Matter

In previous section 'Introduction', we have defined chemistry as a branch of science which deals with the matter, its properties, reactions etc. Today, we are talking about matter. What is this matter which makes up the chemistry? Well, this matter is everything around you, the chair, the computer, the keyboard, the books, the trees, and all such objects are called matter in science. After looking at such objects, what do you observe? You can find two characteristics same about these objects which are; (i) they have mass and (ii) they occupy space. Mass means the stuff stored in matter. Mass and weight are two different topics which will not be discussed in this tutorial. Therefore everything which have mass and occupy space (have volume) is called matter. Is water matter? Yes it is matter because it has both characteristics i.e. it has mass as well as volume (occupies space). Gases are also matter because they have mass and volume. Thus, it can be concluded that everything around us is consist of matter.

Matter exists in three states; (i) solid (ii) liquid and (iii) gas.  These three states are also known as phases of matter. These states have both characteristics of matter but differ in physical form. From example solid is hard and rigid (e.g. book etc.), liquid is fluid i.e. they can flow (e.g. water and oil etc.) and gases are shape less (e.g. air.)

   
  The states of matter can be changed by various facts such as by heating or pressurizing. For example ice is a form of water in solid state. When its temperature rises above the freezing point then it changes its form to water in liquid state. When the temperature of water (liquid) is heated to melting point then it changes to steam which is also a form of water in gaseous state. In doing so the chemical properties are not changed. One molecule* of water is composed of two atoms** of hydrogen and one atom of oxygen. This chemical composition does not change whether the water is in solid or liquid or gaseous phase (state).

We will discuss in detail about these states in the sub-sequent tutorial in the section ‘Matter’.

Two other states have been discovered. They can exist in extreme condition. These two phases will not b discussed here.

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molecule* and atom** will be described in the sub-sequent tutorials.

7 Ways to study chemistry effectively.

Chemistry is difficult subject. If you want to study it effectively, you need a better plan. Well there is no any magical way which can make chemistry easier for you. It can be learnt if practised regularly. It is too much time consuming subject, so you need to study it in a regular way with an effective plan. Here are some ways which you can use in making learning plan.

Learn chemistry in a cumulative way

Chemistry has many topics. Topic 1 leads to the topic 2 and topic 2 leads to the topic 3 and so on. If you did not study topic 2 then you would find difficult to understand the topic 3.  Never leave any topic because it helps you to understand the next topic.

Attend class/lectures

Attending lectures makes your understanding better. It gives you some ideas which improve your knowledge. You can ask question from teacher. Do not hesitate in doing so.

Read the chapter before it is discussed in the class

Pre-reading of the chapter gives you more ideas and understanding of the teacher. It makes your mind to produce more questions which get cleared in the lecture. It is useful for improving your chemical (chemistry)  knowledge.

Use time management strategies

As chemistry is time consuming subject, you need to manage your time well. Do not procrastinate any work related to it.  Use some time saving strategies. For example if you are confused in any topic, you can discuss it with your teacher. It will just take 5-10 minutes but can save your an hour.

Make a study group with your friends

Make a group of your friends who are interested in chemistry. Collaborative learning can solve many problems and improve your knowledge.

Re-read the chapter

Reread the chapter, marking important sections. These sections should be marked in a such a way which you think to be read after the exams. Do not mark the section in the first reading. Do it in second reading because you would have better understood the chapter at this time.

Take a break after clearing a concept

It is useful to take a break after clearing a concept. During this break you can ask yourself whether you have cleared the topic or something missing from mind which is written on the book.

Derivation of units

The SI system provides us seven base units but these seven units cannot describe all kinds of measurements. Some measurement quantities are quite small and some are very large. For describing measurement which cannot be described from seven base units, scientist have created a new way of deriving units which can describe such measurements. For example meter is too small to describe the length of earth from sun. Similarly litre ( 1 litre is 1/1000 m³) is too big to describe the  size of a tear drop. These aspects can be described from derived units. In this tutorial we will learn about two ways of deriving units.

1. Derivation from base units

2. Derivation form metric prefixes

Let us learn these two ways step wise.

Derivation from base units

Many units have been derived from base units. For example; unit of area, density, speed, volume etc. We will take one of them to illustrate you as an example.

Derivation of unit of area and volume

Unit of area is derived from unit of length. For finding area of a rectangular plane, we need to multiply its length and breadth.

A  = l x b

        = m x m

   = m²

Where 'A' is area 'l' is length and breadth is 'b'. As SI unit of length is meter (m), the unit become 'm²'. Similarly for volume's unit become m^3. Here is the table which shows some derived units.

Type of measurement	Name of the derived unit	Symbol
area	square meter	m2
volume	cubic meter	m3
speed	meter per second	m/s
acceleration	meter per second squared	m/s2
density	kilogram per meter cubed	kg/m3

Derivation from metric prefixes

The other way of deriving SI units is using metric prefixes. This is a way to represent very small or large number using metric prefixes . For example; kilometre means 1000 m in the base unit form. This value is derived from the prefix kilo which means 10³ ( 10 x 10 x 10). These prefixes help us to describe large or small quantities easily. It is better to say distance of earth form moon is 384,703 km rather than 384, 403, 000 m. Similarly the size of a typical hair is 0.000003 metres. We can represent it in metric prefixes as 3µm. ('µ' is Greek letter 'mu'. Its  name is micro and value is 10^-6)
See the below table of metric prefixes.

