Two solutions initially at 24.60°C are mixed in a coffee cup calorimeter. when a 100.0 ml volume of 0.100 m AgNO3 solution is mixed with a 100.0 ml sample of 0.200 m nacl solution, the temperature in the calorimeter rises to 25.30°C. Determine the dh for the reaction as written below. Assume that the density and heat capacity of the solutions is the same as that of water. NaCl(aq)+AgNO3(aq) → AgCl(s)+NaNO3(aq)

a. -69 kJ
b. -35 kJ
c. -16 kJ
d. -250 kJ

= - 59.7 kJ/mol

Explanation:

The total volume of the solution is:

= (100 + 100 ) mL

= 200 mL

mass of the solution = 200 × 1.00 = 200 g

Heat gained by the solution:

= mass × specific heat × temperature change in solution

= 200× 4.184 × (25.3 - 24.6)

= 585.76 J

Heat gained by calorimeter

= heat capacity × change in temperature of caiorimeter

= 15.5 × (25.3 -24.6)

= 10.85 J

Thus, total heat released = total heat gained

= 585.76 + 10.85 J

= 596.61 J

The no of moles of AgNO3 = 100/1000 × 0.100 = 0.01 mol

The no of moles of NaCl = 100/1000 × 0.200 = 0.02 mol

From above, it is obvious that AgNO3 is the limiting reagent

∴

ΔH_{rxn} = total heat released/ moles of AgNO3

= -596.61/0.01

= 59661 J/mol

= - 59.7 kJ/mol

c. because step up transformer steps up the input voltage i.e increases the input voltage  

the number of turns are greater on the secondary side of step up transformer  

transformer does not handle dc current

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)