chemistry?
what is it?
Why do we use it?
explain in 3-5 sentences each question.​

The following is the letter explaining how ground water could heat the air in the school.

Dear David Li,

Thank you for your concerns about the proposed groundwater heating system for Riverdale School. I understand your concern that 30°C water may not have enough energy to heat the school, but I assure you that the groundwater system is designed to effectively heat the air in the school.

The groundwater system works by pumping warm water from underground wells into a heat exchanger. The heat exchanger then transfers the heat from the water to the air, which is then circulated throughout the school via a forced air system. This process increases the temperature of the air in the school, providing warmth to the students and staff.

In terms of the temperature of the school, it is important to note that the proposed groundwater system is designed to maintain a stable temperature in the school. This means that the system will work to keep the air temperature at a comfortable level, regardless of the outside temperature. The stable temperature in the school will provide an optimal learning environment for the students, allowing them to focus on their studies.

I hope this explanation clarifies how the groundwater system can effectively heat the air in the school and provides the necessary stability for the students to focus on their learning. If you have any further questions or concerns, please do not hesitate to reach out.

Sincerely, [Your Name]

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If an observer in the northern hemisphere was to face south at noon on January 1, they would be presented with a unique sight.

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The boiling points of alkenes and alkynes are generally lower than those of alkanes.

phase observed:

a.) Methane, Ethane, Propane, and Butane are in a gaseous form in Alkanes (Table 1).

The liquid states of pentene, hexane, heptane, and octane are present.

in alkenes (table 2)

Gaseous forms of ethene, propane, and 1-butane exist.

Both one-pentene and one-hexene are liquids.

c.) Ethyne, propyne, and 2-butane are in the gas phase whereas pentyne is in the liquid phase in the alkynes (table 3).

Number of carbon atoms actually seen:

Alkanes - join one carbon atom to another in a single bond.

Double bonds between carbon atoms are formed in alkenes.

Triple bonds between carbon atoms are formed in alkynes.

Boiling point:The structure of alkanes, alkenes, and alkynes is shown by their boiling points. when a material transitions from the liquid to gas phases, its temperature.

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CH4 is non polar, co and CH3CL is polar and dipole-dipole and dispersion,NH3 is hence hydrogen-bonding, dipole-dipole, and dispersion.

Being non-polar, CH4 As a result, it will only disperse!

Since co and CH3cl are both polar, they will dipole. Interaction

Mey cannot create hydrogen bonds since neither NO nor GDF have been damaged by hydrogen.

Therefore, co and CH3cl are merely dipole-dipole and dispersion.

Because H is connected to its hydrogen atoms, NH can create hydrogen bonds.

NH3 is hence hydrogen-bonding, dipole-dipole, and dispersion.

Intermolecular forces can be divided into three categories: hydrogen bonds, dipole-dipole interactions, and London dispersion forces (LDF). Despite the fact that molecules can have any combination of these three types of intermolecular forces, all substances at least contain LDF.

Classify each substance based on the intermolecular forces present in that substance. Hydrogen bonding, dipole-dipole, and dispersion Dipole dipole and dispersion only Dispersion onlyof 1.CH4, 2. co and ch3cl 3. nh3

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The statement the force of gravity attracts the sun and all the other planets in the solar system toward each other is True.

The force of gravity is a universal force of attraction that exists between any two masses in the universe. It is the force that gives objects weight and keeps them bound to the Earth's surface. The force of gravity is equal to the mass of an object multiplied by the gravitational constant.

Therefore, with this data, we can see that it is True that the gravitational pull between the sun and all the other planets in the solar system causes them to be drawn toward one another.

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Some solute will precipitate If a supersaturated solution is introduced to a mechanical disturbance or a seed crystal.

Any disruption or addition of a seed crystal will cause the solute to precipitate out of solution and crystallize in a supersaturated solution, which is a sensitive system.When the concentrations are on the solubility curve, saturation (crystallization and condensation) takes place. The solution is referred to as supersaturated if the concentrations are higher than the solubility curve. Supersaturation can happen through three different mechanisms: precipitation, nucleation, and metastable. In rare circumstances, it is possible to make a solution that behaves strangely and contains more solute than is found in a saturated solution. This is known as a supersaturated solution. Supersaturated solution or super solution is the term used to describe such a solution.

complete question:If a supersaturated solution is introduced to a mechanical disturbance or a seed crystal, what will happen?