Prefixes	Abbreviations	Value
tera	T	1 000 000 000 000 or 1012
giga	G	1 000 000 000 or 109
mega	M	1 000 000 or 106
kilo	k	1 000 or 103
hecto	h	100 or 102
deca	da	10  or 101
none	none	1
deci	d	0.1 or 10-1
centi	c	0.01 or 10-2
milli	m	0.001 or 10-3
micro	µ	0.000 001 or 10-6
nano	n	0.000 000 001 or  10-9
pico	p	0.000 000 000 001 or  10-12

Scientific Notaion

Scientific notation is a way of expressing very large or small numbers in a contracted form. Numbers like 1500000000 or 0.0000000061 are inconvenient to use. The first number is quite lager to memorize while second number is  quite small to memorize. They can be made convenient to use by writing them in scientific notation as;

1.5 x 10^9
6.1 x 10^-9

Let's learn the art of writing large or small measurements in scientific notation

Parts of scientific notation

Scientific notation has three parts. You can see them in the given figure.

Value of coefficient is equal to or greater than it but its value cannot be increased after 10.
Base is always 10.
Exponent is the power of base i.e. 10 which can raise it according to its quantity.

Tips to remember while writing measurement in scientific notation

Tip #1. If the given measurement is greater than one, the power of ten is positive.

Tip #2. If the given measurement is small than one, the power of ten is negative.

 How to write the numbers in scientific notation

Example 1:- The distance from earth to  sun is 150,000,000 km away from sun. Express  it in scientific notation.

Solution

Here coefficient is 1.5

Power of ten is 8.

As the number is greater than one,
the exponential term is positive here.

1.5 x 10⁸ km

Example 2 :- Size of an typical bacteria is 0.0000064 m. Express the notation in standard form (scientific notation).

Here coefficient is 6.4

Power of 10 is  -6

Exponential power is negative because the given notation is smaller than one.

6.4 x 10^-6 m

Measurement and units

Measurement is an important part of life as well as science. In day to day life we use measurement for various purposes. When we go to a tailor, we describe length and width of cloth using a meter tape. A green-grocer uses weights for weighing vegetables and fruits and gives us our wanted quantity of them. A doctor needs a  thermometer to know the temperature of body of a patient and he advises the patient medical remedies. Similarly in chemistry, measurement has a great importance. In fact in chemistry it needs to be precise and accurate.For making pesticides and insecticides methyl bromide should be mixed with a great accuracy. If it is mixed more than its need, then it will destroy ozone layer. So measurement must be precise and accurate when reported. Let's begin with our topic.

Measurement and its unit

Measurement means comparison of physical quantity with some standard quantity. Standard quantity is an unit which has definite meaning. For example if the length of cloth is 5 m then it means 1m length can be placed fives times to the cloth. Here '5' is the quantity while 'm' (metre) is the unit. Similarly if vegetables' weight is 2 kg then it means vegetables weigh 2 times the 1 kg standard weight. Without unit, measurement is meaning less. So, unit must be mentioned with the quantity of measurement. For example 400 m race is meaningful rather than 400 race.

SI System

Suppose all nations would have their own measuring system then how difficult it would have been become for scientist s to conduct their researches and observation to scientists belonging to other nations. Therefore a need arose for such a measuring system which should be accepted globally. SI System is such a system invented by French in 1960. It has seven base units from which other units have been derived. Let's see them form table 2.1.

Measurement of :-	Name of unit	Abbreviation
Length	meter	m
Mass	kilogram	kg
Time	second	s
Temperature	kelvin	K
Amount of substance	mole	mol
Electric current	ampere	A
Luminous intensity	candela	cd

From these seven base units chemist often need only four of them. Below are some guidelines for writing the names and symbols of units.

1. Units named after a scientist's name always start with a small letter. For example SI unit of temperature is written as 'kelvin' not 'Kelvin'.
2. Symbol of units named after scientists are always written with a capital letter for example symbol of kelvin is 'K'.
3. Symbols and name of units which are not named after scientist's name are always written with small letter. For example; meter = m, kilogram= kg etc.
4. Symbol of units can not be written in plural form. For example '5 kg' is correct while '5 kgs' is wrong.
5. Full stop is not used with abbreviations of units. For example length of cloth is 5 m and width is 2m. (Note:- Full stop is used with the '2 m.' in the example due to grammatical rule.)

What is chemistry?

It's human nature to wonder. In day to day life you came across many things which make you to wonder. For example when you get up in the morning. Your mother would be preparing tea. You wonder when water boils it changes to vapours and when tea leaves are added to it then its colour changes to black. Your mother adds sugar to it to make it sweet while the tea is bitter itself. How sugar makes it sweet? All these questions can be answered by a chemist easily. In this tutorial we will discuss; what is chemistry and what makes it interesting.

Chemistry is not an easy subject. But don't worry you are at right place which can make it simple and interesting. In science it is defined as a branch of it which deals with the matter, its properties, structure, reactivity and behaviour. When you will join my blog, you will find it too much easy and interesting to learn. Before you learn, you must clear its bases first.

Chemists do not just answer question but do a lot more. Industrial chemists are developing many improved eco- friendly materials for aero planes, cars and daily item. Pharmaceutical chemists are developing many new medicines for curing diseases like cancer, diabetes etc. Biochemist helps understanding the role of chemistry in organisms.

Earlier we had said that chemistry is not an easy subject. Because chemistry has number of topics which are easy when learnt in cumulative way. Topic 1 leads to the topic 2 which help in understanding the topic 3 and so on. So, if you want to make chemistry easy then join this exclusive blog today and learn its entire topics one by one in an easier way.