Question

1. the hydrogen released by the reaction of 90 grams of nitric acid on aluminum, was used to make ammonia. How many grams of ammonia were formed ? 3. How many grams of copper(II) oxide can be formed by the oxygen liberated when 150 grams of mercuric oxide are ddecomposed? 4. the iodine formed when 20 grams of chromic iodide are electrolyzed is reacted with sodium . how many moles of sodium iodide are formed? 5. A sample MgO was first dissolved in hydrochloric acid to give a solution of MgCl2 and was then converted to a precipitate of pure, dry Mg2P2O7 weighting 12.00g. calculate the sample of MgO.

Answer 1

1.
2Al(s) + 6HNO3(aq) ------------> 2Al(NO3)3(aq) + 3H2(g)

No of mole of HNO3 = 90 / 63.01 = 1.43 mol

No of moleof H2 PRODUCED = 1.43*3/2 = 2.145 mol

N2 + 3H2 ---> 2NH3

No of mole of NH3 produced = 2.145*2/3 = 1.43 mol

mass of NH3 produced = 1.43*17 = 24.31 grams

3.

2HgO + heat ---> 2Hg + O2

2Cu + O2 ---> 2CuO

No of mole of HgO = 150/216.59 = 0.69 mol

No of mole of O2 produced = 0.69/2 = 0.345 mol

No of mol of CuO produced = 0.345*2   = 0.69 mol

mass of cuo produced = 0.69*79.545 = 54.88 grams