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Chem unit 1 pastpap4

QuestionAnswer
State how you could find the molecular mass of a substance from its mass spectrum. (Molecular mass of a substance is) that of the molecular ion/parent ion OR (m/e value for) peak/ion of largest mass OR (m/e value for) peak/ion furthest to
Suggest how mass spectrometry can be used to estimate the age of the cloth. Any mention of amount /mass/abundance of 14C (in cloth)find proportion of 12C : 14C (in cloth). find proportion of 12C : 14C (in cloth)
Explain why the melting temperature of sodium is very much less than that of Magnesium odium atoms/sodium ions are larger (than magnesium atoms/ions) OR Na+/sodium ions have smaller charge (density) than Mg2+/ magnesium ions
Explain why the melting temperature of sodium is very much less than that of Magnesium sodium has fewer delocalized electrons (than magnesium)/attraction between the positive ions and (delocalized) electrons is weaker in sodium (than magnesium) (1) · sodium is not close-packed (but mg is close-packed)/less energy needed (to break bonds)
Explain why the melting temperature of silicon is very much greater than that of white phosphorus. Silicon is giant covalent / giant atomic/giant molecular/ macromolecular/giant/ structure/giant lattice · Phosphorus made up of simple molecules /small molecules/ P4
Explain why the melting temperature of silicon is very much greater than that of white phosphorus. P4 is molecular covalent /molecular/simple covalent/ Between P4 molecules: weak forces/weak intermolecular forces/weak London forces/weak van der Waals’ forces/weak dispersion forces/weak induced-dipole forces /More energy needed (to break).
Explain why the melting temperature of argon is the lowest of all the elements of Period 3. à Argon monatomic/argon (composed of) single atoms
Explain why magnesium is a good conductor of electricity whereas sulfur is a non-conductor Mg has mobile electrons/delocalized electrons/free electrons/sea of electrons (to carry the charge) ALLOW Mg2+ instead of Mg or Magnesium,
Explain why magnesium is a good conductor of electricity whereas sulfur is a non-conductor ulfur’s electrons are fixed (in covalent bonds)/sulfur’s electrons are involved in bonding/sulfur’s electrons are not free (to move)/no delocalized electrons in sulfur/no mobile electrons in sulphur.
Describe the forces of attraction in an ionic lattice à (Forces of attraction between) oppositely-charged ions/positive and negative ions/cations and anions.
Suggest two forces of repulsion which exist in an ionic lattice à Ions of the same charge (repel)/ positive ions (repel)/negative ions (repel). Nuclei (of the ions repel) ALLOW ‘protons’ (in the ions repel) OR Electron clouds OR electrons (in the ions repel).
Suggest two forces of repulsion which exist in an ionic lattice à The lattice composed of the ions Mg2+ and O2– is stronger than a lattice composed of the ions Mg+ and O–
Explain, in terms of the charges on the ions and the size of the cations, why this is so. Mg2+ AND O2− higher charge / Mg2+ AND O2− higher charge density (than Mg+ and O−) NOTE: both ions needed (1) Second mark: Mg2+ smaller (than Mg+).
Suggest how the lattice energy of Mg2+O2– would differ from that of Mg+O–.--> (Lattice energy of Mg2+O2- is) more exothermic/more negative ALLOW greater/increased/higher/ more/larger/bigger.
Explain the difference between hazard and risk. (substance or procedure that) can cause harm/may cause harm/has the potential to do harm/can be dangerous
Explain the difference between hazard and risk. references to specific hazards such as toxic/flammable /harmful/ irritant /corrosive /oxidizing/ carcinogenic. idea of likelihood/probability/chance that harm will result (from the use of a substance or a procedure).
Give one other safety procedure ,other than the use of a laboratory coat and safety goggles. --> fume cupboard OR Gloves OR u.v. goggles.
Why is a compound with this general formula not a alkene. --> (CnH2n could be a) ring / cyclic (compound)
Which of the following alkenes exhibits E-Z isomerism?--> H3CCH=CHCH3
Which of the following substances, obtained from the fractional distillation of crude oil, has the lowest boiling temperature? --> refinery gas.
Which of the following ions would undergo the greatest deflection in a mass spectrometer? --> 35Cl2+
Which pair of atomic numbers represents elements which are both in the p-block of the Periodic Table? --> 8, 16.
The electronic structure of an atom of an element in Group 6 of the Periodic Table could Be --> 1s2 2s2 2p4
Which of the following formulae for compounds of germanium, Ge, is unlikely to be correct, given the position of germanium in the Periodic Table? --> GeF3
Which of the following covalent bonds is the shortest --> H—F
The electronic configurations of the atoms of four different elements are given below. For which element would you expect the value of the first ionization energy to be the largest?--> 1s2.
Which of the following has the smallest ionic radius? --> Mg2+
Created by: ufuoma