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2 years ago

How does the Doppler effect related to the universal expanding?

1 answer:

7 0

The Doppler effect doesn't just apply to sound. It works with all types of waves, which includes light. Edwin Hubble used the Doppler effect to determine that the universe is expanding. Hubble found that the light from distant galaxies was shifted toward lower frequencies, to the red end of the spectrum. This is known as a red Doppler shift, or a red-shift. If the galaxies were moving toward Hubble, the light would have been blue-shifted.

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Choose the following statements that show evidence for a chemical reaction.

Leno4ka [110]

Explanation:

A chemical reaction is defined as the reaction in which bonds between the reactants either break or form which leads to the formation of a new substance.

For example, $2Li + Cl_{2} \rightarrow 2LiCl$

So, when we drop a sodium metal into water then it produces a frizzing sound which shows the metal is reacting with water.

We know that when two aqueous solutions chemically react with each other then it may lead to the formation of an insoluble substance which is known as precipitate.

This means that formation of a precipitate is also a chemical reaction.

Thus, we can conclude that following are the statements which show evidence for a chemical reaction.

Dropping sodium metal into water produces fizzing.

Mixing two aqueous solutions produces a precipitate.

8 0

3 years ago

The cell potential of a redox reaction occurring in an electrochemical cell under any set of temperature and concentration condi

avanturin [10]

Answer : The actual cell potential of the cell is 0.47 V

Explanation:

Reaction quotient (Q) : It is defined as the measurement of the relative amounts of products and reactants present during a reaction at a particular time.

The given redox reaction is :

$Ni^{2+}(aq)+Zn(s)\rightarrow Ni(s)+Zn^{2+}(aq)$

The balanced two-half reactions will be,

Oxidation half reaction : $Zn\rightarrow Zn^{2+}+2e^-$

Reduction half reaction : $Ni^{2+}+2e^-\rightarrow Ni$

The expression for reaction quotient will be :

$Q=\frac{[Zn^{2+}]}{[Ni^{2+}]}$

In this expression, only gaseous or aqueous states are includes and pure liquid or solid states are omitted.

Now put all the given values in this expression, we get

$Q=\frac{(0.0141)}{(0.00104)}=13.6$

The value of the reaction quotient, Q, for the cell is, 13.6

Now we have to calculate the actual cell potential of the cell.

Using Nernst equation :

$E_{cell}=E^o_{cell}-\frac{RT}{nF}\ln Q$

where,

F = Faraday constant = 96500 C

R = gas constant = 8.314 J/mol.K

T = room temperature = 316 K

n = number of electrons in oxidation-reduction reaction = 2 mole

$E^o_{cell}$ = standard electrode potential of the cell = 0.51 V

$E_{cell}$ = actual cell potential of the cell = ?

Q = reaction quotient = 13.6

Now put all the given values in the above equation, we get:

$E_{cell}=0.51-\frac{(8.314)\times (316)}{2\times 96500}\ln (13.6)$

$E_{cell}=0.47V$

Therefore, the actual cell potential of the cell is 0.47 V

4 0

3 years ago

Ron is writing an essay on the process of photosynthesis.On which of the points should he elaborate

Alika [10]

Answer:

Write down the phases and what happens during each phase.

Explanation:

8 0

3 years ago

Read 2 more answers

When 1. 0 l of 0. 00010 m naoh and 1. 0 l of 0. 0014 m mgso4 are mixed, would a precipitate be formed? show work

koban [17]

When 1. 0 l of 0. 00010 m NaOH and 1. 0 l of 0. 0014 m mgso4 are mixed, there will be no precipitate formed.

<h3>What is a precipitate?</h3>

The precipitate is the solid concentration of a substance that is collected over a solution.

First, we determine the concentration of magnesium and hydroxide

(Mg2+) = 7.00 × 10⁻⁴

(OH−) = 5.00 × 10⁻⁵

Now, we calculate the solubility quotient

Qc = (Mg2+) (OH−) ²

Qc = 7.00 × 10⁻⁴ x (5.00 × 10⁻⁵)²

Qc = 1.75 x 10⁻¹²

The solubility product of the magnesium hydroxide is 1.80 x 10⁻¹¹ which is more than the solubility quotient. Thus, there will be no precipitate form.

Thus, there will be no precipitate formed because the solubility quotient we calculated is less than the solubility product.

To learn more about precipitate, refer to the below link:

brainly.com/question/16950193

#SPJ4

5 0

1 year ago

Write the product concentration expression for the decomposition of ammonia to hydrogen and nitrogen.

stich3 [128]

Lollllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll

4 0

3 years ago