Atmospheric pressure is measured with a barometer. A barometer consists of an evacuated vertical tube with its top end closed and its bottom end resting in a container of mercury that is open to the atmosphere The pressure exerted by the atmosphere acts on the exposed surface of the liquid to force mercury up into the tube. Sea level atmospheric pressure will support a mercury column generally not more than 29.92-in. high. Thus, the standard for atmospheric pressure at sea level is 29.92 in.-Hg, which translates to an absolute pressure of 14.69 psia.
The two basic reference points in all these measurements are standard atmospheric pressure and a perfect vacuum.
Let's break this down. We know from our balanced equation that (in theory) we'll get the same number of moles of copper out of the reaction that we put into it. So we need to find the number of moles of CuSO4 we have in 200.0 grams. Using the molar mass of CuSO4:
200.0 grams CuSO4 * (1 mole CuSO4)/(159.61 grams CuSO4) =
1.253 moles CuSO4
We know that the moles of CuSO4 and Cu are one-to-one, so we should yield the same number of moles of copper. If we multiply by copper's molar mass, we get:
1.253 moles Cu * (63.55 grams Cu)/(1 mole Cu) = 79.63 grams Cu
Universal pH paper turns red if it is very strongly acidic, turns orange if it is strongly acidic, turns yellow if it is weakly acidic, green if it is weakly alkali and blue if it is strongly alkali.
Solution A will turn orange as it is strongly acidic
Solution B will turn blue as it is strongly alkali
Solution C will turn yellowish green as it is neutral
