Select the statements that correctly describe a buffer. a) An acid added to the buffer solution reacts with the weak base of the buffer. b) The pH of a buffer solution is determined by the ratio of the concentration of conjugate base to the concentration of strong acid. c) A buffer is generally made up of a weak acid and its conjugate base. d) The pH of a buffer solution does not change significantly when any amount of a strong acid is added. e) The Ka of a buffer does not change when any amount of an acid is added to the buffer solution.

Explanation:

A buffer is  solution which resists change in pH upon addition of either acids or bases.

The pH of a buffer is calculated by the ratio of the concentration  of base to concentration of acid. The weak acid and conjugate base have a Ka similar to the pH desired.

most historians agree that gabriel mouton, the vicar of st. paul’s church in lyons, france, is the “founding father” of the metric system. he proposed a decimal system of measurement in 1670. mouton based it on the length of one minute of arc of a great circle of the earth (now called a nautical mile, 1852 meters). he also proposed the swing-length of a pendulum with a frequency of one beat per second as the unit of length (about 25 cm). a pendulum beating with this length would have been fairly easy to produce, thus facilitating the widespread distribution of uniform standards. over the years, his work was revised, improved, and extended by a number of french scientists.

the political sponsor of weights and measures reform in the french revolutionary national assembly was the bishop of autun, better known as talleyrand. under his auspices, the french academy appointed several committees to carry out the work of developing a usable system of weights and measures for france. one of the committees recommended a decimalized measurement system based upon a length equal to one ten-millionth of the length of a quadrant of the earth’s meridian (i.e., one ten-millionth of the distance between the equator and the north pole).