Question #a3ca9
1 Answer
Explanation:
Specific rotation can be found from observed rotation by using the formula
#color(blue)([alpha]_(Lamda)^T = (alpha)/(l * c))# , where
Now, path length is usually expressed in decimeters and concentration for solutions in grams per 100 mL.
Another important thing to mention here is that you didn't specify the wavelength of light used,
So, start by converting the concentration from
#"0.120 g"/"30 mL" = "0.004 g/mL"#
#0.004"g"/(1color(red)(cancel(color(black)("mL")))) * (100color(red)(cancel(color(black)("mL"))))/"100 mL" = "0.4 g/100 mL"#
and
#5.0color(red)(cancel(color(black)("cm"))) * "1 dm"/(10color(red)(cancel(color(black)("cm")))) = "0.5 dm"#
This means that the specific rotation will be
#[alpha]_(Lamda)^T = (-0.132""^@)/("0.5 dm " * " 0.4 g/100 mL") = color(green)(-0.66""^@)#