Respuesta :
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 moles of N2O5 that will remain after 4.0 mins is 0.00389 moles
From the given information, the rate law for a first order reaction can be computed as:
[tex]\mathbf{K = \dfrac{1}{t} In (\dfrac{A_o}{A_t}) }[/tex]
where;
- rate constant (K) = 6.82 × 10⁻³ s⁻¹, and;
- time (t) = 4.0 min
- initial number of moles A₀ = 2.00 × 10⁻²
- number of moles at time (t) [tex]A_t[/tex] = ???
∴
the number of moles of N₂O₅ at time (t) is:
[tex]\mathbf{6.82 \times 10^{-3 }= \dfrac{1}{4 \ min \times \dfrac{60\ s}{1 \ min}} \times In (\dfrac{2.00 \times 10^{-2}}{A_t})}[/tex]
[tex]\mathbf{1.6368 = In (\dfrac{2.00 \times 10^{-2}}{A_t})}[/tex]
[tex]\mathbf{ (A_t)= 2.00 \times 10^{-2} \times e^{-(1.6368)}}[/tex]
[tex]\mathbf{ (A_t)=0.00389 \ moles}[/tex]
Learn more about first order rate constant here:
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