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The size of these particles is very small compared to the distance between the particles

The collisions between particles and the walls of the container do not change the kinetic energy of the system

The temperature of a gas is a measure of the average kinetic energy of the particles

From these assumptions we can define the pressure and temperature of any gas.PressureThe pressure of a gas is a measure of the number of collisions of the gas particles with each other and with the sides of the container that they are in.Video: 23VSTemperatureThe temperature of a substance is a measure of the average kinetic energy of the particles.If the gas is heated (i.e

the temperature increases), the average kinetic energy of the gas particles will increase and if the temperature is decreased, the average kinetic energy of the particles decreases

If the energy of the particles decreases significantly, the gas liquefies (becomes a liquid).One of the assumptions of the kinetic theory of gases is that all particles have a different speed

For an ideal gas we assume that all particles in the gas have the same speed.So for an ideal gas we can simply talk about the speed of particles

But for a real gas we must use the average speed of all the particles.Video: 23VT

In grade 10 you learnt how to calculate the molar concentration of a solution

The molar concentration of a solution is the number of moles of solute per litre of solvent ()

This is more commonly given as moles of solute per cubic decimetre of solution ().To calculate concentration we use , where is the molar concentration, is the number of moles and is the volume of the solution.Calculating molar concentrations is useful to determine how much solute we need to add to a given volume of solvent in order to make a standard solution.A standard solution is a solution in which the concentration is known to a high degree of precision

When we work with standard solutions we can take the concentration to be constant.When you are busy with these calculations, you will need to remember the following:===, therefore dividing a volume in by will give you the equivalent volume in

How much sodium chloride (in g) will one need to prepare of a standard solution with a concentration of

The volume must be converted to : To find the mass of we need the molar mass of

We can get this from the periodic table (recall from grade 10 how to calculate the molar mass of a compound).The mass of sodium chloride needed is We will now look at another use of concentration which is for titration calculations.TitrationsA titration is a technique for determining the concentration of an unknown solution

Acid-base reactions and redox reactions are both commonly used for titrations.In grade 10 you did a simple acid-base titration

Now we will look at how to calculate the concentration of an unknown solution using an acid-base titration.When performing a titration we say that the substance of unknown concentration is titrated with the standard solution

A pipette is a measuring device that is used to measure an exact amount of a liquid

If you use a pipette to add liquid to a flask then you would say that the liquid was pipetted into a flask.We can reduce the number of calculations that we have to do in titration calculations by using the following: The and are the stoichiometric coefficients of compounds A and B respectively

It was found that of the sodium hydroxide was needed to neutralise the acid

Using an acid-base titration, it was found that of this solution was able to completely neutralise of a sodium hydroxide solution

First convert the volume into :Then calculate the number of moles of sulfuric acid:Now we can calculate the concentration of the sulfuric acid:Remember that only or of the sulfuric acid solution is used.Exercise 8.2See solutions Acetylene () burns in oxygen according to the following reaction: If of acetylene gas is burnt, what volume of carbon dioxide will be produced

We first work out what mass of magnesium chloride is needed to make a solution with a concentration of

It was found that of the nitric acid was needed to neutralise the base

Write down all the information you know about the reaction, and make sure that the equation is balanced

It was found that of the phosphoric acid was needed to neutralise the base

Write down all the information you know about the reaction, and make sure that the equation is balanced

of this solution is then pipetted into a conical flask and titrated with hydrochloric acid

It is found that of the hydrochloric acid completely neutralises the antacid solution

Remember that only or of the calcium carbonate solution is used

This chapter builds on the work covered in electrostatics in grade 10

Learners should be familiar with the two types of charges and with simple calculations of amount of charge

The following list summarises the topics covered in this chapter.Coulomb's law In this part of the topic learners are introduced to Coulomb's law

This is an inverse square law and has a similar form to Newton's law of Universal Gravitation

Electric fields The concept of an electric field is introduced in this part of the chapter

Learners will see how to draw the electric field lines for different configurations of charges and will learn how to determine the magnitude of the electric field

Learners will also learn how to calculate the electric field at a point due to a number of point charges

