Asmall pebble is heated and placed in a foam cup calorimeter containing 25.0 ml of water at 23.0°c. the water reaches a maximum temperature of 24.2°c. how many joules of heat were released by the pebble? (the specific heat capacity of water is 4.18 j/g•°c and the density of water is 1.00 g/ml)

pH of the buffer is 10.10

Explanation:

trimethylamine is a weak base that, in presence with its conjugate base, trimethylammonium ion, produce a buffer.

To determine the pH of the buffer we use H-H equation for weak bases:

pOH = pKb + log [Conjugate acid] / [Weak base]

pKb is -log Kb = 4.20

pOH = 4.20 + log [N(CH₃)₃] / [NH(CH₃)₃]

Replacing the concentrations of the problem:

pOH = 4.20 + log [0.20M] / [0.40M]

pOH = 3.90

As pH = 14 -pOH