chemistry question?

Question

1-if 5 gr of hydrogen and 5 gr of oxygen are combined to form water which substance would be considered the limiting reagent?
2- which of the following contains the metal with lowest oxidation number
CaCL2
NaBr
FeSO4
MnO2
3- in the reaction 2H2O2--->2H2O, 2,00 moles of hydrogen peroxide will produce how many gr of oxygen

Answer 1

1-Hydrogen would be considered the limiting reagent.
2-NaBr contains the metal with lowest oxidation number.
3-It will produce 32 gr of oxygen.

Answer 2

I have to disagree with the others about the limited reactant. I believe it is Oxygen. I didn't think you could compare substances by looking at their weight. You have to convert them to moles using a balanced equation and their molar ratios:

2 H2 + O2 ---> 2H20

5 g H2 x 1mol H2/ 2g x 2 mol H2O/ 2 mol of H2 ( this is the molar ratio) = 2.5 mol of H2O

now look at Oxygen:

5 g O2 x 1 mol O2/ 32 g x 2 mol H2O/ 1 mol O2 (molar ratio again) = 0.3125 mol of H20


So when we look at this the Hydrogen can make 2.5 moles of water but O2 can only make 0.3125 moles of water and so oxygen is therefore the limited reactant.

Of course I could be wrong but I think that is right.


2 - I think NaBr has the lowest oxidation number. Na has a +1 oxidation number


3 - I don't think your equation is right. 2 H202 ---> 2 H20

First it's not balanced, second the question asks for grams of oxygen and there is no oxygen by itself in the equation. Maybe you mean :

2 H2O2 ---> 2 H2O + O2

The equation is now balanced.

2 mol H2O2 x 1 mol O2/ 2 mol H2O2 x 32 g O2 / 1 mol O2 = 32 g of O2

Hope this helped and I didn't confuse you more! :)

Answer 3

1-since hydrogen and oxygen react in a 2:1 ratio, you would have to convert the two masses to moles and then perform a little bit of basic stoichiometry to see which is present in sub-needed amounts. in this case, it would be the oxygen, you'll have to do the work to get an explanation.

2-Na in NaBr has the lowest oxidation number. bromide is Br-, so Na has to be +1 oxidation.

3-hydrogen peroxide decomposes in a 2:1 ratio to form oxygen, so two moles of hydrogen peroxide creates 1 mole of oxygen.

Answer 4

1 - hydrogen would be the limiting reagent.

2 - FeSO4. This is off the top of my head :P But there is a method to calculate the Ox. state quickly and easily.

3 - 1 mole of O2, or 2moles of O (however you wanna look it at). I believe O is 15.999 (off top of my head) so we can say somewhere in the neighborhood of 32grams. you figure out your sigfigs.

Answer 5

How do you expect to pass the exams when we can't be there to do your work for you?

If you don't know how to convert from grams into moles (or don't know **when** you should convert from grams to moles), you are in big big trouble.

Answer 6

1. Give
2. me a
3. Break

Answer 7

Are you asking us to do your homework? Please learn SOMETHING before they give you the undeserved diploma.