T is amount after time t
<span>Ao is initial amount </span>
<span>t is time </span>
<span>HL is half life </span>
<span>log (At) = log [ Ao x (1/2)^(t/HL) ] </span>
<span>log (At) = log Ao + log (1/2)^(t/HL) </span>
<span>log (At) = log Ao + (t/HL) x log (1/2) </span>
<span>( log At - log Ao) / log (1/2) = t / HL </span>
<span>log (At/Ao) / log (1/2) = t / HL </span>
<span>HL = t / [( log (At / Ao)) / log (1/2) ] </span>
<span>HL = 14.4 s / [ ( log (12.5 / 50) / log (1/2) ] </span>
<span>HL = 14.4 s / 2 = 7.2 seconds </span>
Answer: A
1.68 N
Explanation:
F = ma = 0.024(70.0) = 1.68 N
Mass is equal to protons plus neutrons
To find the protons its the atomic number
[H+][OH-]=10-¹⁴
We are using this formula because we need to find the H+
substitute the value given for hydronium ion for OH-
[H+][4.19×10⁵]=10-¹⁴
[H+]=10-¹⁴÷4.19×10⁵
[H+]=2.387×10-¹⁹
Then the pH of the solution will be
pH= –log¹⁰ [H+]
pH = –log¹⁰ [2.387×10-¹⁹]
pH= –log¹⁰2.387+19log¹⁰
= –0.378+19
pH =18.622
