Physical And Chemical Changes Flashcards
What is matter?
All substances are made up of matter. Anything that has weight and occupies space is called matter.
What is the smallest unit of matter?
Atom is the smallest unit of matter.
How a molecule is formed?
A molecule is formed when two or more atoms are chemically bound together.
What are pure substance?
Pure substances are substances that are made up of only one kind of particles and has a fixed or constant structure.
What are impure substance?
Impure substances are a mixture of different types of atoms or molecules.
Examples of Pure substance.
Elements and compounds are pure substance.
Examples of impure substance.
Salt mixed in water, blood, air etc. are the examples of impure substances.
What are elements?
Substances that consist of only one type of atom and cannot be broken down into simpler substances physically or chemically are known as elements.
What are elements classified into and what are they?
Elements are classified into two board groups: 1. Metals 2. Non-metals.
Give some examples of elements.
There are total 118 elements. Some of them are: Carbon, oxygen, hydrogen, Iron, etc.
What are compounds?
Substances in which two or more elements are combined together chemically in definite proportions are known as Compounds.
What are the examples of Compounds?
Water (H2O), Carbon dioxide (CO2), Sodium chloride (NaCl), Ammonia (NH3), etc. are the examples of Compounds.
What is mixtures? Some examples of mixtures.
Substances in which two or more substances are mixed together physically in no definite proportions are known as mixtures.
Sugar solutions, Air, Salt solution, etc.
How many element are there?
There are total 118 known elements. 94 of them were found naturally from the nature and 24 have been synthesized in the laboratories.
What are Chemical symbols?
The representation of an element using the short form or abbreviation of its name is known as its Chemical symbol.
