Dr. Zhang Chemistry Tutoring 张老师化学家教

Ph. D in Chemistry with years of experience offering chemistry tutoring on AP Chemistry, IB Chemistry, SAT Chemistry, Chemistry 11 and 12, University Level General Chemistry and second year Organic Chemistry including UBC CHEM 111, CHME 113, CHEM 121, CHEM123, CHEM 154, CHEM 203, CHEM 213, CHEM 233, CHEM 205, CHEM 235 and CHEM 245, Langara College CHEM 1114, CHEM 1118, CHEM 1120 and CHEM 1220. I can teach with both English and Mandarin. Please call 604-808-6827. 南开大学化学系博士，UBC化学系博士后，多年经验辅导AP化学，IB化学，SAT化学，十一年级和十二年级化学,大学一年级普通化学和二年级有机化学和物理化学，因材施教，深入浅出，中英文结合，帮你理解要点，抓住重点，取得满意成绩。请电604-808-6827.

UBC Chemistry Tutor

Experienced Ph. D. in chemistry offering tutoring service for UBC CHEM111. CHEM113, CHEM121, CHEM123, CHEM233, CHEM 235, CHEM 205, CHEM 203, CHEM 213, CHEM 235 and CHEM 245. Personalized tutoring tailored to individual needs. Guaranteed improvement and success.  
For your tutoring needs, please call Dr. Zhang at 604-808-6827. 

Vancouver Chemistry Tutor

Ph. D in Chemistry with years of experience offering chemistry tutoring on AP Chemistry, IB Chemistry, SAT Chemistry, Chemistry 11 and 12, University Level General Chemistry and second year Organic Chemistry, UBC CHEM 111/113, CHEM 121/123, CHEM 233, CHEM 205. LANGARA CHEM 1120, 1220, 2216, 2316 and 2416. I can teach with both English and Mandarin. Please call 604-808-6827.

UBC 化学家教

多年经验辅导UBC一年级和二年级各科化学，包括CHEM 111, CHEM 113, CHEM 121. CHEM 123, CHEM 205, CHEM 211 和 CHEM 233. 可用中英文双语教学，助你理解重点，取得好成绩。请与张博士联系，手机604-808-6827， 电邮：vancouverchemistrytutor@gmail.com

AP Chemistry Question of the Day --53

Welcome back to my blog. Here is question 52 I posted yesterday.

52. An 11.1L sample of 0.25mol oxygen gas is converted to ozone. If all the oxygen is converted to ozone, what will the volume of ozone be?

This is a typical stoichiometry question. To solve the question, we have to correctly write the chemical equation and properly balance it.  Ozone and oxygen are allotropes (do you still remember what is allotropes? Allotropes are different forms that an element can exist in) of oxygen and their formula are O3 and O2 respectively.

The balanced chemical reaction should be:

According to the chemical equation, 3mol of oxygen gas will produce 2mol of ozone gas. as a result, 0.25mol of oxygen should produce:

What is the volume of the ozone gas then? Recall Avogadro's law which states that  at constant temperature and pressure, the volume is directly proportional to the mole number. Since 0.25mol oxygen occupies 11.1L. apparently it is not STP. Or else, it should be approximately 0.5mol roughly 11.2L.  We know for ideal gas, the identity of the gas does not matter. As long as they have the same mole numbers, at the same T and P, the volume would be same. As a result, the volume of the ozone would be:

Pay attention that I kept 2 sig figures for my answer because the mole number of ozone has 2 sig fig.

In stoichiometric calculations, dimensional analysis is key. Make sure you align your expressions properly so that the unit can cancel out and only left with what you are asked for.

Here is Question 53 of the series:

53.  A solution appears yellow.  It must be absorbing in the  

    (a) yellow only    (b) red only    (c) green only    (d) blue only   (e) purple only. 

 I will post the answer in my next blog.

Thank you very much for reading my post, I am available to discuss any topics in chemistry. Please give me a call at 604-808-6827 or email me at vancouverchemistrytutor@gmail.com. My website is located at www.vancouverchemistrytutor.com.

Regards!

UBC Chemistry Tutor

Experienced Ph. D. in chemistry offering tutoring service for CHEM 111, 113, 121, 123, 205 and 233.  Personalized tutoring tailored to individual needs. Guaranteed improvement and success.  I can teach with both English and Chinese.

For your tutoring needs, please call Dr. Zhang  at 604-808-6827.

南开大学化学博士，UBC化学系博士后多年经验辅导CHEM 111, 113, 121, 123, 205, 233. 因材施教，帮你理解重点，抓住要点，取得满意考试成绩。可用中英文双语沟通。 如果您有辅导需求，请随时与我联系 604-808-6827。