Answer:
5.8μg
Explanation:
According to the rate or decay law:
N/N₀ = exp(-λt)------------------------------- (1)
Where N = Current quantity, μg
N₀ = Original quantity, μg
λ= Decay constant day⁻¹
t = time in days
Since the half life is 4.5 days, we can calculate the λ from (1) by substituting N/N₀ = 0.5
0.5 = exp (-4.5λ)
ln 0.5 = -4.5λ
-0.6931 = -4.5λ
λ = -0.6931 /-4.5
=0.1540 day⁻¹
Substituting into (1) we have :
N/N₀ = exp(-0.154t)----------------------------- (2)
To receive 5.0 μg of the nuclide with a delivery time of 24 hours or 1 day:
N = 5.0 μg
N₀ = Unknown
t = 1 day
Substituting into (2) we have
[5/N₀] = exp (-0.154 x 1)
5/N₀ = 0.8572
N₀ = 5/0.8572
= 5.8329μg
≈ 5.8μg
The Chemist must order 5.8μg of 47-CaCO3
Answer: The correct option is 2.
Explanation: There are two types of nuclear reactions:
1) Nuclear fission: These reactions are defined as the reactions in which a heavier unstable nuclei breaks into two or more smaller stable nuclei.
2) Nuclear fusion: These reactions are the ones where two smaller nuclei fuse together or combine together to form a larger nuclei.
In the question, we need to find the fusion reaction which forms elements heavier than helium.
Option 1: In this fusion reaction occurs but the nuclei is Helium itself.
Option 2: In this also fusion reaction occurs and the nuclei is heavier than Helium which is Neon.
Option 3 and Option 4: These two reactions are nuclear fission reactions of Uranium-235 because one heavier element is breaking into more than 2 products.
Hence, the correct option is 2.
<span>Answer is: pH of solution of sodium cyanide is 11.3.
Chemical reaction 1: NaCN(aq) → CN</span>⁻(aq)
+ Na⁺<span>(aq).
Chemical reaction 2: CN</span>⁻ +
H₂O(l) ⇄ HCN(aq) + OH⁻<span>(aq).
c(NaCN) = c(CN</span>⁻<span>)
= 0.021 M.
Ka(HCN) = 4.9·10</span>⁻¹⁰<span>.
Kb(CN</span>⁻) = 10⁻¹⁴ ÷
4.9·10⁻¹⁰ = 2.04·10⁻⁵<span>.
Kb = [HCN] · [OH</span>⁻]
/ [CN⁻<span>].
[HCN] · [OH</span>⁻<span>] =
x.
[CN</span>⁻<span>] = 0.021 M - x..
2.04·10</span>⁻⁵<span> = x² / (0.021 M
- x).
Solve quadratic equation: x = [OH</span>⁻<span>] = 0.00198 M.
pOH = -log(0.00198 M) = 2.70.
pH = 14 - 2.70 = 11.3.</span>
Molar mass Ra(OH)2 = 260 g/mol
<span>Moles = 987 g / 260 = 3.80 moles</span>
<h2>♨ANSWER♥</h2>
pl (25*C)
Arginine -----> 10.76
Glutamic -----> 3.08
Asparagine -----> 5.43
Tyrosine -----> 5.63
<u>☆</u><u>.</u><u>.</u><u>.</u><u>hope this helps</u><u>.</u><u>.</u><u>.</u><u>☆</u>
_♡_<em>mashi</em>_♡_
