posted by Mary on .
How would I calculate these? I have the answers because there from a previous test.
1) How much heat is required to raise the temperature of a 5.52-g sample of iron ( specific heat = 0.450 J/g C) from 25.0 degrees C to 79.8 degrees C?
2) You mix 60. mL of 1.00 M silver nitrate with 25 mL of 1.63 M sodium chloride. What mass of silver chloride should you form?
a = mass Fe x specific heat Fe x (Tfinal-Tinitial)
This is a limiting reagent problem. I know that because amounts are given for BOTH reactants.
AgNO3 + NaCl ==> AgCl(s) + NaNO3
mols AgNO3 = M x L = ?
mols NaCl = M x L = ?
Using the coefficients in the balanced equation, convert mols AgNO3 to mols AgCl.
Do the same to convert mols NaCl to mols AgCl.
It is likely that these two values will not be the same which means one of them is wrong; the correct answer in limiting reagent problems is ALWAYS the smaller value and the reagent producing that value is the limiting reagent.
Use the smaller value and convert to grams. g AgCl = mols AgCl x molar mass AgCl.