Search & Filtering
it take for a sample of N2O5 to decay to 60% of its initial value?
features which affect the basicity of a molecule.
II) Suggest a role for residues 83 and 170 in the enzyme mechanism?
III) Comment on the protonation states of His-119 and His-176. What does it tell you about the pKa values of His-119 and His-176?
IV) Describe the role of His-176 in the mechanism. Does the third image represent the end of the reaction? Why?
H2(g) + I2(g) ⇄ 2HI(g) 2-1.58=0.42/2=0.21
At equilibrium, the mixture is found to contain 1.580 mole of HI. (a) What are the concentrations of H2, I2 and HI at equilibrium? (b) Calculate the equilibrium constant Kc.
Calculate the Ka value of chloroethanoic acid (CH2ClCOOH) given that a solution with a concentration of 0.200 mol dm–3 has a pH of 1.77
4. Which is a stronger acid, Phenol (pKa=9.80) o rethanoic acid(Ka=1.76×10–5).Explain your answer.
Calculate the concentration (giving your answer to 3.s.f) of the following weak acids.
(a) benzenecarboxylic acid (C6H5COOH) with a pH = 4.23. Ka =6.46 × 10–5 mol dm–3.
(b) Propanoic acid (CH3CH2COOH) with a pH of 3.09. pKa = 4.87.
Calculate the pH (giving your answer to 2 d.p.) of the following weak acids.
(a) 0.100 mol dm–3 methanoic acid (HCOOH) with Ka = 1.77 × 10–4 mol dm–3
(b) 0.200 mol dm–3 ethanoic acid (CH3COOH) with Ka = 1.76 × 10–5 mol dm–3
(c) 0.025 mol dm–3 pentanoic acid (C4H9COOH) with a pKa = 4.86
(d) 44 g of butanoic acid (CH3CH2CH2COOH), Ka= 1.51 × 10–5 mol dm–3, which was
dissolved in 2 dm3 of water.
Calculate the pH (give your answers to 2.d.p) of the following solution dilutions.
(a) 50 cm3 of 1.00 mol dm–3 hydrochloric acid is added to 200 cm3 of water.
(b) 100 cm3 of 1.00 mol dm–3 Ba(OH)2 is added to 400 cm3 of water at 298 K
Calculate the concentrations (give your answers to 3.s.f) of the following bases at 298K
(a) NaOH with a pH of 13.00
(b) Ba(OH)2 with a pH of 12.20
3. Calculate the pH (give your answers to 2.d.p) of the following bases.
(a) A solution of 40 g of sodium hydroxide dissolved in 500 cm3 of water at 298 K.
(b)80gdm–3 KOH at 298K
#339914 on Dec 2023