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Chemistry question

Hi, please could i have help on this question? I dont understand how I’m supposed to use the energy values to work this out?
Here is the question: https://i.ibb.co/NNKzQxD/IMG-0215.jpg
Thank you!
Original post by anonymous294
Hi, please could i have help on this question? I dont understand how I’m supposed to use the energy values to work this out?
Here is the question: https://i.ibb.co/NNKzQxD/IMG-0215.jpg
Thank you!


Think about how strong your acids and bases are.

Generally, a strong acid-strong base reaction will have a more exothermic enthalpy change (the literature values tend to all be around -56 or -57 kJ/mol) and a reaction between a weak acid and a strong base or between strong acid and a weak base will be a little less exothermic (often these values will range from -50 to -55 kJ/mol).

Essentially you need to look at the known reactant, what your enthalpy change of reaction is and decide whether it is likely a strong or weak acid/base is reacting in light of it.
(edited 4 months ago)
Reply 2
Original post by TypicalNerd
Think about how strong your acids and bases are.

Generally, a strong acid-strong base reaction will have a more exothermic enthalpy change (the literature values tend to all be around -56 or -57 kJ/mol) and a reaction between a weak acid and a strong base or between strong acid and a weak base will be a little less exothermic (often these values will range from -50 to -55 kJ/mol).

Essentially you need to look at the known reactant, what your enthalpy change of reaction is and decide whether it is likely a strong or weak acid/base is reacting in light of it.

Ohh ok so i worked out that p would be ethanol acid becuase it is weaker than sulfuric acid but how do i work out which one is a strong or weak base between ammonia and sodium hydroxide? I thought ammonia is a strong base so i though the answer would be B but the answer is A? Thanks
(edited 4 months ago)
Original post by anonymous294
Ohh ok so i worked out that p would be ethanol acid becuase it is weaker than sulfuric acid but how do i work out which one is a strong or weak base between ammonia and sodium hydroxide? I thought ammonia is a strong base so i though the answer would be B but the answer is A? Thanks

Ammonia is a weak base - this is just something they expect you to memorise.

Though if it helps, a strong base can be thought of as something that dissociates pretty much fully in water to form OH^- ions. NaOH being an ionic compound dissociates into its ions in water, so it meets the description.
Reply 4
Original post by TypicalNerd
Ammonia is a weak base - this is just something they expect you to memorise.

Though if it helps, a strong base can be thought of as something that dissociates pretty much fully in water to form OH^- ions. NaOH being an ionic compound dissociates into its ions in water, so it meets the description.

Thank you!

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