The study of properties of matter and their measurement is an important aspect of the science that relates to the field of chemistry as well as physics. The properties of matter include mass, volume, temperature, and density all these help us to understand the physical behavior of the substance. The matter was first ever explored by Aristotle who proposed the existence of the fundamental elements of life earth, water, air, and fire.
JEE Main 2025: Chemistry Formula | Study Materials | High Scoring Topics | Preparation Guide
JEE Main 2025: Syllabus | Sample Papers | Mock Tests | PYQs | Study Plan 100 Days
NEET 2025: Syllabus | High Scoring Topics | PYQs
The father of modern chemistry Antoine Lavoisier made his important contribution to the law of conservation of masses and developed the systematic method for the naming of chemical substances. Thereafter After lot of scientists discovered the different measuring techniques of physical substances over some time. The measurement is very important as it gives the quantitative idea of how to interpret the data or helps in predicting the nature of matters. By doing all these studies scientists make precise measurements Which are better to understand such physical properties. These discoveries continue to the 19th and 20th centuries for understanding measurement on a more advanced level.
Every substance has unique or characteristic properties. These properties can be classified into two categories – physical properties and chemical properties.
Physical properties are those properties that can be measured or observed without changing the identity or the composition of the substance.
Some examples of physical properties are color, odor, melting point, boiling point, density, etc.
The measurement or observation of chemical properties requires a chemical change to occur. Examples of chemical properties are characteristic reactions of different substances; these include acidity or basicity, combustibility, etc.
Many properties of matter such as length, area, volume, etc. are quantitative in nature. Any quantitative observation or measurement is represented by a number followed by units in which it is measured. For example, the length of a room can be represented as 6 m; here 6 is the number and m denotes meter – the unit in which the length is measured.
The SI system has seven base units and they are listed in Table 1.1. These units pertain to the seven fundamental scientific quantities. The other physical quantities such as speed, volume, density, etc. can be derived from these quantities.
The mass of a substance is the amount of matter present in it while weight is the force exerted by gravity on an object. The mass of a substance is constant whereas its weight may vary from one place to another due to changes in gravity. You should be careful in using these terms.
Volume has the units of (length)3. So in the SI system, the volume has units of m3. But again, in chemistry laboratories, smaller volumes are used. Hence, the volume is often denoted in cm3 or dm3 units.
A common unit, litre (L) which is not an SI unit, is used for measurement of the volume of liquids.
1 L = 1000 mL , 1000 cm3 = 1 dm3 . In the laboratory, the volume of liquids or solutions can be measured by a graduated cylinder, burette, pipette, etc. A volumetric flask is used to prepare a known volume of a solution.
The density of a substance is its amount of mass per unit volume. So SI units of density can be obtained as follows:
S.I unit of density $=\frac{\text { S.I unit of mass }}{\text { S.I unit of volume }}=\frac{\mathrm{kg}}{\mathrm{m}^3}$
This unit is quite large and chemists often express density in g cm-3. where mass is expressed in grams and volume is expressed in cm-3.
There are three common scales to measure temperature oC (degree Celsius), oF (degree Fahrenheit), and K (Kelvin). Here, K is the SI unit. The thermometers are based on these scales. Generally, the thermometer with the Celsius scale is calibrated from 0o to 100o where these two temperatures are the freezing point and the boiling point of water respectively. The Fahrenheit scale is represented between 32o to 212o.
The temperatures on the Fahrenheit and degree Celcius scales are related to each other by the following relationship:
oF = (9/5)(oC) + 32
The Kelvin scale is related to the Celsius scale as follows :
K = oC + 273.15
It is interesting to note that the temperature below 0 °C (i.e. negative values) are possible in the Celsius and Fahrenheit scales but on the Kelvin scale, a negative temperature is not possible.
Example.1
1.S.I unit of luminous intensity is:
1)Mole
2)Ampere
3) (correct)Candela
4)Metre
Solution
Candela is the S.I. unit of luminous intensity.
Hence, the answer is the option (3).
Example.2
2. Chromium is added to steel to impart strength and shine. If the density of chromium is 5.24g/cm3 then the expression in S.I. unit (kg/m3) is:
1) (correct) 5240
2) 5.24
3) 0.524
4) 52400
Solution
1kg = 1000g and 1m3 = 106cm3 5.24 g/cm3 = (5.24 x 10-3 Kg)/10-6m3 = 5240 Kg/m3.
Hence, the answer is the option (1).
Example.3
The density of a certain metal is $10.5 \mathrm{~g} / \mathrm{cm}^3$. If a cube of this metal weighs 630g, what is the length of one side of the cube?
1)3 cm
2) (correct)4 cm
3)5 cm
4)6 cm
Solution
The volume of the cube is equal to the length of one side cubed. Therefore, the volume of the cube is $(4 \mathrm{~cm})^3=64 \mathrm{~cm}^3$. Since the density of the metal is $10.5 \mathrm{~g} / \mathrm{cm}^3$, the mass of the cube can be calculated as $10.5 \mathrm{~g} / \mathrm{cm}^3 \times 64 \mathrm{~cm}^3=672 \mathrm{~g}$. But we know that the actual weight of the cube is 630 g. So, we can calculate the actual volume of the cube. Thus, the length of one side of the cube is $\sqrt[3]{60 \mathrm{~cm}^3} \approx 4 \mathrm{~cm}$
Hence, the answer is the option (2).
Example.4
Assertion: Water boils at a higher temperature at higher altitudes.
Reasoning: Atmospheric pressure decreases with an increase in altitude.
1) (correct)Both assertion and reasoning are true, and reasoning is the correct explanation of the assertion.
2)Both assertion and reasoning are true, but reasoning is not the correct explanation of the assertion.
3)Assertion is true, but reasoning is false.
4)Assertion is false, but reasoning is true.
Solution
At higher altitudes, the atmospheric pressure decreases. As a result, the boiling point of water decreases because the pressure on the liquid decreases, and it requires less energy to change into vapor. This is the reason why water boils at a higher temperature at higher altitudes, both the assertion and reasoning are true, and reasoning is the correct explanation of the assertion.
Hence, the answer is the option (1).
Example.5
5. Which of the following gases have the highest average velocity at the same temperature?
1) (correct)Hydrogen (H2)
2)Oxygen (O2)
3)Nitrogen (N2)
4)Argon (Ar)
Solution
According to Graham's law of diffusion, the rate of diffusion of a gas is inversely proportional to the square root of its molar mass. This means that at the same temperature, lighter gases will have higher average velocities compared to heavier gases. The molar mass of hydrogen (H2) is the lowest among the given options, so it will have the highest average velocity at the same temperature.
Hence, the answer is the option (1).
Matter is anything that occupies space and has mass means all the physical things we see around us are matter from solids to liquid and gaseous. This means that matter is something that has volume, density, and mass as well. So all the qualities are the property of the matter and can be expressed in the form of units. It also has several benefits in the fields of industries and technology, medicine, environmental monitoring, Engineering and construction, Education, and communication.
18 Nov'24 02:27 PM
18 Nov'24 10:33 AM
18 Nov'24 10:00 AM
18 Oct'24 11:04 AM
18 Oct'24 10:57 AM
18 Oct'24 10:52 AM
18 Oct'24 10:27 AM