Chem Help?

[Comessy]

I need help with this question.

 

The concentration of hydroxide ions in a 0.75L solution containing 25g of aluminum hydroxide is ______

 

Aluminum hydroxide is Al(OH)3. Therefore the formula is Al(OH)3 -> Al + 3OH

Atomic weight of 1 mol of Al(OH)3 is 66.01.

 

So to find mols I did 25/66.01 = 0.378.

Divide that by volume (0.75) to get mol/L

 

0.378/0.75 = 0.505mol/L

 

Since its asking for hydroxide I have to multiply that by 3 

0.505 x 3 = 1.51mol/L

 

 

Apparently I did something wrong, but I can't find where. Can someone help?

[Troyanac]

 

If you are interested in something about electronics feel free to ask me.

 

[Curufinwe_wins]

I need help with this question.

 

The concentration of hydroxide ions in a 0.75L solution containing 25g of aluminum hydroxide is ______

 

Aluminum hydroxide is Al(OH)3. Therefore the formula is Al(OH)3 -> Al + 3OH

Atomic weight of 1 mol of Al(OH)3 is 66.01.

 

So to find mols I did 25/66.01 = 0.378.

Divide that by volume (0.75) to get mol/L

 

0.378/0.75 = 0.505mol/L

 

Since its asking for hydroxide I have to multiply that by 3 

0.505 x 3 = 1.51mol/L

 

 

Apparently I did something wrong, but I can't find where. Can someone help?

It's 78 g/mol.

[Walker998]

i practically did my first chemistry GCSE (it's called something else outside the uk) progress test today (minus the harder one assuming i did well on the first one) so sorry, no idea.

[Zefues]

nooo, not chemistryyy

[Comessy]

It's 78 g/mol.

How did you get that?

 

Al - 26.98

O3 - 36.00

H3 - 3.03

       --------

       66.01

[don_svetlio]

This is more-so math than chemistry.

[grayblizzard]

I need help with this question.

 

The concentration of hydroxide ions in a 0.75L solution containing 25g of aluminum hydroxide is ______

 

Aluminum hydroxide is Al(OH)3. Therefore the formula is Al(OH)3 -> Al + 3OH

Atomic weight of 1 mol of Al(OH)3 is 66.01.

 

So to find mols I did 25/66.01 = 0.378.

Divide that by volume (0.75) to get mol/L

 

0.378/0.75 = 0.505mol/L

 

Since its asking for hydroxide I have to multiply that by 3 

0.505 x 3 = 1.51mol/L

 

 

Apparently I did something wrong, but I can't find where. Can someone help?

sorry man im learning chem right now and you are best if i dont say a word

[Curufinwe_wins]

How did you get that?

 

Al - 26.98

O3 - 36.00

H3 - 3.03

       --------

       66.01

Oxygen is 16 g/mol not 12. 16*3=48

[Curufinwe_wins]

This is more-so math than chemistry.

It's stoichiometry but the distinction is blurry... 

[Comessy]

Oxygen is 16 g/mol not 12. 16*3=48

OHHHHH WOW

 

I got it

 

Thanks man. I'm retarded

[Curufinwe_wins]

OHHHHH WOW

 

I got it

 

Thanks man. I'm retarded

Np happens to the best of us. I'm so baller I don't just have a periodic table of the elements. I own a table of the radionuclides...

 

For those that care about the difference... This is your brain:

http://sciencenotes.org/wp-content/uploads/2015/08/ColorPeriodicTable.pdf

 

This is your brain on drugs:

http://www.nndc.bnl.gov/chart/

 

(I mean periodic table vs table of the radionuclides)

[NeatSquidYT]

 

This is your brain on drugs:

http://www.nndc.bnl.gov/chart/

 

[BuckGup]

This is more-so math than chemistry.

Chemistry is math.

[as96]

I sucked at chemistry, can't help you.