the question is "if 0.940 mole of HBr in solution is added to 16.5 grams of MgO in a beaker and then is heated until dry. what are the expected contents of the beaker" idk anything about chemistry, my teacher doesnt actually teach. if you cant answer it is fine, i think ill do a bit more research on it, thank you anyways
That's an acid-base reaction I'm assuming? So between those elements you first need to balance the chemical equation.
Which is:
MgO + 2HBr --> MgBr2 (s) + H2O (l)
Since it's heated until dry that means they're only asking you for the amount of solid made from the reaction.
Since you have 0.94 mole of HBR, according to stoichiometry it takes 2 moles of HBr to make 1 equivalent of MgBr2
Then you just use that stoichiometric ratio to convert the amount of moles you have to products
0.940 mol HBr x (1 mol MgBr2/ 2 mol Hbr) = 0.47 mole MgBr2
And if they want the answer to be in mass, just convert the moles to it's molecular weight
0.47 mol MgBr2 x (184.1g MgBr2 / 1 mole MgBr2) = 86.5g MgBr2, assuming 100% conversion to products
Let me know if you're working on different material than unit conversions though in case the question is asking for something else.
Ok so once again starting off with your balanced equation of
MgO + 2HBr --> MgBr2 (s) + H2O (l)
What the problem wants you to determine first is what is the limiting reactant.
With 0.94mol HBr2 convert it to grams to see which reagent is in excess or you can convert 16.5 g of MgO to moles.
I'll start with 0.94 mol HBr x (80.91g HBr/ 1 mol HBr) = 76.1g HBr
Or 16.5g MgO x (1 mol MgO /40.3g MgO) =0.41 mol MgO
So if you have 0.94 mol Hbr and only 0.41 mol MgO, according to the stoichiometric ratio you need 1 MgO mole to react with 2 Mole Hbr.
Determine which is the limiting reactant:
0.94 mol HBr2 x (1 mol MgO/ 2 mol Hbr) = 0.47 mol MgO, which you do not have since 16.5g MgO is only around 0.41 mol
Thus MgO is your limiting reactant
Now convert the amount of product yielded with the limiting reactant by the same way of using stoichiometric ratios and convert to grams if they want mass.
is anyone here a chemistry genius, im taking a test and I'm about to flunk the whole class, im struggling with a question from the test, if you can help me i would appreciate it, i hope i dont get banned lmao