1. How many Joules of heat are need to change 20.0 grams of water from 8°C to 93 °C?

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.

Declaration of independence basically declares war with britain while bill of rights is document with the rights of the people written down.

Aquantity of that isotope to decay to 1/2 of  its original value

Silicon  6.0x10^23 is avogadro's number so the answer has to be 1 mole of whatever it is. since the molarity of silicon is equal to 28g/mol, this has to be the answer because 28g of si is 1 mole of si.