## anonymous one year ago The formation of sodium hydroxide occurs by adding sodium to water in this reaction: 2Na + 2H2O → 2NaOH + H2 A byproduct of the reaction is hydrogen gas. If 69 grams of sodium fully reacts with water, how many grams of H2 gas are produced? 1.0 gram 2.0 grams 3.0 grams 6.0 grams

1. Abhisar

Hi! from the reaction you can see that 2 moles of Na reacts fully with 2 moles of water and produces one mole of $$\sf H_2$$. So 1 mole of Na will produce 0.5 moles of hydrogen gas. Here you are asked that if 69 grams (which translates to 3 moles of Na) completely reacts then how many grams of hydrogen is produced. Using unitary methods you can easily say that if for one mole of Na 0.5 moles of hydrogen is produced then for 3 moles of Na, $$\sf 3 \times 0.5=1.5$$ moles of hydrogen gas will be produced. Now weight of one mole hydrogen gas is 2, so weight of 1.5 moles of hydrogen gas will be?

2. anonymous

Uh I don't know.

3. Abhisar

I have done most of your work, read it out carefully. You just need to do a small operation.

4. anonymous

Would the answer be 2.0?

5. anonymous

Or 3.0

6. Abhisar

If cost of 1 bag of chocolate is 2\$, then what should be the cost of a bag and a half?