The graph below compares the total amounts of greenhouse gas emissions expected for future mid-size cars, including emissions that occur when moving fuels from their original source to fueling stations where people can buy the fuels for their cars. Amounts are shown in grams of CO (or equivalent greenhouse gas) per mile driven by the mid-size car. Which vehicles are the best choices for environmentally friendly cars? fuel cell electric and battery electric hybrid electric and plug-in hybrid electric conventional internal combustion and hybrid electric conventional internal combustion and battery electric

A) the enthralling of formation for pure element in its standard state is always positivehope this : )

There are no metaphors.

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.