In order to determine the concentration of ammonium ions in
the solution prepared by mixing solutions of ammonium sulfate, (NH4)2SO4, and ammonium
nitrate, first calculate the amount of ammonium ions for each solution.<span>
<span>For ammonium sulfate sol'n: 0.360 L x 0.250 mol(NH4)2SO4/ L x 2 mol NH4+ /1 mol(NH4)2SO4 =
0.18 mol NH4+ <span>For ammonium nitrate sol'n: 0.675 x 1.2 mol NH4NO3/L x 1 mol NH4+ /1 molNH4NO3
= 0.81 mol NH4+
Thus, the amount of NH4+ ions is (0.18 + 0.81) mol or 0.99
mol NH4+. To get the concentration, multiply this to the volume of solution
which is assumed to be additive, such that:</span></span></span>
M NH4+ in sol’n = 0.99 mol NH4+/1.035 L = 0.9565 mol NH4+/ L
sol’n
You see, we must cast our minds back to Charles' law. Charles' law gives the relationship between the volume of a gas and temperature of the gas.
Now, Micheal left the balloon outside at a particular temperature and volume the previous night. Overnight, the temperature dropped significantly and so must the volume of the gas in the balloon!
Remember that Charles' law states that, the volume of a given mass of gas is directly proportional to its absolute temperature at constant pressure. Since the pressure was held constant, the drop in the volume of gas in the balloon can be accounted for by the drop in temperature overnight.
A titration involves the addition of a titrant to an analyte solution. It is a method of volumetric analysis.
When a particular volume of titrant is added, the colour changes to signal the end point of the reaction.
The point at which the colour changes is called the equivalence point. This is the point at which the amount of titrant added is just enough to completely neutralize the analyte solution.
Hence the volume NaOH that needs to be added to the beaker containing HCl to cause a colour change is the volume of NaOH that is just enough to completely neutralize the HCl solution.
