A LEVEL CHEMISTRY OCR A TEST PAPER QUESTIONS AND SOLUTIONS COMPLETE REVIEW MATERIAL

A LEVEL CHEMISTRY OCR A TEST PAPER
QUESTIONS AND SOLUTIONS COMPLETE
REVIEW MATERIAL

●● Empirical formula
Answer: The simplest whole number ratio of atoms of each element in a
compound


●● Molecular formula
Answer: The number and type of atoms of each element in a molecule


●● Anhydrous
Answer: Contains no water molecules


●● Hydrated
Answer: Crystalline compound containing water molecules


●● Celsius to Kelvin
Answer: K=C+273


●● % yield and atom economy
Answer: % yield = (actual/ theoretical) x 100

,atom economy = (desired products/all reactants) x 100


●● Cu2+ in aq solution
Answer: [Cu(H2O)6]2+
Pale blue


●● Fe2+ in aq solution
Answer: [Fe(H2O)6]2+
Pale green


●● Fe3+ in aq solution
Answer: [Fe(H2O)6]3+
Yellow


●● Mn2+ in aq solution
Answer: [Mn(H2O)6]2+
Pale pink


●● Cr3+ in aq solution
Answer: [Cr(H2O)6]3+
Green

, ●● Cu2+ and NaOH (aq)
Answer: Initially:
[Cu(OH)2(H2O)4] (s)
Blue precipitate


Excess:
No change


●● Fe2+ and NaOH (aq)
Answer: Initially:
[Fe(OH)2(H2O)4] (s)
Green precipitate


Excess:
No change


●● Fe3+ and NaOH (aq)
Answer: Initially:
[Fe(OH)3(H2O)3] (s)
Orange precipitate