Did anybody get a little confused on question 20 ?

[bentoscano]

Copper(II)Sulfate solution appears blue because it absorbs red light.

Was this true or false ? I thought this was very hard to understand because I was not sure if they thought that was the sole reason or if that was ONE of the reasons.

Because.

Copper Sulfate appears blue because it abosrbs ALL colours except blue.
Not just Red so I was a bit misled by this question.

[cltf]

I had B then I changed it to D then I was going to change it back but then they called pens down...

[superstar1]

i thought you had to know that circle with complimentary colours... so the complementary colour of blue is orange isnt it,,, so it absorbed orange...im not sure???

[IAmImmature000000]

I chose D......

[superstar1]

i chose c

[Keo]

I chose B, as the flame changed color due to the energy emitted from the jump of wavelengths. Also it appears blue in our eyes therefore it absorbs red, just my thoughts.

[cltf]

The flame in AAS ATOMIZES so from ion to atom et Na+ --> Na therefore it is reduction, not oxidation

[taqi]

what were the choices again? i remember doing the one where it absorbs red, and also emits light as it moves to its ground state, but no the statement about oxidation...

[heba]

well it obviously undergoes oxidation
butttt... wouldnt it absorb orange light coz that the compliment of blue
i put C
hope thats right

[Deank]

Not exact, but no info lost from memory.

The amount of copper in a solution of copper(ll)sulfate can be determined using AAS.
When blue copper sulfate solution is introduced to a flame, green flames can be observed.

I The solution appears blue because it absorbs red light.
II The metal species undergoes oxidation in the flame.
III The flame is green due to electrons moving from an excited state to a lower state.

Which are true?

A. I only
B. I and III only
C. II and III only
D. I, II and III

Since metals undergoes reduction in the flame, the turn from cations to atomic forms, II is false. (Cu^(2+) + 2e^(-) ---> Cu)
Therefore C. and D. are wrong. Since photons emitted is electrons moving from an excited state to a lower state, then III is correct.
So even though the wording of I is dodgy, it must also be correct in the sense that it is blue, because it can't be anything red or reddish.

Hope this helps!