What is the theoretical yield of silver chloride?

AgNO3(aq) + NaCl(aq) = AgCl(s) + NaNO3  

MWt AgNO3 = 169.87; AgCl = 143.32  

From the eqn 169.87 g of AgNO3 yield 143.32 g of AgCl  

1.000g of AgNO3 yield 143.32/169.87 g of AgCl  

Hence 4.27 g will yield (143.32/169.87)×4.27 g of AgCl  

= 3.60 g of AgCl which is the theoretical yield.  

% yield = (2.56/3.60)× 100 = 71.1%  

A skilled chemist (e.g., Marie Curie) would get close to 100%.

your parents i think this could be it

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.