The rate constant for 1st order reaction is
K = (2.303 /t) log (A0 /A)
Where, k is rate constant
t is time in sec
A0 is initial concentration
(6.82 * 10-3) * 240 = log (0.02 /A)
1.63 = log (0.02 /A)
-1.69 – log A = 1.63
Log A = - 0.069
A = 0.82
Hence, 0.82 mol of A remain after 4 minutes.
The material needed to stop a beta particle is c. thin pieces of wood.
2-butane is the correct answer
Answer:
In a voltaic cell (one that happens spontaneously), electrons flow from a negative electrode to a positive electrode (anode cathode). The reaction that happens is a redox reaction where the anode is oxidized (goes from a solid to an ion) and the cathode is reduced (going from an ion to a solid).
Explanation: