New User Special Price Expires in

Let's log you in.

Sign in with Facebook


Don't have a StudySoup account? Create one here!


Create a StudySoup account

Be part of our community, it's free to join!

Sign up with Facebook


Create your account
By creating an account you agree to StudySoup's terms and conditions and privacy policy

Already have a StudySoup account? Login here

Stoichiometry of Chemical Reactions

by: Caitrín Hall

Stoichiometry of Chemical Reactions CHEM 1127Q 001

Marketplace > University of Connecticut > Chemistry > CHEM 1127Q 001 > Stoichiometry of Chemical Reactions
Caitrín Hall
GPA 3.9

Preview These Notes for FREE

Get a free preview of these Notes, just enter your email below.

Unlock Preview
Unlock Preview

Preview these materials now for free

Why put in your email? Get access to more of this material and other relevant free materials for your school

View Preview

About this Document

These notes outline chapter 4 of the textbook.
General Chemistry
Fatma Selampinar (TC), Joseph Depasquale (PI)
Class Notes
Chemistry, outline, stoichiometry
25 ?




Popular in General Chemistry

Popular in Chemistry

This 6 page Class Notes was uploaded by Caitrín Hall on Tuesday March 8, 2016. The Class Notes belongs to CHEM 1127Q 001 at University of Connecticut taught by Fatma Selampinar (TC), Joseph Depasquale (PI) in Spring 2016. Since its upload, it has received 18 views. For similar materials see General Chemistry in Chemistry at University of Connecticut.


Reviews for Stoichiometry of Chemical Reactions


Report this Material


What is Karma?


Karma is the currency of StudySoup.

You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!

Date Created: 03/08/16
Chapter 4:  Stoichiometry of Chemical  Reactions  4.1 Writing and Balancing Chemical Equations  Chemical equation – symbolic representation of a chemical reaction 1. The substances undergoing reaction are called reactants, and their formulas are placed on the left side of the equation 2. The substances generated by the reaction are called products, and their formulas are placed on the right side of the equation 3. Plus signs separate individual reactant and product formulas, and an arrow separates the reactant and product sides of the equation 4. The relative numbers of reactant and product species are represented by coefficients (numbers placed immediately to the left of each formula); it is common to use the smallest possible whole-number coefficients Balancing Equations  Balanced – equal numbers of atoms for each element involved in the reaction are represented on the reactant and product sides H2O ⟶ H +2O (u2balanced) 2H2O ⟶ 2H + 2 (ba2anced) Additional Information in Chemical Equations  Physical states of reactants and products are indicated with a parenthetical abbreviation following the formulas; (s), (l), (g), (aq) Equations for Ionic Reactions  Molecular equation – doesn’t explicitly represent the ionic species that are present in the solution CaCl (aq) + 2AgNO (aq) ⟶ Ca(NO ) (aq) + 2AgCl(s) 2 3 3 2  Complete ionic equation – explicitly represents all dissolved ions 2+ − + − 2+ − Ca (aq) + 2Cl (aq) + 2Ag (aq) + 23O (aq) ⟶ Ca (aq) + 2NO3 (aq) + 2AgCl(s)  Spectator ions – presence is required to maintain charge neutrality but are not chemically nor physically changed by the process  Net ionic equation – complete ionic equation MINUS spectator ions Cl (aq) + Ag (aq) ⟶ AgCl(s) 4.2 Classifying Chemical Reactions  Precipitation Reactions and Solubility Rules  Precipitation reaction – dissolved substances react to form one or more solid products; many involve exchange of ions between ionic compounds in aq. solution (referred to as double displacement, double replacement, or metathesis reactions)  Solubility – the extent to which a substance may be dissolved in a solvent  Soluble substances have relatively large solubility  Insoluble substances have relatively low solubility  A substance will precipitate when concentration exceeds solubility in a solution Acid-Base Reactions  An acid-base reaction is one in which a hydrogen ion is transferred from one chemical species to another o Acid – any substance that will dissolve in water to yield hydronium + ions, H3O HCl(aq) + H O(aq) ⟶ Cl (aq) + H O (aq) 2 3  Strong acids completely react in water  Weak acids partially react with water  generate small + amount of H3O ions o Base – a substance that will dissolve in water to yield hydroxide ions, OH-  Commonly compounds composed of alkali or alkaline earth metal cations combined with hydroxide  Strong bases completely dissociate in water NaOH(s) ⟶ Na (aq) + OH (aq)−  Weak bases react partially to yield hydroxide ions NH (aq) + H O(l) ⇌ NH + (aq) + OH (aq) 3 2 4  Neutralization reaction – acid-base reaction in which the reactants are an acid and a base, while the products are often and salt and water (neither reactant is water) acid + base ⟶ salt + water Oxidation-Reduction Reactions  Oxidation = loss of electrons = increase in oxidation number  Reduction = gain of electrons = decrease in oxidation number 2Na(s) + Cl (g) ⟶ 2NaCl(s) 2  It helps to separate the reaction into 2 half-reactions 2Na(s) ⟶ 2Na (s) + 2e − − − C2 (g) + 2e ⟶ 2Cl (s) o Here, the sodium is a reducing agent (reductant)—usually metals—that that is oxidized, while chlorine is an oxidizing agent (oxidant)—usually nonmetals) that is reduced  Oxidation number – the charge an element’s atoms would possess if the compound was ionic o The oxidation # of an atom in elemental form is zero o The oxidation # of a monatomic ion = ion’s charge o Oxidation numbers for common nonmetals:  Hydrogen: +1 when combined with nonmetals, −1 when combined with metals  Oxygen: −2 in most compounds, sometimes −1, very rarely -1/2, positive values when combined with F  Halogens: -1 for F, -1 for other halogens except when combined with oxygen or other halogens (then they are varying positive #s) o The sum of oxidation numbers for all atoms in a molecule or polyatomic ion equals the charge on the molecule or ion  Subclasses of redox reactions o Combustion – the reductant, or fuel, and oxidant, usually oxygen, react vigorously and produce significant amounts of heat, and often light, in the form of a flame o Single-displacement (replacement) reactions – redox reactions in which an ion in solution is displaced by the oxidation of a metal Zn(s) + 2HCl(aq) ⟶ ZnCl (aq)2+ H (g) 2 Balancing Redox Reactions via the Half-Reaction Method 1. Write the two half­reactions 2. Balance all elements except oxygen and hydrogen 3. Balance oxygen atoms by adding H O2molecules +  4. Balance hydroge  atoms by adding H ions 5. Balance charge by adding electrons 6. If necessary, multiply each half­reaction’s coefficients by the smallest possible  integers to yield equal numbers of electrons in each 7. Add the balanced half­reactions together and simplify by removing species that  appear on both sides of the equation 8. For reactions occurring in basic media (excess hydroxide ions), carry out these  additional steps:  −  +  o Add OH ions to both sides of the equation to equal the number of H ions o On the side of the equation containing both H and OH ions, combine  these ions to yield water o Remove any redundant water molecules    9. Check to see that both the number of atoms and the total charges are balanced 4.3 Reaction Stoichiometry  Stoichiometry – relationships between the amounts of reactants and products of a chemical reaction  Used to determine the amount of one reactant required to react with a given amount of another reactant or to yield a given amount of product  Stoichiometric factor – ratio of coefficients in a balanced chemical equation, used in computations relating amounts of reactants and products  Example problem: How many carbon dioxide molecules are produced when 0.75 mol of propane is combusted according to this equation? C H +5O ⟶3CO +4H O 3 8 2 2 2 4.4 Reaction Yields   Limiting reactant – the reactant present in an amount lower than required by the reaction stoichiometry, thus limiting the amount of product generated  Excess reactant – the reactant present in an amount greater than required by the reaction stoichiometry Percent yield – the extent to which a reaction’s theoretical yield is achieved  Theoretical yield – the amount of product that may be produced by a reaction under specified conditions  Actual yield – the amount of product obtained in practice Percent yield = (actual yield/theoretical yield) x 100% 4.5 Quantitative Chemical Analysis  Quantitative analysis – the determination of the amount or concentration of a substance Titration  Buret – device used to make incremental additions of a solution  Titration analysis – quantitative chemical analysis method that involves measuring the volume of a reactant solution required to completely react with the analyte—substance whose concentration must be measured  Titrant – substance whose concentration is known  Equivalence point – volume of titrant solution required to react completely with the analyte; provides a stoichiometric amount of titrant for the sample’s analyte according to the titration reaction o Indicators are added to solutions to impart a change in color at or near EQ o Other indicator: distinct change in appearance (i.e. halt of bubble formation)  End point – the volume of titrant actually measured; theoretically equal to EQ point Gravimetric analysis – quantitative analysis in which a sample is subjected to some treatment that causes a change in the physical state of the analyte that permits its separation from the other components  Mass measurement of a component of the analysis system & known stoichiometric amounts of compounds involved  calculation of analyte concentration  Required change of state may be achieved by physical and chemical processes o Often the analyte is subjected to a precipitation reaction  precipitate is isolated  mass of precipitate is used to calculate analyte concentration  Combustion analysis – gravimetric method of analysis in which the weighed sample of a compound is heated to a high temperature under a stream of oxygen gas, resulting in complete combustion to yield gaseous products of known identities


