温哥华化学家教

化学家教多年经验专业辅导各个级别的化学课程，包括十年级科学，十一年级和十二年级化学，AP化学， IB化学，SAT化学UBC和LANGARA大学一年级普通化学和大学二年级有机化学，物理化学和分析化学。张老师从南开大学化学系博士毕业，在UBC化学系工作8年，具有牢固的化学知识基础和丰富的实际工作经验，如果您有家教需要，请和张老师联系，电话：604-808-6827， 电邮：vancouverchemistrytutor@gmail.com

AP Chemistry Question of the Day --61

Welcome back to my blog. here is Question 60 I posted earlier.
60. Glycerol has lower vapour pressure than does ethanol at room temperature. Which of glycerol and ethanol has the lower boiling point?

The correct answer should be ethanol.

Vapour pressure is the pressure of the vapour when at a certain temperature the liquid and the vapour reach equilibrium in a closed container. Vapour pressure is only dependent on the nature of the substance and temperature. For a given substance, its vapour pressure is only dependent on temperature.  As temperature increases, vapour pressure increases. When the vapour pressure reaches the atmosphere pressure, the temperature is defined as boiling point. As a result, the higher the vapour pressure, the lower the boiling point.

Following is question 61 of the series:

 61. In an experiment to determine the percentage of water in a solid hydrate by heating, what is the best indication that all the water has been removed?
(A)  The solid melts.
(B)  The solid changes color.
(C)  Water vapor no longer appears.
(D)  Successive weighings give the same mass.

I will post the answer in my next blog.
Thank you very much for visiting my blog. I am available to discuss any topics in Chemistry at all levels. Please shoot me an email at vancouverchemistrytutor@gmail.com or give a call at 604-808-6827.

张老师化学家教

首先祝贺张老师的同学们在六月份SAT化学考试中取得了好成绩，SX同学取得了800分满分。
南开大学化学博士，UBC化学系博士后多年经验辅导AP化学，IB化学， SATII化学，十一年级和十二年级化学， 大学一年级普通化学，大学二年级有机化学和物理化学，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。请电604-808-6827与张老师联系。
张老师的个人网页：www.vancouverchemistrytutor.com
张老师的博客：http://vancouverchemistry.blogspot.ca

Congratulations to my hard working students

I am so happy today that I heard back from my three students who sat the June 8th SAT II Chemistry exam got  scores of 800, 770 and 740. All of them were first time takers of the exam. Good job! I am so proud of you.