what are the environmental impacts of coal

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 =[tex]\frac{Given\;mass}{Molar\;mass}[/tex]

Using the formula

Number of moles of  NaOH[tex](n_B)=\frac{W_B}{M_B}=\frac{22.9}{40.01}[/tex]

[tex]n_B=0.572moles[/tex]

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

Number of moles of water[tex](n_A)=\frac{77.1}{18.02}[/tex]

[tex]n_A=4.279 moles[/tex]

Now, mole fraction of NaOH

=[tex]\frac{n_B}{n_B+n_A}[/tex]

[tex]=\frac{4.279}{0.572+4.279}[/tex]

=0.882

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

Answer:

D. Two Plates are colliding.

Answer:

D

Explanation:

The ring of fire has very large amount of plate collision so it cannot be B.

It can't be A either because the ring of fire has nothing to do with radioactive element decay.

The two main things with the ring of fire is the fact that there are a lot of volcanos and earthquakes, so it cannot be C.

Since the ring of fire has so many collisions of plates, and none of the other answers are correct, the answer is D.

Hope this helps!

Answer:

The nuclear decay of radioactive elements is a process that is a useful tool for determining the absolute age of fossils and rocks. It is used as a clock, in which daughter elements or isotopes converted from parent isotopes by decaying at a particular time.

Radioactive decay rates are constant and do not change over time. It is measured in half-life. A half-life is a time it takes half of a parent isotope to decay and converted into a stable daughter isotope. How many parent isotopes and daughter isotopes present in the fossil or their abundance can help in determining the age of fossil or rock.

Answer:

D. Solids

Explanation:

Answer:

B

Explanation:

When water evaporate, it moves faster

Answer:

1.82g of Zn remain

Explanation:

Zinc, Zn, reacts with hydrochloric acid, HCl, as follows:

Zn + 2HCl → ZnCl2 + H2

Where 1 mole of Zn reacts with 2 moles of HCl

To solve this question we must find the moles of each reactant. With the moles of HCl we can find the moles of zinc needed for a complete reaction and the mass of zinc that remains:

Moles Zn -Molar mass: 65.32g/mol-

6.72g * (1mol / 65.38g) = 0.1028 moles Zn

Moles HCl:

100.0mL = 0.1000L * (1.50mol / L) = 0.150moles HCl

The moles of Zn that react with 0.150 moles HCl are:

0.150 mol HCl * (1mol Zn / 2mol HCl) = 0.075 moles of Zn are required

The moles that remain are:

0.1028 moles Zn - 0.075 moles of Zn = 0.0278 moles Zn

The mass is:

0.0278 moles Zn * (65.38g / mol) =

Answer:

The correct answer is - Mosquitoes transmit the virus as parasites which feed on the blood of host organisms and inject the virus during feeding.

Explanation:

According to the CDC, the seasonal West Nile virus is caused by the mosquitoes of freshwater transmit this disease to humans and others. These mosquitoes are feed on the birds and pick these viruses.

These viruses stick on mosquitoes and when they feed on the blood of humans they transmit these viruses by injecting viruses into the blood of humans.

an element is a substance that cannot be split into simpler substances by a chemical means . for example - hydrogen, oxygen, nitrogen, carbon, iron, aluminium, copper, silver and gold some example of elements.

Nuclear fusion is not yet a practical energy source due to no available environment on the earth.

Nuclear fusion is not yet a practical energy source because it requires very hot environment which is not possible on the earth. Nuclear fusion reactions occur only on the sun because the temperature is very high and environment is suitable for the reaction,

So we can conclude that Nuclear fusion is not yet a practical energy source due to no available environment on the earth.

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Explanation:

2/1×1.25

=2.5 mole of NaCl are produced

weight of NaCl produced = moles × molar mass of NaCl

weight of NaCl produced = 2.5×58.5

weight of NaCl produced =146.5 grams

Answer: Carbon dioxide reacts with calcium hydroxide solution to produce a white precipitate of calcium carbonate. Limewater is a solution of calcium hydroxide. If carbon dioxide is bubbled through limewater, the limewater turns milky or cloudy white.

Explanation:

****Isra****

Answer:

HCl, H2O, and NH3 are the most polar of these, so they won't behave ideally because the particles have greater attractive forces between them. How does the kinetic-molecular theory explain the pressure exerted by gases? ... Particles are always in motion and when they are contained, they are elastic collisions.

The particles have high intermolecular forces, reducing the elasticity of their collisions.

Polar molecules are formed when a high electronegative atom combined with a less electronegative atom.

Ammonia, sulfur dioxide, hydrogen sulfide, are polar gases.

The non-polar gases are inert gas or noble gas.

The polar compounds are asymmetrically array.

Thus, the correct option is 4, The particles have high intermolecular forces, reducing the elasticity of their collisions.

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Answer:

See Explanation

Explanation:

The way by which a metal is obtained from its ore is determined by the chemical reactivity of the metal.

Metals that are highly reactive are chiefly obtained by electrolysis of the metal salt. These metals are found high up in the metal activity series.

Metals that are at the middle of the series are moderately reactive and are obtained by electrolysis or by reduction since they still form ionic salts.

Metals that are far lower in the series can only be obtained by heating them in air because they are mostly unreactive.

