Nat5 chemistry unit one

• The chemical formula for sodium bromide is NaBr.
• The chemical formula for calcium phosphide is Ca3(PO4)2.
• The chemical formula for titanium tetrachloride is TiCl4.
• The chemical formula for dinitrogen trioxide is N2O3.
• The chemical formula for ammonium sulfate is (NH4)2SO4.
• The chemical formula for iron(II) chloride is FeCl2.
• The chemical formula for copper(II) hydroxide is Cu(OH)2.
• The correct values for a, b and c required to balance the equation are a = 2, b = 1 and c = 2.
• The gram formula mass (GFM) of a substance is known as the mass of one mole.
• Relative atomic masses of selected elements can be found in the SQA Data Booklet.
• These can be used to calculate the gram formula mass of a substance.
• One mole of calcium chloride has a mass of 111 g.
• To calculate the mass of a higher number of moles, or even calculate the number of moles in a certain mass, a formula triangle can be used.
• The concentration of a solution is measured in moles per litre (mol l -1 ) and can be calculated using this formula triangle.
• The concentration of the solution formed when 0.25 moles of potassium nitrate are dissolved in 500 cm 3 of water is 0.5 mol l -1 .
• The volume always has to be changed into litres when working with solutions.
• The number of moles in 200cm 3 of 0.5 mol l -1 sodium hydroxide (NaOH) solution is 0.
• The mole and concentration of solutions are important in chemistry.
• The gram formula mass of oxygen is 16g.
• The gram formula mass of lithium chloride is 42.5g.
• The mass of 1 mole of carbon dioxide is 12g.
• The mass of 1 mole of sodium sulphate is 119g.
• The number of moles in 24g of carbon is 2 moles.
• The number of moles in 50g of calcium carbonate (CaCO 3 ) is 2 moles.
• The mass of 0.5 moles of magnesium chloride is 47.75g.
• The number of moles of potassium hydroxide used to make 100cm 3 of 0.1 mol l -1 solution is 10 moles.
• The concentration of hydrochloric acid solution used if 2 moles are dissolved in 100cm 3 of water is 20 mol l -1.
• The volume of sodium hydroxide needed to produce a 0.1 mol l -1 solution containing 0.5 moles of solute is 5 litres.
• The pH scale measures the acidity or alkalinity of a solution.
• Acids have a pH of less than 7.
• Alkalis have a pH more than 7.
• Water and neutral solutions have a pH of exactly 7.
• The pH is a measure of the concentration of hydrogen ions in a solution.
• Alkalis are soluble bases and can be formed when a metal oxide is dissolved in water.
• Acids can be formed when a non-metal oxide is dissolved in water.
• Acidic and alkaline solutions can conduct electricity because they have ions that are free to carry charge.
• When an acid is diluted the concentration of H + ions is decreased and the pH increases towards 7.
• Alkalis contain OH - ions.
• Ionic lattice compounds have high melting points and boiling points and can conduct electricity when molten or in solution as the ions are free to move.
• Covalent network compounds have very high melting points and boiling points, are hard and do not conduct electricity.