In this chapter you will learn exactly how to determine this force and about a basic law of electrostatics.Ratio and proportion - Physical Sciences, Grade 10, Science skillsEquations - Mathematics, Grade 10, Equations and inequalitiesUnits and unit conversions - Physical Sciences, Grade 10, Science skillsScientific notation - Physical Sciences, Grade 10, Science skills

This chapter takes the ideas of magnetism and the ideas of electricity and combines them into one

The following list summarises the topics covered in this chapter.Magnetic fields are associated with current carrying wires The idea that magnetism and electricity are linked is introduced

The concept of a magnetic field around a current carrying wire is explored and a simple method to determine the direction of the magnetic field is explained

Faraday's law Faraday's law relates the emf produced to the magnetic flux around a loop of conductor

The concept of electromagnetic induction is introduced and some simple calculations using Faraday's law are shown

Electromagnetism describes the interaction between charges, currents and the electric and magnetic fields to which they give rise

An electric current creates a magnetic field and a changing magnetic field will create a flow of charge

This has resulted in the invention of many devices which are useful to humans, for example cellular telephones, microwave ovens, radios, televisions and many more.

The study of electrical circuits is essential to understand the technology that uses electricity in the real-world

We depend on electricity and electrical appliances to make many things possible in our daily lives

This becomes very clear when there is a power failure and we can't use the kettle to boil water for tea or coffee, can't use the stove or oven to cook dinner, can't charge our cellphone batteries, watch TV, or use electric lights.Units and unit conversions - Physical Sciences, Grade 10, Science skillsEquations - Mathematics, Grade 10, Equations and inequalitiesGraphs - Mathematics, Grade 10, Functions and graphs

When a chemical reaction occurs, bonds in the reactants break, while new bonds form in the product

Hydrogen reacts with oxygen to form water, according to the following equation:In this reaction, the bond between the two hydrogen atoms in the molecule will break, as will the bond between the oxygen atoms in the molecule

New bonds will form between the two hydrogen atoms and the single oxygen atom in the water molecule that is formed as the product.For bonds to break, energy must be absorbed

The energy that is needed to break a bond is called the bond energy or bond dissociation energy

Bond energies are measured in units of .Bond energy Bond energy is a measure of bond strength in a chemical bond

It is the amount of energy (in ) that is needed to break the chemical bond between two atoms

Remember when we discussed bonding (chapter 3) we used the following energy diagram:We can use this diagram to understand why bond breaking requires energy and bond making releases energy

When a bond breaks, the atoms move apart and the distance between them increases (i.e

the atom moves to the right on the -axis or from point X to point A)

Looking at the diagram we see that when this happens, the energy increases (i.e

the energy at point A is greater than the energy at point X)

So when a bond breaks energy is needed.When a bond forms the atoms move closer together and the distance between them decreases (i.e

the atom moves to the left on the -axis or from point A to point X)

Looking at the diagram we see that when this happens, the energy decreases (i.e

the energy at point X is less than the energy at point A)

So when a bond forms energy is released.Looking at the example of hydrogen reacting with oxygen to form water:We see that energy is needed to break the bonds in the hydrogen molecule and to break the bonds in the oxygen molecule)

And we also see that energy is released when hydrogen and oxygen bond to form water)

When we look at the entire reaction and consider both bond breaking and bond forming we need to look at the enthalpy of the system.Enthalpy Enthalpy is a measure of the total energy of a chemical system for a given pressure, and is given the symbol H

A chemical system is a closed system that contains only the reactants and products involved in the reaction.As we learn about exothermic and endothermic reactions we will see more on the concept of enthalpy.

Up to now you have looked at reactions as starting with the reactants and going to the products

For acids and bases we also need to consider what happens if we swop the reactants and the products around

And that when (the base) gains a proton it forms (the acid)

In your own words explain what is meant by the term conjugate acid-base pair

A conjugate acid-base pair is a reactant and product pair that is transformed into each other through the loss or gain of a proton

So for example an acid loses a proton to form a base

The acid and the resulting base are said to be a conjugate acid-base pair

This chapter looks at the lithosphere and explores mining in more detail

Mining is very important in South Africa as a large part of the economy depends on gold, diamond and coal mining

This chapter looks at the history of mankind, what the lithosphere is, what is in the lithosphere and then goes on to look at mining