Hence, moderately reactive metals at the middle of the series are not obtained by roasting in air.

Answer:

(1s)^2 (2s)^2 (2p)^3

Explanation:

Nitrogen has 7 electrons. Hence, the structure will be,

=>(1s)^2 (2s)^2 (2p)^3

Hope it helps:)

The electronic configuration is used to explain the orbitals of an atom and it helps to determine the physical and chemical properties of the elements. The electronic configuration of Nitrogen is 1s² 2s² 2p³. The correct option is B.

The distribution of electrons in the atomic orbitals is given by the electronic configuration. It is a standard notation in which all the electrons holding atomic subshells are arranged in a sequence. Each element has a unique electronic configuration.

The electronic configuration of an element can be written in two ways, in standard notation, and in condensed form. In the case of elements with larger atomic numbers, the electronic configuration becomes lengthy in standard notation. So in such cases condensed form is generally used.

The electronic configuration of 'N' of atomic number 7 in standard form is 1s² 2s² 2p³ and in condensed form it is [He] 2s²2p³.

Thus the correct option is B.

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Answer:

V = 25.7 L.  

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us to solve for the volume of hydrogen, by firstly calculating the moles of this gas produced by 37.6 g of magnesium, according to the 1:1 mole ratio between them:

[tex]n_{H_2}=37.6gMg*\frac{1molMg}{24.305gMg}*\frac{1molH_2}{1molMg}=1.55molH_2[/tex]

Now, we use the ideal gas equation:

[tex]PV=nRT[/tex]

To solve for the volume, and obtain:

[tex]V=\frac{nRT}{P}\\\\V=\frac{1.55mol*0.08206\frac{atm*L}{mol*K}*293.15K}{1.45atm}\\\\V=25.7L[/tex]

Regards!

Answer:

Explanation:

The pH of a solution can be found by using the formula

[tex]pH = - log [ { H_3O}^{+}][/tex]

From the question we have

[tex]ph = - log(5.67 \times {10}^{ - 4} ) \\ = 3.2464[/tex]

We have the final answer as

Hope this helps you

Answer:

Gamma rays and X-rays

Explanation:

All the things she said

All the things she said

Running through my head

Running through my head

Running through my head

All the things she said

All the things she said

Running through my head

Running through my head

All the things she said

This is not enough

This is not enough

Answer:

(d) soap.

Explanation:

A soap is obtained by alkaline hydrolysis of a fat to yield the soap and glycerol. This process is known as saponification.

A soap solution is usually basic. Since phenolphthalein turns pink in an alkaline solution, then when phenolphthalein is added to a soap solution, the solution soon turns pink because it is alkaline in nature.

As a matter of fact, a soap sometimes has almost the pH of baking soda!

Answer:

10.

Explanation:

We need 10 question to separate ten arthropods into different branches because each arthropod belongs to separate branch and each branch needs explanation. Phylum Arthropoda is considered as the largest phylum in the animal world, and insects form the largest class within this phylum due to its highest number of individual or organisms. Each arthropods are different from one another so they needs more questions to separate them from each other.

Answer:

[tex]187.[/tex]

Explanation:

[tex]7.5 \div 0.30 = 25[/tex]

[tex]7.5 \times 25 = 187.5[/tex]

Answers:

There's many factors, such as the temperature, rainfall, food available, and the surrounding terrain, that all can effect an animal's characteristics.

Answer:

1.25 moles of magnesium chloride are produced

Explanation:

Based on the reaction:

Mg(s) + 2HCl (aq) → MgCl₂(s) + H₂(g)

1 mole of magnesium, Mg, reacts with 2 moles of hydrochloric acid, HCl, to produce 1 mole of magnesium chloride, MgCl₂ and 1 mole of hydrogen gas.

To solve this question we have to tak, from the chemical equation:

2 mol HCl = 1mol MgCl₂

That means, the moles of MgCl₂ produced from 2.50mol HCl are:

2.50 mol HCl * (1mol MgCl₂ / 2mol HCl) =

Answer:

D. the capacity to do work

Explanation:

the basic definition of energy is the ability to do work

Answer:

püvinlbxyfsswgrxzvnnchcyv nkivtcdg

Answer:

Explanation:

acceleration is inversely proportional to the mass of an object.

Newton's second law states that "the acceleration produced on a body is directly proportional to the resultant force anf inversely proportional to its mass".

Answer:

D. The Sun

Explanation:

The Sun does not affect global wind belts.

Land breeze does not affect global wind belts whereas other factors such as air pressure, Coriolis effect and the sun affected global wind patterns.

Unequal heating of the Earth's surface forms large global wind patterns. Those area which are near the equator, the sun warm air and this warm air rises at the equator and moves toward the poles. At the poles, the cooler air sinks and moves back toward the equator.

So we can conclude that land breeze does not affect but sun creates affect on the global wind pattern.

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Answer:

Explanation:

If the choices are:

A. Molarity is defined as moles of solute per liter of solvent.

B. % by mass is defined as grams of solute per 100 g of solvent.

C. % by volume is defined as grams of solute per 100 L of solution.

D. Molarity is defined as moles of solute per liter of solution.

E. All of the above.

then the ans is E

Answer:

They are inversely related.

Explanation: