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tino4ka555 [31]
3 years ago
11

Question 20 (3 points) Why is the moon visible? Question 20 options: It is on fire. It reflects sunlight. Earth lights it up. It

gives off light. Question 21 (3 points) What planet do scientists believe prevented the asteroids in the asteroid belt from forming a planet? Question 21 options: Jupiter Neptune Mars Earth Question 22 (3 points) Which of the following is greater, the moon's period of rotation or its period of revolution? Question 22 options: the moon's rotational period They are equal. the moon's revolution period around Earth Neither are known. Question 23 (3 points) What condition is necessary for a lunar eclipse to occur? Question 23 options: The sun is in the moon's shadow. The moon is in Earth's shadow. The moon is in the sun's shadow. Earth is in the moon's shadow. Question 24 (3 points) What is a difference between a total solar and a total lunar eclipse? Question 24 options: A solar eclipse happens once every 28 days. A lunar eclipse happens only during a full moon. In a solar eclipse, the sun moves between Earth and the moon. In a lunar eclipse, the moon moves between the sun and Earth. In a solar eclipse, it is Earth that is caught in the umbra of the moon. In a lunar eclipse, it is the moon that is caught in the umbra of Earth. A solar eclipse can be viewed anywhere on Earth. A lunar eclipse can only be seen from the side of Earth facing the moon. Question 25 (3 points) Which manned space mission visited the moon several times? Question 25 options: Voyager 1 Apollo Mercury Gemini
Chemistry
1 answer:
alexgriva [62]3 years ago
5 0

20. Answer is "it reflects sunlight".<span>

<span>The moon is </span>not a star<span> <span>as sun. Hence, </span></span>moon can't produce light by itself<span>. The only reason that we can see the moon is </span>it reflects the sunlight<span>. According to the distance from the sun to the moon, the light reflection can be varied.</span>

21. Answer is "Jupiter".

Asteroid belt<span> <span>is a </span></span>region which is located between Mars and Jupiter and consists of asteroids and minor planets.<span> This asteroid belt has the </span>4%<span> <span>as the mass </span>of our moon. Due to the </span>Jupiter's strong gravity<span>, it is </span>prevented a forming of new planet by this asteroid belt.

22.<span> Answer is "</span>they are equal".

The period of revolution is the time which is taken by a mass to go completely one round around another mass. For moon, the period of revolution is 27 days.<span>
The period of rotation</span> is the time taken by a mass to complete one round around its own axis. It is about 27 days for moon. 

</span>23.<span> Answer is "</span>The moon is in Earth's shadow".

<span>Lunar eclipse happens when </span>Sun, Earth and moon are directly aligned each other <span>and Earth is located in between the Sun and the moon. </span>Then the moon is covered by the Earth's shadow.

24.<span> Answer is "</span>In a solar eclipse, it is Earth that is caught in the umbra of the moon. In a lunar eclipse, it is the moon that is caught in the umbra of Earth".

In total lunar eclipse, Earth is located between Sun and the moon and they are directly aligned to each other. The moon is totally covered with the Earth's shadow.
Total solar eclipse can be seen when the moon is located between sun and Earth by completely covering the sun. 

25. According to the given choices, we can get "Apollo"<span> as the answer.

Apollo 8 is the first manned mission to the moon. From that there were several manned mission including <span>first manned landing on the moon. The Apollo program was conducted by USA.</span> </span>

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Hydrogen is manufactured on an industrial scale by this sequence of reactions: Write an equation that gives the overall equilibr
RideAnS [48]

The question is incomplete. The complete question is :

Hydrogen is manufactured on an industrial scale by this sequence of reactions:

$CH_3(g) + H_2O(g) \rightleftharpoons CO(g) + 3H_2(g    ) \ \ \ \ \ \ \ \ \ \ K_1$

$CO(g) + H_2O(g) \rightleftharpoons CO_2(g) + H_2(g) \ \ \ \ \ \ \ \ \ \ \ \  K_2$

The net reaction is  :

$CH_4(g) + 2H_2O(g) \rightleftharpoons CO_2(g) + 4H_2(g) \ \ \ \ \ \ \ \ \ K$

Write an equation that gives the overall equilibrium constant K in terms of the equilibrium constants K_1 and K_2. If you need to include any physical constants, be sure you use their standard symbols, which you'll find in the ALEKS Calculator.

