🔑 Here are all the KEYS to Exam 1

Coverage: Exam 1 covers all the material that was covered on LE's 01-09 and HW01, HW02, and HW03. Most of the exam is over Chapter 2 (Gases) from the gchem site. There will be about 3 questions that are "fundamentals" (Chapter 1) which means you would be balancing and equation and calculating stoichiometric quantities (especially gases). Know that this exam is really about gases.

About ChemBook Those chapters are listed as a reference. You are NOT being tested on ChemBook content - so don't email me and ask. But if you'd like some nice tie-ins to the real world, then read some chembook stuff. Many former CH301 and CH302 students have pointed out how much they liked chembook as an extra reference. Plus, some of the chembook pages and info is presented better than in gchem which is why I will often reference from chembook. Feel free to dig into OpenStax as well if you want. It's all the same chemistry. 🙂

Learning Outcomes for Exam 1

Realize that many of this are repeated in one way or another. These cover the Fundamentals and Gases chapters.

Learning Outcomes for Fundamentals and "Life"

Students will know...

1. how to count stuff
2. how to mathematically convert from one type of unit to another utilizing a set of conversion factors
3. the names, formulas, and physical state of the first 10 alkanes (in play on all exams)
4. Know which elements exist as diatomic molecules
5. the MAIN Metric Prefixes for Chemistry Class as listed in section 10.2 of chembook - it's the last table there
6. Properly use a scientific calculator such that any number in scientific notation can be entered and used in various calculations.
7. Know and use the various common metric prefixes for scientific measurements.
8. Convert from any given unit of measure to another when provided a unit equivalence table (unit factors).
9. Interpret and report measured or calculated values to the proper number of significant figures.
10. how to fully balance a chemical reaction and identify the coefficients
11. how to do composition stoichiometry calculations - figuring out the percent of a specific element in a given compound
12. how to do reaction stoichiometry calculations converting moles to moles and also moles to grams and grams to grams or anything else
13. how to predict product amounts when given arbitrary amounts of reactants - limiting reactant problems (like #20 on HW01)
14. the same outcomes as the two previous ones but with gas moles using the ideal gas law to get pressure or volume of the gas reactants.
15. anything else we learned and did in class, on HW, that I forgot here

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Learning Outcomes for Composition Stoichiometry

Students will be able to...

1. Write a complete chemical formula, including if necessary hydrates of water.
2. Interpret chemical formulas in reference to the number of each type of atom present.
3. Calculate the molar mass of a given compound (chemical formula).
4. Calculate the percent composition of a chemical compound.
5. Explain the difference in atoms, molecules, and formula units for a given compound.
6. Calculate microscopic amounts (molecules and atoms) contained within macroscopic amounts (grams or pounds).
7. Determine the empirical formula for a compound from percent composition data.
8. Apply the concepts of Compositional Stoichiometry to empirical and molecular formulas.

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Learning Outcomes for Reaction Stoichiometry

Students will be able to...

1. Write, balance, and label a chemical reaction using whole number coefficients.
2. Write formulas and balance a combustion reaction between a fuel (alkane) and oxygen.
3. Use provided data on synthesis and decomposition to confirm the conservation of matter and law of definite proportions.
4. Explain the role of the stoichiometric coefficients.
5. Use dimensional analysis to convert between mass, moles, and number of atoms and compounds.
6. Explain the difference in the two terms "limiting reactant" and "reactant in excess".
7. Correctly identify the limiting reactant of a given reaction.
8. Calculate the yield (both absolute and percentage) of a product in a chemical reaction.
9. Calculate the excess amount of the reactant that is in excess for a chemical reaction.
10. Qualitatively (microscopic illustrations, chemical reactions) and quantitatively express the conservation of mass and conservation of atoms for chemical processes.

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Learning Outcomes for Gases

Students will be able to...

