Chapter 18 Worksheet 1
Entropy and the 2nd and 3rd Laws of Thermodynamics: Criterion for Spontaneity
Chemical thermodynamics (thermochemistry) is the study of energy flow during a chemical reaction.
Thermodynamics allows you to:
1. predict whethe
Complete the following questions and problems relating to molality.
1) Write the equation for molality:
M= moles solute/ kg of solvent
2) Write the equation for molarity:
M=moles solute/ L of solution
3) Explain in words how molality an
Hesss Law Practice Problems
1. Given the following equations and Ho values, determine the heat of
reaction (kJ) at 298 K for the reaction:
B2H6(g) + 6 Cl2(g)
2 BCl3(g) + 6 HCl(g)
Ho/kJ = -112.5
Ho/kJ = -493.4
Ho/kJ = -92.3
BCl3(g) + 3 H2O(l)
H3BO3(g) + 3
Chapter 6 Practice Problems
1. How much energy is needed to change the temperature of 50.0 g of water 15.0oC?
2. How many grams of water can be heated from 20.0 oC to 75oC using 12500.0 Joules?
3. What is the final temperature after 840 Joules is absorbed
Hess's Law Worksheet (2) Chemistry
(1) Find the H for the reaction below, given the following reactions and subsequent H values:
PCl5(g) PCl3(g) + Cl2(g)
P4(s) + 6Cl2(g) 4PCl3(g)
4PCl5(g) P4(s) + 10Cl 2(g)
answer = 249.8 kJ
H = -2439 kJ
H = 3438 k
Ions: Atoms with a positive or negative charge.
-Ions are when positive ions that give electrons to negative ions and form a bond.
-Ions involve transfers electrons.
-What holds an ionic bond is the electrostatic attraction.
Covalent bonds are a chemi