Based on their activation energies and energy changes and assuming that all collision factors are the same, which of the following reactions would be fastest? (a) ea = 57 kj/mol , δe = 13 kj/mol (b) ea = 47 kj/mol , δe = -29 kj/mol (c) ea = 34 kj/mol , δe = -10 kj/mol .

C is the fastest reaction.

Explanation:

Let us consider a generic reaction aA ⇄ bB.

The reaction rate would be:

  [1]

where,

r is the reaction rate

k is the rate constant

n is the reaction order

So we can see that the reaction rate depends on the rate constant. We can find out this constant using the Arrhenius equation:

   [2]

where,

A is the collision factor

R is the universal gas constant

T is the absolute temperature

If A and T are the same for different reactions, k will only depend on Ea. According to [2], the lower Ea, the higher the k. According to [1], the higher the k, the higher the r. And when r is higher the reaction is faster. All in all, C has the lowest Ea (34 kJ/mol), so it is the fastest reaction.

i do not get it   at all

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).