I think it is the first choice
Hope that helped!
<span>Answer: 8.15s
</span><span />
<span>Explanation:
</span><span />
<span>1) A first order reaction is that whose rate is proportional to the concenration of the reactant:
</span><span />
<span>r = k [N]
</span><span />
<span>r = - d[N]/dt =
</span><span />
<span>=> -d[N]/dt = k [N]
</span><span />
<span>2) When you integrate you get:
</span><span />
<span>N - No = - kt
</span>
<span></span><span /><span>
3) Half life => N = No / 2, t = t'
</span><span />
<span>=> No - No/ 2 = kt' => No /2 = kt' => t' = (No/2) / k
</span><span />
<span>3) Plug in the data given: No = 0.884M, and k = 5.42x10⁻²M/s
</span>
<span /><span /><span>
t' = (0.884M/2) / (5.42x10⁻²M/s) = 8.15s</span>
The molar mass or As is 74.9g. Start with 281g multiply by (1mol/74.9g) = 3.75 mols
Put what you don’t want on the bottom (in this case grams) so they the u it’s cancel (if you multiply by grams and the divide by grams they cancel. Ultimately leave what you want on the top ( This case mols) then do the math
Answer:
It will have 5 valence electrons as its in group 5.
The atom will gain as its closer to the full configuration 8.
The charge will be 3- as it will gain 3 electrons.
