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nikklg [1K]
3 years ago
10

Pretend your friend was absent from class today...

Chemistry
2 answers:
NemiM [27]3 years ago
7 0
Incomplete question
Dovator [93]3 years ago
5 0

Answer:

how and why elements what?? why they exist?? im gonna assume that's what you meant, so elements exist because we're all on earth and without elements, we don't have resources to live. the earth is made of elements and if there were none, we wouldn't even have a planet

Explanation:

^

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Fireworks are chemical reactions that release energy. Which of these phenomena are caused by chemical reactions that release ene
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4 0
3 years ago
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When a hydrogen atom covalently bonds to another atom, how many electrons associated with this hydrogen atom become involved in
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Explanation:

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8 0
3 years ago
How is the Nazca plate moving in relation to the Pacific plate?
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4 0
2 years ago
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What is the change in internal energy (ΔΕ) of a system when 5 kJ of work is done on the system while it releases 13 kJ of energy
meriva

The change in internal energy (ΔΕ) of a system : -8 kJ

<h3>Further explanation  </h3>

The laws of thermodynamics 1 state that: energy can be changed but cannot be destroyed or created  

The equation is:  

 \tt \Delta U=Q+W

Energy owned by the system is expressed as internal energy (U)  

This internal energy can change if it absorbs heat Q (U> 0), or releases heat (U <0). Or the internal energy can change if the system does work or accepts work (W)  

The sign rules for heat and work are set as follows:  

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• The system releases heat, Q -  

• The system does work, W -  

• the system accepts work, W +  

5 kJ of work is done on the system : W = +5 kJ

releases 13 kJ of energy to the surroundings : Q = -13 kJ

\tt \Delta E=-13+5=-8~kJ

6 0
2 years ago
Which element would be expected to have chemical and physical properties closest to those of rubidium?
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7 0
3 years ago
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