Introduction:
Chemistry is that the branch of science that deals with the composition, structure and properties of matter.
Matter
Anything which has mass and occupies space is thought as matter.
as an example: Air, water, table, pencil, etc.Matter can exist in three physical states viz. solid, liquid and gas.
classification of matter, states of matter
Classification of Matter:
On the premise of chemical composition of assorted substances matter is classified as follows:
classification of matter, varieties of mixture,
1. Homogeneous mixture: Uniform composition of constituent particles.
2.Heterogeneous mixture: Nonuniform composition of constituent particles.
Elements:Simplest variety of pure substance, which may neither be decomposed into nor built from simpler substances by ordinary physical and chemical methods.
Contains just one quite atoms.
For example: Hydrogen, Oxyen, Nitrogen, etc.
Compounds:A variety of matter formed by combining two or more elements in an exceedingly definite ratio by mass.
Can be decomposed into its constituent elements by suitable chemical methods
For example: H2O, O2, NO2, etc.
Properties of Matter and Their Measurement
Properties of matter is classified into two categories:
Physical properties: These are the properties which may be measured or observed without changing the identity or the composition of the substance. as an example: Mass, size, colour, odour, freezing point, boiling point, density etc.
Chemical properties: These are the properties which may be measured by bringing a activity within the state or identity of a substance. as an example: Acidity, basicity, combustibility etc.
Basic physical quantities and their SI units:Mass:
It is the quantity of matter present in an exceedingly substance.
It is a relentless quantity.
Its SI unit is kilogram (Kg).
Weight:
It is the force exerted by gravity on an object.
It varies from one place to a different thanks to change in gravity.
Its SI unit is Newton.
Volume:
It is the degree of space occupied by a substance.
Its SI unit is metric capacity unit (m)3.
Another common unit is litre (L). 1 cubic metre = 1000 Liters (1 m3 = 1000L)
1 L = 1000 mL, 1000 cm3 = 1 dm3
Density:
It is the quantity of mass per unit volume.
Its SI unit is kilogram per cubic metre (kg/m3)
Another common unit is gram per cubic metre (g/cm3).
Temperature:
It is the degree of warmth present in an exceedingly substance.
Its SI unit is Kelvin (K)
Another common units are: C (°C) and degree Fahrenheit (°F)
units for temperature, relation between units of temperature
Uncertainties in Measurement
Scientific Notation
Numbers are represented in N × 10n form.
Where,
N = Digit term
n = exponent having positive or negative value.
Examples,
12540000 = 1.254 × 107
0.00456 = 4.56 ×10-3
Precision
It refers to the closeness of outcomes of various measurements taken for the identical quantity
Accuracy
It refers to the agreement of a selected value to actuality value of the result.
Significant Figures
To express a measurement accurately, it must be represented by the digits that are known with certainty. These are called as Significant figures.
Rules for determining the numerous figures:
All non-zero digits are significant. For example, 3.14 has three significant figures.
Zeroes preceding the primary non-zero digit don't seem to be significant. For example, 0.004 has one digit.
Zeroes between two non-zero digits are significant. For example, 6.002 has four significant figures.
Zeroes at the top of variety are significant once they are on the correct side of the mathematical notation. For example, 14.0 has three significant figures.
Counting numbers of objects have infinite significant figures.
Calculations Involving Significant Figures
1. Addition & Subtraction
In addition or subtraction, the ultimate result should be reported to the identical number of decimal places as that of the term with the smallest amount number of decimal places.
For example:
significant figures for addition subtraction
2. Multiplication & Division
In multiplication and division, the result should be reported to the identical number of great figures because the term with least number of great figures.
For example:
significant figures for multiplication and division
Rounding Off the Numerical Results
While limiting the result to the specified number of great figures, the amount of great figures is reduced. For this:
The last digit retained is increased by 1, if the subsequent digit is ≥ 5.
For example: 25.468 is written as 25.5
And, 489.654 is written as 489.7
The last digit retained is written as if digit is ≤ 4. For example: 12.93 can be written as 12.9
Chemistry is that the branch of science that deals with the composition, structure and properties of matter.
