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hammer [34]
3 years ago
9

Which of the changes are chemical changes?

Chemistry
1 answer:
puteri [66]3 years ago
7 0

A chemical change results from a chemical reaction, while a physical change is when matter changes forms but not chemical identity. Examples of chemical changes are burning, cooking, rusting, and rotting. Examples of physical changes are boiling, melting, freezing, and shredding.
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Answer:

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Explanation:

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3 years ago
the difference in energy between the n=1 and n=2 energy levels in a hydrogen atom is 1.64x10^-18 J. what happens when an electro
CaHeK987 [17]

Answer:

It emits 1.64 x 10⁻¹⁸J of energy

Explanation:

The n = 1 is a lower quantum level compared to n = 2.

When a hydrogen atom moves from a higher level to a lower one, it simply emits the energy difference between the two levels.

  • If a hydrogen atom moves from a lower energy level to a higher one such as from 1 to 2, they absorb the energy difference to attain the new excited state.
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Write the salient features of long form of Periodic Table .​
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Answer:

(1) It shows arrangement of elements based on modern periodic law.

(2) There are 18 vertical columns known as groups.

(3) There are 7 horizontal rows known as periods.

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3. Human activity can cause changes in one of the Earth's systems that lead to subsequent alterations in a different system. For
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answer: Surface water in nearby areas can become polluted.

Explanation:

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