of the atom that has no charge.
What is a proton?
A proton is a subatomic particle with a positive charge.
What is a region where electrons are likely to be found?
An electron cloud is a region where electrons are likely to be found.
What is the Atomic mass unit?
Atomic mass unit is a unit of mass that describes the mass of an atom or molecule.
How do the number of protons define an element?
The number of protons define an element. An isotope has the same number of protons, but different numbers of neutrons. So for example, all isotopes of Carbon have 6 protons, and all isotopes of Oxygen have 8 protons.
What is the Atomic mass or mass number mean?
The atomic mass or mass number is the total of protons and neutrons, usually found at the bottom of the element symbol. So, if helium has 2 protons and 2 neutrons, it has an atomic mass, or mass number of 4.
What does the atomic number mean?
The atomic number is the number of protons, usually found at the top of an element symbol.
What does the Periodic Law state?
The Periodic Law states that properties of elements change periodically with the elements’ atomic numbers.
Describe what the vertical columns mean on the periodic table.
Each vertical column on the periodic table is called a group, since they have similar chemical properties.
What are the rows on the periodic table called?
Each horizontal row is called a period.
What two factors determine speed?
Two factors that determine speed are distance and time.
What is the difference between speed and velocity?
The main difference between speed and velocity is velocity has direction and speed does not.
What is the definition of a force?
A force is a push or pull exerted on an object to change the object’s motion.
What happens when net forces equal zero?
When net forces equal zero, they are balanced.
What is the only type of force that can change the direction or speed of an object?
Only an unbalanced force can change the direction or speed of an object.
Describe Newton’s first Law.
Law 1: The law of inertia, which states an object at rest wants to stay at rest, and an object moving at a constant speed in a straight path will continue to do so, unless an unbalanced force acts on it.
Describe Newton’s second Law.
Law 2: F = ma, or a = F/m; acceleration is caused by a force acting on a mass.
Describe Newton’s third law:
Law 3: Action-Reaction; for every action, there is an equal and opposite reaction.
What is friction?
Friction is the force that opposes the motion between two surfaces in contact.