Answer:
answer A
Explanation:
A) the quantity of usable energy declines with each transformation → True . Since the entropy increases , the amount of energy that can not be converted to useful energy increases and since the total amount of energy is conserved, the quantity of useful energy decreases.
B) energy can be neither created nor destroyed → False in the context of entropy , since the energy is conserved regardless of the changes in entropy (First law → conservation of energy vs second law → increase of entropy)
C) life should be impossible → False . Since the second law states that the entropy of the <u>universe </u>increases with time . Then the system (life) can experience a decrease in entropy at the expense of a larger increase in entropy of the surroundings ( so the net increase is positive)
D) it is not possible to observe an increase in molecular organisation → False . Same as C. A system can experience a decrease in entropy at the expense of a larger increase in entropy of the surroundings ( so the net increase is positive)
<u>Given:</u>
Mass of solvent water = 4.50 kg
Freezing point of the solution = -11 C
Freezing point depression constant = 1.86 C/m
<u>To determine:</u>
Moles of methanol to be added
<u>Explanation:</u>
The freezing point depression ΔTf is related to the molality m through the constant kf, as follows:
ΔTf = kf*m
where ΔTf = Freezing point of pure solvent (water) - Freezing pt of solution
ΔTf = 0 C - (-11.0 C) = 11.0 C
m = molality = moles of methanol/kg of water = moles of methanol/4.50 kg
11.0 = 1.86 * moles of methanol/4.50
moles of methanol = 26.613 moles
Ans: Thus around 26.6 moles of methanol should be added to 4.50 kg of water.
Answer: 1. Sodium Benzoate
Explanation: An anti-oxidant is a substance that can help prevent or stop the damage done by free radicals. Examples include; Sulphur Dioxide, Sulphite Salts, Citric Acid, e.t.c
Sodium benzoate is a pure preservative.
Answer:
Explanation:
The relation between equilibrium constant and Ecell is given below .
E⁰cell = (RT / nF ) lnK , F is faraday constant T is 273 + 25 = 298 K
E⁰cell = 1.46 - 1.21 = .25 V
n = 2
Putting the values
.25 = (8.314 x 298 lnK) / (2 x 96485 )
lnK = 19.47
K = 2.85 x 10⁸
2 )
Change in free energy Δ G
Δ G ⁰ = nE⁰ F
n = 4
E⁰ = .4 + .83 = 1.23 V
Δ G ⁰= 4 x 1.23 x 96485
= 474706 J / mol
3 )
E⁰cell = (RT / nF ) lnK
n = 2
1.78 = 8.314 x 298 lnK / 2 x 96485
lnK = 138.638
K = 1.62 x 10⁶⁰
Answer:
Ammonia, urea, uric acid
Explanation:
The given compounds are:-
Urea which has a molecular formula of 
and has 2 atoms of nitrogen per molecule.
Ammonia which has a molecular formula of 
and has 1 atom of nitrogen per molecule.
Uric acid which has a molecular formula of 
and has 4 atoms of nitrogen per molecule.
Thus,
The order from least to most nitrogen is:-
Ammonia, urea, uric acid
