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algol13
3 years ago
8

How do scientists know that the universe is expanding?

Chemistry
2 answers:
aksik [14]3 years ago
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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Given a balanced chemical equation below: 3Cu(s) + 2H3PO4 --- > Cu3(PO4)2 + 3H2 How many moles of copper are needed to react
Harman [31]

Answer:

7.5 moles

Explanation:

We'll begin by writing the balanced equation for the reaction. This is given below:

3Cu + 2H3PO4 —> Cu3(PO4)2 + 3H2

From the balanced equation above,

3 moles of Cu reacted with 2 moles of H3PO4.

Therefore, Xmol of Cu will react with 5 moles of H3PO4 i.e

Xmol of Cu = (3 x 5)/2

Xmol of Cu = 7.5 moles

Therefore, 7.5 moles of Cu are needed to react with 5 moles of H3PO4.

4 0
3 years ago
a solution must be at a higher temperature than a pure solvent to boil. what colligative property can be employed to achieve thi
Kazeer [188]

Boiling-point elavation.

6 0
3 years ago
Read 2 more answers
What mass of oxygen gas is consumed in a reaction that produces 4.60 mol sulfur dioxide?
babunello [35]

Answer:

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7 0
2 years ago
How many CO2 molecules in 0.0189 mol of CO2?
Blizzard [7]

Answer:

option C is correct = 1.14 × 10²² molecules of  CO₂

Explanation:

Given data:

Number of moles of CO₂ = 0.0189 mol

Number of molecules = ?

Solution:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

For example,

18 g of water = 1 mole = 6.022 × 10²³ molecules of water

For given question:

1 mole of CO₂ =  6.022 × 10²³ molecules of  CO₂

0.0189 mol of CO₂ ×  6.022 × 10²³ molecules of  CO₂ / 1mol

1.14 × 10²² molecules of  CO₂

Thus, option C is correct.

4 0
3 years ago
This <br> Question please
Marizza181 [45]

Answer:

See detailed explanation.

Explanation:

Hello!

i. In this case, since the given chemical reaction is exothermic due to the negative change in the enthalpy of reaction, we infer that according to the mentioned principle, by lowering the temperature the reaction will shift rightwards and therefore the yield is increased; thus, you need a lower temperature than the specified.

ii. In this case, since the reaction has less moles at the products side, according to the mentioned principle it'd be necessary to rise the pressure in order to increase the yield, since the increase of pressure favors the reaction side with the fewest number of moles.

Best regards!

4 0
2 years ago
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