1a) Define relative isotopic mass. (2)the mass of an atom of an isotope compared with 1/12 of the mass of an atom of c-12
1b) Fill the table in for the atomic structure of a potassium atom and ion. (3)
39K 19protons 20 neutrons 19 electrons
41K+ 19p 22neut 18electrons
1c) How many molecules are in 6.(something)g of SiCl4? (3) 3.01 x10 ^22
1d) Draw the symbols for each particle shown in the ionic lattice structure of KCl. (2)
alternating k+ and Cl- Ions
3a) A precipitation reaction was used to identify the iodide present in Potassium Iodide. State the reagent used for this reaction (1) AgNO3
3b) Write the ionic equation to show the reaction between this reagent and the Iodide ion, including state symbols. (2)ag+(aq) + i-(aq)= agi(s)
3c) What colour would the precipitate containing the iodide ion show? (1)yellow
3d) A mixture of potassium iodide and bromine was present in a solution. What solvent can be used to identify the presence of iodide in this solution? (1)conc nh3
4) a) - Using oxidation numbers, state why the reaction of P4 was a disproportionation reaction (3)
P has been both reduced and oxidised. Oxidised from 0 to +3 and reduced from 0 to -1.
4b)
5a) Describe the reactivity of the group 2 metals with chlorine as you descend the group. (5)
-increase nuclear charge outweighed by increase atomic radius
-more shells;more electrons;more inner shielding effect by inner electrons;
decrease nuclear attraction. easier to remove outer elect to react with halogens. reactivity increases hence reaction more vigorous down the group
5b) State why using graphite or diamond for the first ionisation energy for carbon was (unnecessary?) (1)
Ionisation energy is the same because both measure when they are gaseous atoms ?
5c) Fill the boxes in of the table stating the properties of lithium, carbon and fluorine (6)
Li = electrostatic attraction between the positive metal ions and delocalised electrons
C = giant and the shared pair of electrons in the covalent bond
F2=Van der Waals and between other F2 atoms
- A student suggested the bond angles in H-N-H would be larger in NH3BF3 than NH3, suggest why. (3 marker I think)
NH3 has 3 bonding pairs 1 lone pair.
NH3BF3 has 4 bonding pairs.
Electron pairs repel.
Lone pairs repel more than bonding pairs (-2.5) and so H-N-H drawn in more slightly so smaller.
- What bond angles are present in the F-B-F in:
i) BF3 120
ii) NH3BF3 109.5 (2)
- Phosphene gas reacts with oxygen to form P4010 and water. Write out the equation for this reaction. (1).
4PH3 + 8O2 = 6H2O + P4O10
- Why does PH3 have a lower boiling point than NH3? (1) hydrogen bonding stronger than Van der Waall/dipole to dipole (I wrote VDW)
- Why is N2SO4 described as a salt? (1)
The H+ion in acid has been replaced by the positive metal Na+ ion
- State the main types of intermolecular forces in NH3 and PH3 (2)
Hydrogen bonding and dipole to dipole
- Give the equation for the reaction between Aluminium Oxide and sulphuric acid, including state symbols. (2)
Al2O3 (s)+ 3H2SO4(aq) -------- Al2(SO4)3 (aq) + 3 H2O (l)
- Work out the number for X in (metal).XH2O 0.321/ 0.0200= 16
- Write out the equation for the reaction between Chlorine and water. Explain why the litmus paper turned red. (2)acid produced, ph decreases, increas in h+
Cl2 + HCl --> HCl + HClO acid has H+ ions so acidic
- Define 'dative covalent bond'. (1 ) sharing of a pair of electrons between 2 covalently bonded atoms where one of the atoms supplies both electrons.
- Using dot and cross diagrams, draw the bonding in NH3BF3 and label the dative covalent bond. (2)
H3N->BF3
dative covalent donated by N to B
- main ions in Al2(SO4)3 (1)
Al3+ and SO4^ 2-
- Volume of PH3 gas produced = 360cm cubed
- 22.5 for another calculation
- bleaching ion ClO-
The questions are muddled up and the marks don't add up to 60 but couldn't think of anymore.