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Term 1, week 7

More work on moles. I hope you are becoming familiar with the formula n=m/M
  • complete p52/53 in the lab book
Be careful: nitrogen gas consists of 2 N atoms, oxygen gas has 2 O atoms, the sulfur molecule  has 3 sulfur atoms.
The rest of the week we will be looking at stoichiometry. This is looking at the balanced chemical equation and looking at the ratios at the reactants combine to form the ratios of the products. This knowledge can then be used to predict the amount of product formed if we know the mass of one of the reactancts or vice versa. We are working in proportions, the ratio values we are using must be in moles. Think of when you bake biscuits. If you want to make double the number of biscuits then everything in the ingredients list will have to be doubled.
The number of moles of each substance involved in the reaction is shown by the number which is placed before the substance.
  • read p46-48 in the study guide
  • complete p54-55 in the lab book.
  • Do Act 7D in the study guide. (we will be looking at these in the VC)
  • go to Bestchoice    
  • http://bestchoice.net.nz/ and complete the activities under chemical calculations
  •  *mass/molar mass                                                                                                                             *moles and Avogadro                                                                                                                                                                                                                                                                                                     *constructing equations                                                                                                                       *more practice
Don't do any questions with %compostion or empirical/molecular formula in them. That is next week!!
Remember to bring your calculator to the VC on Thursday.