the mass spectrum for an unknown element is shown above. according to the information in the spectrum, the atomic mass of the unknown element is closest to 90amu 90 a m u 91amu 91 a m u 93amu 93 a m u 94amu

In the redox reaction that is catalyzed by lactate dehydrogenase, the oxidizing agent of this reaction is NAD+ and the reducing agent is lactic acid.

The lactate dehydrogenase (LDH) test examines for signs of injury to the body's tissues. LDH is an enzyme located in almost every cell of your body, including your blood, muscles, brain, kidneys, and pancreas. The enzyme depends on sugar into energy. The LDH test estimates the amount of LDH in your blood or other body fluid.

LDH delivers lactic acid as an end outcome through a fermentation reaction. In the process, LDH releases electrons from NADH and makes NAD+, which is channelized in the glycolysis pathway to produce ATP.

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There are 5 postulates in Dalton's atomic theory.

1. All the matter is made up of atom, they are tiny and indivisible.

2. All atoms in an element posses same properties ,mass and size but  different atom have different size and masses .

3. Atoms cannot be Sub-divided ,destroyed or can be created.

4. Compounds are formed when atoms of different elements merge with each other in a whole number ratio.

5. It can be rearranged, combined or separated by chemical reaction.

Dalton's atomic theory is on the nature of matter. He states that all matter is made up of atom and it is the smallest fundamental unit. it cannot be created or destroyed. it can be converted from one form to the other. its limitations are it does not talks about sub-atomic particles. It does not account isotopes and isobars.

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Dependent variables could be height, number of leaves, biomass, etc. The constants could be the amount of water fed to the plants and other environmental conditions apart from the temperature.

Experimental variables could be independent, dependent, or constant.

Independent variables are supplied by the researcher and are often varied or manipulated to produce different effects on experimental systems or subjects.

Dependent variables are measured. Their values are often affected by whatever independent variable the researcher supplies.

Constant variables are uniform throughout the experimental groups or subjects.

Thus, in this case, the aim is to test the effect of temperature on the growth of a plant. The independent variable is the different temperatures.

The dependent variable would be any feature of the experimental plants that indicate growth. It could the height, the number of leaves, etc.

The constant variable would be other conditions the experimental plants are subjected to.

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The mass of the remaining excess reactant after 32.5 g of KO₂ and 27.9 g of H₂O react is 22.5 g and the excess reactant is KO₂.            

The balance chemical reaction is:

    4KO₂(s) + 2H₂O(l) → 4KOH(s) + 3O₂(g)

List of given data:

Given Mass of KO₂ = 32.5 g

Given Mass of H₂O = 27.9 g

Molar Mass of KO₂ = 71.0 g

Molar Mass of H₂O = 18.0 g

To calculate the number of moles-

Number of moles =     Given mass    

                                       Molar mass

a) moles of KO₂ =    32.5     moles = 0.45 mol

                                  71.0

b) moles of H₂O =   27.9   moles = 1.55 mol

                                 18.0

KO₂ is the limiting reactant, since it gives smaller amount of KOH and H₂O is the excess reactant as  it is the only other reactant.

To calculate the mass of remaining excess reactant KO₂,

The mass of excess reactant used up,

Using Molar ratio-

1.55 mol H₂O x 4 mol KO₂ = 3.1 mol KO₂

                         2 mol H₂O

3.1 mol KO₂ x 71.0 g KO₂ =  55.0 g KO₂

                       4 mol KO₂

we start with-

32.5 g of KO₂ and using up 55.0 g

Mass of excess reactant KO₂ = 55.0 g - 32.5 g

                                                 = 22.5 g

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48.64 grams of oxygen are required to react with 14.0 grams of octane (C₈H₁₈) in the combustion of octane in gasoline.

To find the oxygen required, the given data's are:

Mass of octane = 14 grams.

Octane is a hydrocarbon which burns in gasoline in presence of oxygen.

According to the given balanced chemical equation,

C₈H₁₈ + 25/2O₂ → 8CO₂ +9H₂O or

2C₈H₁₈ + 25O₂------> 16CO₂ + 18H₂0

At first to find the moles of octane,

Molar mass of octane = 114.2 g/mol,

The mole of octane can be calculated as,

Moles = grams / Molar mass

          = 14g / 114.2 g/mol

          = 0.122 mol.

The moles of octane is 0.122 mol.

Using mole ratio from the balanced equation to find moles of O₂,

The mole ratio of octane and O₂ is 2 : 25. Let us use this as a conversion factor.

0.122 mol C₈H₁₈ × ( 25 mol O2/ 2 mol C₈H₁₈)

= 0.122 × 12.5

= 1.525 mol

We have 1.525 mol O₂.

Now, Converting moles of O₂ to grams,

The molar mass of O₂ is 32 g/mol.

The grams of O₂ can be calculated as,

1.525 mol × 32 g/mol = 48.64 grams.

48.64 grams of oxygen are required.

Hence, 48.64 grams of oxygen are required to react with 14.0 grams of octane ( C₈H₁₈ ) in the combustion of octane in gasoline.

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When the experiment is performed with 0.35g of potassium, less hydrogen gas is created, which has an impact on the volume of gas produced.

What are the properties of potassium?

A silvery-white metal, potassium is malleable enough to be easily sliced with a knife. Within a few of seconds, potassium metal combines quickly with ambient oxygen to produce flaky, white potassium peroxide.

