Answer: Option (d) is the correct answer.
Explanation:
Endothermic process is a process in which energy or heat is absorbed by reactant species.
For example, melting of ice cubes is an endothermic process as it is absorbing heat from the surrounding and gives a cooling effect.
Thus, we can conclude that the process in which a substance gains energy is an endothermic process.
Answer: 65.38g of Ca(OH)2 is needed
Explanation:
From The equation of reaction
2 HCl + Ca ( OH ) 2 ⟶ CaCl 2 + 2 H 2 O
NB: Molar mass of HCl= 1+35.5=36.5
Ca(OH)2= 74
From The stoichiometric equation
2mol of HCl(36.5×2=73) require 1mol of Ca(OH)2 (74g)
Hence 64.5g of HCl will require 64.5×74/73= 65.38g of Ca(OH)2
Answer: The standard potential is -0.141 V
Explanation:
To calculate the Gibbs free energy for given value of equilibrium constant we use the relation:
where,
= standard Gibbs free energy = ?
R = Gas constant = 8.314 J/Kmol
T = temperature = 298 K
K = equilibrium constant =
Putting values in above equation, we get:
Also
where n = no of electrons gained or lost = 3
F = Faradays constant = 96500 C
= standard potential = ?
Thus the standard potential is -0.141 V
Explanation:
1) Initial mass of the Cesium-137== 180 mg
Mass of Cesium after time t = N
Formula used :
Half life of the cesium-137 = = initial mass of isotope
N = mass of the parent isotope left after the time, (t)
= half life of the isotope
= rate constant
Now put all the given values in this formula, we get
Mass that remains after t years.
Therefore, the parent isotope remain after one half life will be, 100 grams.
2)
t = 70 years
N = 35.73 mg
35.73 mg of cesium-137 will remain after 70 years.
3)
N = 1 mg
t = ?
t = 224.80 years ≈ 225 years
After 225 years only 1 mg of cesium-137 will remain.
Dispersion forces are the only type of intermolecular force operating between non-polar molecules, for example, dispersion forces operate between hydrogen (H2) molecules, chlorine (Cl2) molecules, carbon dioxide (CO2) molecules, nitrogen tetroxide (N2O4) molecules and methane (CH4) molecules.
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