posted by hannah .
Calculate the number of liters of hydrogen, measured at STP, that can be produced from the reaction of 0.155 mol of aluminum according to the following unbalanced chemical reaction equation.
i got .193 L of H2 but it was wrong. i only have one submition left!
You didn't include the unbalanced equation. Is it something like
2Al + 6HCl ==> 3H2 + 2AlCl3 or
2Al + 3H2SO4 ==> 3H2 + Al2(SO4)3
Actually, I think any reaction chosen will be a 3/2 ratio as see below.
0.155 moles Al x (3 moles H2/2 moles Al) = 0.155 x (3/2) = 0.2325 moles H2.
Since one mole occupies 22.4 L at STP so
0.2325mol x 22.4 L/mol = ??
2Al(s) + 2NaOH(aq) + 2H2O(l) 2NaAlO2(aq) + 3H2(g) (unbalanced)
sorry i forgot. it was unbalanced but then i balance it
So my answer didn't change because the ratio still is 3/2.
0.155 moles Al x (3 moles H2/2 moles Al) x (22.4L H2/mol H2) = ??L H2.
I tried to duplicate your error by substituting errors student often make; however, I never could come up with 1.93 L.
thanks so its
5.21 L h2?
thanks for the help: can you help me with another one?
Some sulfuric acid is spilled on a lab bench. It can be neutralized by sprinkling sodium bicarbonate on it and then mopping up the resultant solution. The sodium bicarbonate reacts with sulfuric acid as follows.
2 NaHCO3(s) + H2SO4(aq) --> Na2SO4(aq) + 2 H2O(l) + 2 CO2(g)
Sodium bicarbonate is added until the fizzing due to the formation of CO2(g) stops. If 34 mL of 6.0 M H2SO4 was spilled, what is the minimum mass of NaHCO3 that must be added to the spill to neutralize the acid?
i got 5.7 and it said my answer was off by more than 10%
How much H2SO4 was spilled(how many moles?) M x L = 6.0 x 0.035 = 0.204
Convert moles H2SO4 to moles NaHCO3. That will be 0.204 x 2 = 0.408.
Now convert moles NaHCO3 to grams. g = moles x molar mass.