How is human use of coal connected to water and air quality?​

Final answer:

The fluoride concentration is 1 ppm for a solution of 500 grams of fluoride in 500,000 liters of water. Following the WHO's guidelines, an average person would ingest 1.92 milligrams of fluoride ion by drinking 1,920 mL of water at this concentration.

Explanation:

To calculate the concentration of fluoride in parts per million (ppm) for a solution that consists of 500 grams of fluoride in 500,000 liters of water, you can use the definition of parts per million. Parts per million is the ratio of solute-to-solution mass multiplied by 106. Therefore, you first need to convert the mass of fluoride from grams to milligrams and then divide by the total volume of solution in liters.

To get the mass of fluoride in milligrams, multiply 500 grams by 1000 (since there are 1000 milligrams in a gram). That gives you 500,000 milligrams. Next, since the volume of water is already in liters, we keep it as is. We then use the formula for ppm:

ppm = (mass of solute in mg) / (volume of solution in L)

Now, by substituting the values we have:

ppm = 500,000 mg / 500,000 L = 1 ppm

Assuming the World Health Organization's maximum recommended concentration of fluoride ion is 1.0 ppm, then an average person drinking 1,920 mL (1.92 liters) of this water would consume:

fluoride intake = concentration (ppm) × volume of water (L)

In milligrams, this becomes:

fluoride intake = 1 ppm × 1.92 L = 1.92 mg

Thus, an average person would ingest 1.92 milligrams of fluoride ion per day.

Answer:

                     BaI₂.5H₂O

Explanation:

Given Data:

                   Mass of Hydrated BaI₂ = 10.222 g

                   Mass of dried BaI₂ = 9.520 g

                   Mass of Water removed  =  10.222-9.520 = 0.702 g

                   M.Mass of BaI₂ = 391.136 g/mol

                   M.Mass of Water  =  18.02 g/mol

Now,

         Calculate moles of dried BaI₂ as,

Moles  =  Mass / M.Mass

Moles  =  9.520 g / 391.136 g/mol

Moles  =  0.02434 moles

         Calculate moles of Water as,

Moles  =  Mass / M.Mass

Moles  =  0.702 g / 18.02 g/mol

Moles  =  0.0389 moles

Then,    

          Calculate Mole ratio of BaI₂ and water as,

              = 0.02434 moles BaI₂ / 0.0389 moles Water

              =  0.625

Now,

We will convert this mole ratio to a whole number by multiplying it with a nearest integer,

             =  0.625 × 8

             =  5

Hence, this means for every one mole of BaI there are 5 moles of Water.

Result:

                                             BaI₂.5H₂O

Answer:

b

Explanation:

In photosynthesis, light energy from the sun is harvested and it is converted into chemical energy. The primary source of energy used by producers during photosynthesis is light energy from the sun. The correct option is B.

The process which takes place in the chloroplasts through photosynthetic pigments like chlorophyll a, chlorophyll b, carotene and xanthophyll to synthesize nutrients by using carbon dioxide, water and sunlight is known as the photosynthesis.

The plants use light energy to convert carbon dioxide and water into glucose and oxygen. This sugar molecules are used by the green plants as the energy source which helps them to grow.

The process photosynthesis is also exhibited by the algae, cyanobacteria, etc. to convert solar energy into chemical energy. Light is the major factor which complete this process.

Thus the correct option is B.

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Answer:

the boiling of 10g of liquid water

Answer:

The correct option is "the condensation of 10 g of gaseous water"

Explanation:

In condensation,gaseous stats is changes into  liquid. So it will release more energy to convert from one state to another state.So it is exothermic process in which heat is released.

Answer: the world wouldn’t be the same today

Explanation:

Answer:

1,100,160J or 262.94 kcal

Explanation:

The juice is frozen at 0 degrees Celsius and I assume that it will become gas at 100 degrees Celsius. So we change the form of the water from solid to liquid, then to gas. That means we have to find out how much heat needed to change water form too, not only the heat needed to increase its temperature.

The latent heat of water is 4.2J/g °C while the heat of fusion is 334 J/g and the heat of vaporization is 2260 J/g. The energy needed will be:

360g * 4.2J/g °C * (110-0°C ) + 360g * 334 J/g + 360g * 2260 /g = 1,100,160J or 262.94 kcal.

Final answer:

The energy required to heat the frozen can of juice from 0 degrees Celsius to 110 degrees Celsius is 163.08 kJ.

