31. B
32. C
33. C
34. C
35. A
36. A
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Answer: The enthalpy of combustion, per mole, of butane is -2657.4 kJ
Explanation:
The balanced chemical reaction is,
The expression for enthalpy change is,
Putting the values we get :
2 moles of butane releases heat = 5314.8 kJ
1 mole of butane release heat = 
Thus enthalpy of combustion per mole of butane is -2657.4 kJ
The correct term for each statement is as follows;
- Caves being formed by acid rain dissolving underground limestone - weathering
- Deltas forming at the mouths of rivers - deposition
- Glaciers scraping rocks across the earth’s surface - erosion
- Rocks being made smooth by tumbling across a stream bed - weathering
- Ponds filling up with sediment and becoming marshes - deposition
<h3>What is weathering?</h3>
Weathering in geology is the mechanical or chemical breaking down of rocks in situ by weather or other causes. options 7 and 14 are the case in this scenario as there is a breakdown of limestone and rocks.
Erosion is the result of having been worn away or eroded, as by a glacier on rock or the sea on a cliff face. Agents of erosion are water, ice or wind. Options 12 is an example of erosion because glaciers are wearing off rocks.
Deposition is the laying down of sediment carried by wind, flowing water, the sea or ice. Sediment can be transported as pebbles, sand and mud, or as salts dissolved in water. Options 8 and 15 are examples of deposition.
Learn more about weathering and deposition at: brainly.com/question/367069
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Answer:
<em>C. The electron-withdrawing fluorine atoms pull electron density from the oxygen in trifluoroacetate. The negative charge is more stabilized in trifluoroacetate by this effect.</em>
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Explanation:
<em>The structures of trifluoroacetate and acetic acid are both shown in the image attached.</em>
<em>The trifluoroacetate anion (CF3CO2-), just like the acetate anion has in the middle, two oxygen atoms.</em>
<em>However, in the trifluoroacetate anion, there are also three electronegative fluorine atoms attached to the nearby carbon atom attached to the carbonyl, and these pull some electron density through the sigma bonding network away from the oxygen atoms, thereby spreading out the negative charge further. This effect, called the "inductive effect" stabilizes the anion formed,the trifouoroacetate anion is thus more stabilized than the acetate anion.</em>
<em>Hence, trifluoroacetic acid is a stronger acid than acetic acid, having a pKa of -0.18.</em>
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<u><em>Hope this helps!</em></u>
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Ca= 2 ve
Be=2 ve
Mg=2 ve because they are in Group 2a.
They are slightly less reactive than Group 1a, but more dense that Group 1a.