The general techniques used across all types of mining are looked at and then gold mining is explored in greater detail

Learners can do the mining section as a project (either in groups or individually) that they then present to the class

If learners do a project ensure that each mineral listed in CAPs (iron, phosphate, coal, diamond, copper, platinum, zinc, chrome, asbestos, manganese and gold) is covered by at least one learner in the class.This topic provides a great opportunity to look at social justice and economic concerns

The various class discussions and debates provided give learners the chance to think about some critical issues in South Africa.In Grade 10 we studied the elements

We learnt about the different elements and the compounds that could be formed from those elements

Where did mankind find them and how has he used them?This chapter will explore the part of the Earth known as the lithosphere

We will find out what the lithosphere is and how the elements are distributed within it.

In Grade 10 we studied motion but not what caused the motion, in Grade 11 we learnt about forces and how they can alter the motion of an object

In this chapter we will focus on what happens when two bodies undergo a contact interaction and how their motion is affected

We are introduced to two new concepts, momentum and impulse.We can begin by considering some scenarios to set the context

Most people have some intuition for physics based on their everyday experiences but they haven't formalised it

We can use our intuitive answers to lead into more structured thinking about physical events.Momentum transfer doesn't require a contact interaction but we won't consider any non-contact scenarios in this chapter.Everyone has experienced a mosquito landing on their arm and it can happen quite unnoticed

Consider the case of a falcon landing on your arm (ignore the sharp claws for now)

Would you still notice if the mosquito flew the same way as a falcon, or if the falcon copied the flight of a mosquito before landing

You probably would still notice, but try to think about what makes them so different.Look at a motorcycle, motorcar and truck

Which of them is more likely to result in less damage in a collision situation, why

What factors would you change to reduce potential damage.Why is the Moon's orbit largely unaffected when it is hit by asteroid?The factors that come up in these considerations are how fast things are moving and how massive they are

A falcon moving at the same speed as a mosquito still has a much larger mass

Even if a mosquito moved as fast as a falcon it wouldn't bother us because the mass of a mosquito is so small.If a motorcycle, motorcar and truck were all moving at the same speed then it would be much safer to be in a collision with the motorcycle but a truck doesn't have to be moving as fast as a motorcycle to have a huge impact in a collision because of its large mass.There is an interplay between mass and speed (velocity to be precise) that governs what would happen if these objects came into contact with another object

There are two quantities that depend on mass and velocity, kinetic energy and momentum

Momentum is different to kinetic energy and is what we will focus on in the first part of this chapter

In the second part we will cover some of the differences between kinetic energy and momentum.Units and unit conversions - Physical Sciences, Grade 10, Science skillsEquations - Mathematics, Grade 10, Equations and inequalitiesTechniques of vector addition - Physical Sciences, Grade 10, Vectors and scalarsNewton's laws - Physical Sciences, Grade 11, ForcesThe following must be covered by the end of this chapter:Momentum:The definition of momentum.The calculations done on momentum using p = mv and the change in momentum under the influence of a resultant force.The understanding of the vector nature of momentum and the applications concerning momentum.Representing momentum using vector diagrams.Newton's second law expressed in terms of momentum:State Newton's second law in terms of momentum.Expression of Newton's second law in terms of symbols.Emphasis on the vector nature of momentumThe relationship between the net force and change in momentum for a variety of motions by using different examples.Do calculations on the change in momentum when a resultant force acts on an object to change the velocity.Conservation of momentum:Definition of :A systemInternal forcesExternal forcesIsolated systemState the law of conservation of momentum.Explain the difference between elastic and inelastic collisions by using the concept of kinetic energy before and after a collision.Do calculations on the principle of conservation of momentum.Do practical demonstrations on the principle of conservation of momentum.Applications of the principle of conservation of momentum.Impulse:Definition of impulse.The understanding of the vector nature of impulse.The change in momentum and impulse are equal to each other (impulse-momentum theorem).Calculations done by using the impulse-momentum theorem.Units and unit conversions - Physical Sciences, Grade 10, Science skillsEquations - Mathematics, Grade 10, Equations and inequalitiesTechniques of vector addition - Physical Sciences, Grade 10, Vectors and scalarsNewton's laws - Physical Sciences, Grade 11, Forces