If 1.2 grams of sodium are reacted with 4.00 mL water, how much NaOH is produced? density of water= 1.00g/mL
answered below.
you lost me
You can't find it or you don't understand my answer I gave below?
i don't really understand your answer
ok. Follow the steps.
Post your work for parts 2a and 2b.
moles Na = g/atomic mass = ??
moles H2O = g/molar mass = ??
ok.
0.0522 moles Na
0.222 moles H2O
Very good.
Now you use these two values to see which one is the limiting reagent. You do that by converting moles Na to mols H2 and moles H2O to moles H2. The conversion is done by using the coefficients in the balanced equation. Here is how you do the conversion of moles Na to moles H2.
0.0522 moles Na x (1 mole H2/2 moles Na) = 0.522 x 1/2 = 0.0261 moles H2 gas if we were to use 0.0522 moles Na and all of the water we needed. Notice how the moles Na in the numerator of the first term cancel with the unit moles Na in the denominator of the second term. What we have done is canceled the unit we don't want and we are left with the unit (moles H2) we want to keep. Now you do the moles H2O to moles H2.
Would it just be .222 moles H2O x (1 mole H2/2 moles H2O) because this would cancel the H2O and it would leave me with 0.111 mole H2?
very good. Note, too, that the coefficients of H2 and H2O are the numbers that go into the fraction of
0.222 x (1 mole H2/2 moles H2O). It's the coefficients of the balanced equation that go in the fraction and the fraction is ALWAYS placed so that the unit we don't want cancels and the unit we want to keep stays. Note the fraction is
(1 mole H2/2 mole H2O). What if we decided to do it the other way like this,
0.222 moles H2O x (2 moles H2O/1 moles H2) = ??. See the unit moles H2O doesn't cancel and we have some kind of a weird unit like moles2H2O/moles H2 as an answer.
Ok. So we now have 0.0261 moles H2 produced if we use 0.0522 moles Na and all of the water we need to react with all of it. AND we have 0.111 moles H2 produced if we use 0.222 moles H2O and all of the Na we need to react with all of the H2O. Obviously, both 0.111 and 0.0261 can't be correct. One of them is wrong. Why and which one? Let's analyze each one.
For 0.0261 moles H2 we use 0.0522 moles Na and all of the water we need. For 0.111 moles H2 we use 0.222 moles H2O and all of the Na we need. The small number is ALWAYS what we get. If you don't see that, I can show you another way.