Here are two ICE box equilibrium questions for you:

 

The attached review guide is designed for general chem.  It is good practice, but doesn't cover the higher level concepts

Complete the attachment: Kinetics Review Part I

Complete (as much as possible) the attached file practicing reaction mechanisms.  Also attached here is the "Method of Initial Rates" worksheet we worked on in class last Friday.

Assessment today. Topics include:

You should study your homework from May 12, May 6, May 2, and April 28. 

 

Here is the problem worked on in class on Monday, May 16:

Aluminum metal can be oxidized by hydrochloric acid solution. Determine the minimum volume of 0.75 M HCl required to completely oxidize 1.00 gram of aluminum metal.

Tutoring after school today

This assignment is actually due on the day of the assessment, which has been moved to Wednesday May 19th. 

 

solve the following applied stoichiometry problems:

solve the applied stoichiometry problems:

We are beginning a study of reaction rates (how fast or slow a chemical reaction proceeds, and the factors affecting rate).  For homework, read section 17.1a-c from your textbook and complete questions (1-11) from the Chapter 17 file attached at the right.

Solve the following stoichiometry problems:

1. 24.8 grams of an impure ore containing copper (II) carbonate reacts with excess hydrochloric acid.  13.4 grams of copper (II) chloride are formed in the solution. 
   • write the balanced equation and net ionic equation
   • determine the mass of copper (II) carbonate in the ore sample, and determine the % of copper (II) carbonate in the ore sample.
2. 100.0 mL of a water sample containing the pollutant sodium sulfide (Na₂S) solution is reacted with excess aluminum chloride solution in a precipitation reaction to form solid aluminum sulfide and sodium chloride solution.  The solid aluminum sulfide precipitate was filtered out, dried and its mass was found to be 15.0 grams.  
   
   • Write a balanced equation and net ionic equation, and determine the correct states of matter for the products.
   • Use the mass of the precipitate and balanced equation to calculate the number of moles (instead of mass) of the pollutant (Na₂S).
   • Divide your moles of Na₂S by the volume of the solution to determine the concentration of sodium sulfide in the polluted water sample.

Each of the following reactions shows two solutions reacting and results in the formation of a precipitate in solution.  Use your notes from Wednesday as a guide for writing balanced equations, net ionic equations and models for each reaction (remember that all nitrate salts and alkali metal salts are soluble):

As practice/review of balancing acid-base neutralization reactions, complete the questions from the attached file. 

1. 2.00 grams of NaCl are dissolved in 50.0 ml of water and the temperature drops from 25.0^oC to 22.0^oC.
   • did the water absorb or release heat?
   • calculate the heat energy change (q) for the water.  (mCdeltaT)
   • what is the heat energy change (q) for the dissolving process (for the solution formation)? did the dissolving process absorb or release heat?
   • calculate the heat of solution per mole of NaCl.
   • write a balanced equation for dissolving NaCl
   • write models for the process
   • lastly, write a picture of the lab set up showing the direction of heat flow in the calorimeter.
2. Repeat everything for question #1 but this time for the following chemical reaction:  0.50 grams potassium reacts with 50.0 ml of 1.00 M HCl.  The temperature rises from 25.0^oC to 48.0^oC.  This time determine the heat of solution per mole of potassium (potassium is the limiting reactant).

No Homework tonight :)

 

Use your notes and understanding of weak acid equilibria and weak base equilibria to complete the questions from the attached file.  For each question, make sure you write a balanced chemical equation for the dissociation of the weak acid (or base) in water.

For each of the following, write a balanced acid-base neutralization reaction (remember: acid + base forms a salt + water), and with the quantities given, determine the concentration of the unknown:

Use your lab notes from Thursday March 31 and Monday April 4 to help with these questions.

Read section 16.1 and 16.2 in your text and complete questions 1-24 from the chapter 16 file at the right

• Yes?  good for you :)
• No?  Well now its late; better get started because it is worth points that matter!

• Each lab experiment has a resource article (attachment) which you should read before you begin the experiment, and a lab procedure (additional attachment) which describes the steps to carryout.
• For each of the two labs, when you finish, Write a three paragraph discussion that includes the following:
  • paragraph one (introduction): background information on the topic (which you can get from the resource reading).
  • paragraph two: describe your data and observations from the experiment using formats that are appropriate (words, data tables, charts, pictures, sketches, graphs, etc.).
  • paragraph three (conclusion): draw conclusions about your data and findings.  What does the data suggest/show?  It is very important to draw connections between the introduction and your experimental findings, so talking about the resource article and how it relates to your results is a must.
• Enjoy the experiments.  They are great applications of real world chemistry.  And take a picture of you (and your lab partners if you worked together) with your lab set-up for one extra credit point.
• The assignments are due the day we return from spring break.