Select the correct answer below:

there will be further dissolution

some solute will precipitate

the solution will heat up

depends on the solution

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The amount of d will be produced in the hypothetical reaction is calculated as 35g

Raw materials called reactants engage with one another to create products. Under the appropriate conditions, such as temperature, time, or pressure, the chemical bonds of the reactants are broken, and the atoms create new bonds that result in various combinations.

A      + B     =>     C     + D

25g     21g         11g       xg

According to the law of conservation of mass

=> Reactants - Products = 0

25 + 21 -(11 + x) =0

X => 25 + 21 - 11  = 35g

When atoms develop or destroy chemical bonds, chemical processes happen. Reactants are the substances that commence a chemical reaction, while products are the substances that are produced as a result of the reaction. A substance that is present following a chemical reaction is known as a product.

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Answer:

Answer: A, C, and D

Momentum can be thought of as mass in motion. An object has momentum if it has its mass in motion. It matters not whether the object is of large mass or small mass, moving with constant speed or accelerating; if the object is MOVING, then it has momentum!

Explanation:

i did it to

The net ionic reaction for each of the reaction is

a) [tex]3Pb^{2+} + 6Cl^----- > 3PbCl{2}[/tex]

b) [tex]3Sr^{2+} + 2PO_{4} ^{3-} ---- > Sr_{3}( PO_{4}) _{2}[/tex]

c) [tex]2Ag^+ + 2I^- --- > 2AgI[/tex]

d) [tex]Cu^+ + CO_{3} ^{2-} ----- > Cu_{2} CO_{3}[/tex]

We have to note that if we talk about the net reaction equation, we can be able to talk about the final ionic reaction after we have removed the spectator ions. Note that when we speak of the spectator ions, we mean the ions that do not take part in the reaction.

In this case, we have been give the precipitate in each of the reactions and we can use the formula of the precipitate to be able to deduce the net ionic reaction that took place.

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Initially there are 3.4 mol of a and 7.5 mol of b in a 20.0 l container. if there is 0.57 mol of a at equilibrium then the value of kp is 0.0036.

Kp will be used to represent the equilibrium constant expression in terms of partial pressure. Equilibrium constant Kp is measured when the partial pressure of products is divided by the partial pressure of the reactants as well as the partial pressure will be raised with some power which is equal to the coefficient of the substance present in the balanced chemical equation.

                     A    +     B     ⇆     2C

t = 0              3.4         7.5            0

Equilibrium  3.4 - x     7.5 - x      2x

According to the question,

2x = 0.57

x = 0.57/2 = 0.285

Kc = (2x)²/{(3.4 - x) (7.5 - x)}

Kc = (0.285)²/(3.115 × 7.215)

Kc = 0.081225/22.47425

Kc = 0.0036

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The reaction you provided is a combination of an oxidation-reduction (redox) reaction and an acid-base reaction. The oxidation-reduction component of the reaction is the conversion of As(III) to As(V) and the conversion of NO3- (nitrate) to NO (nitric oxide). The acid-base component of the reaction is the conversion of H+ (hydrogen ions) to H2O (water).

Here is the step-by-step oxidation-reduction reaction:

As(III) (arsenite) is oxidized to As(V) (arsenate) by losing electrons:

As(III) → As(V) + 3e-

NO3- (nitrate) is reduced to NO (nitric oxide) by gaining electrons:

NO3- + 4H+ + 4e- → NO + 2H2O

The electrons lost by As(III) are gained by NO3-:

As(III) + NO3- → As(V) + NO + 2H2O

The acid-base component of the reaction is the conversion of H+ (hydrogen ions) to H2O (water) by reacting with the water generated by the oxidation-reduction reaction:

2H+ + 2H2O → 4H+

The overall balanced equation of this redox reaction is:

As₂O3 + H+ + NO3- → H₂ASO4 + NO

Please note that As₂O₃ is Arsenic trioxide and H₂ASO₄ is Arsenic Acid and NO is Nitric oxide.

These comprise variables that you alter to test a hypothesis, variables that you measure to ascertain findings, and variables that you maintain constant to design an experiment that is legitimate.

The fundamental categories of variable that are pertinent to experiments are as follows. A variable that is altered as part of an experiment is known as an independent variable. constant variables used throughout the investigation. the amount of water provided to each plant, the room's temperature and lighting conditions, and other factors. Three dependent and one independent variables make up this experiment. The biomass of the crops during harvest is the dependent variable. The definition of your variables and the choices you make regarding their manipulation and measurement are crucial components of experimental design.

