20)
1 answer:
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Answer: They can be separated by physical processes
Explanation:
Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: Copper
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: water
Mixture is a substance which has two or more components which do not combine chemically and do not have any fixed ratio in which they are present.they can be separated by physical processes. Example: salt in water. It can be separated by evaporation which is a physical process.
Answer:
The balanced half-reaction for the reduction of dichromate ion to chromium ion in acidic aqueous solution:
Explanation:
The reaction :
Balancing of reaction in an acidic medium:
Step 1: Balance the atoms in the reaction:
Step 2: Balance oxygen atom by adding water on the side where no oxygen or less oxygen atom is present;
Step 3: Balance the hydrogen atom by adding hydrogen ions on the side where water is absent:
Step 4: Now balance charge by adding electrons on the side where more positive charge is present
The balanced half-reaction for the reduction of dichromate ion to chromium ion in acidic aqueous solution: