Conduction: In the conduction, the heat is transferred from the hotter body to the colder body until the temperature on both bodies are equal.
In thermal equilibrium, there is no heat transfer as the heat is transferred till the temperature on the bodies are not same.
In the given problem, an iron bar at 200°C is placed in thermal contact with an identical iron bar at 120°C in an isolated system. After 30 minutes, the thermal equilibrium is attained. Then, the temperature on both iron bars are equal.Both iron bars are at 160°C in an isolated system.
But in an open system, the temperatures of the iron bars after 30 minutes would be less than 160°C. There will be heat lost to the surrounding. The room temperature is 25°C. There will be exchange of the heat occur between the iron bars and the surrounding. But It would take more than 30 minutes for both iron bars to reach 160°C because heat would be transferred less efficiently.
First, we need to calculate moles of hydrazoic acid NH3:
moles NH3 = molarity * volume
= 0.15 m * 0.025 L
= 0.00375 moles
moles NaOH = molarity * volume
= 0.15 m * 0.015 L
= 0.00225 moles
after that we shoul get the total volume = 0.025L + 0.015L
= 0.04 L
So we can get the concentration of NH3 & NaOH by:
∴[NH3] = moles NH3 / total volume
= 0.00375 moles / 0.04 L
= 0.09375 M
∴[NaOH] = moles NaOH / total volume
= 0.00225 moles / 0.04 L
= 0.05625 M
then, when we have the value of Ka of NH3 so we can get the Pka value from:
Pka = -㏒Ka
= - ㏒ 1.9 x10^-5
= 4.7
finally, by using H-H equation we can get PH:
PH = Pka + ㏒[salt/ basic]
PH = 4.7 +㏒[0.05625/0.09375]
∴ PH = 4.48
Isotope ¹⁸F⁻ contains:
1) p⁺ = 9; number of protons.
Fluorine has a<span>tomic number Z = 9 (total number of protons).
2) e</span>⁻<span> = 10; </span>number of electrons.<span>
In element number of electrons and protons are the same, because element has neutral charge, but because in this example, fluorine is anion with negative charge, it has one electron more.
3) n</span>° = 9; number of neutrons.
<span>Mass number
A = 18 is total number of protons and neutrons in a nucleus, so number of neutrons is A-Z = 18-9=9.</span>
Answer:
The element will be 
Explanation:
Given that,
Number of proton = 80
Number of neutron = 81
Number of electron = 79
We know that,
The atomic number is equal to the number of proton.
So, the atomic number is 80.
According to atomic number,
The element will be mercury.
We need to calculate the atomic mass
Using formula of atomic mass
Put the value into the formula
We need to find the element
Using atomic mass and atomic number
So, the element will be
Put the value of A and Z
Hence, The element will be
I would be inclined to go with A, C and D
