Notes from Mondays class

5.1 Changes in Matter and Energy

Thermochemistry – The study of the energy changes that accompany physical or chemical changes in matter.

-energy can be transferred or converted onto other forms.

Eg:

The Energy of the Universe is ________________

Heat and energy Changes (p298)

What energy changes are involved in lighting a match?

In this example we can define:

Chemical system:

Surroundings:

Types:

Heat (Q) -

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Temperature (T) –

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Calorimetry: Measuring Energy Change (p300)

q = m c D T

specific heat capacity: quantity of heat needed to raise the temperature of a gram by 1 °C

ice: 2.0 J/(g°C)

Water: 4.18 J/(g°C)

Steam: 2.01 J/(g°C)

Aluminum: 0.900 J/(g°C)

Calculating Quantity of Heat (q)

When 600mL of water in an electric kettle is heated from 20°C to 100°C how much heat flows into the water:

Heat Transfer and Enthalpy Change (p302)

In any system there are Kinetic and Potential energies

Enthalpy (H) – total internal energy of a substance at a constant pressure.

Scientist have not found a way to measure the sum of all these energies

We study the changes in enthalpy (DH): the difference in enthalpies of reactants and products during a change.

-enthalpy change is equal to the change of energy to the surrounding

- energy is either added or removed from the surroundings

Types of enthalpy change:

Endothermic change –

Exothermic Change –

Ex: In a calorimetry experiment 7.46 g of potassium is dissolved in 100mL of water at an initial temperature of 24.1°C. The final temperature of the solution is 20.0°C. What is the molar enthalpy of solution of potassium chloride?

Representing Exothermic Reactions (5.3)

Method 1: use a thermochemical equation- balanced chemical equation that indicates the amount of heat released

H2(g) + 1/2 O2(g) ® H2O(l) + 285.8kJ .

Method 2: thermochemical with DH values

H2(g) + 1/2 O2(g) ® H2O(l) DH rxn = -285.8 kJ

Method 3: Molar Enthalpies

: The energy change associated with the reaction of one mole of a substance. Measured at SATP

DH°_f = -285.8 kJ/mol H2O(l)

Other types:

Method 4: Enthalpy diagram

Stoichiometry and Thermochemical Equations

Ex. Aluminum reacts readily with chlorine gas to produce aluminum chloride. The reaction is highly exothermic.

2 Al(s) + 3Cl2(g) ® 2AlCl3(s) DHo = -1408kJ

a) What is the enthalpy change for 1 mole AlCl3?

b) What is the enthalpy change when 1.00 kg of Al reacts with excess Cl2?

Pre-Lab 2: Kinetics

SCH4U

Pre-lab 2: Kinetics (Molar Enthalpy of Solution)

Background:

Physical and chemical changes always involve an exchange of energy. Nearly all of the time, that energy exchange has a component called HEAT. We can measure the amount of heat given off or taken in by a chemical reaction by measuring the temperature change in the surroundings. This is called CALORIMETRY. Today, you will be measuring the heat given off or taken up by the dissolution of sodium hydroxide (NaOH) in water.

For your pre-lab introduction section:

1. Write out the equation of what is occurring in the system (NaOH dissolving in water).
2. Describe some real life examples of when enthalpies are important to you.
3. Predict what you think you will observe based on the procedure below.
4. Solve the following: If 5 g of NaOH_(s) dissolves in 300 mL of water and the temperature rises from 25 to 35 ^◦C, what is the molar enthalpy of solution of NaOH in water and what is your % error based on the information above?

Procedure:

0. Wear safety goggles at all times!

1. Measure 100 mL of water into one Styrofoam cup. Record the exact volume.
2. Cut the rim off another cup so that it will nestle inside the first when inverted (with no spaces for heat to enter or escape).
3. Punch a hole in bottom of the second cup and insert a thermometer inside. DO NOT use the thermometer to punch this hole! Place the second cup with thermometer inside the first so that the thermometer is reading the temperature of the water. Record the temperature.
4. Measure out 3 g of NaOH. Record the exact mass.
5. Lift off the second cup and add the NaOH to the bottom cup. Immediately replace the top (with thermometer. Record the maximum or minimum temperature reached. Carefully swirl the two cups while measuring.

