Paper 1 Inorganic and physical 2024 past paper Flashcards
(27 cards)
What are halide ions?
F- (fluoride), Cl- (chloride), Br-(bromide), I-(iodide)
What is the ionic equation between a halide and a halogen above it in the periodic table?
Br2 + 2I- -> 2Br- + I2
Why can’t bromine oxidise bromide or chloride ions?
It is a weaker oxidising agent than chlorine and bromine.
How do you test for chloride ions?
White precipitate with silver nitrate. Add dilute ammonia and it will dissolve.
How do you test for bromide ions?
Cream precipitate with silver nitrate. It won’t dissolve with dilute ammonia but it will dissolve with concentrated ammonia.
In cold water, magnesium reacts slowly to form …..
Magnesium hydroxide (Mg(OH)2 and hydrogen gas
In steam, magnesium reacts quickly to form …..
Solid magnesium oxide (Mg)O and hydrogen gas
When calcium reacts with water, which element is reduced and which is oxidised?
Calcium is oxidised (0 to +2)
Hydrogen is reduced (+1 to 0)
Define electronegativity
The ability of an atom to attract a pair of electrons in a covalent bond.
Why is the C-Cl bond polar?
Chlorine has a higher electronegativity than carbon
Why is the molecule CCl4 non-polar?
CCl4 is symmetrical so the dipoles cancel out.
How do van der Waals forces arise?
The random movement of electrons create a temporary dipole which induces a dipole in another molecule and the temporary dipoles in different molecules attract.
How do you test for ammonium ions?
Add sodium hydroxide and red litmus paper will turn blue.
How do you test for sulphate ions?
Add acidified BaCl2 and a white ppt of BaSO4 forms
How do you test for carbonate ions?
Effervesce with acid and the gas turns limewater cloudy
How do you test for magnesium ions?
Add sodium hydroxide and a white ppt of Mg(OH)2 forms.
Why does SF6 form an octahedral shape?
6 bond pairs which all repel equally. The bond angle is 90 degrees.
What is the shape and bond angle of SF3+ and why?
Trigonal pyramidal - bond angle 107 degrees because the lone pair- bond pair is greater than bond-pair repulsion so bond angle is reduced from 109.5 degrees
Considering what ionisation is and what chlorine is, give an equation for the process than occurs in a mass spectrometer?
How does the detector in a mass spectrometer enable abundance of each ion to be determined?
The abundance is proportional to the size of the CURRENT
How is percentage uncertainty calculated when the uncertainty of a balance is 0.005g and a substance is measured by difference of mass?
0.005 X 2 / mass of substance x 100
Define standard enthalpy of formation.
The enthalpy change when ONE MOLE of a substance is formed from its ELEMENTS in their standard states.
What is an oxidising agent?
An electron ACCEPTOR
What is the half-equation to show the oxidation of copper to copper(II) ions?
Cu + Cu2+ + 2e-
