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
Answer:
Formula of oxide is 
Explanation:
The given compound consists of Fe and O.
So, mass of oxygen in sample = (mass of sample) - (mass of Fe in sample)
= (6.285 g ) - (4.396 g)
= 1.889 g
Molar mass of O = 16 g/mol and molar mass of Fe = 55.845 g/mol
So, ratio of number of moles of Fe and O (Fe : O)
= 
= 0.0787 : 0.118
= 
= 1 : 1.5
= 2 : 3
So, formula of oxide is
Radioactive decay => C = Co { e ^ (- kt) |
Data:
Co = 2.00 mg
C = 0.25 mg
t = 4 hr 39 min
Time conversion: 4 hr 39 min = 4.65 hr
1) Replace the data in the equation to find k
C = Co { e ^ (-kt) } => C / Co = e ^ (-kt) => -kt = ln { C / Co} => kt = ln {Co / C}
=> k = ln {Co / C} / t = ln {2.00mg / 0.25mg} / 4.65 hr = 0.44719
2) Use C / Co = 1/2 to find the hallf-life
C / Co = e ^ (-kt) => -kt = ln (C / Co)
=> -kt = ln (1/2) => kt = ln(2) => t = ln (2) / k
t = ln(2) / 0.44719 = 1.55 hr.
Answer: 1.55 hr
Answer:
D. 2.0 M CuCl2
Explanation:
The ionic strength of a solution shows the concentration of its ions in that given solution of the compound. Dissolved ionic compounds always dissociate into ions. The total amount of ions in solution will definitely affect the properties of the solution. The concept of ionic strength was first introduced by Lewis and Randall in 1921 while describing the activity coefficients of strong electrolytes.
The ionic strength of CuCl2 is 6M as shown:
ionic strength = 0.5*[(+2)^2*2M + (1-)^2*4M] = 6 M
The higher the ionic strength of a solution, the greater its non ideal behavior.
CuCl2 shows the greatest ionic strength hence the greatest non ideal behavior.
