Answer:
A
Explanation:
Your answer would be A because Earth is formed from cold gases collapsing due to gravity. The Solar System was formed when a huge amount of dust and gas began to collapse under its own gravity, and as the cloud collapse it started to spin causing the material within the cloud to gather into a swirl and then formed into planets and as the planets are formed they kept this spinning motion.
Answer:
a new substance is formed, if heat is formed, color change, the evolution of gas, and bubbles or fizzing
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NH3 is a weak alkali that does not dissociate fully into its solution. Which of the following is true about NH3?
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A. It has a very low pH.
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B. It's dissociation is a reversible reaction.
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C. It has a high H+ concentration.
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D. It will release all of its OH- ions.</h2>
Explanation:
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NH3 is a weak alkali that does not dissociate fully into its solution: It's dissociation is a reversible reaction.
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Reactions are also :
Reversible reaction
A reaction in which products can combine back to give reactants under same given condition .
Example : N₂+H₂-------NH₃
Irreversible reaction
A reaction in which the products cant combine back to give reactants under same set of conditions .
Example : Burning of paper
Eta Carinae could be as large as 180 times the radius of the Sun, and its surface temperature is 36,000-40,000 Kelvin. Just for comparison, 40,000 Kelvin is about 72,000 degrees F. So it's the blue hypergiants, like Eta Carinae, which are probably the hottest stars in the Universe.