Answer:
The enthlapy of solution is -55.23 kJ/mol.
Explanation:
Mass of water = m
Density of water = 1 g/mL
Volume of water = 50.0 mL
m = Density of water × Volume of water = 1 g/mL × 50.0 mL=50.0 g
Change in temperature of the water ,ΔT= 27.0°C - 22.3°C = 4.7°C
Heat capacity of water,c =4.186 J/g°C
Heat gained by the water when an unknown compound is dissolved be Q
Q= mcΔT
heat released when 0.9775 grams of an unknown compound is dissolved in water will be same as that heat gained by water.
Q'=-Q
Q'= -983.71 J =-0.98371 kJ
Moles of unknown compound = 
The enthlapy of solution :
The enthlapy of solution is -55.23 kJ/mol.
Answer:
-86.02 kJ/ mole
Explanation:
The moles of the acid used = Molarity × Volume (L) =
= 0.50 (0.0372 L)
= 0.0186 moles
The heat released = -1.6 kJ
∴ 0.0186 moles neutralization of HA heat is: -1.6 kJ
The molar heat of neutralization due to one mole of the unknown acid = -1.6/0.0186
= -86.02 kJ/ mole
Answer:
Explanation:
Mol of NaI = 0.405 mol
Molarity of solution = 0.724 M
Molarity is given by
The required volume is .
Answer: 85.7 mL
Explanation:
Given the information from the question as plotted in the graph i will be uploading along side this answer,
Average of total volume of DCPIP used is
= (1.21 + 1.11 + 1.06)mL / 3
= 1.12 mL
and corresponding ( ascorbic acid ) is 0.70 g/L
Two parameter given as volume of DCPIP in final syringe and total volume of DCPIP are quite ambiguous
700mg ⇒ 1 L
THEREFORE volume that contains 60mg = (1000/700) × 60 = 85.7 mL
Answer:
NaI > Na2SO4 > Co Br3
meaning that NaI has the highest freezing point, and Co Br3 has the lowest freezing point.
Explanation:
The freezing point depression is a colligative property.
That means that it depends on the number of solute particles dissolved.
The formula to calculate the freezing point depression of a solution of a non volatile solute is:
ΔTf = i * Kf * m
Where kf is a constant, m is the molality and i is the van't Hoff factor.
Molality, which is number of moles per kg of solvent, counts for the number of moles dissolved and the van't Hoff factor multipllies according for molecules that dissociate.
The higher the number of molecules that dissociate, the higher the van't Hoff, the greater the freezing point depression and the lower the freezing point.
As the question states that you assume equal concentrations (molality) and complete dissociation you just must find the number of ions generated by each solute, in this way:
NH4 I → NH4(+) + I(-) => 2 ions
Co Br3 → Co(+) + 3 Br(-) => 4 ions
Na2SO4 → 2Na(+) + SO4(2-) => 3 ions.
So, Co Br3 is the solute that generate more particles and that solution will exhibit the lowest freezing point among the options given, Na2SO4 is next and the NaI is the third. Ordering the freezing point from higher to lower the rank is NaI > Na2SO4 > CoBr3, which is the answer given.
