Fundamental Ideas In Chemistry Flashcards
Why do liquids and gases take the shape of their container?
They do not have a fixed shape as there is space between the particles.
Why do gases not have a fixed volume?
There is lots of space between the particles.
The particles in solids _____ in fixed positions.
Vibrate
Which state of matter has the most energy?
Gases
What is the change of state from solid to gas called?
Sublimation
What are the two things that can happen when a substance loses or gains energy?
Its temperature can change or its state can change.
If a substance has a sharp melting point, it is a ____ substance.
Pure
How can we identify the melting point of a substance from a graph?
A horizontal line
What is the name of the section in the middle of an atom?
The nucleus
What three particles are found in the atom?
Neutron, electron, proton
What is the charge of a neutron?
No charge
What does the atomic number (Bottom) represent?
The number of electrons and protons in the atom
How do we work out the number of neutrons?
The difference between the atomic number (Bottom) and the mass number (Top)
What is matter?
Anything that has mass and volume
How many electrons can the 1st shell contain?
2
How many atoms can the 1st and 2nd shells contain?
8
How many atoms can the 4th shell contain?
Any amount
What is the relative atomic mass?
The mass of the atoms in the element in comparison to hydrogen.
How do we work out the relative formula mass?
Add together the relative atomic masses of all the elements in the compound.
What is Avagadro’s number?
6.02x1023
The mass of a mole of particles is equal to the…
Relative formula mass
How do we calculate number of particles?
Number of moles x Avagadro’s number
How do we calculate number of moles?
Mass of substance/Mr
How do we calculate percentage of an element in a compound?
Mass of element in compound/relative formula mass of compound x 100
What are the three subatomic particles?
Protons, neutrons, electrons
What is the first step of an equation involving moles?
Convert grams to moles
What is the second step of an equation involving moles?
Look at the ratios
What is the third step of an equation involving moles?
Convert moles back to grams
What is the top number in the periodic table?
The relative atomic mass
What is the bottom number in the periodic table?
The atomic number
What is an isotope?
An isotope is something that can have two forms: they have the same number of protons and electrons, but different numbers of neutrons.
