A 0.568-g sample of fertilizer contained nitrogen as ammonium sulfate, . It was analyzed for nitrogen by heating with sodium hydroxide. The ammonia was collected in 45.2 mL of 0.192 M (hydrochloric acid), with which it reacted. This solution was titrated for excess hydrochloric acid with 42.4 mL of 0.133 M . What is the percentage of nitrogen in the fertilizer

7.49% of nitrogen

Explanation:

The reaction of ammonium sulfate ((NH₄)₂SO₄) with NaOH is:

(NH₄)₂SO₄ + NaOH → Na₂SO₄ + 2 H₂O + 2 NH₃

Then, the ammonia is collected in HCl, thus:

NH₃ + HCl → NH₄Cl

And the excess of HCl is neutralized with NaOH, thus:

HCl + NaOH → H₂O + NaCl

That means moles of NH₃ are the difference between initial moles of HCl and the excess moles of HCl.

Initial moles of HCl are:

0.0452L × (0.192mol / L) = 8.68x10⁻³ moles of HCl.

Excess moles are:

0.0424L × (0.133mol / L) = 5.64x10⁻³ moles of HCl.

The difference is:

8.68x10⁻³ moles of HCl - 5.64x10⁻³ moles of HCl =

3.04x10⁻³ moles of HCl ≡ moles of NH₃ ≡ moles of nitrogen.

As nitrogen weights 14.0g/mol:

3.04x10⁻³ moles N × (14.0g / mol) = 0.04256g of nitrogen

Percentage of nitrogen is:

(0.04256g of nitrogen / 0.568g) × 100 = 7.49% of nitrogen

both adhesion and cohesion are attractions.

they are different in that adhesion is the force of attraction between the molecules of two different substances, whereas cohesion is the force of attraction between molecules of the same substance.

possible examples include capillary action, in which the adhesion between water and glass causes the water to rise in a narrow tube against the force of gravity.

because of hydrogen bonding, water is extremely cohesive.

this causes molecules on the surface of water to be drawn inward, which is why drops of water form beads on smooth surfaces.

hope this .