2g of Na2O*(1 mole/62g)= moles of x
moles of x*(4 Na/2 moles of Na2O)= moles of y
moles of y*(23g/mole)=????
What is the mass of sodium needed to make 2 g of sodium oxide (4Na + O2 → 2Na2O)?
Ar values: O = 16, Na = 23.
please help I'm really struggling. also please try to explain it to the simplest form because I really don't understand.
2 answers
All of these stoichiometry problems are worked alike. Here is the 4 step process.
4Na + O2 → 2Na2O
Step 1. Write and balance the equation. You have that.
Step 2. Convert whatever you have to mols. If a solid then mols = grams/molar mass = ?. If a solution then mols = M x L = ? In this case, the molar mass of Na2O is approx 62 so mols = 2/62 = approx 0.03 but that's just a close guess. You should do it more accurately.
Step 3. Using the coefficients in the balanced equation, convert mols of what you have to mols of what you want. You have mols Na2O and you want to convert that to mols Na.
0.03 mols Na2O x (4 mols Na/2 mols Na2O) = about 0.06. Note that mols Na2O in the numeratorof the first term cancels with mols Na2O in the denominator of the second term which leaves mols Na which is what you want. In practice you ALWAYS know that the coefficient of the unit you are converting to goes on top and the coefficient of mols you have goes on the bottom.
4. Now convert mols of what you want to grams. grams = molsl x molar mass - about 0.06 x 23 = about ?
Copy this. It can come in handy for every chemistry course you take.
4Na + O2 → 2Na2O
Step 1. Write and balance the equation. You have that.
Step 2. Convert whatever you have to mols. If a solid then mols = grams/molar mass = ?. If a solution then mols = M x L = ? In this case, the molar mass of Na2O is approx 62 so mols = 2/62 = approx 0.03 but that's just a close guess. You should do it more accurately.
Step 3. Using the coefficients in the balanced equation, convert mols of what you have to mols of what you want. You have mols Na2O and you want to convert that to mols Na.
0.03 mols Na2O x (4 mols Na/2 mols Na2O) = about 0.06. Note that mols Na2O in the numeratorof the first term cancels with mols Na2O in the denominator of the second term which leaves mols Na which is what you want. In practice you ALWAYS know that the coefficient of the unit you are converting to goes on top and the coefficient of mols you have goes on the bottom.
4. Now convert mols of what you want to grams. grams = molsl x molar mass - about 0.06 x 23 = about ?
Copy this. It can come in handy for every chemistry course you take.
4 answers