Flashcards
Princles of chemistry
Cards in this deck (54)
- 1Describe the particles in a solid. (e.g. spacing, arrangement, movement and forces)Close together and touching one another
Regular, repeating pattern
Vibrate about a fixed position, but do not move apart
The force between particles in stronger than in a liquid or gas - 2Describe the particles in a liquid. (e.g. spacing, arrangement, movement and forces)Close together and touching one another
Irregular arrangement
Move around and slide past one another
Forces are not as strong as in a solid, but stronger than in a gas - 3Describe the particles in a gas. (e.g. spacing, arrangement, movement and forces)Spaced far apart
An irregular arrangement
Move freely and constantly collide with one another
Non-existent forces between particles - 4What is the change called when: * a solid changes to a liquid? *a liquid changes to a solid? *a liquid changes to a gas? *a gas changes to a liquid? *a solid changes to a gas?* solid-liquid = Melting
*liquid-solid = Freezing
*liquid - gas = Boiling/evaporating
*gas - liquid = Condensing
*solid - gas = Subliming - 5Explain, in terms of particles, the change between a liquid to a gas.The particles gain kinetic energy and move further apart.
Eventually the forces of attraction between the particles are completely broken and they are able to escape from the liquid. - 6Explain, in terms of particles, the change between a liquid to a solid.The particles lose kinetic energy and this allows the forces of attraction between the particles to hold them together.
The particles arrange themselves into a regular pattern are no longer able to slide past one another. - 7Give two pieces of evidence to support the particle theory.*Dilution of coloured solutions - Potassium Manganate crystals are dissolved in water a purple solution is formed- large number of particles in small amount of solid
*Diffusion- Bromine from one flask to another- particles in gas easily mix together - 8What is an atom?Smallest particle of an element that can take place in a chemical reaction
- 9What is an element?A substance made up of atoms which all contain the same number of protons.
- 10What is a compound?A substance made up of two or more elements chemically combined together.
- 11What is a mixture?A combination of two or more substances that are not chemically joined together.
- 12What is a molecule?The smallest particle that can have a separate, independent existence.
- 13When should you carry out filtration?To separate an undissolved solid from a mixture of the solid and a liquid/solution (e.g. sand from a mixture of sand and water)
- 14When should you carry out evaporation?To separate a dissolved solid from a solution, when the solid has similar solubilities in both hot and cold solvent (e.g. sodium chloride from a solution of sodium chloride in water)
- 15When should you carry out crystallisation?To separate a dissolved solid from a solution, when the solid is much more soluble in hot solvent than in cold (e.g. copper sulphate from a solution of copper sulphate in water)
- 16When should you carry out simple distillation?To separate a liquid from a solution (e.g. water from a solution of sodium chloride in water)
- 17When should you carry out fractional distillation?To separate two or more liquids that are miscible with one another (e.g. ethanol and water from a mixture of the two)
- 18What are miscible liquids?Liquids which will mix together.
- 19When should you carry out paper chromatography?To separate substances that have different solubilities in a given solvent (e.g. different coloured inks that have been mixed together to make black ink)
- 20What is thermal decomposition?Breaking down by using heat
- 21What is electrolysis?The decomposition of a substance by passing an electric current through it
- 22What is an atom made up of?Proton
Electron
Neutron - 23Relative charge, relative mass and position of the three sub-atomic particlesNeutron- charge 0, mass 1, nucleus
Proton- charge 1, mass 1, nucleus
Electron- charge -1, mass 0, electron shells - 24What is the atomic number?Number of protons in the nucleus of an atom of an element
- 25What is the mass number?Number of protons + number of neutrons in the nucleus of an atom of an element
- 26What is the top number showed by the element in the periodic table?Mass number
- 27What are isotopes?Atoms that have the same atomic number (same number of protons) but different mass numbers (different number of neutrons)
- 28Electrons exist ............. the nucleus of atoms in different ................ ....................... called ................. .................... . There are several .................. ....................... .around
energy levels
electron shells
electron shells - 29What is Ar?Relative atomic mass (Mean mass of all the isotopes of a particular element)
- 30What is Mr?Relative formula mass- The sum of all the relative atomic masses of all the atoms present in the formula of a substance.
