Answer:
T = 100.63 °C
Explanation:
To solve this question, we need to know what are we talking about here. In this case, we want to know the boiling point of a solution with Urea in water. This is a colligative property, so, the expression to use to calculate that is the following:
ΔT = m * K / MM * kg water (1)
Where:
ΔT: difference of temperatures (Tb of solution - Tb water)
m: mass of the urea
K: ebulloscopic constant of the water (0.52 ° C / m)
MM: molecular mass of urea
The boiling point of water is 100 °C, we have the mass of the urea, but not the molar mass. The urea has the formula CH₄N₂O, so the molar mass can be calculated using the atomic mass of the elements (I will use a rounded number for this):
MM = 12 + (4*1) + (2*14) + 16 = 60 g/mol
Now, we can calculate the ΔT and then, the boiling point of the solution:
ΔT = 12 * 0.52 / 60 * 0.165
ΔT = 6.24 / 9.9
ΔT = 0.63 °C
the value of ΔT is a difference between the boling point of water and the solution so:
ΔT = Ts - Tw
Ts = ΔT + Tw
Replacing we have:
Ts = 100 + 0.63
<h2>
Ts = 100.63 ° C</h2>
Answer:
the entropy change of the fluid during the process process is is 1.337 kJ/K, the change for the source is -1.337 kJ/K and the total entropy change is 0
Explanation:
since the Carnot cycle is a reversible cycle, the entropy change is related with the heat exchanged through:
ΔS =∫dQ/T
since the temperature remains constant
ΔS =∫dQ/T=(1/T)*∫dQ = Q/T
Q= heat added to the system
T= absolute temperature = 400°C= 673 K
therefore
ΔS = Q/T = 900 kJ/ 673 K = 1.337 kJ/K
ΔS working fluid = 1.337 kJ/K
since the process is reversible, the entropy change of the universe (total entropy change) is 0 (there is no entropy generation). thus
ΔS universe = ΔS working fluid + ΔS source = 0
ΔS source= -ΔS working fluid = -1.337 kJ/K
Answer:
Molarity = 5.22 M
Explanation:
Given data:
Mass of sodium chloride = 7.0 g
Volume of solution = 23.0 mL ( 23.0/1000 = 0.023 L)
Molarity = ?
Solution;
Number of moles of NaCl = 7.0 g/ 58.4 g/mol
Number of moles of NaCl = 0.12 mol
Molarity = moles of solute / volume in litter
Molarity = 0.12 mol / 0.023 L
Molarity = 5.22 M
4 NH₃ + 3O₂ --> 2N₂ + 6H₂O
First, make sure that this is a balanced equation.
There are 4 moles of nitrogen on the left side, and 4 moles of nitrogen on the right side.
There are 12 moles of hydrogen on the left side, and 12 moles of hydrogen on the right side.
There are 6 moles of oxygen on the left side, and 6 moles of oxygen on the right side.
The equation is therefore balanced, and we may proceed.
a) the mole ratio for NH₃ to N₂ is 4 to 2, which can be simplified to 2:1 or 2/1.
b) the mole ratio for H₂O to O₂ is 6 to 3, which can be simplified to 2:1 or 2/1.
Answer:
Explanation:
Due to Coulomb´s law electric force can be described by the formula 
, where K is the Coulomb´s constant (
), 
= Charge 1 (Na+ in this case), 
is the charge 2 (Cl-) and r is the distance between both charges.
Work made by a force is W=F.d and total work produced is the change in energy between final and initial state. this is 
.
so we have ![W=W_{f} -W_{i} =(K\frac{q_{(Na+)}q_{(Cl-)}rf}{r_{f} ^{2}})-(K\frac{q_{(Na+)}q_{(Cl-)}ri}{r_{i} ^{2}})=Kq_{(Na+)}q_{(Cl-)[\frac{1}{{r_{f}}} -\frac{1}{{r_{i}}}]](https://tex.z-dn.net/?f=W%3DW_%7Bf%7D%20-W_%7Bi%7D%20%3D%28K%5Cfrac%7Bq_%7B%28Na%2B%29%7Dq_%7B%28Cl-%29%7Drf%7D%7Br_%7Bf%7D%20%5E%7B2%7D%7D%29-%28K%5Cfrac%7Bq_%7B%28Na%2B%29%7Dq_%7B%28Cl-%29%7Dri%7D%7Br_%7Bi%7D%20%5E%7B2%7D%7D%29%3DKq_%7B%28Na%2B%29%7Dq_%7B%28Cl-%29%5B%5Cfrac%7B1%7D%7B%7Br_%7Bf%7D%7D%7D%20-%5Cfrac%7B1%7D%7B%7Br_%7Bi%7D%7D%7D%5D)
Given that ri= 1.1nm= 
and rf= infinite distance
![W=(9x10^{9})(1.6x10^{-19})(-1.6x10^{-19})[\frac{1}{\alpha }-\frac{1}{(1.1x10^{-9})}]=2.1x10^{-19}J](https://tex.z-dn.net/?f=W%3D%289x10%5E%7B9%7D%29%281.6x10%5E%7B-19%7D%29%28-1.6x10%5E%7B-19%7D%29%5B%5Cfrac%7B1%7D%7B%5Calpha%20%7D-%5Cfrac%7B1%7D%7B%281.1x10%5E%7B-9%7D%29%7D%5D%3D2.1x10%5E%7B-19%7DJ)
