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3 years ago

The half of the moon facing the sun is always lit, but the different phases happen because:

Chemistry

1 answer:

zvonat [6]3 years ago

7 0

Answer:

we only see parts of the lit side as the moon goes around the earth

Explanation:

Unlike the sun, the moon orbits the Earth. This is the reason why we see the different phases of the moon. The reflection of the moon is being illuminated back to us with the help of the sun. So, as the moon circles the Earth, we only see parts of the lit side. Such changes helps us see the moon in different phases such as the Third Quarter, Crescent, New Moon, Full Moon, etc.

For example, during "Full Moon," the moon's entire face is lit up by the sun. Thus, we see the entire moon's lit portion.

Thus, this explains the answer.

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What Communication system do submarines use ?

PolarNik [594]

Answer:

Explanation:

I think its like radar or something like that- im not too sure sorry

7 0

3 years ago

In the laboratory, hydrogen gas is usually made by the following reaction: Zn(s) + 2 HCl(aq) → H2(g) + ZnCl2(aq) How many liters

IrinaK [193]

Answer: The volume of hydrogen gas collected over water is 2.13 L

Explanation:

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

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Given mass of zinc = 5.566 g

Molar mass of zinc = 65.4 g/mol

Putting values in above equation, we get:

$\text{Moles of zinc}=\frac{5.566g}{65.4g/mol}=0.0851mol$

For the given chemical reaction:

$Zn(s)+2HCl(aq.)\rightarrow H_2(g)+ZnCl_2(aq.)$

As, HCl is present in excess. So, it is considered as an excess reagent.

Zinc is considered as a limiting reagent because it limits the formation of product.

By Stoichiometry of the reaction:

1 mole of zinc produces 1 mole of hydrogen gas.

So, 0.0851 moles of zinc will produce = $\frac{1}[1}\times 0.0851=0.0851mol$ of hydrogen gas

To calculate the volume of hydrogen gas, we use ideal gas equation, which is:

PV = nRT

where,

P = Pressure of hydrogen gas = Total atmospheric pressure - vapor pressure of water = (752 - 18.65) mmHg = 733.35 mmHg

V = Volume of the hydrogen gas

n = number of moles of gas = 0.0851 moles

R = Gas constant = $62.3637\text{ L.mmHg }mol^{-1}K^{-1}$

T = Temperature of hydrogen gas = $21^oC=[21+273]K=294K$

Putting values in above equation, we get:

$733.35mmHg\times V=0.0851mol\times 62.3637\text{ L.mmHg }mol^{-1}K^{-1}\times 294K\\\\V=\frac{0.0851\times 62.3637\times 294}{733.35}=2.13L$

Hence, the volume of hydrogen gas collected over water is 2.13 L

5 0

3 years ago

What is the mole fraction of NaOH in an aqueous solution that

astraxan [27]

Answer:

The mole fraction of NaOH in an aqueous solution that contain 22.9% NaOH by mass=0.882

Explanation:

We are given that

Aqueous solution that contains 22.9% NaOH by mass means

22.9 g NaOH in 100 g solution.

Mass of NaOH(WB)=22.9 g

Mass of water =100-22.9=77.1

Na=23

O=16

H=1.01

Molar mass of NaOH(MB)=23+16+1.01=40.01

Number of moles = $\frac{Given\;mass}{Molar\;mass}$

Using the formula

Number of moles of NaOH $(n_B)=\frac{W_B}{M_B}=\frac{22.9}{40.01}$

$n_B=0.572moles$

Molar mass of water=16+2(1.01)=18.02g

Number of moles of water $(n_A)=\frac{77.1}{18.02}$

$n_A=4.279 moles$

Now, mole fraction of NaOH

= $\frac{n_B}{n_B+n_A}$

$=\frac{4.279}{0.572+4.279}$

=0.882

Hence, the mole fraction of NaOH in an aqueous solution that contain 22.9% NaOH by mass=0.882

4 0

3 years ago

This flow chart shows the amount of energy that is emitted by each type of light. ultraviolet > blue light > yellow light

harina [27]

Answer:

Explanation:

In photoelectric effect , radiation of some energy is made to fall on metal plate which results in the ejection of electrons by the metal plate . The kinetic energy of electrons comes from the energy of radiation falling on metal plate . Some of energy of radiation falling on metal plate is used in the process of bringing the electron to the surface and it is called threshold energy . The radiation must have at least this energy to see to it that electrons are ejected . and the rest of the energy of radiation is used in imparting kinetic energy to the electron .

The red light radiation has least energy so it is least likely to eject electrons from metal plate and produce photoelectric effect .

3 0

3 years ago

Read 2 more answers

Predict: If the skater starts at a height of 2m on one side of the ramp and starts to move, how high will he get on the other si

OverLord2011 [107]

Answer:

Sliding friction

Explanation:

SLiding friction produces force

7 0

3 years ago