Analysis questions: (to be completed after the lab)

1. Calculate the molar enthalpy of solution of NaOH in water.
2. Calculate your % error.
3. What assumptions are we making in this experiment?
4. What sources of error are there in this experiment and how would each effect your result (overshoot or undershoot of the molar enthalpy of solution)?
5. Write the reaction you have performed using four of the different methods you’ve studied.

Some Info on Formal Lab Reports

Formal Report Guide

Title: At the beginning of your report, write the title of your investigation. The title should describe the experiment. Include the date the report is submitted and the names of all lab partners.

Introduction: The introduction is a series of paragraphs that address the theories, principles, equations and overall relevance of every scientific aspect referred to in the report. The introduction provides the reader with all the necessary information to understand what you did, why you did it and the overall impact of your investigation on current scientific understanding. Remember to cite your information. Do not discuss your observations, analysis or conclusions.

Hypothesis: This is the question that you will attempt to answer in the investigation. If it is appropriate to do so, state the question in terms of independent and dependent variables. Based on the information addressed in the introduction section, formulate a tentative explanation for what should happen (a hypothesis). Create your hypothesis before you conduct the investigation.


Materials: This is a detailed list of all materials used, including sizes and quantities where appropriate. Draw a diagram to show any complicated setup of apparatus. Do not use a reference to the textbook as the materials section is a list of only the materials used in your investigation.

Procedure: Describe, in detailed and numbered steps, the procedure you followed in carrying out your investigation. Include steps for proper disposal of wastes. Do not use a reference to the textbook.

Observations: Include all qualitative and quantitative observations that you made. Be as precise as appropriate; include any unexpected observations; and present your information in a form that is easily understood (ie: chart or graph). Do not analyze or explain the observations, just record exactly what you observed.

Analysis: Interpret your observations and present the evidence (in the form of tables, graphs, or illustrations is appropriate). Include any calculations (the results of which can be shown in a table). Make statements about any patterns or trends you observed. If questions are available from the text, use these as a guide, but do not simply answer the question sequentially. Conclude the analysis with a short statement, based only on the evidence you have gathered, answering the question/hypothesis that initiated the investigation.

Conclusion: The conclusion is an extension of the theory section, discussing the overall relevance of what was concluded from your investigation. If questions are available from the text, use these as a guide to formulate a conclusion, but do not simply answer the question sequentially. You should also evaluate the experimental design and the validity of the data you gathered for your analysis. Use statistics (ie: average values, % difference, % yield, etc) to strengthen your argument.

References: Include a work cited page based on the format addressed in the Scientific Citation rules available on the course website

This is the lab rubric i will be using to mark your Labs

http://teachers.colonelby.com/jcheeseman/SCH4U%20Laboratory%20Report%20Rubric.doc

Part 1 organic questions

Unit 2: Organic Chemistry

PART 1 CHAPTER 1


1.1 Functional Groups 10 #1-4, #1-3
1.2 Hydro Carbon pg 15 #1-2, pg 18 #3-6, pg 21 #7-8 pg 22 # 1-4
1.3 reactions , pg 27 #1-3, pg 30 # 4-7 ,pg 31 #1-4
1.4 Organic Halides , pg 33 #1-2, pg 35 #3-5, pg 37 #6
1.5 Alcohols Ethers pg 41 #1-3, pg 42 #4-5, pg 44 #7-9, pg 46 #11, pg 48 #12-13, #1-7
1.6 Aldehyde and ketones pg 51 #1-5
1.7 Carboxylic Acids and Esters pg 56 #6-8, pg 57 # 1-5, pg 60 #1-2, pg 63 # 3-7, pg 66 # 11-12, pg 67 # 13-14, pg 68 #1-4
1.8 Amides , pg 72 #1-3, pg 76 #4-6, pg 77 #7, pg 78 #8-10


For each class of compounds above, we will learn:

1. How to name them and what they look like (Structure and Nomenclature)
2. Common names used and common uses to which they are put
3. Chemical and Physical properties
4. How to make them (Synthesis) and how they react (Reactivity)

Notes

this is the web page that I get the class notes for organic.

http://fc.gecdsb.on.ca/~earl/4u/ORunitplan.htm

Welcome

welcome to the Merivale Night School Chemistry blogg. I will be posting note and stuff.