The surface tension of water is 7.28 ✕ 10−2 j/m2 at 20°c. predict whether the surface tension of heptane would be higher or lower than that of water at the same temperature. explain your answer.

Lower  

Explanation:

Surface tension occurs because molecules at the surface do not have molecules above them, so they cohere more strongly to their neighbours.

The stronger cohesive forces make it more difficult to move an object through the surface than when it is beneath the surface.

The attractive forces in water are strong because of hydrogen bonding.

A hexane molecule is nonpolar, so the only attractions are the weak London dispersion forces.

The cohesive forces at the surface are much lower than those in water, so the surface tension of hexane is lower than that of water at the sane temperature.

Answerthis solution will not form a precipitateexplanationsolubility equilbrium:         pbf₂(s)  ⇄ pb²⁺(aq) + 2 f⁻(aq)the solubility product expression is    (we exclude solids from the equilibrium expression).now suppose we have the trial ion product q, which we can define as    then, we can interpret  q as the product of the concentration of the ions that we have and ksp as the product of the ion concentrations that are needed to form a saturated solution.if q > ksp, then that implies that there will be a surplus of ions that exceed the amount that is required to form a saturated solution. a precipitate will then form (the precipitate continually  forms until the surplus ions are removed and q is decreased to ksp's value).if q = ksp, the saturated solution that forms is barely saturated and the precipitate will be minimal.if q < ksp, then the ion concentration will not be enough to form a saturated solution (so no precipitate).using our information, we calculate the trial ion product:     since q = 2.7  × 10⁻⁸ < ksp =  4  ×  10⁻⁸, a precipitate will not form.