(B) Answer the following questions in one word:
1) Name the method used to separate stones from grains.
2) Name the change in which no new substance is formed.
(C) Classify the following into fast or slow changes:
(rusting of iron, growth of a tree)
Q III (A) Define the following terms:
1) Sedimentation
2) Chemical change
3) Saturated solution
(B) Give scientific reasons:
1) Alum is used in loading.
2) A metal rim is slightly smaller than a wooden wheel on which it is to be fixed.
Q IV Write a short note on: Threshing
Q V Answer the following questions in detail:
Answers
Answer:
1.picking
2.physical change
3.rusting of an iron
4.Sedimentation is the tendency for particles in suspension to settle out of the fluid in which they are entrained and come to rest against a barrier.
4.Chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances.
5. The term saturated solution is used in chemistry to define a solution in which no more solute can be dissolved in the solvent. It is understood that saturation of the solution has been achieved when any additional substance that is added results in a solid precipitate or is let off as a gas.
Explanation:
Answer:
hey dear here is your answer
(B)
1. winnowing
2.Physical change
(C)
both are slow changes
QUES III -- (a) Sedimentation
Image result for sedimentation define
Sedimentation is the tendency for particles in suspension to settle out of the fluid in which they are entrained and come to rest against a barrier. ... Settling is the falling of suspended particles through the liquid, whereas sedimentation is the termination of the settling process.
Chemical change
A chemical change happens when one chemical substance is transformed into one or more different substances, such as when iron becomes rust. Chemical changes occur through the process of chemical reactions, and the resulting substances have different properties because their atoms and molecules are arranged differently.
Saturated solution
The term saturated solution is used in chemistry to define a solution in which no more solute can be dissolved in the solvent. It is understood that saturation of the solution has been achieved when any additional substance that is added results in a solid precipitate or is let off as a gas.
(b)
1) Alum is a substance which is used to fast the process of loading.. when alum is dropped in solution then the heavy particles of that solution becomes more heavy due to alum's chemical reacts with them and made them more heavier than before. and after becoming more heavier the particles settle depending fastly.
2) The metal rim is always made slightly smaller than the wooden wheel. The metal rim is heated. On heating, the rim expands and fit onto the wheel. Cold water is then poured over the rim.
Q iv
Threshing is the process of loosening the edible part of grain (or other crop) from the straw to which it is attached. It is the step in grain preparation after reaping. Threshing does not remove the bran from the grain.
hope it helps