For each of the following reactions write balanced equations and balanced net ionic equations.  Also identify the species oxidized and the species reduced in each reaction:

For homework

 

Use your notes to assist you in writing balanced equations, balanced net ionic equations, and models for the following sets of single replacement reactions.  Also, try to determine which species is oxidized (LEO) and which is reduced (GER):

We are beginning our study of chemical changes/chemical reactions.  As a good introduction to this, read sections 7.1 and 7.2 from your textbook and complete questions 1-8 from the Chapter 7 file attached at the right, and read section 8.1 from your textbook on types of chemical reactions and complete questions 1-11 from the Chapter 8 file to the right

 

Review Topics HChem Assessment Solutions spring 2016

• Balanced chemical equations for dissolving (ionic vs. molecular)
• Models to show the dissolving process
• Solubility of solutes in solvents (looking at chemical formulas or models)
o non-polar solutes in non-polar solvents
o polar or ionic solutes in polar solvents
• Entropy and enthalpy changes associated with solution formation
o calorimetry to quantify enthalpy changes
o identifying reactions as exo/endothermic and implications
o practical applications: hot packs. cold packs
• Quantifying solution concentration
o knowing mass of solute and volume solution, determine concentration
o knowing volume and concentration, describe how to prepare solution
o diluting solutions and doing serial dilutions
• Using color of solutions
o explaining why there is color (transition metal d-orbitals or organic molecule highly conjugated pi bonding systems)
o justifying relationship between light absorbance and color
o justifying relationship between light absorbance and concentration
 absorption spectrum
 generating a Beer’s law graph
 determining molar absorptivity constant
 practical applications: identifying unknown concentration from Beer’s Law

For homework, as practice using spectrophotometry, open the link to the PhET Beer's Law simulation (https://phet.colorado.edu/en/simulation/beers-law-lab).  Follow the steps below.  Note that if you are not able to access the program, then just search the internet for absorbance vs concentration data (of copper (II) sulfate or some other transition metal ion salt) to analyze in the manner described in bold print below.

For homework, complete the attached file on making solutions.  Remember, enrichment next Wednesday (7:05 am for extra credit) and assessment next Thursday on solutions.

As a followup to our study of solutions, complete the following questions:

Read section 15.2 and 15.3 and complete questions (21-31) from Chapter 15 file at the right.

 

1. show the equation for dissolving aluminum chloride in water
2. show models for the dissolving of aluminum chloride in water
3. calculate the concentration of a solution made by dissolving 5.00 grams of aluminum chloride in enough distilled water to make 100.0 ml of solution.
4. show the equation for dissolving iron (II) fluoride in water
5. show models for the dissolving of iron (II) fluoride in water
6. calculate the concentration of a solution made by dissolving 4.00 grams of iron (II) chloride in enough distilled water to make 50.0 ml of solution
7. show the equation for dissolving aluminum oxide in water

 

In class we reviewed writing equations and models to describe the dissolving process.  Quantitatively describing solution concentration (in Molarity) was introduced.  For homework, complete the five questions from the attached "Solution Concentration Practice" file.  An additional resource page is included for two of the questions.  You will need a periodic table.  Also note that question #2 and #4 contain polyatomic ions.  Attached is the polyatomic ion resource page.  Recall previously that we said polyatomic ions would be large since they contain two or more atoms.

As a review of calorimetry and specific heat capacity, complete the attached worksheet.  Remember:  q=(m)(C)(deltaT).  In many of the cases in this worksheet you are working with substances other than water.  Specific Heat values are given for those substances.  Also, notice that no substances are changing state, so you need not be concerned with enthalpy of fusion or enthalpy of vaporization.

Read sections 15.1 and 15.2 in your text and complete questions (1-21) from the Chapter 15 file attached at the right.

We are transitioning from pure states of matter to homogeneous mixtures (solutions). For homework, read and outline section 15.1 in your textbook. 

 

There will be an additional assignment to follow. I'll post it on Monday.  Here it is: open the Chemwiki link below and read and outline their discussion on "Solution Types and Energetics," only up through "The Hydrophobic Effect."

 

 

 

Homework is to study for the assessment and complete the review questions worked on in class on Wednesday

Extra Credit Enrichment today (7:05 am); must be on time for extra credit.  Bring your notes, lab work and homework with you.

 

 

Complete the attached file checking your understanding of structures, IMFs, energy and change of state.

Homework comes in two parts.

       2. complete the attached two page worksheet on conceptual aspects of cooling/warming behavior and temperature-vapor pressure relationships.

 

For each of the following questions, do the following:

• Identify whether energy absorbed or released by the system?
• sketch the cooling (or warming) curve and label completely
• calculate the heat energy change

1. 12.0 grams of ice at -15.0^oC is warmed to its melting point and melted completely.
2. 20.0 grams of water at 40.0^oC is cooled to its freezing point, frozen completely and cooled further to -10.0^oC.
3. 15.0 grams of water at 80.0^oC is warmed to its boiling point, boiled completely and warmed further to 115.0^oC.
4. This question involves two changes taking place simultaneously. Determine the mass of ice that can be melted by the heat released as 10.0 grams of steam at 110.0^oC cools to its condensation point and condenses completely.

Read section 14.2 in your text about changing state between liquid and vapor, and complete questions (21-29) from the chapter 14 file at the right.  Also,read section 10.4 and complete questions (25-32) from the chapter 10 file at the right.

The NGSS performance expectation we are currently working on is HSPS 1.3 which asks students to compare observable properties of a substance (like melting/freezing point temperature, state of matter of a substance at room temperature, temperature changes when a substance vaporizes, or even the viscosity of liquids) to the strength of the intermolecular forces of attraction. Through our lab investigations and class discussions we have been looking at molecular structure, intermolecular forces of attraction (IMFs), changes of physical state and energy.  For homework, use any of your notes and lab work to write a concise discussion that shows your clear understanding of the relationships between the topics above.  An effective way to do this is to compare two substances; and include chemical structures and diagrams/graphs to help support your claims.

Read section 14.1B and C from your textbook on energy and change of state for water, and complete questions (11-20) from the Chapter 14 file to the right.  Also read section 10.2 on the flow of energy and cooling/warming behavior, and complete question (13-19) from the Chapter 10 file to the right

Read sections 10.1 through 10.2A in your textbook on energy and energy change.  Complete questions 1-12 from the file attached at the right: "Chapter 10 - Energy."