In an experiment as described in the Principles section, 158 mL of O2 is collected over water. The mass of the O2 is measured to be 0.207 g, the temperature is 290 K and the barometric pressure that day is 754 mm Hg. Calculate the value of R in the units L, atm, K, mol. Remember: The pressure measured is the pressure of a mixture of water vapor and the gas we are interested in, O2. To correctly calculate the partial pressure of O2, the vapor pressure of the water must be accounted for.

Hey how did you manage to type such a big lab report

A.(nh4)(2co3)is the correct answer 

C, small, hard spheres with insignificant volumes

Sink to the bottom. addition of potassium nitrate past it’s dissolution capacity at a particular temperature will cause the extra to just sink to the bottom of the glass.however, if you were to raise the temperature of the solution prior to dissolving it, and then slowly decrease the temperature after the dissolution, you would create a “supersaturated” solution - a solution that has more solute dissolved into it than should be allowed. if you add any extra solute past this, the entire solution would “crystallize,” and this is how you get those cool videos on youtube.