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Based on the solubility of salt (NaCl) in water at room temperature which is 35.9 grams of NaCl per 100 grams of water,  if 50 grams of NaCl are stirred into 100 grams of water, there will remain an excess of undissolved sodium chloride in the solution.

The greatest concentration of a solute that may dissolve in a solvent at a specific temperature is known as the solubility of that solute.

There are three types of solutions based on the amount of dissolved solute:

The solution is deemed saturated when the solute concentration reaches its maximum.

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What will happen is that the unit will cancel out leaving out a factor, hence, option B is the answer.

A unit of measurement is a specific magnitude of a quantity that has been established and recognized by law or convention and is used as a benchmark for measuring other quantities of the same kind. A multiple of the unit of measurement can be used to express any other quantity of that type. A length, for instance, is a physical quantity.

A unit is a quantity with a fixed magnitude that is used to determine other quantities' magnitudes in the same way. Any standard used to compare measurements is known as a unit. Measurements of a property that have been recorded using multiple units can be converted, for example, from centimeters to inches.

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Answer:

The units cancel out so the answer is B

Explanation:

Water boils at a temperature lower than 100° C at higher altitudes because atmospheric pressure is lower as you increase altitude.

Boiling point is defined as the point at which the vapor pressure of the liquid and the pressure of the environment surrounding it are equal.

At boiling temperature, because there is no difference between the atmospheric pressure around the liquid and the vapor above it, the liquid changes into vapor.

Basically on a mountain top, the atmospheric pressure is somewhat lower than at sea level, because there is a lower "weight" of atmosphere pushing down. Therefore, the temperature at which the vapor pressure reaches the same value as atmospheric pressure is somewhat lower than at sea level.

This is why when we try to make tea on a very high mountain it is not very successful - the water does boil, but the temperature at which it boils is so insufficient to get the flavor and extracts out of the tea!

On a mountaintop, the ambient pressure is reduced from 1 atmosphere, and thus we heat to a temperature reduced from the normal boiling point such that the liquid vapor pressure is equal to the reduced ambient pressure.

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1. 2Na : Cl2

2. 24 and 36.

3. The reactant mass is 372 grams and the product mass is 372 grams.

4. 3.92 moles

To calculate T2:

ln(5) = (53.11*10^3 J/mol)/(8.314 J/mol.K) * (1/293 - 1/T2)

T2 = (53.1110^3 J/mol)/(8.314 J/mol.Kln(5)) + (1/293)^-1

T2 = 674.9 K

Therefore, the temperature at which the vapour pressure of the substance is 5 times higher than it was at 293 K is 674.9 K.

The heat of vaporization is the energy required to convert one mole of a substance from the liquid to the gaseous state. The vapor pressure of a substance is the pressure exerted by its vapor when in equilibrium with its liquid form at a given temperature.

Vaporization is the process of transforming a liquid into a gas. It is also known as evaporation. Since we know that the particles of a gas are moving faster than those of a liquid, an input of energy must be required for a liquid to become a gas.

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2 of 1H NMR signals for this isomer of xylene and the ratio 1:1 in which they appear.

An aromatic hydrocarbon called xylene is utilised extensively as a solvent in both industry and medical technologies. It is a colourless, sweet-smelling liquid or gas that is present in crude wood spirit but also naturally exists in petroleum, coal, and wood tar. Its chemical formula is C6H4(CH3)2, and it is known as dimethyl benzene because it has a six-carbon ring that has two methyl groups linked to it. The three isomeric forms of it are ortho-, meta-, and para-xylene. In the production of coke fuel, the catalytic reforming process and coal carbonization result in the production of xylene, an essential petrochemical. Depending on the source, it can also be found in crude oil in concentrations ranging from 0.5% to 1%.

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The molar molar concentration of the solution is 1.4 M. of a solution made by  dissolving 2. 9g sodium acetate, NaC2H3O2 in water.

What is the molar concentration of a solution made by dissolving 2. 9g sodium acetate, NaC2H3O2 in water to a total volume of 25mL?

