Bill sets up an experiment to determine and predict the velocity of a marble at the end of a track. He uses an electronic balance to weigh the marble. He then places the marble at the top of the track and releases it. Artie uses the time it takes the marble to pass through a photogate at the bottom of the track to calculate the velocity of the marble. ill notes that his prediction is significantly higher than his calculated velocity. Which error explains this difference? A) Bill forgot to account for friction. B) Bill forgot to zero the balance and found a weight for the marble that was too low. C) Bill weighed the marble in a weighing dish and failed to account for the mass of the weighing dish. D) Bill didn't position the photogate correctly and got the time required for the top of the marble to pass through, rather than reach the middle.

Ifound this on google “laws of chemical combination. it states that matter can neither be created nor destroyed. it stated that a given compound always contains exactly the same proportion of elements by weight.” i hope this you for what your looking for.

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.