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3 years ago

How do scientists know that the universe is expanding?

2 answers:

7 0

It is known that the elements captivate and emit specific wavelengths of light, that is, the part of the electromagnetic spectrum. By examining the wavelengths of light discharged by an object in space, one can attain an ample amount of information. The astronomers studied the variation in the position of lines in the spectrum from a star, this can predict the distance of the star, that is, and whether it is moving away or towards us, and how quickly it is moving.

While studying the radiation discharged by the galaxies or the distant stars, the scientists witnessed the shifting of emission spectra towards the red region of the electromagnetic spectrum, that is, the witnessed wavelengths are longer than anticipated.

There is something, which is responsible for the wavelength of the radiation to stretch. However, in spite of a real variation in the wavelength, this procedure was something identical to the Doppler Effect.

DanielleElmas [232]3 years ago

4 0

Galaxies are moving away from us and the farther away a galaxy is the faster it is moving away from us. The galaxies seem to be receding from us because the entire universe is getting larger.

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Determinación de pH Expresa las siguientes concentraciones de [H+ ] en función del pH • [H+] = 0.001 M • [H+] = 0.002 M • [H+] =

Pavel [41]

Answer:

• pH = 3.0

• pH = 2.70

• pH = 3.61

• pH = 8.28

• pH = 1.40

Explanation:

El pH es una medida en química usada para determinar el grado de acidez o basicidad en una solución.

Se define como:

pH = -log₁₀ [H⁺]

<em>El - logaritmo de la concentración molar de H⁺</em>

<em />

Para las concentraciones de H⁺ dadas:

• [H+] = 0.001 M

pH = -log (0.001M) = 3

pH = 3.0

• [H+] = 0.002 M

pH = -log (0.002M)

pH = 2.70

• [H+] = 2.45X10-4 M

pH = -log (2.45X10-4 M )

pH = 3.61

• [H+] = 5.2X10-9 M

pH = -log (5.2X10-9 M)

pH = 8.28

• [H+] = 0.04 M

pH = -log (0.04M)

pH = 1.40

8 0

3 years ago

20 points

ArbitrLikvidat [17]

The answer is Na+ Cl- and F+. Hope this helps!!!

8 0

3 years ago

Read 2 more answers

Geologic time is a way to _______.

mylen [45]

Answer: Geologic time is a way to measure the sequence of events on Earth over time

Explanation:

3 0

3 years ago

german

Order of metals from least reactive to most reactive: B <C <A <D

<h3>Further explanation</h3>

Reducing agents are substances that experience oxidation

Oxidizing agents are substances that experience reduction

The metal activity series is expressed in voltaic series

The more to the left, the metal is more reactive (easily release electrons) and the stronger reducing agent

The more to the right, the metal is less reactive (harder to release electrons) and the stronger oxidizing agent

So that the metal located on the left can push the metal on the right in the redox reaction

Let's analyze the statement in the problem

I. Only A, C and D react with 1 mol/L HCl to give H₂(e)

M + HCl ⇒ MCl + H₂(MCl : alkali, MCl₂ : alkaline earth)

A, C and D can react with 1 mol / L HCl, meaning metals A, C and D are located to the left of element H (more reactive), and B in the right of element H

II. When A is added to solutions of the other metal ions, metallic B and C are formed but not D.

This means that metal A is more reactive than metals B and C, while D is more reactive than A, so metal D is the most reactive

3 0

2 years ago

What does the cell theory state?

strojnjashka [21]

C, that cells cannot be created nor destroyed.

Cells are produce by other cells. Cells can not be man-made nor destroyed.

6 0

3 years ago