C1 Flashcards
What is an element?
One type of atom.
What group is group 1?
The alkali metals
What group is group 2?
The alkaline earth metals
What is in-between group 2 and 3?
The transition metals which can have a charge of +1 to +3
What group are group 7?
The halogens
What group are group 0?
The noble gases
What is a compound?
They contain more than one type of atom that are chemically bonded to eachother.
What is the structure of one atom?
It has a central nucleus made of neutrons and protons and has electrons orbiting round the outside. They all have the same number of protons and neutrons.
What are reactants?
The substances in a chemical equation that you start with.
What are products?
The substances in a chemical equation that are made in the reaction.
Why do you balance equations?
Because no atoms are ever created or destroyed so there must be the same amount of atoms on both sides of the chemical equation.
What is the Law of conservation of mass?
The total mass of the products formed in a reaction is equal to the total mass of the reactants.
What are the 4 state symbols?
s-solid
a-aqueous
g-gas
l-liquid
What does aqueous mean?
When a substance is dissolved in water.
What is a mixture?
Made up of two or more substances(elements or compounds) that are not chemically bonded to each other.
What are the 4 means of separation?
Filtration, crystallisation, distillation and chromatography.
What is filtration?
Used to separate substances that are insoluble in a particular solvent from those that are soluble in the solvent.
This is through the use of filter paper.
What is crystallisation?
It is used to obtain a sample of pure salt from the salt solution. You would evaporate the water from a solution by heating an evaporating dish on a water bath. When crystals start to appear, heating should be stopped and the rest of the water is left to evaporate to get the salt.
What is distillation?
Heating a solution until the substance with the lowest boiling point is evaporated. The vapour then goes into a condenser. There the vapour is cooled into a liquid for collection in a receiving vessel.
What is fractional distillation?
This is used to separate mixtures of miscible liquids(liquids that dissolve in each other). You add fractionating column to the apparatus for distillation filled with glass beads. The hottest point is at the bottom of the fractionating column so the beads condense the vapour with the lowest boiling point so they do not enter the condenser. Then the liquid that made it through is separated from the other.
What is chromatography?
Chromatography works because some compounds in mixture will dissolve better than others in the solvent chosen. A capillary tube is used to dab a spot of the solution on a pencil line near the bottom of the chromatography paper. The paper is then placed in a solvent, allowing it to soak up the paper, running through the spot of the mixture. The characteristics can show which parts are related.
What did John Dalton do?
He suggested that substances were made up of atoms that were tiny hard spheres. He also suggested that each chemical element had its own type of atom that differed from others in their mass. He believed the atoms could not be divided or split.
What did JJ. Thomson do?
He discovered the electron and theorised a different model of the atom. He said the electrons must be embedded in a could of positive charge as he knew atoms have no charge, so there must be something to balance out the electron. This was called the plum pudding model.
What was the evidence for a nucleus?
The gold foil experiment where two scientists fired alpha particles at the thinnest piece of gold foil they could make. They thought the particles would pass right through the god atoms but in fact some bounced off.
