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iVinArrow [24]
3 years ago
12

Give at least two ways to know if a reaction is endothermic or exothermic

Chemistry
1 answer:
mafiozo [28]3 years ago
5 0

Answer:

An exothermic reaction is a chemical reaction that releases energy by light or heat. Endothermic reaction is a chemical reaction that absorbs energy or heat from its surroundings

Explanation:

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If antique brass is 30.0% zinc and 70.0% copper, how many grams of antique brass can be made from 18.0 grams of zinc and 32.8 gr
wariber [46]

Answer: 51.86

Explanation:

3 0
3 years ago
Explain why the Amazon River does not create deltas?
jeka57 [31]

Answer:

The ocean currents are too strong by the Amazon River to form deltas.

Explanation:

The Atlantic has sufficient wave and tidal energy to carry most of the Amazon's sediments out to sea, thus the Amazon does not form a true delta. The great deltas of the world are all in relatively protected bodies of water, while the Amazon empties directly into the turbulent Atlantic.

4 0
2 years ago
The half-life of nitrogen-13 is 10.0 minutes. if you begin with 53.3 mg of this isotope, what mass remains after 25.9 minutes ha
zimovet [89]

Hello!

The half-life is the time of half-disintegration, it is the time in which half of the atoms of an isotope disintegrate.

We have the following data:

mo (initial mass) = 53.3 mg

m (final mass after time T) = ? (in mg)

x (number of periods elapsed) = ?

P (Half-life) = 10.0 minutes

T (Elapsed time for sample reduction) = 25.9 minutes

Let's find the number of periods elapsed (x), let us see:

T = x*P

25.9 = x*10.0

25.9 = 10.0\:x

10.0\:x = 25.9

x = \dfrac{25.9}{10.0}

\boxed{x = 2.59}

Now, let's find the final mass (m) of this isotope after the elapsed time, let's see:

m =  \dfrac{m_o}{2^x}

m =  \dfrac{53.3}{2^{2.59}}

m \approx \dfrac{53.3}{6.021}

\boxed{\boxed{m \approx 8.85\:mg}}\end{array}}\qquad\checkmark

I Hope this helps, greetings ... DexteR! =)

3 0
3 years ago
What happens when the vapor pressure of a liquid is equal to the external pressure? The liquid freezes The intermolecular forces
Makovka662 [10]

Answer:

The liquid boils.

Explanation:

Vapor pressure is simply defined as the pressure exerted on a substance (solid/liquid) by the vapor of the substance collected just at the top of the surface of the substance. In concise words, it is the pressure of Vapor that is in contact with its solid or liquid state.

For a liquid, it is the pressure of the Vapor gathering at the top of the surface of the liquid.

When this Vapor pressure matches the external pressure, the temperature stays constant and the molecules of the liquid all through the liquid can gain enough energy, rise to the surface of the liquid and break free in gaseous form; thereby, boiling.

The definition of boiling point basically explains that it is the point at which temperature stays constant, and the vapour pressure of the liquid matches the atmospheric/external pressure around the liquid and its liquid molecules change into vapor.

This is why liquids boil faster at higher altitudes; the atmospheric pressure at higher altitudes is reduced, hence, the temperature at which liquid boils at this high altitude is normally lower than its known boiling point temperature.

It is also why food cooks to a temperature higher than the boiling point of water in a pressure cooker/pot. The added pressure ensures that the cooking water boils at temperatures higher than its boiling point; thereby exposing the cooking ingredients to a higher temperature, leading to faster cooking.

Hence, it is obvious why boiling is the answer to this question.

6 0
3 years ago
The average weather conditions over a long period of time is known as
frosja888 [35]

Answer: it’s climate

Explanation:

5 0
2 years ago
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