Chemical anylisis (topic 8)

Question 1

what colour will a flame turn for lithium ions, Li+

Answer 1

crimson

Question 2

what colour will a flame turn for sodium ions, Na+

Answer 2

yellow

Question 3

what colour will a flame turn for potassium ions, K+

Answer 3

lilac

Question 4

what colour will a flame turn for calcium ions, Ca2+

Answer 4

orange-red

Question 5

what colour will a flame turn for
copper ions, Cu2+

Answer 5

green

Question 6

what steps are needed to carry out a flame test for cations

Answer 6

1. clean a platinum wire loop by dipping it into HCl
2. hold the loop over a blue flame untill no colour is being given off to make sure that it is clean
3. dip the loop in your sample
4. hold over a blue flame and record the colour you see

Question 7

what colour percipitate is formed when hydroxide (OH-) is reacted with calcium (Ca2+)

Answer 7

white

Question 8

what is the formula for when hydroxide (OH-) reacts with calcium (Ca2+)

Answer 8

Ca2+ + 2OH- → Ca(OH)2

Question 9

what colour percipitate is formed when hydroxide (OH-) is reacted with Copper (II) (Cu2+)

Answer 9

blue

Question 10

what is the formula for when hydroxide reacts with Copper (II) (Cu2+)

Answer 10

Cu2+ + 2OH- → Cu(OH)2

Question 11

what colour percipitate is formed when hydroxide (OH-) is reacted with Iron (II) (Fe2+)

Answer 11

Green

Question 12

what is the formula for when hydroxide reacts with Iron (II) (Fe2+)

Answer 12

Fe2+ + 2OH- → Fe(OH)2

Question 13

what colour percipitate is formed when hydroxide (OH-) is reacted with Iron (III) (Fe3+)

Answer 13

brown

Question 14

what is the formula for when hydroxide reacts with Iron (III) (Fe3+)

Answer 14

Fe3+ + 3OH- → Fe(OH)3

Question 15

what colour percipitate is formed when hydroxide (OH-) is reacted with Aluminium (Al3+)

Answer 15

white at first, to colourless

Question 16

what is the formula for when hydroxide reacts with Aluminium (Al3+)

Answer 16

Al3+ + 3OH- → Al(OH)3

Question 17

what colour percipitate is formed when hydroxide (OH-) is reacted with Magnesium (Mg2+)

Answer 17

White

Question 18

what is the formula for when hydroxide reacts with Magnesium (Mg2+)

Answer 18

Mg2+ + 2OH- → Mg(OH)2