Inorganic and Physical Chemistry Flashcards
Suggest a reason, other than apparatus inaccuracy, why the Mr value determined from the experimental results differs from the actual Mr. Explain your answer.
The volume of the gas in the syringe (V) is greater than the true
volume (because some air leaked into the syringe.
Mr = m/n = m × RT/PV so if V is too large, Mr is too small.
Suggest, with a reason, an appropriate safety precaution that the student should take when using the toxic chloroalkane, X, in the experiment.
Carry out in a fume cupboard
To avoid toxic vapour
Suggest a reason why the value calculated might differ from the mean bond enthalpy quoted in a data source.
Mean bond enthalpy found by taking an average for Xe–F in a range of compounds
In terms of sub-atomic particles, state the difference between the isotopes.
They have different numbers of neutrons.
State how, if at all, the chemical properties of these isotopes differ.
Give a reason for your answer.
No difference in chemical properties
Because all have the same electronic structure (configuration)
OR they have the same number of outer electrons
SrCO3 –> SrO + CO2
Give a reason why the mass of the solid sample changed during the experiment.
CO2 gas escapes or is lost
Strontium metal can be extracted by heating strontium oxide with aluminium metal.
In this reaction, strontium vapour and solid aluminium oxide are formed.
Write an equation for the reaction and state the role of the aluminium in the process.
Explain why strontium forms a vapour but aluminium oxide is formed as a solid.
3SrO + 2Al –> Al2O3 + 3Sr
Al acts as a reducing agent
Sr is collected as a vapour because
Al2O3 is an ionic lattice and so has strong ionic attractions
Than Sr which is a metallic structure with (relatively) weaker bonding
Bromine (Br2), strontium chloride (SrCl2) and iodine monochloride (ICl) all havesimilar Mr values.
Suggest, with reasons, the order of melting points for these three substances.
SrCl2> ICl > Br2
SrCl2 strong ionic bonds/(strong electrostatic attraction between opposite ions)
Lattice so many strong bonds to overcome
ICl has dipole-dipole between molecules - weaker than ionic bonds
Br2 has van der Waals forces between molecules – much weaker
Write an equation for the reaction of chlorine with cold water.
State a reason why chlorine is added to drinking water, and suggest a disadvantage of treating water in this way.
Cl2 + H2O ⇌ HCl + HClO
Kills bacteria
Some people find the taste unpleasant
*Which is the correct classification for the element yttrium (Y)?
d block
*Which of the following is a correct statement about the trend in atomic radius across Period 3 of the Periodic Table?
radius decreases because nuclear charge increases
*A measuring cylinder has an uncertainty of ± 5 cm3.
What is the minimum volume of liquid that can be measured if the percentage error in the volume is to be less than 0.20%?
2.5 dm3
*Element Q forms a sulfate with formula QSO4
Which of these could represent the electronic configuration of an atom of Q?
[Ne]3s2
*Which equation represents a reaction that does take place?
Cl2 + 2NaI 2NaCl + I2
*The following equilibrium was established in a container with volume V cm3 at 393 K and 200 kPa.
M2(g) + R(g) RM2(g) ∆H = +150 kJ mol–1
Which change would increase the yield of RM2 ?
remove RM2 as it is formed
