C1 Flashcards
Name a difference between elements and compounds
element- 1 type of atom
compound- different types of atom chemically bonded
What is a molecule?
Two or more atoms bonded together
What is the Law of conservation of mass?
In a chemical reaction, total mass of products = total mass of reactants
what is a mixture?
Two or more substances that are NOT chemically combined together
what is the purpose of filtration?
Filtration is used to separate an insoluble solid from a pure liquid or a solution
What is distillation?
Distillation is a separation technique used to separate a solvent from a mixture
What is crystallisation?
A separation technique used to obtain large crystals of a solute from a solution.
How does fractional distillation worK?
A fractionating column is fitted above the mixture, with several condensers coming off at different heights. The column is hot at the bottom and cool at the top. Substances with high
boiling points condense at the bottom and substances with lower boiling points condense on the way to the top.
In chromatography, how many spots are produced by a pure substance?
1
What was the plum pudding model?
the atom is a ball of positive charge with negative electrons embedded in it
Describe the Nuclear model, made by Rutherford
- the mass of an atom is concentrated at its centre, the
nucleus - the nucleus is positively charged
What did Bohr discover?
electrons orbit the nucleus in shells
What is the relative mass of a proton?
1
What is an isotope?
Atoms of an element with the same number of protons and electrons but different numbers of neutrons.
Which shell in an atom has the lowest energy level?
First
