Answer:
2578.99 years
Explanation:
Given that:
100 g of the wood is emitting 1120 β-particles per minute
Also,
1 g of the wood is emitting 11.20 β-particles per minute
Given, Decay rate = 15.3 % per minute per gram
So,
Concentration left can be calculated as:-
C left = ![[A_t]=\frac{11.20\ per\ minute}{15.3\ per\ minute\ per\ gram}\times [A_0]= 0.7320[A_0]](https://tex.z-dn.net/?f=%5BA_t%5D%3D%5Cfrac%7B11.20%5C%20per%5C%20minute%7D%7B15.3%5C%20per%5C%20minute%5C%20per%5C%20gram%7D%5Ctimes%20%5BA_0%5D%3D%200.7320%5BA_0%5D)
Where,
![[A_t]](https://tex.z-dn.net/?f=%5BA_t%5D)
is the concentration at time t
![[A_0]](https://tex.z-dn.net/?f=%5BA_0%5D)
is the initial concentration
Also, Half life of carbon-14 = 5730 years
Where, k is rate constant
So,
The rate constant, k = 0.000120968 year⁻¹
Time =?
Using integrated rate law for first order kinetics as:
![[A_t]=[A_0]e^{-kt}](https://tex.z-dn.net/?f=%5BA_t%5D%3D%5BA_0%5De%5E%7B-kt%7D)
So,
![\frac {[A_t]}{[A_0]}=e^{-0.000120968\times t}](https://tex.z-dn.net/?f=%5Cfrac%20%7B%5BA_t%5D%7D%7B%5BA_0%5D%7D%3De%5E%7B-0.000120968%5Ctimes%20t%7D)
![\frac {0.7320[A_0]}{[A_0]}=e^{-0.000120968\times t}](https://tex.z-dn.net/?f=%5Cfrac%20%7B0.7320%5BA_0%5D%7D%7B%5BA_0%5D%7D%3De%5E%7B-0.000120968%5Ctimes%20t%7D)
<u>t = 2578.99 years</u>
Answer is: Cl and Na.
sodium and chlorine are in third period and they have very different properties. Sodium is solid metal and chlorine is gaseous nonmetal.
They form compound NaCl (Sodium chloride), because sodium lost one valence electron and form cation Na⁺, chlorine gain one electron and form anion Cl⁻.
Electron configuration of sodium atom: ₁₁Na 1s² 2s² 2p⁶ 3s¹.
Electron configuration of chlorine atom: ₁₇Cl 1s² 2s² 2p⁶ 3s² 3p⁵.
Other examples are metal-metal pairs and they do not form cation and anion.
Answer:
Total pressure of the mixture is 12.2 atm
Explanation:
Let's apply the Ideal Gases law to solve this
Total pressure . V = Total moles . R . T
Total moles = 0.4 m of He and 0.6 mole of Ne → 1 mol
P . 2L = 1 mol . 0.082 L.atm/mol. K . 298K
P = ( 1 mol . 0.082 L.atm/mol. K . 298K) /2L
P = 12.2 atm
The error is in the formula is bracket so the correct is Mg(OH)₂
The incorrect or error in the formula is bracket that would be that the compound contain only 1Mg atom and 1 oxygen atom and 2 hydrogen atom but is wrong when you write it in an electron dot diagram you will see that it is wrong there be unshared paired of electron and the correct formula is Mg(OH)₂
Know more about Mg(OH)₂
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Answer:
c) HCl and NaCl
Explanation:
Since all the solutions are on a 1:1 mole ratio the comparison is straight forward.
The lowest pH will be for solution c) which has a strong acid, HCl, which ionizes 100 % and the neutral salt NaCl (which is neutral since it is derived from the reaction of the strong acid HCl and the strong base NaOH).
Solutions a) and b) are buffers of the weak base NH₃ and its conjugate acid NH₄⁺ and weak acid H₃PO₄ and its conjugate weak base NaH₂PO₄ respectively.
Solution c) is a basic solution being a mixture of the weak base NH₃ and the strong base NaOH
Solution e) is a mixture of a weak base NH₂ and weak acid HC₂H₃O₂
