A Level questions

1. A Level questions

2. Moles A student took 1g of Citric acid C6H8O7.xH2O and dissolved it in 100cm3 of water. 10cm3 of this solution neutralised 14.3cm3 of 0.1M NaOH Citric acid is a tribasic acid and can be written as H3Y Write a balanced equation between citric acid and NaOH Show that the number of moles of citric acid that was neutralised was 4.77x10-4 Hence calculate the anhydrous mass of citric acid present in the 1g of hydrated citric acid Hence work out the value of x in C6H8O7.xH2O

3. Trends • Explain why • K has a lower Boiling Point than Ca • Si has a higher Boiling Point than P • Mg is a worse conductor than Al • F atoms are smaller than N atoms • F atoms have a lower first IE than Ne atoms but a higher first IE than Na atoms • H2O has a lower melting point than Na2O but a higher melting point than CO2

4. Shapes • Draw dot ‘n’ cross diagrams of SO3, Cl2S, PF3, SiCl4 Predict the shape of these 4 molecules • Draw dot ‘n’ cross diagram of NaCl, MgCl2 Explain why MgCl2 has the higher Melting Point Explain why neither conduct electricity when solid but both do when molten.

5. Reactivity • Why is Mg less reactive than Ca? • How could you show this? • Why is I2 less reactive than Cl2 • How could you show this • Which decomposes at a lower temp CaCO3 or MgCO3?

6. Observations What do you see when you (write a balanced equation to show obs) Add CaCO3 to HCl Add CaO to HCl Add AgNO3 to NaBr followed by Dil NH3 Conc NH3 d. Add AgNO3 to NaCl followed by Dil NH3 Conc NH3 e. Add AgNO3 to NaI followed by Dil NH3 Conc NH3