chapter 8 - reactivity trends

Question 1

properties of group 2 metals

Answer 1

• have hydroxides which are alkaline - have reasonably high melting and boiling points - have low densities - form colourless compounds

Question 2

uses of group 2 compounds

Answer 2

• Ca(OH)2 regulates soil pH - Mg(OH)2 acid reflux in pregnancy - CaCO3 comabts excess acid in stomach

Question 3

group 7 properties

Answer 3

• low melting and boiling point - exist as diatomic molecules - boiling point increases down the group

Question 4

colours of halogens when dissolved in organic solvents

Answer 4

chlorine - pale green bromine - brown/orange iodine - violet

Question 5

test for halides

Answer 5

test using silver nitrate chloride - white precipitate bromide - cream precipitate iodide - pale yellow precipitate

Question 6

additional test for halides

Answer 6

testing by adding excess ammonia chloride - dilute NH3 dissolves the precipitate bromide - concentrated NH3 dissolves precipitate iodide - NH3 doesn’t dissolve precipitate

Question 7

test for sulfates

Answer 7

test using barium chloride - forms a white precipitate (of barium sulfate)

Question 8

test for carbonates

Answer 8

test using an acid - effervesces

Question 9

solubility rules

Answer 9

• group 1, ammonium and nitrate compounds are always soluble - chlorides and sulfates are soluble with some exceptions - all carbonates and metal hydroxides are insoluble with exceptions of group 1 and ammonium compounds