The reaction A → B + C is known to be zero order in A with a rate constant of 3.8× 10–2 mol/L • s at 25° C. An experiment was run at 25°C where [A]0 = 1.0 × 10–3 M. What is the rate after 6.5 minutes? Group of answer choices

The rate is 0.038 M/s

Explanation:

The reaction follows a zero order

Let the concentration of A after 6.5 minutes be y

Rate = k[y]^0 = change in concentration/time

k (rate constant) = 3.8×10^-2 mol/L.s

Initial concentration of A = 1×10^-3 M

Change in concentration = 1×10^-3 - y

Time = 6.5 minutes = 6.5×60 = 390 seconds

3.8×10^-2×1 = 1×10^-3 - y/390

0.001 - y = 0.038×390

0.001 - y = 14.82

y = 0.001 - 14.82 = -14.819 M

Rate = change in concentration/time = [0.001 - (-14.819)]/390 = (0.001+14.819)/390 = 14.82/390 = 0.038 M/s

answer: atomic mass was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.

explanation:

originally atomic mass was used to arrange elements on the periodic table from left to right in a row. each column then shows similar properties of elements of a group.

in modern periodic table, the atoms are arranged in increasing atomic number. as atomic number represents the number of protons in an atom which is unique for every atom.