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3 years ago

As a star forms, at what point do nuclear reactions begin to occur?

2 answers:

7 0

The energy of the stars comes from nuclear fusion processes. For stars like the sun which have internal temperatures less than fifteen million Kelvin, the dominant fusion process is proton-proton fusion. For more massive stars which can achieve higher temperatures, the carbon cycle fusion becomes the dominant mechanism. For older stars which are collapsing at the center, the temperature can exceed one hundred million Kelvin and initiate the helium fusion process called the triple-alpha process.

Scrat [10]3 years ago

3 0

Stage 3. Hydrogen fuses to form helium and nuclear reactions begin to occur.

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Three energy changes that result in movements accuring in your body as sit down reading book?

Rom4ik [11]

Gravitational to Kinetic to Chemical

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3 years ago

When objects exchange charge, why do we say it's the negative charge that moves and not the positive?

Novay_Z [31]

Answer:

It is said that the negative charge moves because the electrons in the atoms of any object are taken or given to the atoms of another object.

Explanation:

The atom is made up of protons, electrons and neutrons. The number of protons is exactly the same to the number of electrons for a certain element. For example, hydrogen: it has a proton, and therefore, an electron.

The electron has a negative charge. The proton has a positive charge. And the neutron has no charge, so it is neutral. While the atom has the same number of protons and electrons, it will not be electrically charged.

An example of how a charge exchange occurs between two objects is through the case of rubbing. This makes the atoms of the two objects close enough that there is an electron transfer, causing any of the objects to gain or lose electrons as a consequence of each other interaction. In the case of transferring electrons, the atom will have a greater number of protons, so it will be positively charged. When the atom receive electrons, it will have a greater number of electrons, so it will be negatively charged.

Therefore, since it is the electrons that move from one atom to another, then it is the negative charge that moves (characterized by the electrons) and not the positive charge (characterized by the protons).

6 0

3 years ago

How much does the speed of a car increase if it accelerates

Nata [24]

Answer:

12.5 m/s

Explanation:

a = Δv / Δt

2.5 m/s² = Δv / 5 s

Δv = 12.5 m/s

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3 years ago

Evaluate the use of hydrogen as a fuel. Explain how hydrogen is produced. Write about the environmental impact of using diesel a

posledela

Explanation:

Hydrogen is used as a fuel because it has a high calorific value per molecule when burned in air and also burns explosively. When burned in air, it reacts with oxygen to produce water which is safe for the environment. This same property of hydrogen of high explosiveness makes it difficult to store safely.

Hydrogen can be produced through the electrolysis of water. However this is high energy consuming. The most common method is called steam-methane reforming. Methane from hydrocarbon is mixed with steam under high pressure and reacts to produce hydrogen and carbon monoxide.

Diesel and petrol and other petroleum products when burned produce carbon dioxide which is a greenhouse gas. Greenhouse gases when increasing in the atmosphere, cause greenhouse effect that results in global warming.

Learn More:

For more on hydrogen fuel check out;

brainly.com/question/2666329

#LearnWithBrainly

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4 years ago

Enzymes speed up a biological reaction by

lord [1]

B) lowering the activation energy !
__________
hope it helps!

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3 years ago