2019 AP Chemistry FRQ: Question 3

Here is Question 3. Explaining it with a student beside me would be quick, but doing it online takes a surprising amount of time.

My goal is to explain all the AP Chemistry and AP Biology questions.

I have realized that will take much longer than expected.

Answer: CO₃²⁻(aq) + Ca²⁺(aq) → CaCO₃(s).

Draw the Ca²⁺ ions.

0.93 g CaCO₃ / (100.1 g mol⁻¹) = 0.0093 mol Na₂CO₃.

Too high: the calculated amount of CaCO₃ would be overestimated, leading to an overestimated molarity.

Yes, the solution conducts electricity because it contains mobile ions.

In AP Chemistry written responses, it is important to keep the answer concise and include the key terms.

You need to write sentences, but even excellent prose will not earn marks if it is long-winded and omits

the required keywords.

What students fear most is not knowing what to write or how much to write.

With plenty of question practice and practice identifying key terms, they can write without hesitation.

Fortunately, AP Chemistry does not require pages of English in its free responses, which reduces the burden on students who find English writing difficult.

Working through published question books, free-response questions, and past papers should help build the right feel for the exam.

I usually teach AP Chemistry for at least three months, not all day every day but around four hours a week. After roughly three months, students’ skills noticeably improve. With enough questions, they learn the techniques and begin to perform well.

The 2019 AP Chemistry free-response questions

can be downloaded at https://apcentral.collegeboard.org/pdf/ap19-frq-chemistry.pdf.

For more detailed answer wording,

https://www.tutorjacob.com/2019-ap-chemistry-free-response-answers

Solutions and explanations to the 2019 AP Chemistry FRQs

www.tutorjacob.com

visit the page above.