Question

1. (a) A student is diluting a stock solution of a Vitamin C solution. The concentration of the stock solution is 3.687x10 M. 4.00 mL of the stock solution was transferred into a 50 ml volumetric flask and diluted to the mark with water. What is the final concentration of the dilute Vitamin C solution? (Refer to page 70 in the lab manual). (b) Would a solution prepared the same way but with 2.00 ml of the stock solution have a higher or lower concentration? Circle the correct answer. HIGHER LOWER 2. Convert a percent transmittance reading of 36.2% into absorbance (Refer to pages 11 and 65 of the lab manual). 3. Will the boiling point of a liquid at standard atmospheric pressure (760 mm Hg) be higher or lower than its observed boiling point if it is boiled at a lower atmospheric pressure? (Refer to pg 67 in the lab manual). Circle the correct answer. HIGHER LOWER

answers plzz and thank you.

Answer 1

Q.1

Ans a) We have formula for this type of problem, which is...

M₁V₁ = M₂V₂ ....................1

here M₁ is initial concentraation of solution = 3.687*10^-8 M

V₁ is initial volume of solution = 4.00 mL

M₂ is final concentration of solution = ?

V₂ is final volume of solution = 50 mL

so from the above equation 1....

(3.687*10^-8) * 4.00 = M₂ * 50

or, M₂ =(3.687*10^-8 ) * 4 /50

or, M₂ = 2.949*10^-9

Ans b) If a solution is prepared in the same way the resulting concentration will be lower. Because the volume taken (2mL) this time is less than before (4mL).

Q2.

Ans... We have a formula to convert percent transmittance into absorbance, which is...

Absorbance (A) = 2 - log (%T)

= 2 - log (36.2)

=0.441

Q3.

Ans... The boiling point of a liquid is the temperature at which its vapour pressure becomes equal to atmospheric pressure (external pressure). If the liquid  is boiled at lower pressure then its vapour pessure becomes equal to external pressure before reaching to its original boiling point and hence the resulting boiling point will be lower.