Explanation:

To calculate the amount of energy required to heat the frozen can of juice, we need to consider three steps:

Heating the can from 0 degrees Celsius to its melting point, which is 0 degrees Celsius

Melting the ice at 0 degrees Celsius

Heating the water from 0 degrees Celsius to 110 degrees Celsius

The energy required for each step can be calculated using the formula Q = mcΔT, where Q is the energy, m is the mass, c is the specific heat capacity, and ΔT is the change in temperature.

For the first step, Q = (360g)(4.18 J/g°C)(0 - 0) = 0 J.

For the second step, Q = (360g)(333.55 J/g)(0 - 0) = 0 J.

For the third step, Q = (360g)(4.18 J/g°C)(110 - 0) = 163,080 J = 163.08 kJ.

Adding up the energies from each step, the total energy required to heat the frozen can of juice is 163.08 kJ.

Answer: a. 410 K

b. 296 K

c. 394 K

d. -180 °C

e. 224°C

f. -3 °C

Explanation:

For °C to K : use °C + 273 = K

For K to °C : use °C = K - 273

Answer:

D. If the distance between the crests of the waves increase, the frequency decreases.

Explanation:

Wavelength is the distance between two successive crests and troughs while frequency is the number of complete cycle per seconds

Velocity = Frequency × wavelength

Frequency and wavelength are inversely proportion

Final answer:

Wavelength and frequency are inversely related. As the distance between the crests of the waves increases (wavelength increases), the frequency decreases. The correct answer is D.

Explanation:

The question asks how wavelength and frequency are related. The relationship between wavelength and frequency is an important concept in physics, particularly in the study of waves. Wavelength and frequency are inversely related, meaning as one increases, the other decreases. This inverse relationship is explained by the equation c = λν, where c is the speed of the wave, λ (lambda) is the wavelength, and ν (nu) is the frequency. Therefore, if the distance between the crests of the waves increases, which means the wavelength increases, the frequency of the waves decreases since the number of waves passing a given point per unit time becomes fewer.

Given this explanation, the correct answer to the question is: D. If the distance between the crests of the waves increases, the frequency decreases. This is because the increase in distance between crests (increase in wavelength) leads to a reduction in how many waves can pass a given point in a specific amount of time (decrease in frequency).

The volume of a gas that has its Celsius temperature increased from 2°C to 4°C, while the pressure remains constant, would increase slightly due to the principles of Charles's Law in physics.

The concept behind this question is called Charles's Law from physics. This law states that the volume of a given mass of an ideal gas is directly proportional to its temperature on the absolute temperature scale (Kelvin), if pressure and the amount of gas remain unchanged.

In your case, the Celsius temperature of a fixed mass of gas is increased from 2°C to 4°C, a change of 2 degrees. In Kelvin this is a change from 275K to 277K since we add 273 to convert Celsius to Kelvin. Using Charles's Law, under these conditions, the volume of the gas would increase slightly, not significantly. As the change in temperature is very small, the change in the volume would also be small.

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Increasing the temperature from 2°C to 4°C while keeping pressure constant will result in a slight increase in the gas's volume, according to Charles's law.

The student's question is about what happens to the volume of a gas when its Celsius temperature is increased from 2°C to 4°C while the pressure remains constant.

Charles's law states that the volume of a gas is directly proportional to its temperature when the pressure is held constant. Hence, increasing the temperature in degrees Celsius – or more relevantly, in Kelvin – will also increase the volume of the gas slightly.

Since the increase in temperature from 2°C to 4°C is minimal (equivalent to an increase from 275.15K to 277.15K), the change in volume will be correspondingly small. Thus, the correct answer is that the volume of the gas will be increased slightly.

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Answer:

Yes there is

Explanation:

For facts

The maximum limit of a metal to which the force applied will not leave any deformation, this limit is called as elastic limit. If the force is applied beyond the elastic limit the metal will retain the deformation.

A metal  is an element that can easily form positive ions called cations and tends to make metallic bonds. Some of the important properties of metal are :

Elasticity of the metals by which the metal are able to regain the original shape and size even after the removal of the load; all cutting tools and metallic objects maintain their original shape due to this property.

Every metal has an optimal limit of deformation called as elastic limit, beyond this the metal will retain the deformation even after the removal of applied forces.

Plasticity is the another property of metal in which a permanent deformation occur without any fracture whenever it is subjected by external forces, it can be used  in forming shaping an extruding operation.

Ductility is the property of metals in which they can be drawn into wires or elongated, it is completely depend on tenacity and hardness, it can be higher in cold condition; For example Gold, Platinum, silver, iron etc.

