1. Find the absolute and percent relative uncertainty and express each answer with a reasonable number of significant figures.
a) 3.4 (±0.2) + 2.6 (±0.1) =
b) [3.4 (±0.2) × 10‐8 ] ÷ [2.6 (±0.1) × 103 ] =
c) 3.4 (±0.2) ÷ 2.6 (±0.1) =
d) [3.4 (±0.2) – 2.6 (±0.1)] × 3.4 (±0.2) =
2. a) A solution is prepared by dissolving 0.2222 (±0.0002) g of KIO3 [FM 214.0010 ±0.0009] in 50.00 (±0.05) mL. Find the molarity and its uncertainty with an appropriate number of significant figures.
b) Would the answer be affected significantly if the reagent were only 99.9% pure?
3. Calculate the pH of
a) 5.0 × 10‐4 M HNO3
b) 5.0 × 10‐4 M (CH3)4N+ OH‐
4. Using activity coefficients correctly, calculate the pH of
a) 0.050 M HBr
b) 0.050 M NaOH
5. Find the pH and fraction of dissociation (α) of a 0.010 0 M solution of the weak acid HA with Ka = 1.00 × 10-4.
6. A 0.100 M solution of the weak acid HA has a pH of 2.36. Calculate pKa for HA.
7. a) Calculate the concentration of Tl+ in a saturated solution of TlBr in water (Ksp = 3.7 x 10-9).
b) Calculate the concentration of Tl+ in a saturated solution of TlBr in 0.9 % w/v NaCl solution. Include activity effects.
c) Comment on the difference between you answers to a) and b) above.
8. List some applications for the following spectroscopic methods. In each case give reasons why the method is mostsuitable for the given application:
a) HNMR spectroscopy
b) Florescence spectroscopy
c) Atomic emission spectroscopy
d) XRF spectroscopy
9. Calculate the energy range of photons in:
a) The X‐Ray region of the spectrum
b) The visible region of the spectrum
c) UVA, UVB and UVC. Which part of the UV spectrum is most damaging to skin? Why?
10. a) Describe what happens to a molecule when it absorbs IR radiation.
b) Do all molecules absorb IR radiation? Why/Why not?
c) When you go outside on a sunny day you feel the warmth of the sun – what is responsible for this?
11. . How could IR spectroscopy distinguish between the following?
a) a ketone and an aldehyde d. cis‐2‐hexene and trans‐2‐hexene
b) a cyclic ketone and an open‐chain ketone
c) benzene and cyclohexene
d) a primary amine and a tertiary amine