Two 1+ ions are needed in order to balance one 2- ion.
The items are answered below and are numbered separately for each compound.
The freezing point of impure solution is calculated through the equation,
Tf = Tfw - (Kf)(m)
where Tf is the freezing point, Tfw is the freezing point of water, Kf is the freezing point constant and m is the molality. For water, Kf is equal to 1.86°C/m. In this regard, it is assumed that m as the unit of 0.25 is molarity.
1. NH4NO3
Tf = 0°C - (1.86°C/m)(0.25 M)(2) = -0.93°C
2. NiCl3
Tf = 0°C - (1.86°C/m)(0.25 M)(4) = -1.86°C
3. Al2(SO4)3
Tf = 0°C - (1.86 °C/m)(0.25 M)(5) = -2.325°C
For boiling points,
Tb = Tbw + (Kb)(m)
For water, Kb is equal to 0.51°C/m.
1. NH4NO3
Tb = 100°C + (0.51°C/m)(0.25 M)(2) = 100.255°C
2. NiCl3
Tb = 100°C + (0.51°C/m)(0.25 M)(4) = 100.51°C
3. Al2(SO4)3
Tb = 100°C + (0.51°C/m)(0.25 M)(5) = 100.6375°C
To do this, you would first add together the molar mass of all involved elements, to find how many grams are in a mole of Cu(OH)2. Keep in mind, the molar mass is equal to the atomic mass of an element in grams. For example the molar mass of copper (Cu) would be 63.55 (with 2 sig. figs.)
Therefore, now we add together the mass of all elements involved.
Cu: (63.55)+O2(15.99x2=31.98)+H2(1.01x2=2.02)
63.55+31.98+2.02= 97.55g per mole of Cu(OH)2.
Now, divide what we have by how much it takes to get a mole of the stuff.
68.1/97.55= 0.698mol Cu(OH)2
Explanation:
they are located in the neucleus