1 - Stoichiometric Relationships

• The molecular formula of X is CH202.
• Savemyexams.co.uk provides revision notes, topic questions, past papers for IB Chemistry DP1.
• The formula for converting from cm to dm is: 960/1000 = 0.960 dm.
• The content of Savemyexams.co.uk includes elements, compounds, mixtures, equations, state changes, the molecule concept, moles-mass problems, experimental formula, and more.
• Silicon dioxide has a giant covalent structure, but the simplest formula (the formula unit E) is SiO2.
• The full chemical equation for the reaction is Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s).
• Step 1: Break down reactionants into their respective ions Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s).
• Step 2:Cancel the spectator ions on both sides to give the ionic equation Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s).
• An asymmetric equation is a short hand way of describing a chemical reaction using chemical symbols to show the number and type of each atom in the reactants and products.
• A word equation is a longer way of describing a chemical reaction using only words to show the reactants and products.
• During chemical reactions, atoms cannot be created or destroyed.
• The number of each atom on each side of the reaction must be the same.
• Revision Notes, Topic Questions, Past Papers State changes are physical changes that are reversible and do not change the chemical properties or chemical make up of the substances involved.
• Vaporization involves the change of liquid to gas, but unlike boiling, vaporization occurs only at the surface and takes place at temperatures below the boiling point.
• Boiling occurs at a specific temperature and takes place at a specific temperature.
• State changes can be represented graphically.
• Savemyexams.co.uk also provides resources on reacting masses and volumes, including reaction yields, Avogadro's law and molar gas volume, the ideal gas equation, gas laws relationships, real gases, standard solutions, concentration calculations, and more.
• Elements are substances made from one kind of atom.
• Compounds are substances made from two or more elements chemically combined.
• Elements take part in chemical reactions in which new substances are made.
• In these reactions, atoms combine to get the fixed ratios that will give them full outer shells of electrons, producing compounds.
• The properties of compounds can be quite different from the properties of the elements that form them.
• The properties of sodium chloride are different from sodium and chlorine.
• The mole is the number of particles equivalent to the relative atomic mass or molcular mass of a substance in grams.
• The mole applies to atoms, molecules and ions.
• The value of the mole is 6.02 x 10^23 grams mol.
• The mass of a substance with this number of particles is called the molar mass.
• One mole of a substance contains the same number of fundamental units as there are atoms in exactly 12.00 g of C.
• If you had 6.02 x 10^23 atoms of carbon-12 in your hand, you would have a mass of exactly 12.00 g.
• One mole of water would have a mass of (2 x 1.01 + 16.00) = 18.02 g.
• The empirical formula is the simplest whole number ratio of the atoms of each element present in one molecule or formula unit of the compound.
• The empirical formula can be calculated from a knowledge of the masses of each element in a compound.
• The empirical formula can also be deduced from data that gives the percentage composition by mass of the elements in a compound.
• The molcular formula gives the actual numbers of each element present in the formula of the compound.
• The molcular formula can be found by dividing the relative molcular mass by the relative molcular mass of the empirical formula and finding the multiple that links the empirical formula to the molcular formula.
• The molcular formula can be multiplied by this number to find the molcular formula.
• The molecular formula is the formula that shows the number and type of each atom in a molecule.
• The molecular formula of ethanoic acid is CH3COOH.
• The empirical formula is the simplest whole number ratio of the atoms of each element present in one molecule.
• The empirical formula of ethanoic acid is CH2O.