THE EFFECT OF TEMPERATURE ON REACTION RATES

In a certain reaction, the reactants need an amount of energy, because their molecular energy is low, but the activation energy is high.
This type of reaction named as endotermic reaction (remember the concept of thermochemistry)
To achieve the best collision, you have to heat the reactants in order to increase the the molecular energy till the same as the activation energy. At that point, the reaction will occur.

COLLISION THEORY

According to the picture, why the first collision can make the reactants react one of another, and the second picture, there is a cross; its means that the reactants cannot react.

Is the position of collision very important point?

Is there any other reason to make the reactants react?

The third and the fourth pictures are impossible for reactants to react.

Why the position of molecules determines the best collision?

THE EFFECT OF PRESSURE ON DIFFERENT REACTIONS

Use this illustration for comparing reaction rates in different pressure.
For the above picture, both reactants are gases.
You can give an example to make clear your explanation.
After comparing gases, please compare the second picture.
In this reaction, one reactant is a solid. What happens with the rate in this condition? Give an example, becareful think about the properties of solid reactant.

THE EFFECT OF CONCENTRATION ON REACTION RATE

Hallo students, what do you think ab
out reaction rates?
This topic is simple, isn't it?
Okay, the first picture illustrates the reaction between particles in the solution. Water is as a solvent.
The second reaction is a reaction between solid and solution.
Firstly discuss the effect of concentration on reaction rate.
Secondly describe the effect of concentration of a solution when reacts with a solid reactant

TEMPERATURE AND COLLISION THEORY

Please think that the change of temperature can affect the rate of reaction as shown in both pictures. By using collision theory, explain that A particles collide with B particles. It would be better if you make a plan first, than explain step by step clearly.
Becareful, this factor is temperature rather than concentration.

After make a conclusion, compare all the factors you have learnt and make a general conclusion by bringing all the factors.

FACTOR AFFECTING RATE OF REACTION

Look at both pictures. Compare these picture, explain which factor affects the rate of reaction?
Make a plan first, than write the data. Discuss your data and come to the conclusion, relate with your hypothesis. Don't forget to explain the variables.
Try to use collision theory in explaing the process.

Explain the equipments needed in this experiment.
Write a complete report.

CONCENTRATION AFFECTS RATE OF REACTION

Okay students, now if you use HCl(aq) 3 M, what will happen with the rate of reaction when you compare this with the same mass of marble chips in HCl(aq) 1 M? Which one is faster? Explain the reason.
Is that because of the more H+ ions in the solution? What do the H+ ions act during the reaction?
After explaining this process, please think about another factor affecting rate of reaction by using this reaction.

PLANNING AN EXPERIMENT

This picture ilustrates the reaction between marble chips, CaCO3(s) and an acid, for example HCl(aq). The big red circles are acid molecules and the small red circles are H+(aq) and Cl-(aq).
1. Write down the molecular equation of this reaction. Write a complete equation.
2. Write the ionic equation.
3. If you double or triple the concentration of acid, what will happen with the reaction? Is the process will faster of slower than the first?
4. Make a plan to observe the rate of reaction if you manipulate the concentration of the acid.

HESS' LAW TASK

Hallo students, now you have to develop your understanding about Hess' law. Hess' law states about the summation of reaction, to sum the enthalpy change of step reactions in finding the enthalpy change of target reaction.

This diagram is an energy level diagram or named as an enthalpy diagram.

Look at the diagram, then write the step reactions and the target reaction. Okay, please do right now.

ENTHALPY DIAGRAMS

Write the thermochemistry equation for the forward and reverse reactions. What does the difference between these equations?


The following is another enthalpy diagram as another example to make you understand.

Write thermochemistry equation of the reaction as shown in the second diagram and describe the equation.

Make a conclusion for your explanation above.

ENTHALPY CHANGE

This diagram shows enthalpy changes.

Why the first arrow tell us that the enthalpy change of reaction is A --> B; and why the second arrow, the enthalpy change is proposed for the reverse reaction, B --> A.

