chem

Question 1

Chemistry

Answer 1

Chemistry is the branch of science that deals with properties, structure, preparation and reactions of material substances

Question 2

Importance of chemistry

Answer 2

In industries, agriculture, medicine

Question 3

The use of chemistry in diff sectors

Answer 3

It provides a method to isolate life saving drugs as well as synthesize them
it establishes industries that provide utility goods
it helps provide a method to manufacture pesticides, fertilizers, alkali , acids etc.

Question 4

Matter

Answer 4

Matter is anything and everything that occupies space and has mass

Question 5

Classification of matter

Answer 5

Matter is classified into pure substances and mixtures

Question 6

Mixtures

Answer 6

contains particles of 2 or more pure substances that are present in any ratio
their composition is variable
the pure substances forming a mixture are called components

Question 7

Homogeneous

Answer 7

they are the mixtures where components are mixed thoroughly/ completely
the components are uniformly distributed throughout the mixture and composition is uniform

Question 8

Heterogeneous

Answer 8

they are mixtures where the components have not dissolved completely
the composition is not uniform throughout the mixture and sometimes different components are visible

Question 9

Pure substances

Answer 9

their characters differ from that of mixtures they consist of constituent particles of fixed composition

Question 10

Elements

Answer 10

The particles of elements consist only one type of atom
these particles may exist as atoms or molecules

Question 11

Compounds

Answer 11

They consist of atoms of different elements in a definite ratio

Question 12

Properties of matter and its measurement

Answer 12

each substance has a unique property
physical (MP, BP, density, odor, color)
chemical (composition, combustibility, reactivity )

Question 13

measurement

Answer 13

Physical properties can be measured without changing the composition
Fr measuring chemical properties a chemical change needs to occur

Chemists describe and interpret a substance only by the basic knowledge of their chemical and physical properties and can be determined by careful measurement and experimentation

Question 14

Measurement of physical properties

Answer 14

Quantitative measurement of properties is required for chemical investigation
Any kind of quantitative measurement is represented by a number followed by a unit which it is measured in
Earlier two methods were there the English and the metric system
The metric system was originated in France
in late 18th century

Question 15

International system of units

Answer 15

It was established by a 11th general conference on weights and measures (GCPM)
The GCPM is an inter governmental treaty that was created by a diplomatic treaty called the meter convention signed in Paris 1875

Question 16

SI unit

Answer 16

The SI unit has 7 basic units, the units pertain 7 fundamental scientific quantities
The physical quantities like volume, density, speed can be derived from these basic quantities
the SI units allow the use of prefixes to indicate multiple or submultiples of a unit