Benzene diazonium chloride decomposition help?

Benzene diazonium chloride, C6H5NNCl, decomposes by first order rate law. If the rate constant at 20 C is 4.3*10-5/s, how long will it take for 61% of the compaound to decompose? I saw someone already asked a similar question but the solution was hard to follow. Please help!

The integrated first order equation is:
ln[C6H5NNCl] = ln[C6H5NNCl]o – kt.
The left side of the equation is the concentration of the reactant at any time t, so if 61% of the C6H5NNCl decomposes, then 39% remains. The concentration on the right side of the equation is at time t = 0; so we can let [C6H5NNCl]o = 100 and [C6H5NNCl] = 39. Just substitute;
ln(39) = ln(100) – (4.3*10-5/s) t;
Solving, t = 21,899 s; or about 6 hr 5 min.

One Response to “Benzene diazonium chloride decomposition help?”

  • Schmedley says:

    The integrated first order equation is:
    ln[C6H5NNCl] = ln[C6H5NNCl]o – kt.
    The left side of the equation is the concentration of the reactant at any time t, so if 61% of the C6H5NNCl decomposes, then 39% remains. The concentration on the right side of the equation is at time t = 0; so we can let [C6H5NNCl]o = 100 and [C6H5NNCl] = 39. Just substitute;
    ln(39) = ln(100) – (4.3*10-5/s) t;
    Solving, t = 21,899 s; or about 6 hr 5 min.
    References :

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