Download heats of reaction

Name: _________________________________________
Date:____________________________
Optional Homework 3 – do not turn in!!!
1.) Use the standard enthalpies of formation (online or in appendix of text) to calculate the standard enthalpy
change for each of the following chemical reactions:
a.
NH3 (g) + HCl (g) → NH4Cl (s)
∆Hrxn =???
b. MgCl2 (s) + Ca (s) → Mg (s) + CaCl2 (s) ∆Hrxn = ???
2.) Write balanced heat of formation reactions for each of the following. Do not forget to include the ∆Hf values from
the table for the phases listed. Use your appendix (∆H values) to write balanced formation equations determine
whether these reactions are exo or endothermic.
a.
CaCl2 (s)
b. NaHCO3 (s)
c.
HNO3 (l)
3.)
Calculate the mass, in grams, of 8.622 x 1023 chlorine atoms
4.) Calculate the % mass of each element in the following compounds:
a.
H2C2O4
b. SnF4
5.) Give formulas for the following molecular compounds:
a.
dinitrogen tetraoxide
b. sulfur hexachloride
c.
diiodine heptoxide
6.) Complete the following table:
IONS
sulfite
sodium
Na2SO3
ammonium
calcium
aluminum
hydrogen carbonate
phosphate
7.) Name the following ionic compounds
Species
Name
Species
SrCl2
NO
Ga2S3
NO2
Zn(ClO4)2
PBr5
CrO3
PBr3
Name
HINT: prove/rationalize your answer for CrO3 by writing the equation of the ions coming together to make the
product CrO3. Put your suspected charges on the line to MAKE sure you have the correct species!
Cr+ ____________
+
O- _________________ → CrO3
8.) One of the most widespread environmental carcinogens is benzo[α]pyrene (mm = 252.30 g/mole). It is found
in coal dust, cigarette smoke, and in charcoal grilled meat. Analysis of this hydrocarbon shows 95.21 mass %
carbon and 4.79 mass % hydrogen. What is the empirical formula of benzo[α]pyrene? What is the molecular
formula of benzo[α]pyrene?
9.) A dry cleaning solvent (mm = 146.99 g/mole) contains C, H, and Cl. When a 0.250 gram sample was studied
by combustion analysis, 0.451 grams of CO2 and 0.0617 grams of H2O were formed. Calculate the molecular
formula