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:
2,760 grams NaCl
Explanation:
To find grams of NaCl, you need to (1) convert moles of Na to moles of NaCl (via mole-to-mole ratio from reaction) and (2) convert moles of NaCl to grams (via molar mass from periodic table). The final answer should have 3 significant figures based on the given measurement.
2 Na + Cl₂ --> 2 NaCl
Molar Mass (NaCl) = 22.99 g/mol + 35.45 g/mol
Molar Mass (NaCl) = 58.44 g/mol
47.2 moles Na 2 moles NaCl 58.44 grams
---------------------- x --------------------------- x ------------------------- =
2 moles Na 1 mole NaCl
= 2,758.368 grams NaCl
= 2,760 grams NaCl
The volume at 100 mmHg : 0.656 L
<h3>
Further explanation</h3>
Boyle's Law
<em>At a constant temperature, the gas volume is inversely proportional to the pressure applied </em>
V₁=3.5 L
P₁=2.5 kPa=18,7515 mmHg
P₂=100 mmHg
