Chemistry ATP

Question 1

describe the test for nitrate ions

Answer 1

add aqueous sodium hydroxide
• then (reduction with) aluminium (foil) (and warm)
• (ammonia gas produced which) turns damp red litmus blue

Question 2

adding excess ammonia to copper (ii) sulphate

Answer 2

blue ppt dissolves into dark blue solution

Question 3

aluminum and NAOH

Answer 3

white ppt, dissolves in excess to form a colorless solution

Question 4

aluminum and NH3

Answer 4

white ppt, insoluble in excess

Question 5

ammonium and NAOH

Answer 5

ammonia gas produced if warmed

Question 6

calcium NAOH

Answer 6

white ppt insoluble in excess

Question 7

calcium and NH3

Answer 7

faintly visible white ppt

Question 8

chromium3+ and NAOH

Answer 8

green ppt green solution in excess

Question 9

chromium and NH#

Answer 9

grey green ppt insoluble in excess

Question 10

iron II and naoh and nh3

Answer 10

green ppt insoluble in excess

Question 11

iron III naoh and nh3

Answer 11

red brown ppt insoluble in excess

Question 12

zinc with both reagents

Answer 12

white ppt dissolves in excess to form colorless solution

Question 13

li

Answer 13

red

Question 14

na

Answer 14

yellow

Question 15

k

Answer 15

lilac

Question 16

Ca

Answer 16

orange red

Question 17

cu

Answer 17

blue green

Question 18

test for chloride, bromide, iodide

Answer 18

add nitric acid and add aqueous silver nitrate

• white ppt
• cream ppt
• yellow ppt

Question 19

test for nitrate NO3 2-

Answer 19

add aqueous NAOH and aluminium foil, warm gently, gas released is ammonia

Question 20

sulfates

Answer 20

acidify with nitric acid, add aqueous barium nitrate, white ppt forms

Question 21

sulfite SO3 2-

Answer 21

add acid , test the gas released. decoulorizes acidified potassium maganate solution so2 gas released