Ashley Week 4 Midterm Review

[Chem_Mod]

Hi everyone,

In preparation for your midterm, this week's workshop will be formatted similar to a mock exam, where you will be able to work on the worksheet similar to a practice exam in test conditions from 3-4pm. Then, during my drop-in session at 4pm, I'm planning to hold a review session where you can ask any questions, whether on my worksheet(s) or anything to help you all prepare for your midterm. I will be posting my worksheet/practice exam here on this post at 3pm and release an answer key after the end of my drop-in. Please note that questions on this practice worksheet may not cover all topics that will be tested on the exam, but I hope these questions will help give you some more practice for your midterm! Hope to see you tomorrow, and wishing you all good luck on Wednesday!

[Alyssa_Miao_3B]

Will we need to be able to do #14 since it's about buffers? If so, can you explain how to get the right answer?

[Chem_Mod]

Will we need to be able to do #14 since it's about buffers? If so, can you explain how to get the right answer?

You won't need to know how to create a buffer for the midterm, but you should be able to calculate the pH of salts/if you have multiple initial concentrations. Your equation would be HCNO + H2O <-> CNO- + H+. In your ice table, not only would you have the initial concentration of HCNO present, but you would also have CNO- present (since you also add NaCNO to your buffer). Then, you can work out the equilibrium expressions for each species. Hope this helps, and let me know if you have any other questions!

[Caitlin_Chheda_1K]

For number 9, will we need to know how to calculate the value of x from a cubic function for the midterm?

[Megan Wang 3D]

For number 9, you can use algebra to find x which should not use the cubic function.

[Alyssa_Miao_3B]

Does anyone know why answers B and D are incorrect for #10?

[kayla fullerton 3A]

Can someone explain why the answer to #4 is D? In other words, why would compressing the gas mixture into a smaller volume favor the reverse reaction of an endothermic reaction?

[kayla fullerton 3A]

Does anyone know why answers B and D are incorrect for #10?

B and D are wrong because of the charges of their respective ions. In B, CH3COO- is a base, and therefore would not accept/react with OH- because they are both negatively charged. In D, CH3COOH is acting as an acid, and therefore would only give up its own H+ ion, rather than accepting/reacting with H+ ions already in the solution.

[Patrick Essio 1H]

Can somebody please explain number 15? I am so lost.