Answer:
M1 = 49.04 g/mol
Explanation:
The pure benzonitrile has freezing point -12.8°C. By adding a nonvolatile compound, the freezing point will be changed, a process called cryoscopy. The freezing point will be reduced. In this case, the new freezing point is -13.4°C. The variation at the temperature can be calculated by the equation:
ΔT = Kc*W*i
Where ΔT is the variation at the freezing temperature (without the solute less with the solute), Kc is the cryoscopy constant (5.34 for benzonitrile), W is the molality, and i the Van't Hoff correction factor, which is 1 for benzonitrile.
((-12.8-(-13.4)) = 5.34*W
5.34W = 0.6
W = 0.1124 mol/kg
W = m1/M1*m2
Where m1 is the mass of the solute (in g), M1 is the molar mass of the solute (in g/mol), and m2 is the mass of the solvent (in kg).
m1 = 0.551 g, m2 = 0.1 kg
0.1124 = 0.551/M1*0.1
0.01124M1 = 0.551
M1 = 49.04 g/mol
The process that describes the transfer of heat through matter by activity of the molecules would be conduction. This type of heat transfer due to the motion of electrons and ions. within a body. As molecules collide with each energy is transferred and released which cause temperature to rise or drop.<span />
<span>Balancing the choices, we have as follows:
A. 3AgBr + GaPO4 → Ag3PO4 +GaBr3
B. 3H2SO4 + 2B(OH)3 → B2(SO4)3 + 6H2O
C. Fe + 2AgNO3 → Fe(NO3)2 + 2Ag
D. C2H4O2 +2O2 → 2CO2 + 2H2O
Therefore, the correct answers are option A and B. Hope this answers the question. Have a nice day.</span>
