Question 3 (2 points) (01.01 MC)
Carlos is trying to determine how music affects the growth of bean plants. He hypothesizes that classical music will cause a plant to grow at a
higher rate than no music or rap music. He grows nine bean plants in similar lighting, temperature, and soil conditions. Three are exposed to
classical music 24 hours a day, three are exposed to rap music 24 hours a day, and three are grown in complete silence. Carlos measures the
growth of the plants every day and finds that the plants all seem to have the same rate of growth
What is missing from Carlos's scientific investigation? (2 points)
A specific hypothesis predicting a relationship between independent and dependent variables
Controlled variables to ensure only the independent variable is being changed
Experimental data collected regularly that can be recorded and analyzed
Research on what other scientists have observed and investigated on this topic

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.