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Tick the most appropriate answer.
Who discovered that radioactive rays are given out by uranium?
- Henri Becquerel
- Marie Curie
- Pierre Curie
- Schmidt
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Give one example that illustrates the following characteristics of a chemical reaction:
Change in state
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How do the following help in bringing about a chemical change?
pressure.
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How do the following help in bringing about a chemical change?
light.
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How do the following help in bringing about a chemical change?
catalyst .
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How do the following help in bringing about a chemical change?
heat.
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What are (i) positive catalysts and (ii) negative catalysts? Support your answer with one example for each of them.
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Name three biochemical catalysts found in the human body.
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MATCH THE COLUMNAS
| 1. Jpham Dalton | a. Neutrons |
| 2. Atom | b. Model of the atom |
| 3. Chadwick | c.The atomic theory of matter |
| 4. Rutherfrod | d. Positively charged |
| 5. Protons | e. Electricity neutral |
| 6. Nuclear fusion | f. Generator of electricity |
| 7.Gamma -rays | g. High penetrating power |
| h.Energy in sun |
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TRUE \ FALSE
Elements combine in definite proportions to form compounds.
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TRUE \ FALSE
Elements having a tendency to accept electrons are called metals
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TRUE \ FALSE
Neils Bohr gave the theory to explain the arrangement of protons in an atom.
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TRUE \ FALSE
Cathode rays are a stream of fast moving particles that travel in random directions.
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WRITE SHORT ANSWER
Define an ionic compound.
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WRITE SHORT ANSWER
What is radioactivity?
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WRITE SHORT ANSWER
Name three inert gases.
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ANSWER IN DETAIL
State the postulates of the Dalton’s atomic theory.
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ANSWER IN DETAIL
Enlist the features of Bohr’s model of an atom. How did he correct the Rutherford’s model ?
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