15 mins
~Savannah
Jokes from Savannah~
A man goes to the doctor, concerned about his wife’s hearing. The doctor says, “Stand behind her and say something and tell me how close you are when she hears you.”
The man goes home, sees his wife in the kitchen, cutting carrots on the countertop. About 15 feet away he says, “Honey, what’s for dinner?” Nothing. He gets halfway to her and repeats the same question. Nothing. Very concerned, he gets right behind her and asks again “What’s for dinner?”
She turns around and says “For the THIRD time, beef stew!”
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Q: What do you get when you cross a vampire with a snowman?
A: Frostbite!
Answer:
A) The reverse of the reaction is spontaneous
Explanation:
Spontaneous means those reaction which occur own their own or just need an initiation. As we know that,
∆G = ∆H-T∆S,
A reaction is spontaneous if ∆G Comes out to be negative . Because only those reactions occur in which either ∆H ( enthalpy change) is negative or ∆S (entropy change) is positive or both condition satisfied , as if in a reaction, let
A + B ------> B + C
If ∆G is positive when reaction proceed in forward direction, i.e. , it means it will be negative if proceed in backwards direction i.e on reactants side . Which means for such reaction backwards reaction is spontaneous.
Answer:
7. A) I, II
; 8. D) 2.34e9 kJ
Step-by-step explanation:
7. Combustion of ethanol
I. The negative sign for ΔH shows that the reaction is exothermic.
II. The enthalpy change would be different if gaseous water were produced.
That's because it takes energy to convert liquid water to gaseous water, and this energy is included in the value of ΔH.
III. The reaction is a redox reaction, because
- Oxygen is reacting with a compound
- The oxidation number of C increases
- The oxidation number of O decreases.
IV. The products of the reaction occupy a smaller volume than the reactants, because 3 mol of gaseous reactant are forming 2 mol of gaseous product.
Therefore, only I and II are correct.
7. Hindenburg
Data:
V = 2.00 × 10⁸ L
p = 1.00 atm
T = 25.1 °C
ΔH = -286 kJ·mol⁻¹
Calculations:
(a) Convert temperature to kelvins
T = (25.1 + 273.15) K = 298.25 K
(b) Moles of hydrogen
Use the <em>Ideal Gas Law</em>:
pV = nRT
n = (pV)/(RT)
n = (1.00 × 2.00 × 10⁸)/(0.082 06 × 298.25) = 8.172 × 10⁶ mol
(c) Heat evolved
q = nΔH = 8.172 × 10⁶ × (-286) = -2.34 × 10⁹ kJ
The hydrogen in the Hindenburg released 2.34e9 kJ
.
I really don't know and it sucks when i need help and people are giving me false answers.