Make a description to explain this evidence by using examples.

DETERMINING ENTHALPY CHANGE

Explain this picture clearly. Look at the calorimeter, there is a metal in the water.
Suggest the metal used in this reaction, find an experimental data and then determine the enthalpy change in kJ/mol.

CALORIMETRY TASK

This is a simple picture of calorimeter. This equipment used in the chemistry laboratory for estimating an enthalpy change in a reaction.
Your task is explaining the use of this equipment, plan an experiment by using this equipment. Choose a certain reaction, for example neutralisation reaction between strong acid, HCl(aq) and strong base, NaOH(aq).
Your explanation including how to use termometer; why there is a difference between the experimental data from scientist and your result.

GEOMETRY OF WATER

After you learnt molecular geometry of methane and ammonia, make paragraphs to explain geometry of water, including comparison of water with methane and ammonia.

Please explain both pictures. For the first picture, explain according to the order of the picture. Similarly, explain the second picture.
Don't forget to compare geometry of the 3 compounds. For doing this, you can draw all the 3 compounds.

RADIUS OF ATOMS AND IONS

Hallo everybody, this moment we discuss about radius of atoms and ions.

Your task is finding keywords rather than writing paragraphs. Look at the picture, why does the radius of cation is smaller than its atom? Okay, this is a clue for you. To find keywords, you have to make questions, answer these questions. Ask something by using the words what, how, and why. Then from your answers, hopefully you can find a lot of keywords. Don't forget to think about electron configurations, inner shell, outer shell, orbitals, valence electrons, the position of elements in the periodic table, ionisation energy, etc. Use the value of atomic and ionic radii.

PERIODIC PROPERTIES TASK

Now focus your writing on the periodic properties as shown in the diagram.
Please use your logical thinking in doing this. Firstly what do you want to explain; secondly ...; and what will you do next. Then finally ....
If you don't know the order, its okay, just explain one by one; and then please think about the relationship between the properties you have explained. Think about cause and effect; so you will realise which one come first.
The paragraphs you have to write is about 250 words. Is it okay?

ELECTRONEGATIVITY TASK

This is another periodic property of elements in the periodic table.
What is the meaning of electronegativity?
Why the arrow of increasing electronegativity is different with increasing atomic radius?
So your task is, write paragraphs about 2oo words to clarify these periodic properties of elements. Don't forget to include explanation which element is the most electropositive one and which element is most electronegative. What the effect of these properties are.

MOLECULAR SHAPES TASK

To predict molecular shape, the VSEPR theory (Valence Shells Electron Pairs Repulsion) can help us. Use balloon for simple prediction of molecular shapes.
Make 3 dimension shapes, if possible use different balloon for different atom. Firstly you can make a linear shape. Please give an example of each shape. For example : hydrogen molecule, H2 is linear. Make a table to show each molecule has certain shape. Complete your table with Lewis structure, determine bonding pair (BP) and lone pair (LP) electrons. Firstly think about symmetrical shapes, then unsymmetrical shapes. Mention about their molecular polarities, polar or non polar molecules.

WATER COVALENT BONDING TASK

This is another example of polar covalent bond. Write an explanation text about 150 words, around 3 - 4 paragraphs.

You have to choose the best sentences which have a full meaning and short. Don't make it to long, because you will loose the relationship between concepts.

The paragraphs move from general to the specific concepts, from concreate to abstract theories.
Please try, you have to develop your writing step by step gradually, OK? So do it.

POLAR COVALENT BONDING TASK

Students, develop your thinking to the next bonding, that is polar covalent, as seen in the picture.
Before explaining this bond, firstly distinguish between polar and non polar covalent bonds. It is about polarity of bonding. The bond of H2 and Cl2 are different with the bond of HCl. The first are molecules of elements, on the other hand, the last is a molecular compound.
In writing the paragraphs, mention about electronegativity, the position of bonding electron pair (BP) between H - Cl, and the effect of this BP.