hello peeps. EOYs coming soon! be prepared to uh, drive the night car.

Anyway, i've come up with some Chem questions to help me/you/whatever get into the appropriate mood for studying. i came up with them myself, so forgive me if their too evil or hard for you. but i honestly think that it should be not much problem for most people who have studied.

So, let's get started!
1. A pure white powder, when heated strongly, sublimes. The gases evolved are tested with a piece of moist red and blue litmus paper. When the experiment is over, both pieces of paper have changed colour.

a) Deduce the formula of the powder, and thus write the equation for its decomposition.

b)Which piece of paper changed colour first? Explain your answer.

c)Explain why the pieces of litmus paper had to be wetted first.

2. Some powder A was added to excess solution of hydrochloric acid in a flask E. Effervescence was observed, and a white precipitate C was seen settling after a while at the bottom of the flask. The gas evolved was bubbled into another flask F containing solution B. After a while, a white precipitate D was observed at the bottom of the second flask too. Further tests on a mole of A showed that it contained 3 moles of ions.

a) Deduce the identities of A, B, C and D.

b) How would the pH of the solutions in E and F differ compared to that at the beginning of the experiment?

c) After filtering out C and D, you forgot to label them and now you don't know which is which. Describe a short test to differentiate between the two substances.

3. Explain, in terms of electronic structure, why you think mercury is a liquid at room temperature, despite it having other metallic properties.

a) Name another metal that is liquid at room temperature. (Hint: It's in Group 1.)

4. Define the terms

a) isotope

b) allotrope

c) atomic mass

d) pH

5. Gary made the following statement, ”Ammonia acts like both an acid and a base.” Do you agree with this statement? Explain your answer.

So, i guess that's it for now! will try to post answers soon. Anybody wants to try answering them? =)

Till next post...