Lab 3 Flashcards
how do you identify the percent concentration by mass?
(mass of solute/ mass of solution) x 100%
what color did the malachite CuCO3 x Cu(OH)2 turn?
light mint green
what was the limiting reactant?
CuSO4 x 5H2O
what were the observations when combining the copper(II) sulfate and sodium carbonate?
foaming/ bubbling
blue- green precipitate formed
what were all the chemical changes for this reaction?
color change
gas being produced
precipitate formed
what was the color of copper(II) hydroxide solution?
opaque azure blue color
what was the color of the Cu(OH)2 precipitate?
sky blue
what was the color of the Cu(CH3COO)2 pigment?
bright blue (ocean vibes)
how do you find the % yield?
(actual yield/ theoretical yield) x 100
why was it particularly important to wash the verdigris in acetate?
to get rid of NaOH
why is it more difficult to precipitate cupric acetate (verdigris) than cupric carbonate hydroxide (malachite)
because verdigris is soluble in water so we instead use glacial acetic acid to rinse it
why does malachite have a blue- green colour? what wavelength of light does it absorb?
blue- green because it is formed by the transition metal copper
wavelength between 610nm and 750nm so red is absorbed and blue- green color is emitted (what we see with the human eye)
why does copper make the product colored?
because it absorbs photons in the visible range and they have unfilled d orbitals which form coordination compounds which are usually colored