Matter
Anything which has mass and occupies space is thought as matter.
as an example: Air, water, table, pencil, etc.Matter can exist in three physical states viz. solid, liquid and gas.
classification of matter, states of matter
Classification of Matter:
On the premise of chemical composition of assorted substances matter is classified as follows:
classification of matter, varieties of mixture,
1. Homogeneous mixture: Uniform composition of constituent particles.
2.Heterogeneous mixture: Nonuniform composition of constituent particles.
Elements:Simplest variety of pure substance, which may neither be decomposed into nor built from simpler substances by ordinary physical and chemical methods.
Contains just one quite atoms.
For example: Hydrogen, Oxyen, Nitrogen, etc.
Compounds:A variety of matter formed by combining two or more elements in an exceedingly definite ratio by mass.
Can be decomposed into its constituent elements by suitable chemical methods
For example: H2O, O2, NO2, etc.
Properties of Matter and Their Measurement
Properties of matter is classified into two categories:
Physical properties: These are the properties which may be measured or observed without changing the identity or the composition of the substance. as an example: Mass, size, colour, odour, freezing point, boiling point, density etc.
Chemical properties: These are the properties which may be measured by bringing a activity within the state or identity of a substance. as an example: Acidity, basicity, combustibility etc.
Basic physical quantities and their SI units:Mass:
It is the quantity of matter present in an exceedingly substance.
It is a relentless quantity.
Its SI unit is kilogram (Kg).
Weight:
It is the force exerted by gravity on an object.
It varies from one place to a different thanks to change in gravity.
Its SI unit is Newton.
Volume:
It is the degree of space occupied by a substance.
Its SI unit is metric capacity unit (m)3.
Another common unit is litre (L). 1 cubic metre = 1000 Liters (1 m3 = 1000L)
1 L = 1000 mL, 1000 cm3 = 1 dm3
Density:
It is the quantity of mass per unit volume.
Its SI unit is kilogram per cubic metre (kg/m3)
Another common unit is gram per cubic metre (g/cm3).
Temperature:
It is the degree of warmth present in an exceedingly substance.
Its SI unit is Kelvin (K)
Another common units are: C (°C) and degree Fahrenheit (°F)
units for temperature, relation between units of temperature
Uncertainties in Measurement
Scientific Notation
Numbers are represented in N × 10n form.
Where,
N = Digit term
n = exponent having positive or negative value.
Examples,
12540000 = 1.254 × 107
0.00456 = 4.56 ×10-3
Precision
It refers to the closeness of outcomes of various measurements taken for the identical quantity
Accuracy
It refers to the agreement of a selected value to actuality value of the result.
Significant Figures
To express a measurement accurately, it must be represented by the digits that are known with certainty. These are called as Significant figures.
Rules for determining the numerous figures:
All non-zero digits are significant. For example, 3.14 has three significant figures.
Zeroes preceding the primary non-zero digit don't seem to be significant. For example, 0.004 has one digit.
Zeroes between two non-zero digits are significant. For example, 6.002 has four significant figures.
Zeroes at the top of variety are significant once they are on the correct side of the mathematical notation. For example, 14.0 has three significant figures.
Counting numbers of objects have infinite significant figures.
Calculations Involving Significant Figures
1. Addition & Subtraction
In addition or subtraction, the ultimate result should be reported to the identical number of decimal places as that of the term with the smallest amount number of decimal places.
For example:
significant figures for addition subtraction
2. Multiplication & Division
In multiplication and division, the result should be reported to the identical number of great figures because the term with least number of great figures.
For example:
significant figures for multiplication and division
Rounding Off the Numerical Results
While limiting the result to the specified number of great figures, the amount of great figures is reduced. For this:
The last digit retained is increased by 1, if the subsequent digit is ≥ 5.
For example: 25.468 is written as 25.5
And, 489.654 is written as 489.7
The last digit retained is written as if digit is ≤ 4. For example: 12.93 can be written as 12.9
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