if a student mixes 250 grams of Na2O with 300 grams of H2O how many grams of NaOH ?
This is a limiting reagent problem (LR) and I work these the long way.
Na2O + H2O ==> 2NaOH
mols Na2O = grams/molar mass = ?
mols H2O = grams/molar mass
Using the coefficients in the balanced equation convert mols Na2O to mols NaOH.
Do the same for mols H2O to mols NaOH.
It is likely that the two values will not be the same which means one of them is not right; the correct value in LR problems is ALWAYS the smaller value and the reagent responsible for that number is the LR.
Using the smaller value, convert mols to grams. grams NaOH = mols NaOH x molar mass NaOH. If I punched in the right numbers on my calculator I think the answer is approx 160 grams. I think a more interesting question would have been to calculate the M NaOH solution.
To find out the number of grams of NaOH that will be produced when 250 grams of Na2O reacts with 300 grams of H2O, we need to understand the chemical reaction occurring between them.
The reaction between Na2O and H2O leads to the formation of NaOH (sodium hydroxide). The balanced chemical equation for this reaction is:
Na2O + H2O -> 2NaOH
From the balanced equation, we can see that one molecule of Na2O reacts with one molecule of H2O to produce two molecules of NaOH.
To determine the number of moles of Na2O and H2O, we need to divide the given masses by their respective molar masses. The molar masses are:
- Na2O: 61.98 g/mol
- H2O: 18.02 g/mol
Number of moles of Na2O = 250 g / 61.98 g/mol
Number of moles of H2O = 300 g / 18.02 g/mol
Next, we need to determine the limiting reactant. The limiting reactant is the one that will be completely consumed first, limiting the amount of product formed. To find this, we compare the mole ratios of Na2O and H2O with the balanced equation.
From the balanced equation, we can see that for each molecule of Na2O, we need one molecule of H2O. Therefore, the mole ratio is 1:1.
If the mole ratio between Na2O and H2O is 1:1, it means that the reactants are in a stoichiometric ratio. This implies that both reactants are completely used up, and no reactant is left in excess. Hence, none of the reactants will limit the reaction.
Now, we can calculate the grams of NaOH produced using the moles of Na2O as the stoichiometric factor. From the balanced equation, we can observe that one mole of Na2O produces two moles of NaOH.
Number of moles of NaOH = Number of moles of Na2O * (2 moles of NaOH / 1 mole of Na2O)
Lastly, we determine the grams of NaOH using the molar mass of NaOH (39.997 g/mol).
Grams of NaOH = Number of moles of NaOH * Molar mass of NaOH
By following these steps, you should be able to calculate the grams of NaOH produced when 250 grams of Na2O reacts with 300 grams of H2O.