What is Matter: -
Mater is defined as anything that has mass and occupies space.
Composition of matter: - matter consist of any one of the following particles. To
Solid state (particles are tightly packed and are held by strong forces)
Liquid state (particles are not held tightly together)
Mater is defined as anything that has mass and occupies space.
Composition of matter: - matter consist of any one of the following particles. To
1. Atoms.
2. Molecules. Or
3. Ions
1. An Atom is the smallest particle of an element that can take part in a chemical reaction.
2. A molecule is the smallest particle of a substance that exist alone and still possess the properties of the substance. E.g H2O, O
3. An Ion is a charged particle, it is formed when an atom loses or gains electrons. E.g Na+, Cl-
QĺRadicals are group of atoms with a single charge. E.g Na+, Cl-, OH-
Matter generally is made up of any one or more of the particles mentioned above.
States of matter
matter can exist in three states.
i. the solid
ii. the liquid and
iii. the gaseous state.
SOLID: - In solids the particles of matter are densely packed and are held by strong forces of attraction (force of cohesion).
Properties of solids
i., solids have fixed, or definite volumes
ii. solids also have fixed shapes.
iii solids cannot be compressed
LIQUIDS: -In liquids the molecules (particles) are close together in an orderly manner with little freedom of movement. Molecules in a liquid are close together but are not held so
rigidly in position and can move past one another.
Properties of Liquids
i. a liquid no fixed or definite shape but it takes the shape of its container,
ii. liquids have a fixed or definite volume
iii. liquids cannot be compressed.
GAS: - In a gas, the particles/molecules are separated by distances that are large compared with the size of the molecules.
Properties of gases
i.; gasses have no fixed or definite volume (will occupy entire volume of its container)
ii. gases have no fixed shape.
iii. gases can be compressed
Gases differ from liquids and solids in the distances between their individual particles.
Gases (particles of gases are wide apart)
The three states of matter can be inter-convertible without changing the composition of the substance. Upon heating, a solid it will change into a liquid form at a particular temperature.
The temperature at which this transition occurs is called the melting point of the solid. Further heating will convert the liquid into a gas at a particular temperature called the boiling point of the liquid. Cooling a gas on the other hand, will cause it to change into a liquid, this process is called Condensation. When the liquid is cooled further, it will change into the solid form and the process is known as Freezing.
Some solids change directly to the gaseous without passing through the liquid state and vice Versal. These processes are both known Sublimation and Deposition.
Changes in the state of Matter
Now remember we defined chemistry as the study of the composition, properties and the uses of mater as well as the principle that underlies the changes that matter undergoes, and so far, we are told that mater consist of one or any two of atoms, molecules or ions. now the properties of matter can be divided into two, that is, physical properties and chemical properties.
PROPERTIES OF MATTER
The properties of matter can be grouped into two
i. Physical properties are those properties that a substance (matter) shows by itself (i.e those properties that you see when you look at, touch or smell the substance) these include Temperature, Pressure, Colour, Smell, Density, Solubility, Melting and boiling points.
ii. Chemical properties on the other hand are those properties that matter exhibits when it comes in contact with other substances like acids, bases, even water to form new substances.
Physical and Chemical change
A physical change is one that is easily reversible and in which no new substance is formed.
example of physical changes is.
i. Dissolving sodium chloride in water
ii. Changing water to ice
iii. Evaporation of liquids
iv. Melting of candle wax
A chemical change is one which is not easily reversible and in which a new substance is always formed.
example of changes is.
i. burning of wood, paper, or clothe.
ii. rusting of iron when exposed to air and moisture.
iii. decomposition of organic matter.
iv. dissolving a metal like calcium or magnesium in dilute acids.
v. the hardening of cement when exposed to air.
OBJECTIVE QUESTIONS
1. Which of the following is a physical change
a). Dissolving sugar on water
b). Addition of acid to base
c). Burñing of wood
d). Rusting of iron
2.
THEORY QUESTIONS
1(i). State two differences between the properties of solids and gasses
(ii). What process does each of X, Y and Z represent in the changes shown below?
2.
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