CHAPTER 1 Flashcards
What is an element?
Made of one type of atom
What is a compound?
Substance made of different types of atoms bonded together
Differences between compounds and mixtures
Mixtures aren’t chemically combined
What is filtration
Separate insoluble substances from a solution
What is crystallisation
Evaporate water from solution to leave crystals
What is fractional distillation
When liquid are separated because of their boiling points
What did JJ Thompson discover
Electron
What is an ion
Atoms with different numbers of electrons
What is an isotope
Different number of electrons
What is an atom
The smallest part of an element
What do the symbols in the periodic table represent
Atoms
What is a compound
Different types of atoms bonded together
What is the law of conservation of mass
The total mass of products formed = mass of reactants
What holds a compound together
Chemical bonds
Is hydrogen a metal or non metal
Hydrogen is a metal. A metal must conduct heat and electricity which solid hydrogen does. The properties of metals like malleability are just coincidence
With open containers, why does it sometimes look like the law of conservation is broke
With gases, the carbon dioxide formed will escape or oxygen will enter. When gas escapes, the law is kept because oxygen will react with the metal to keep the same weight the same
What is an element determined by
Number of protons
When you change the number of neutrons, you get an
isotope
When you change the number of electrons you get an
Ion
How to separate elements in a compound
Chemical reaction
What does filtration separate
One solute that is soluble in a solvent and one isn’t
How does crystallisation work
Filter the substances, then evaporate the liquid to leave the material
When should heating be stopped during crystallisation
When the solution is just forming crystals
What are elements ordered by in a stable
Smaller number - atomic number
How to calculate the relative atomic mass using isotopes
Multiple percentage by mass, add and then divide by 100
What are the columns in the periodic table called
Groups
What does the symbol of an element show
One atom of the element
What do chemical equations show
The reactants and the products
What happens in a chemical reaction
The atoms in the reactants get rearranged into the products
What is an aqueous solution
A substance that has been dissolved in water
Process of filtration
Pour the mixture through a filter funnel
Process of evaporation
Heat the solution with a Bunsen burner
Keep heating until all the liquid has gone and you are left with dry crystals
Process of crystallisation
Gently heat the solution
once some of the liquid has evaporated, stop heating
Leave the solution to cool
Now more crystals will form
Filter out the crystals out and then you’re done
Process of chromatography
Draw a pencil line of the paper
Place blobs of your in
Place the paper in water so the ink isn’t touching the solution
The solvent will move up the paper and carry the ink
When to use simple distillation
When you want to separate a liquid from a solution
Process of simple distillation
The solution is heated to evaporate the part of it with the lowest boiling point first
This vapour is cooled, condensed and collected
When to use fractional distillation
When you have a mixture of liquids with similar boiling points
Process of fractional distillation
You heat the mixture until it reaches the boiling point of the first liquid
This liquid evaporates first
It reaches the top of the column, runs down the tubs and is collected
You repeat this with higher temperatures
What did John Dalton suggest
Atoms were tiny hard spheres
Who discovered the electron
JJ Thompson
Who discovered and the nucleus and how
Geiger and Marsden fired atoms at gold foil and some rebounded
who discovered that electrons were in shells
Niels Bohr
Who found there were neutrons in the nucleus?
James Chadwick
Charge of a proton
+1
Mass of proton
+1
Charge of neutron
0
Mass of neutron
1
Charge of electron
-1
Mass of electron
very small
What is the mass number
The mass of nucleus
What is the atomic number
The number of electrons or protons
When an atom gains electrons what is the charge on the ion
-
When an atom loses electrons what is the charge on the ion
+
Why will isotopes of the same element have the same chemical properties
Their chemical properties depend on their electronic structure
How to write the electronic structure
Number of electrons in first shell, followed by second and third
What determines how an element reacts
Electrons in outer shell
What experiment did JJ Thompson do and how did this lead to him finding the electron
He found that the mysterious particle was attracted to a positive charge, showing they must be negatively charged
What was Bohrs experiment
he noticed light was given out when electron were heated - they were moving between energy levels
Why is it impossible to predict the mass of crystals that can be obtained during crystallisation
Mixtures have no fixed composition
What was Geiger and Marsden’s experiment
They fired alpha particles at gold foil
Due to the current model of the atoms which was the plum pudding one, they expected most of the particles to pass straight through. The positive alpha particles pass straight through. The positive alpha particles were detected by the negative electrons