To calculate the molar concentration of the solution, we first need to determine the number of moles of sodium acetate present. This can be done using the formula:

moles = mass / molar mass

Where mass is the amount of sodium acetate in grams and molar mass is the molar mass of sodium acetate (82.03 g/mol).

so, moles = 2.9 g / 82.03 g/mol = 0.035 moles

Next, we can use the formula for molarity (M):

M = moles of solute / liters of solution

We know that the total volume of the solution is 25 mL, we will convert it into liter (L)

so, M = 0.035 moles / (25 x 10^-3 L) = 1.4 M

Therefore, the molar concentration of the solution is 1.4 M.

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Sodium chloride solution that can be prepared from the stock solution is 2,000 mLA.

A 0.45% sodium chloride solution needs to be prepared. A 1,000 ml supply of sodium chloride 0.9% is available at the drugstore. As directed by your doctor, the final amount of the 0.45% sodium chloride solution that can be prepared from the stock solution is 2,000 mLA. This solution is typically supplied by injection into a vein. It can be given at home, in a doctor's office, or in a hospital. If you intend to use this product at home, ask your health care practitioner for all preparation and usage instructions. Check the product visually for any specks or dis-coloration before using. In the event of either, do not use the liquid. If you intend to combine this solution with another medication, check with your doctor or pharmacist first before acting, do this. Find out how to handle and dispose of medical supplies properly. Your age, weight, health, and how you respond to treatment all go into the dosage.

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Answer:

-a covalent bond.

Explanation:

The enthalpy change for a reaction where activation energy for both forward and reverse reactions is the same value is zero.

Enthalpy change (ΔH) is a measure of the heat absorbed or released during a chemical reaction. It is the difference in the enthalpy of the reactants and products. The activation energy (Ea) is the energy required to overcome the energy barrier between the reactants and products to allow a chemical reaction to occur.

If the activation energy for both the forward and reverse reactions of a chemical process is the same value, it means that the energy required to go from reactants to products is the same as the energy required to go from products to reactants. Therefore, the enthalpy change of the reaction is zero. The enthalpy change of the reaction is given by the difference in the enthalpy of the reactants and products.

ΔH = H(products) - H(reactants)

Therefore, if the activation energy for the forward and reverse reactions is the same, the enthalpy change for the reaction is zero.

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Account for a relative atomic mass of magnesium that was less than usual on another planet Because the atomic mass stated is a weighted average of such different isotopes.

The amount of neutrons within the nucleus can cause two atoms of the same element to possess the same Atomic Number however a different Relative Atomic Mass. Isotopes were elements having varying mass numbers. The quantity of electrons has no effect on the relative atomic mass.

The weight in grams of both the number of atoms from an element represented in 12.00 g of carbon-12 was described as the element's absolute atomic mass. To determine the relative atomic mass of chlorine, take the average mass of one chlorine atom and multiply it by 100.

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The study of chemicals originating from plants and animals is referred to as biochemistry.

Brioche mixes biology and chemistry to study living things. It propels advancements in forensics, medicine, or nutrition, among other fields of science and medicine. Understanding chemical interactions at the molecular level through biochemistry can aid in expanding your understanding of the universe and its applications.

Structured biology, enzymology, and metabolism are the three subfields of biochemistry, a branch of both biology and chemistry. Biochemistry has proven effective in elucidating life processes that use these three disciplines over the later decades of the 20th century.

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The compound octane is a hydrocarbon with the molar mass of 114.26 g/mol. It contains 8 carbon atoms and 18 hydrogens. Hence, the molecular formula is C₈H₁₈.

Hydrocarbons are organic compounds containing carbon -hydrogen bonds. Alkanes are saturated hydrocarbons with the general formula of CₙH₂ₙ₊₂.

Given the molar mass of octane  = 114.26 g/mol

mass of hydrogen = 18.17 g.

atomic mass of H = 1.009 g/mol

then, number of moles of H  = 18.17 /1.009 = 18 moles.

Thus, there are 18 hydrogens.

Now, the mass of carbons = 114.26 -18.17 = 96.6 g

atomic mass of carbon = 12 g/mol

no.of moles of carbon = 96.6/12 = 8 moles

Thus, there are 8 carbons.

Therefore, the molecular formula of octane is C₈H₁₈.

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The molar mass of a compound is defined as the sum of the molar masses of the various elements that makes up the compound.