Buy Material

Are you sure you want to buy this material for

25 Karma

Buy Material

BOOM! Enjoy Your Free Notes!

We've added these Notes to your profile, click here to view them now.


You're already Subscribed!

Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'

Why people love StudySoup

Bentley McCaw University of Florida

"I was shooting for a perfect 4.0 GPA this semester. Having StudySoup as a study aid was critical to helping me achieve my goal...and I nailed it!"

Allison Fischer University of Alabama

"I signed up to be an Elite Notetaker with 2 of my sorority sisters this semester. We just posted our notes weekly and were each making over $600 per month. I LOVE StudySoup!"

Jim McGreen Ohio University

"Knowing I can count on the Elite Notetaker in my class allows me to focus on what the professor is saying instead of just scribbling notes the whole time and falling behind."


"Their 'Elite Notetakers' are making over $1,200/month in sales by creating high quality content that helps their classmates in a time of need."

Become an Elite Notetaker and start selling your notes online!

Refund Policy


All subscriptions to StudySoup are paid in full at the time of subscribing. To change your credit card information or to cancel your subscription, go to "Edit Settings". All credit card information will be available there. If you should decide to cancel your subscription, it will continue to be valid until the next payment period, as all payments for the current period were made in advance. For special circumstances, please email


StudySoup has more than 1 million course-specific study resources to help students study smarter. If you’re having trouble finding what you’re looking for, our customer support team can help you find what you need! Feel free to contact them here:

Recurring Subscriptions: If you have canceled your recurring subscription on the day of renewal and have not downloaded any documents, you may request a refund by submitting an email to

Satisfaction Guarantee: If you’re not satisfied with your subscription, you can contact us for further help. Contact must be made within 3 business days of your subscription purchase and your refund request will be subject for review.

Please Note: Refunds can never be provided more than 30 days after the initial purchase date regardless of your activity on the site.