Chromium

Question 1

What oxidation states does Cr come in?

Answer 1

III and VI

Question 2

What can happen to Cr if it’s in acidic conditions?

Answer 2

It can be easily protonated

Question 3

Oxyanions of Cr(VI) are_____?

Answer 3

Highly soluble

Question 4

What colour is Cr(III) and Cr(VI)?

Answer 4

3 is green

6 is yellow

Question 5

What form is Cr3 made under?

Answer 5

Anaerobic conditions

- not very soluble and therefore precipitates as Cr(OH)3 under most acidic conditions

Question 6

What form does chromium come in?

Answer 6

Chroimite

Or FeCr2O4

Question 7

What Cr is more toxic?

Answer 7

6 is more toxic than 3

Question 8

What does Cr(6) do to make it so toxic?

Answer 8

Can enter cells and oxidizes the DNA and RNA bases

Question 9

The Cr metal is what?

Answer 9

Bright and shiny

- used in electropathy

Question 10

What is Cr(3) used in?

Answer 10

Leather tanning

Question 11

How do you remove Cr from water?

Answer 11

Cr(6) doesn’t precipitate, so you have to convert it to Cr(3)
- reducing agent is Fe(II)

Question 12

What is CCA ?

Answer 12

Chromated Copper Arsenate is a wood preserver that is soluble
- mixed with metal oxides then dried wood via vacuum

Question 13

How does Cr6 convert to Cr3?

Answer 13

6 reacts with organic compounds within the wood