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Answer:

The answer is D~all of these

D. Electronegativity and first ionization energy both increase as you

move up the periodic table.

There are various kind of elements that are present in periodic table. Some elements are harmful, some are radioactive, some are noble gases. Therefore, the correct option is option D that is Electronegativity and first ionization energy both increase as you move up the periodic table.

Periodic table is a table in which we find elements with properties like metals, non metals, metalloids and radioactive element arranges in increasing atomic number.

Periodic table help a scientist to know what are the different types of elements are present in periodic table so that they can discover the new elements that are not being discovered yet. Electronegativity and first ionization energy both increase as you move up the periodic table.

Therefore, the correct option is option D.

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Answer:

2.11 * 10²² atoms of silver

Explanation:

There will be 2.11 × 10^22 atoms of silver in 3.78 g of silver.

The term "mole" refers to a unit of measurement used to describe the number of atoms, molecules, ions, or formula units in a given chemical compound. It is comparable to other counting units like a pair (2) and a dozen (12). Avogadro's number (6.02214076 ×10²³ mol) of molecules or formula units make up one mole of a substance.

The mass of 1 mole of a chemical and the number of grams per mole are determined by the compound's molar mass. In other terms, the molar mass is the sum of the masses of all the atoms that make up a mole of a certain molecule, expressed in grams. As a result, the molar mass is measured in grams/mole.

Therefore in this case,

3.78 g Ag = [tex]\frac{1 mol Ag}{ 107.8682}[/tex] ×/[tex]\frac{6.022 * 10^{23} atoms of Ag}{1 mol Ag }[/tex]

= 2.11 × 10²²

Therefore, 2.11 × 10²² atoms in this mass of silver.

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Answer:

C. 239

Explanation:

-34 + 273.15 = 239.15

The equation to convert celsius into kelvin is C = K - 273.15

Answer:

I got the answers but it won't let me post it correctly on here....

Explanation:

9.) 10-2.76 =0.0174 [H30+]= 1.74*10-3 M

10.)10-3.65=0.00224  [H3O+] =2.24*10-2 M

11.)10-3.65=0.00224 [OH-]= 2.224*10-4M

12.)10-6.87=0.00000135  [OH-]= 1.35*10-7M

The [H3O+] and [OH-] of solutions a, b, c, and d are calculated using the formulas for pH and pOH. The [H3O+] for solutions a and b come out to be 1.74 x 10^-3 M and 2.2 x 10^-4 M respectively, while the [OH-] for solutions c and d are 2.2 x 10^-4 M and 1.37 x 10^-7 M respectively.

To calculate the [H3O+] and [OH-] in solutions, we need to use the formulas for pH and pOH. Where pH = -log[H3O+] and pOH = -log[OH-]. Therefore, for a solution with a given pH, [H3O+] can be calculated as [H3O+] = 10^-pH, and for a solution with a given pOH, [OH-] is calculated as [OH-] = 10^-pOH.

For solution a, pH = 2.76, [H3O+] = 10^-2.76 = 1.74 x 10^-3 M. Similarly, for solution b, pH = 3.65, [H3O+] = 10^-3.65 = 2.2 x 10^-4 M. For solution c, pOH = 3.65, [OH-] = 10^-3.65 = 2.2 x 10^-4 M. For solution d, pOH = 6.87, [OH-] = 10^-6.87 = 1.37 x 10^-7 M.

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Answer:

Standard Temperature and Pressure. Standard temperature is equal to 0 °C, which is 273.15 K. Standard Pressure is 1 Atm, 101.3kPa or 760 mmHg or torr. STP is the "standard" conditions often used for measuring gas density and volume.

The  values of standard temperature and  standard pressure are 273.15 K and 1 atmospheric pressure.

Standard temperature and pressure are defined as a standard set of conditions required for experimental measurements  which are established to allow comparison between different sets of data.

Standards which are commonly used are those International Union of pure and applied chemistry and national institute of standards and technology.These are not universally accepted standards  but are the ones which are commonly used.

Standard conditions of pressure and temperature are necessary  to define standard reference conditions used to express volumes of liquids and gases.

These values are important to physicists, chemists ,engineers ,pilots and navigators.

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1. The period number tells us about the number of shells in an element(for example Na located in third period has three electron shells)

2. Group number tells us the amount of electrons present in the valence shell thus also tells us about the ionic charges they form

3. They all have a stable electronic configuration with complete valence shells hence they also don't form ions.

Final answer:

The period of an element denotes the number of electron shells, while the group indicates the number of valence electrons. Group 18 elements, noble gases, share the common trait of having a full valence shell, making them non-reactive.