1. Describe pressure from a macroscopic and microscopic perspective.
2. Relate Boyles, Charles', and Avogadro's gas laws to observations of gas behavior.
3. Calculate the values for state functions (n, V, T, P) using the ideal gas equation.
4. Define the conditions of STP and SATP.
5. Relate the number density and mass density for a given gas, including quantitative calculations such as mass, molecular weight, and density.
6. Relate partial pressures and the total pressure as described by Dalton’s Law of Partial Pressure.
7. Apply the concept of the gas laws to gas phase reactions.
8. Perform stoichiometric calculations using gas properties, masses, moles, limiting reagents, and percent yield.
9. Relate kinetic energy to the temperature of a gas.
10. Relate temperature, molar mass, and gas velocity.
11. Describe the effect of molar mass and temperature on the Maxwell-Boltzmann gas velocity distribution.
12. Apply kinetic molecular theory to a variety of gas phenomena including diffusion and effusion.
13. Calculate relative effusion and diffusion rates using Graham’s Law.
14. Explain the quantitative relationship between state functions (n, T, V, and P) as described by kinetic molecular theory.
15. Describe macroscopic gas behavior using a small particle model of a gas.
16. State when the ideal gas model fails to predict the behavior of gases observed in nature and in the laboratory.
17. Explain what the breakdown of the ideal gas law reveals about the assumptions of kinetic molecular theory.
18. Explain the general principles of the hard sphere model and van der Waal's model of gas.

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More Help on Exam 1

Jimmy's Help Videos on Exam 1 topics.

• Composition Stoichiometry
• Reaction Stoichiometry Easy, Medium, Hard
• Reaction Stoichiometry Limiting Reagent
• Reaction Stoichiometry Example with overview
• Gas Law Stoichiometry
• Full Lecture Rxn Stoich Pt 1
• Full Lecture Rxn Stoich Pt 2

Formulas YOU should know

The Ideal Gas Law (IGL):

   \(PV=nRT\)

Gas Laws "contained" in the IGL:

Boyle's Law:    \(P_1V_1 = P_2V_2\)    (constant n, T)

Charles' Law:    \(\displaystyle{V_1\over T_1} = {V_2\over T_2}\)    (constant n, P)

Avogadro's Law:    \(\displaystyle{V_1\over n_1} = {V_2\over n_2}\)    (constant P, T)

Gay-Lussac's Law:    \(\displaystyle{P_1\over T_1} = {P_2\over T_2}\)    (constant n, V)

Inflate a Tire Law:    \(\displaystyle{P_1\over n_1} = {P_2\over n_2}\)    (constant V, T)

Nobody Does This Law:    \(n_1T_1 = n_2T_2\)    (constant P, V)

(note that you will be tested on the actual relationships of the physical properties and not the scientist's names)

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and because density (ρ) is m/V and molar mass (M) is m/n, then you also know the molar mass of an ideal gas via:

\[{M={\rho RT\over P}}\]

Dalton's Law of Partial Pressures
\[P_{\rm total}=P_{\rm A} + P_{\rm B} + P_{\rm C} + \cdots\]

mole fraction of gas A:   \(x_{\rm A}=P_{\rm A}/P_{\rm total}\)

Dalton's Law of Partial Pressures: \[P_{\rm total}= P_{\rm A} + P_{\rm B} + P_{\rm C} + \cdots \]

Kinetic Energy of an Ideal Gas: \[E_{\rm k} = {3\over 2} RT\]

Root Mean Squared Speed of particles: \[v_{\rm rms} = \sqrt{3RT\over M}\]

Van der Waal's Equation of State
\[\left(P+a{n^2 \over V^2}\right)(V-nb)=nRT\]

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Practice Problem Sets

Here are two practice problem sets for you to work on and get some experience working through these types of problems.

Composition Stoichiometry Extra Practice.pdf     HTML version

Gas Law Stoichiometry Extra Practice.pdf     HTML version

Sorry, but we do not have any answer keys to all these problem. The HTML version of the Gas Stoich does have answers. Talk with other students about the problems and try to reach a correct conclusion/answer.

There is even MORE great practice problems (with keys) and helpsheets on the gchem site in Chapter 1 there under "Additional Content > Helpsheets and Worksheets". Here's a direct LINK to that page.

Exam protocol All you need to know about HOW to take our in-class exams.