***Chemistry - Fall 2005***

[Princess74]

Who else is taking Chemisrty this semester? I thought maybe we can check in with each other, and help each other out.

If there is enough of us maybe we can even get a sticky.

I am taking Health Science Chemistry 1.

[lalajenn]

Probably too late but here is some info I found about Limiting Reactants:

LIMITING REACTANTS (LIMITING REAGENTS)

A balanced equation shows the RELATIVE proportions between reactants and between

products. This relation is fixed but the actual amounts of reactants present can vary. This

can mean that sometimes there can be an excess of one or more of the reactants. In other

words the quantity of one reactant will control the amount of products that will be formed.

1. Calculate the amount of product (moles or grams, as needed) that can be

formed from each reactant.

2. Determine which reactant is limiting.(The reactant that gives the least amount

of product is the limiting reactant and the other reactant is in excess. The limiting

reactant will determine the amount of product formed in the reaction.)

EXAMPLE

How many moles of H2O will be formed when 4.0 moles of H2 are allowed to react

with 1.0 mole of O2 according to the reaction:

2 H2 + O2 ----> 2 H2O

[Answer: 2 mol H2O]

EXAMPLE

How many moles of BaSO4 will be produced from a mixture of 3.5 moles H2SO4

and 2.5 moles BaCl2 using the reaction:

H2SO4 + BaCl2 -----> BaSO4 + 2 HCl

[Answer: 2.5 moles BaSO4]

EXAMPLE

A mixture of 35.0 g of hydrogen and 270 grams of oxygen react to form water.

How many grams of water will form?

2 H2 + O2 ----> 2 H2O

[Answer: 304 g H2O]

EXAMPLE

How many grams of SiO2 will form when 10.0 grams of silicon are mixed with

11.0 grams of oxygen gas?

Si + O2 ----> SiO2

[Answer: 20.7 g SiO2]

Not sure if that will help or not.

[Paula7]

Thanks for the all in the info lalajenn. Test is tonight and I am SO lost. There are TOO many calculations. Mole to Mole, Mole to Gram! I liked the examples but need the part that's missing, how did they get that answer? Big ole F coming to me!! I hate feeling so lost!

[Fun2, BSN, RN]

Thanks for the all in the info lalajenn. Test is tonight and I am SO lost. There are TOO many calculations. Mole to Mole, Mole to Gram! I liked the examples but need the part that's missing, how did they get that answer? Big ole F coming to me!! I hate feeling so lost!

It may be too late, but as I posted before, http://www.sartep.com/chemistryx/Worksheets/worksheets.cfm has worksheets to download as well.

Try to answer the questions by thinking what you have and what you need:

Set your equation up to be able to eliminate each (g, J, mol, etc) in order to end up with the end product that the question is asking.

I wish I could actually write out stuff on here!

Good luck!

Our 5th test is a take home test. Our final is only questions over the presentations that we have to do Monday. We don't have any labs left to do, and our lab notebooks are dure Monday.

ugggh It's almost over for me!

[Shannon RN 2be]

Thanks so much for all the support.

I just got Chemistry for dummies and I am hoping it will help. Has anyone used any guides that were helpful in chmistry?

I feel so lost and I have a test on Monday.

Hugs

Shannon

[Paula7]

Fun2care. Thanks so much for that link. Those worksheets are great. Still feeling an F coming on but I'm looking forward to using that website for future chapters! Thanks again!

Glad your sememster is coming to a close. Take home test? Nothing better! :)

[lalajenn]

On the website I got that from, there wasn't any work that went along with it. They just gave the answer. Wish they showed the work with it too so than I can know how they got to the answer. Hope you did well on your test tonight!!!

Thanks for the all in the info lalajenn. Test is tonight and I am SO lost. There are TOO many calculations. Mole to Mole, Mole to Gram! I liked the examples but need the part that's missing, how did they get that answer? Big ole F coming to me!! I hate feeling so lost!

[Fun2, BSN, RN]

Shannon, I hope that does help. Good luck!

Paula7, I hope your test went well.

[Fun2, BSN, RN]

We are doing gas systems, and I am lost!

I don't know whether it is hard, or I just can't concentrate to figure it out.

We had about 45 min - 1 hour lecture over 1 chapter, and have to figure out the other 2 chapters on our own.

I have 50 questions to answer on our take home test, and a few questions on the extra credit homework.

I think this is simple math, using simple equations, and I am dumbfounded! ugggh!

Well, at least I finished my lab notebook today. So, I don't have to worry about that all weekend.

The test and homework aren't due until Wednesday, our last day, but I really wanted to get them finished this weekend. I guess I'll be going to the tutoring center after our presentations are finished Monday.

I hope everyone is doing well! Your semester is half-way finished!!!!! Good luck!

[lalajenn]

We will be getting to gases on down the line. We just had a test/homework grade on compounds and their bonds and now doing quantities and all. Good luck!!

We are doing gas systems, and I am lost!

[Fun2, BSN, RN]

We will be getting to gases on down the line. We just had a test/homework grade on compounds and their bonds and now doing quantities and all. Good luck!!

Thanks and good luck to you too! I hope you can concentrate! lol

[Paula7]

test did not go well! i will get my grade back tonight but i was so lost!

i even wrote on the test, "please drop this test score!" :chuckle

i am going to be quite embarrassed when she hands it back!

good luck everyone and thanks!

[Fun2, BSN, RN]

test did not go well! i will get my grade back tonight but i was so lost!

i even wrote on the test, "please drop this test score!" :chuckle

i am going to be quite embarrassed when she hands it back!

good luck everyone and thanks!

well, maybe you did better than you thought. keep a positive attitude, study hard, and it will be over before you know it. good luck! :)