Explanation:

Understanding Periods and Groups on the Periodic Table

1. The period (row) in which an element is located corresponds to the number of electron shells that contain electrons. Elements in the same period have the same number of shells, with the number of electrons increasing as you move from left to right across the table.

2. The group (column) identifies the number of valence electrons in an element's outer shell. For example, all Group 1 elements have one valence electron, whereas Group 17 elements have seven valence electrons, which is significant for their chemical properties and reactivity.

3. The elements in Group 18, known as the noble gases, have a common characteristic in their electron configurations: they all have filled outer electron shells. This complete valence shell renders them very stable and non-reactive, thus they are also called inert gases.

Answer:

it is  0.0572

Hope you will find my answer helpful

To find the mole fraction of the solute in a 3.73 m aqueous solution, one must calculate the moles of solute and solvent. Upon doing so, the mole fraction is determined by dividing the moles of solute by the total moles of the mixture. The approximate mole fraction for the solute in this case is 0.063.

To calculate the mole fraction of solute in a 3.73 m aqueous solution, we need to know both the number of moles of the solute and the solvent. The given information indicates that we have 3.73 mol of solute (e.g., NaCl) per 1 Kg of water (solvent).

In this example, we calculate the number of moles of water using its molar mass, which is approximately 18.015 g/mol. Since we have 1.0 kg (or 1000 g) of water, we divide the mass by the molar mass to get the moles of water: 1000 g / 18.015 g/mol ≈ 55.5 mol. Now, we have the necessary information to calculate the mole fraction.

The mole fraction is the moles of solute divided by the total moles of both solute and solvent. Using the moles we found earlier:

So, the mole fraction of the solute is approximately 0.063.

Answer: Organic chemistry

Explanation:

Answer : The volume of [tex]O_2[/tex] gas needed are, 90 L

Explanation : Given,

Volume of [tex]H_2S[/tex] = 60 L

Now we have to determine the volume of [tex]O_2[/tex] needed.

As we know that at STP, 1 mole of gas contains 22.4 L volume of gas.

The given balanced chemical reaction is:

[tex]2H_2S(g)+3O_2(g)\rightarrow 2SO_2(g)+2H_2O(g)[/tex]

By the stoichiometry we can say that, 2 moles of [tex]H_2S[/tex] react with 3 moles of oxygen gas to give 2 moles of [tex]SO_2[/tex] gas and 2 moles of water vapor.

From the balanced reaction we conclude that,

As, [tex]2\times 22.4L[/tex] volume of [tex]H_2S[/tex] react with [tex]3\times 22.4L[/tex] volume of [tex]O_2[/tex] gas

So, [tex]60L[/tex] volume of [tex]H_2S[/tex] react with [tex]\frac{3\times 22.4L}{2\times 22.4L}\times 60L=90L[/tex] volume of [tex]O_2[/tex] gas

Thus, the volume of [tex]O_2[/tex] gas needed are, 90 L

Answer: 3.2778x10-10 moles Ca

Explanation: solution

1.974x10-¹⁴ atoms Ca x 1 mole Ca/ 6.022x10²³ atoms Ca

= 3.278x10-10 moles Ca

Answer:

Explanation:

                    x mol         6 mol

2 Al (s) +    3 S (s) →       Al2S3 (s)

                 3 mol          1 mol

6 mol Al2S3  x 3 mol S/ 1 mol  Al2S3 = 18 mol S

According to law of conservation of mass, conservation of mass is illustrated by none of the equation  as  the  number of atoms of reactants and products is  not same in any equation.

According to law of conservation of mass, it is evident that mass is neither created nor destroyed rather it is restored at the end of a chemical reaction .

Law of conservation of mass and energy are related as mass and energy are directly proportional which is indicated by the equation E=mc².Concept of conservation of mass is widely used in field of chemistry, fluid dynamics.

Law needs to be modified in accordance with laws of quantum mechanics under the principle of mass and energy equivalence.This law was proposed by Antoine Lavoisier in the year 1789.

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Answer: S8 + 8O2 => 8SO2

Explanation: The equation is now balanced. Both Sulfur have 8 atoms in the reactant and product side. Oxygen have 16 atoms on each side.

The one to determine the number of core electrons an atom has To subtract the group number from the atomic number. Therefore, option B is correct.

