Originally Answered: Please! I need Chemistry help?
There are lots of things you can do to get help in class. I know the feeling of being completely lost - the important thing is to get it together before the test, so look for someone smart and with some time on their hands who also takes the class who can explain it to you. If that's not possible, ask the professor/teacher or the TA if there is one. Also, if there's a textbook, READ THROUGH IT! Start from the very beginning and if you get confused about something ASK someone. It really really helps, I promise.
As for your questions, they're quite easy.
1. Solid silver hydroxide is written as AgOH(s). If you didn't know that, you're much further back than you should be, and you need to go back to the beginning and look at the unit on nomenclature. Hydrobromic acid is HBr(aq). It's aqueous because all acids are aqueous. It's kind of hard to figure out what will happen when two things are mixed, but usually if you have a strong acid and a strong base, they form water and one other thing. That's called an acid-base equation. It's obvious that you have an acid, but where's the base? Well, whenever you see the word HYDROXIDE, think base. OH- is pretty much the strongest base around.
So... what's your equation?
AgOH(s) + HBr(aq) --> H2O(l) + AgBr
How did I get that? Well, just imagine that each compound breaks up. If AgOH breaks up, you get Ag+ and OH-. If HBr breaks up, you get H+ and Br-. Well, whenever you have OH- and H+ together in the same container, they will combine to form water, H2O. So you know H2O is one of the things that's formed. Well, what else is lying around? Ag+ and Br-, from each compound. Combine those and you get AgBr. Easy as pie.
2. Aqueous strontium hydroxide is Sr(OH)2(aq) and hydroiodic acid is HI(aq). Again, if you don't know why, go back to nomenclature. Notice that you've got a hydroxide and a base again - ACID/BASE REACTION! So you know water will be formed!
Sr(OH)2(aq) + HI(aq) --> H2O(l) + SrI2
Well, now you need to balance it, so put a 2 in front of the H2O and a 2 in front of the HI and you've got it balanced.
Hope I helped! I know even this can be confusing if you don't have a grasp of earlier material, so I really urge you to read the textbook if there is one. It will help. I promise.