What is Matter?

In the universe, there is matter, energy, and void space. The universe contains energy and void space. The definition of matter can be considered as something which possesses mass and consumes space. Chemistry is that branch of science which deals with the study of matter. Under chemistry, nature, composition, and the changes occurring to matter are discussed.

Matter

Matter can change from one form to another. This change can be both chemical and physical. In a chemical change the characteristic properties of the starting matter change and it becomes different from of matter at the end. Chemical reactions are examples for this chemical change. The combustion of propane is an example, where propane and oxygen change to carbon dioxide and water. All matter has Chemical properties and physical properties. Chemical properties are defined as the properties which change the chemical characteristics of matter. On the other hand, physical changes do not involve changes in the basic chemical characteristics of a matter. It involves only a change in the state of the matter. Liquids changing to gas and solids changing to liquids are all examples of this. More precisely water can exist as a liquid, gas (vapor state), and solid (ice). In all these three states the chemical composition of the water remains the same, only the physical state changes. 

States of matter:

• Solid: It has a definite shape and definite mass. Solid do not have the ability to flow. The components that make up the solids are very much close to each other and there is not much gap between them. Hence, solids are hard.
• Liquid: It has a definite mass but no fixed shape. It tends to take the shape of the vessel in which it is kept. Liquids have the ability to flow. The components that make up the liquids are far from each other as compared to solids.
• Gas: It does not have any fixed shape. Gas can only be contained in a closed container. For example, balloon, when balloons are filled with gas, the gas inside takes the shape of the balloon but if the end of the balloon is not tied, the gas escapes. Gases have the ability to flow. The components that make up gases are very far from each other, compared to both solids and liquids.

The transformation of matter from one state to another is thus a physical change that does not involve any chemical changes.  Another kind of physical change can be observed when the mixing of matter takes place for instance, when sugar is dissolved in water.  The physical properties of matter include density, color, odor, melting point, boiling point, viscosity, solubility and so on.  Thus, a physical change in the matter can alter any of the above physical properties of matter.

Measurement 

A measurement should contain two parts. First part of measurement is the numerical part which contains a number. The second part of measurement is the unit part which contains the appropriate unit. A measurement without both the two parts is blank data that cannot be used for calculations as well as assumptions. For example, if the weight of a person is given as 57. This measurement only contains the number part, there is no unit. With the unit we cannot figure out whether it is 57 kilogram or 57 pounds or 57 grams thus we cannot use it for any calculations and from this we cannot make any assumptions. For instance, if it is 57 kilograms, we can make assumptions like this weight probability belongs to an adult or this weight is does not belong to a baby. Without the unit, we are not able to make any assumptions.

Thus, for better communication, a number with the unit can only be considered as a measurement. Measurements can be considered scientific notations. While expressing a measurement scientifically the rules of significant figures must be followed. The use of significant figures will increase the accuracy of a measurement.

In different regions of the world different unit systems are there.  The conversion from one unit to another is possible, for instance, in the United States of America, the units are pounds for weight, miles for distance, gallons for volume, and so on is used. A person from a different country may not easily understand these units. Different countries or regions followed their local standards for regular use. This created a lot of confusion in the scientific society.  Thus, a need for an international standardization for the unit system arose.

About 1960, the International System of Units was introduced to global logical associations (contracted SI). The SI uses a portion of the metric units and is based on the decimal scale. The main difference is that the SI is more restrictive: It makes the use of certain metric units more difficult while favoring others. While the SI has advantages over the more developed decimal system, it also brings major burdens. As a result, American physicists have been slow to accept it.

Forms of measurement and SI units

Some of the measurements and SI units were given which include thermal units, electrical units, and so on. Other units (non-SI units) were also used to measure these forms of measurement. Conversion of one unit to another will make these units equivalent. 

• Length-meter
• Volume-Cubic meter
• Mass-Kilograms
• Time-Seconds
• Temperature-Kelvin (degree Celsius is another common unit)
• Force-Newton
• Electric charge-Coulomb
• Torque-Newton meters
• Electrical resistance-Ohm
• Electric potential/Potential difference/Voltage-Volt
• Density- grams per cubic centimeter
• Power-Watt (which is equivalent to joule per second)

Context and Applications   

This topic is significant in the professional exams for both undergraduate and graduate courses, especially for  

• Bachelors in Chemistry and Physics
• Masters in Chemistry and Physics.