Solution :

$CH_3(g) + H_2O(g) \rightleftharpoons CO(g) + 3H_2(g    ) \ \ \ \ \ \ \ \ \ \ K_1$

$K_1 = \frac{[CO][H_2]^3}{[CH_4][H_2O]}$     ...............(1)

$CO(g) + H_2O(g) \rightleftharpoons CO_2(g) + H_2(g) \ \ \ \ \ \ \ \ \ \ \ \  K_2$

$K_2 = \frac{[CO_2][H_2]}{[CO][H_2O]}$  ...................(2)

$CH_4(g) + 2H_2O(g) \rightleftharpoons CO_2(g) + 4H_2(g) \ \ \ \ \ \ \ \ \ K$

$K=\frac{[CO_2][H_2]^4}{[CH_4][H_2O]^2}$

On multiplication of equation (1) and (2), we get

$K_1 \times K_2=\frac{[CO][H_2]^3}{[CH_4][H_2O]} \times \frac{[CO_2][H_2]}{[CO][H_2O]}$

$K_1K_2=\frac{[CO_2][H_2]^4}{[CH_4][H_2O]^2}$  .................(4)

Comparing equation (3) and equation (4), we get

$K=K_1K_2$

4 0
2 years ago
Aqueous sulfuric acid reacts with solid sodium hydroxide to produce aqueous sodium sulfate and liquid water . If of water is pro
sergeinik [125]

The question is incomplete, here is the complete question:

Aqueous sulfuric acid reacts with solid sodium hydroxide to produce aqueous sodium sulfate and liquid water. If 12.5 g of water is produced from the reaction of 72.6 g of sulfuric acid and 77.0 g of sodium hydroxide, calculate the percent yield of water. Be sure your answer has the correct number of significant digits in it.

<u>Answer:</u> The percent yield of water in the reaction is 46.85 %.

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}     .....(1)

  • <u>For NaOH:</u>

Given mass of NaOH = 77.0 g

Molar mass of NaOH = 40 g/mol

Putting values in equation 1, we get:

\text{Moles of NaOH}=\frac{77.0g}{40g/mol}=1.925mol

  • <u>For sulfuric acid:</u>

Given mass of sulfuric acid = 72.6 g

Molar mass of sulfuric acid = 98 g/mol

Putting values in equation 1, we get:

\text{Moles of sulfuric acid}=\frac{72.6g}{98g/mol}=0.741mol

The chemical equation for the reaction of NaOH and sulfuric acid follows:

H_2SO_4+2NaOH\rightarrow Na_2SO_4+2H_2O

By Stoichiometry of the reaction:

1 mole of sulfuric acid reacts with 2 moles of NaOH

So, 0.741 moles of sulfuric acid will react with = \frac{2}{1}\times 0.741=1.482mol of NaOH

As, given amount of NaOH is more than the required amount. So, it is considered as an excess reagent.

Thus, sulfuric acid is considered as a limiting reagent because it limits the formation of product.

By Stoichiometry of the reaction:

1 mole of sulfuric acid produces 2 moles of water

So, 0.741 moles of sulfuric acid will produce = \frac{2}{1}\times 0.741=1.482moles of water

Now, calculating the mass of water from equation 1, we get:

Molar mass of water = 18 g/mol

Moles of water = 1.482 moles

Putting values in equation 1, we get:

1.482mol=\frac{\text{Mass of water}}{18g/mol}\\\\\text{Mass of water}=(1.482mol\times 18g/mol)=26.68g

To calculate the percentage yield of water, we use the equation:

\%\text{ yield}=\frac{\text{Experimental yield}}{\text{Theoretical yield}}\times 100

Experimental yield of water = 12.5 g

Theoretical yield of water = 26.68 g

Putting values in above equation, we get:

\%\text{ yield of water}=\frac{12.5g}{26.68g}\times 100\\\\\% \text{yield of water}=46.85\%

Hence, the percent yield of water in the reaction is 46.85 %.

8 0
3 years ago
A 7.50-g sample of iron is heated in oxygen to form an iron oxide. if 10.71 g of the oxide is formed, what is its empirical form
Zielflug [23.3K]
Answer is: empirical formula is Fe₂O₃.
m(Fe) = 7,50 g.
m(iron oxide) = 10,71 g.
n(Fe) = m(Fe) ÷ M(Fe).
n(Fe) = 7,50 g ÷ 55,85 g/mol = 0,134 mol.
m(O) = m(iron oxide) - m(Fe).
m(O) = 10,71 g - 7,50 g = 3,21 g.
n(O) = 3,21 g ÷ 16 g/mol = 0,20 mol.
n(Fe) : n(O) = 0,134 mol : 0,2 mol = 2 : 3.
3 0
3 years ago
A container measures 30.5 cm X 202 cm X 153 cm. It has a mass of 1030 g. What is the density of the liquid?
SOVA2 [1]

Answer:

alright

Explanation:

here

7 0
3 years ago
‼️I WILL MARK BRAINLIEST
weeeeeb [17]

Ba(OH)2 + 2 HNO3 -----> Ba(NO3)2 + 2 H2O


1) Calculate moles of Ba(OH)2 used.


0.65 mol / L x 0.0234 L = 0.01521 mol Ba(OH)2


2) Calculate moles of HNO3 used.


0.01521 mol Ba(OH)2 x 2 HNO3 / 1 Ba(OH)2 = 0.03042 mol HNO3


3) Calculate molarity of HNO3.


0.03042 mol / 0.0425 L =


so the answer is 0.716 M !

4 0
3 years ago
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