- 31What is a mole?1 mole is the amount of substance that contains 6 x 10^23 particles (atoms, molecules or formulae) of the substance.
- 32How do you calculate the mass of 1 mole?the relative atomic mass (Ar) expressed in grams
- 33How do you calculate the mass of a substance (in grams) from the amount (number of moles)?amount of moles x Mr
- 34How do you calculate the amount in moles from the mass of the substance?Mass of substance (grams) / Mr
- 35What is the molar volume?One mole of any gas has a volume of 24dm^3 at room temperature and pressure.
- 36How to work out the volume of gas (in dm^3 and cm^3) from the amount of gas?Volume in dm^3 = amount x 24
Volume in cm^3 = amount x 24 000 - 37How to work out the amount of gas (in moles) from the volume of gas in a) dm^3 b) cm^3a) volume (in dm^3) / 24
b) volume (in cm^3) /24 000 - 38What is the empirical formula?The simplist whole number ratio
- 39How do you work out the empirical formula? (e.g. percentage composition: aluminium = 52.94 %; oxygen = 47.06 % empirical formula of Aluminium Oxide?)Divide by Ar (Al= 52.94 / 27=1.96
O= 47.06 / 16=2.94)
Divide by smallest to find ratio
(Al =1.96/1.96 = 1
O=2.94 / 1.96 = 1.5)
2:3
Al2O3 - 40What is the molecular formula?The exact number of atoms
- 41How do you work out the amount of dissolved substance (in moles) using the concentration?[volume of solution (in cm^3) x concentration of solution (in mol/dm^3)] / 1000
- 42What is the theoretical yield?The maximum amount of a product that could be formed from a given amount of a reactant
- 43How do you calculate a percentage yield?(Yield obtained / theoretical yield) / 100
- 44What is an ion? How are ions formed?An electrically charged atom or group of atoms
By the loss or gain of electrons - 45What things make ionic compounds? What is an ionic bond?atoms of metals and atoms of non-metals
Electrostatic force of attraction between oppositely charged ions (e.g. transferred electrons) - 46There are no ..................... in ionic compounds.Molecules
- 47Why do ionic compounds have a high melting and boiling point?Electrostatic forces are strong and there is many of them to break in an ionic crystal. Therefore a large amount of energy is required to overcome the forces.
- 48When are covalent bonds formed? What is a covalent bond?Between atoms of non-metallic elements
The force of attraction between the nuclei of two atoms and a pair of electrons shared between them - 49Simple molecular substance have .......... melting and boiling points because the forces of attraction between the molecules are ....... and therefore ........... energy is required to overcome them.low
weak
little - 50Give 2 examples of giant covalent structures made from carbon. Describe the bonding in them. Describe the forces in them.Diamond - Each carbon atom forms four single covalent bonds. 3D structure formed. Covalent bonds are strong. No weak forces in the structure.
Graphite - Each carbon atoms forms 3 single covalent bonds. Layered structure formed. Covalent bonds- strong. Forces of attraction between layers -weak - 51Describe the uses and properties of diamond.Very high melting point
Very hard and abrasive
Does not conduct electricity
Cutting tools
Jewellery - 52Describe the properties and uses of graphite.Very high melting point.
Soft and slippery.
Conducts electricity.
Lubricant
Electrodes for electrolysis - 53Describe the structure of metals. Properties of metalsGiant, 3D lattice structure of positive ions in a sea of delocalised valence electrons
High melting and boiling points
Good conductors of electricity
Malleable and ductile - 54What are the conditions of electrolysis? What is the electrolyte?Ionic compounds when molten
or an aqueous solution
Substance being electrolysed