The molar mass of the medication, C₁₇H₂₀O₅S can be obtained as follow:

Molar mass of C₁₇H₂₀O₅S = (17 × 12) + (20 × 1) + (5 × 16) + 32

Molar mass of C₁₇H₂₀O₅S = 204 + 20 + 80 + 32

Molar mass of C₁₇H₂₀O₅S = 336 g/mol

The number of mole of medication in one tablet can be obtained as follow:

Mole = mass / molar mass

Number of mole of one tablet = 0.125 / 336

Number of mole of one tablet = 0.000372 mole

The number of mole of firocoxib that Dobby takes each day can be obtained as follow:

Mole = mass / molar mass

Number of mole of tablets taken each day = 0.1875 / 336

Number of mole of tablets taken each day = 0.000558 mole

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Answer:

The correct response is:

1• Cu(1)CI 5.00 A, 10 min Mass of Cu deposited =4.97g

This is true because by using Faraday's laws of electrolysis, the mass of copper deposited is directly proportional to the current and time.

The molar mass of copper is 63.5 g/mol, and the Faraday constant is 96485 C/mol.

Cu(1)CI has a current of 5.00 A and a time of 10 min, so the mass of Cu deposited can be calculated as:

mass of Cu deposited = (5.00A * 10min * 96485C/mol) / (63.5g/mol) = 4.97g

The other options are not true as they don't match the given current and time.

60 years must pass to reduce a 25 mg sample of cesium 137 to 6.25 mg.

A first-order reaction is one in which the rate of reaction is linearly dependent on the concentration of only one reactant, ie. in a first-order reaction, the rate is affected by changes in the concentration of only one of the reactants. Radioactive decay is an first order reactio of chemical kinetics.

Equation of first order reaction is : kt = 2.303 log [A₀]/[A]

Given, half life = 30 years means that k(30) = 2.303 log [A₀]/[A₀/2]

k(30) = 2.303 x log 2

k(30) = 2.303 x 0.3010

k(30) = 0.693

k = 0.693/30

k = 0.0231

Now, we know the value of k. Putting this value in the first order reaction :-

kt=2.303 log [A₀]/[A]

0.693/30 x t(in years) = 2.303 log 25/6.25

(log2 x 2.303 x t)/30 = 2.303 log 4

(log2 x 2.303 x t)/30 = 2.303 x 2log2

t/30 = 2

t=60years

Other approach would be, in this first order reaction of chemical kinetics, according to question, one half life passes. After one half life, amount of radiactive substance becomes half. So, if initially we had 25 mg of cesium-137, after one half life, we'd have half of this value = 12.5 g remaining cesium-137. After another half life, we'd have half of this value = 6.25 mg. Hence, we reached the required amount of sample in 2 half lives = 2 x 30 years = 60 years.

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The equilibrium constant, Ka, for the acid is 1.08 x [tex]10^{-13}[/tex].

For the equilibrium constant, Ka, for a monoprotic acid, we can use the relationship between the acid's dissociation constant (Ka) and the acid's concentration and the pH of the solution.

The relationship between the acid's dissociation constant (Ka), the acid's concentration (c), and the pH of the solution (pH) is given by the following equation:

Ka =   [tex]\frac{(H+)^{2}}{HA}[/tex]          

Where [H+] is the concentration of hydrogen ions in the solution, [HA] is the concentration of the acid, and [A-] is the concentration of the conjugate base.

We know that the acid concentration is 0.0126 M and the pH of the solution is 6.51. We can use this information to calculate the hydrogen ion concentration in the solution using the following equation:

pH = -log[H+]

[H+] =  [tex]10^{-pH}[/tex]

[H+] = [tex]10^{-6.51}[/tex] = 3.16 x [tex]10^{-7}[/tex]

So, the hydrogen ion concentration in the solution is 3.16 x 10^-7 M

We can now use this information to calculate the equilibrium constant, Ka, for the acid:

Ka =  [tex]\frac{(H+)^{2}}{HA}[/tex]

Ka =  [tex]\frac{(3.16 * 10^{-7}) ^{2} }{ 0.0126}[/tex]

Ka = 1.08 x [tex]10^{-13}[/tex]  

So, the equilibrium constant, Ka, for the acid is 1.08 x [tex]10^{-13}[/tex].

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Answer:

Explanation:

a) 202.4 g

b) 185.24 m

c) 0.13 dm

d) 6.91 L

e)0.0546 mol

f) 2.7 s

g) 42kg

h) 0

i) -0.11 g

j) -0.34 mL