5. To keep your lunch cold at the beach, would you want a material that minimizes heat transfer or maximizes heat transfer? Explain (keep it short please)

Minimizes heat transfer

Explanation:

To keep my lunch from getting cold at the beach, a material the minimizes heat transfer will be the most desirable.

Such material should be modified to prevent had transfer by convection, conduction and radiation. This kind of material is desirable because heat generally flows from a place of high amount to that of low amount. Since the food will mostly have a temperature higher than the ambient one, it is expected that heat will flow away from the food to the environment. This will make the food cold. If such heat transfer is prevented, then, the food will remain hot.

1) according to the law of conservation of mass ,in all chemical reactions total mass is unchanged

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.