The charge number of an atomic nucleus is the chemical element's atomic number, also known as nuclear charge number. This is the number of protons present in the nucleus of each atom of that element, or the proton number, for conventional nuclei. Ordinary chemical elements can be uniquely identified by their atomic number.

The number of protons in an atom is the atomic number. It is sometimes referred to as the proton number for this reason. The capital letter Z is used to represent it in calculations. The word zahl, which meaning number of numerals in German, is where the letter Z originates.

The atomic number, or number of protons, is displayed in the upper left. The element's letter sign appears in the centre.

Thus, option B is correct.

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Answer:3

Explanation: I

'm not sure

The maximum number of orbitals with n = 4, L = 1 is 16, distributed among s, p, d, and f subshells.

There can be a total of 16 orbitals. These include: one 4s orbital, three 4p orbitals, five 4d orbitals, and seven 4f orbitals. Each subshell has a specific number of orbitals based on the values of ml.

The student has asked about the maximum number of orbitals with n = 4 and L= 1. In quantum chemistry, the principal quantum number n determines the shell, and the azimuthal or angular momentum quantum number L (also denoted as l) determines the subshell type. For n = 4, l can have values of 0 (s subshell), 1 (p subshell), 2 (d subshell), and 3 (f subshell). When l = 1, which is the p-type subshell, the magnetic quantum number ml can have three values: -1, 0, and +1. Thus, there are three orbitals corresponding to the p subshell when n = 4 and l = 1, namely the 4p orbitals.

Answer: A)

Explanation:

the deposition environment has changed from wind-dominated in the past to stream-dominated today.

Final answer:

The presence of dune features in the streambeds suggests that the geologic history of the area involved a change in the depositional environment from wind-dominated to stream-dominated over time.

Explanation:

The geologist studying the presence of dune features in streambeds can conclude about the geologic history of the area that there has been a change in the depositional environment. Specifically, the correct answer is D.

The depositional environment has changed from wind-dominated in the past to stream-dominated today. This conclusion is based on the understanding that dunes, with their characteristic cross-bedding patterns, are typically formed by wind in desert environments.

Thus, finding these dune features preserved in current streambeds indicates that the area was once a desert with active wind erosion and deposition, but now it is characterized by stream erosion and deposition.

Erosion and deposition are dynamic processes that reflect changes in Earth's surface through time. The study of sedimentary structures like cross-bedding is fundamental in reconstructing paleoenvironments and understanding how the forces of wind, water, and other elements have shaped the landscape.

Recognizing cross-bedding patterns within sediments allows geologists to determine the direction of the ancient winds or water flows that created them.

Answer: 9.18 L

Explanation: Solution attached.

Convert mass of CH2O to moles

Derive V from PV= nRT

Substitute the values.

An unstable isotope changes until it reaches a different element that is stable.

An unstable isotope changes until it reaches a different isotope of the same element that is stable.

Explanation:

Radioactive decay is the breakdown of an unstable (heavier) atom into stable (lighter) atom. It mainly involves the loss of atomic nucleic particles such as protons and neutrons. If protons are lost in the decay, then the element of the atom will change. However, if only a few neutrons are lost, the element may remain the same but the products will be a more stable isotope of the same element with fewer neutrons (hence also mass number)

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The statements that best describe the process of radioactive decay are:

The statements that best describe the process of radioactive decay are:

1. An unstable isotope changes until it reaches a different element that is stable.

  - This statement is correct. Radioactive decay involves the transformation of an unstable isotope into a different element, which can be stable.

2. An unstable isotope changes until it reaches a different isotope of the same element that is unstable.

  - This statement is also correct. In some cases, the process of radioactive decay can lead to the formation of a different isotope of the same element, and this isotope may remain unstable.

The other statements are not accurate:

- An unstable isotope changes until it reaches a different isotope of the same element that is unstable.

- An unstable isotope changing into a different element that is unstable is not a common outcome of radioactive decay.

- A stable isotope does not change into a different element through radioactive decay.

In summary, radioactive decay involves the transformation of unstable isotopes into different elements or isotopes, which can be either stable or unstable.

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The probable question may be:

Which statements best describe the process of radioactive decay? Check all that apply.

An unstable isotope changes until it reaches a different element that is unstable.

An unstable isotope changes until it reaches a different element that is stable.

A stable isotope changes until it reaches a different element that is unstable.

A stable isotope changes until it reaches a different element that is stable.

An unstable isotope changes until it reaches a different isotope of the same element that is unstable.

An unstable isotope changes until it reaches a different isotope of the same element that is stable.

Answer:

no <3

Explanation: