Chemistry Flashcards
What is a molecule?
The general name for a combination of multiple atoms, this can be an element or a compound.
What is a mixture?
2 or more substances that are combined but not chemically bound together.
What is a compound?
A compound is a combination of 2 or more substances that are chemically bound together.
What is distillation?
The action of purifying a liquid by a process of heating and cooling
What is crystallisation?
When a product is made as a solution, one way to separate it from the solvent is to make crystals. This involves evaporating the solution to a much smaller volume and then leaving it to cool. As the solution cools, crystals form, and these can be obtained by filtration.
What is filtration?
This technique is used to separate an insoluble solid from a liquid. It can be used to obtain a product that is free from unreacted chemicals, by-products or solvent.
What do all the atoms of a particular element have in common?
They all have the same number of protons?
What is the relative charge of:
Protons
Neutrons
Electrons
Proton: +1
Neutron: 0
Electron: -1
What is plum pudding?
The plum pudding model was simply an atom full of ‘positive jelly’ with negative electrons floating around in it.
What do electrons determine and why?
They determine an atom’s chemical properties as they are the parts that touch other atoms as they are on the outside.
Lithium, Sodium and Potassium all have one electron in their outer shell, suggest whether they will react similarly or differently in water and explain why,
They are similar chemically and are in the same group on the Periodic Table so will react similarly.
What are isotopes?
Atoms of the same element with a different number of neutrons but the same number of protons.
What is an ion?
An ion is an atom that has lost or gained electrons so it is charged. It usually does this to get a noble gas configuration.
What is mass number?
Mass number is the amount of protons + neutrons in the nucleus of an atom. Atomic number is the number of protons in each atom of an element.
Name the sub-atomic particles found in the nucleus of an atom.
Protons and Neutrons
What is the maximum number of electrons that can occupy each of the first two energy levels (or shells)?
8
Explain the overall charge of any atom
The overall charge of any atom is neutral
How can an atom become an ion with a 2+ charge?
An atom can gain 2 electrons from another atom and become an ion.
What is atomic number?
Atomic number is the number of protons in each atom of an element
What is an element?
It is a substance made up of one type of atom that is found in the Periodic Table
How would you separate salt and water?
You would evaporate the mixture by heating it to it’s boiling point and turning a liquid into a gas.
What is condensation?
A gas turning into a liquid by decreasing the temperature
What are melting point and boiling point?
Melting point is the temperature at which a solid turns to a liquid.
Boiling point is the temperature at which a liquid turns into a gas.
What is chromatography?
The process of separating substances according to solubility and condensity
