In the reaction AgNO3(aq) + HCl(aq) AgCl(s) + HNO3(aq) + heat, when 0.70 mole of AgNO3 and 0.70 mole of HCl react, the temperature of 50 g of water increases from 15°C to 30°C. If the specific heat of water is 4.18 J/g•°C, how much energy was produced in the AgNO3 reaction?

Question

In the reaction AgNO3(aq) + HCl(aq)  AgCl(s) + HNO3(aq) + heat, when 0.70 mole of AgNO3 and 0.70 mole of HCl react, the temperature of 50 g of water increases from 15°C to 30°C. If the specific heat of water is 4.18 J/g•°C, how much energy was produced in the AgNO3 reaction?

A.	2100 J
 		B.	42 J
 		C.	1050 J
 		D.	3100 J

The answer I got was 3135.

DrBob222 · Accepted Answer

I obtained 3538; I suspect D is the correct answer since the 0.70 mols restricts the answer to 2 significant figure and 3100 is that. Technically the 50 number of grams H2O has only 1 s.f. but I guess they ignored that.