Potassium metal is a good conductor of heat and electricity, is soft and white with a silvery luster, and has a low melting point. A flame colored with potassium has a lavender hue, and its vapour is green. With 2.6 percent of the mass of the crust's mass, it is the eighth most common element there.

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Energy is released because it is a combustion reaction.

Combustion reaction -

Hydrocarbon bonds are broken during combustion events, and more energy is always released during the formation of water and carbon dioxide bonds than was consumed to break the initial hydrocarbon bonds. Burning materials that are primarily made of hydrocarbons produces energy because of this. This is an exothermic reaction.

2C₂H₆ + 7O₂ → 4CO₂ +  6H₂O + Heat

(ethane)

In the process of burning, or combustion, the reactant takes up oxygen and oxidizes it, releasing energy in the form of heat and light. It happens quickly. Along with the energy created during burning, carbon dioxide and water vapor are also produced.

Hence heat and light which are forms of energy are released during combustion reaction.

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Vapours should be contained to the reaction flask.

What is  properly refluxing?

Reflux is the process of heating a chemical reaction for a predetermined period of time while steadily employing a condenser to cool the resulting vapour back into liquid form. The condensation of the vapours created above the reaction results in their constant return to the flask as a condensate.

Therefore,

When a reaction is properly refluxing, where should you see the vapors from the heated mixture

Vapours should be contained to the reaction flask.

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The pressure in a 20.4 l cylinder filled with 0.682 mol of nitrogen gas at 324 k  is 0.889 atm.

The force exerted perpendicular to an object's surface per unit area across which that force is spread is known as pressure (symbol: p or P).445 Gauge pressure, sometimes written gauge pressure, is the pressure in relation to the surrounding air pressure.

Pressure is expressed using a variety of units. Some of these come from dividing a unit of force by a unit of area; the standard unit of pressure in the imperial and U.S. customary systems is the pound-force per square inch (psi), which is equivalent to one newton per square meter (N/m2) in the SI.

using the ideal gas formula:-

[tex]p = \frac{nRT}{V}[/tex]

   = [tex]\frac{ 0.682 mol * 0.0821 L .atm.K^{-1 }mol^{-1} * 324k }{20.4}[/tex]

   =0.889 atm

The pressure in a 20.4 l cylinder filled with 0.682 mol of nitrogen gas at 324 k  is 0.889 atm.

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Answer:

Protons=12

Electrons=12

Neutrons=12

Reduce Vehicle Emissions decrease the amount of CO2 being removed from the atmosphere

Many of us drive cars every day, which are one of the greatest sources of CO2 in our environment. With a share of 31% of all emissions, this is the second-largest source of carbon dioxide produced in the US. However, this is not simply restricted to personal vehicles; anything that has an engine powered by gasoline or diesel contributes to this issue.

Limiting the quantity of CO2 your own car emits is the best personal solution to this problem. To make all of your journeys a little less wasteful, choose a hybrid or gas-efficient car. Additionally, carpool with colleagues or acquaintances, or whenever possible, take public transit to reduce the automobiles moving through the streets.

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automobiles moving through the streets.

At neutral pH, both H-indictor and OH-indicator will co-exist in an equilibrium, so the color will be a mixture of the two.

Acid base indicators are generally weak protolytes that change color in solution according to the pH.

The acid-base equilibrium of a weak acid type of indicator, i.e., H-indicator in water can be expressed as-

            HI + H₂O ⇄ H₃O⁺ + I⁻

The acid, HI, and conjugate base, I⁻, have different colors. The equilibrium expression for this process is

             K = [I⁻] [H₃O⁺]

                         [HI]

This can be expressed in logarithmic form :

            pH = pK + log [I⁻]

                                    [HI]

Now, from the equation it can be predicted whether the indicator is in its acid or base form depending on the pH.

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269.8 temperature in kelvin of your freezer if the new volume of the bottle is 1.81

Kelvin having a thermometric scale on which the unit of measurement equals the Celsius degree and according to which absolute zero is 0 K, the equivalent of −273.15°C

Here given data is an empty 2.00 L soda bottle at room temperature (25.0°C) means 298.15 kelvin and then you put the soda in the freezer then the process is assumed to be a constant pressure and moles

Charles law applies V₂/V₁ = T₂/T₁

Then you have to use absolute temperature scale means in kelvin and 2 be the state solving

T₂ = T₁(V₂/V₁) = 298.15 K (1.81 L / 2L)

= 269.8 temperature in kelvin in the freezer if the new volume of the bottle is 1.81L

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4 half-lives should have elapsed if 6. 25% of the parent isotope remains in an exceeding fossil at the time of analysis.

What are parent-isotope?

Parent isotopes are the isotopes of a specific chemical element that can undergo radioactive decay to form a different isotope from a different chemical element. During this decay, these isotopes release decay particles like alpha, beta, and gamma rays.

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If a beaker of water is mixed with BTB, the colour of water will turn to yellow to determine the presence of carbon dioxide in the water.

What kind of chemical is Bromothymol Blue (BTB) ?

A pH indicator is bromothymol blue. It is frequently used to determine whether carbonic acid is present in a liquid, which is one application where it is necessary to measure chemicals that would have a pH that is quite neutral. The sodium version of the acid indicator is usually offered in solid form.

It displays acids and bases by changing color, making bromothymol blue a pH indicator. Bromothymol blue changes color when an acid or base (such as sodium sulfite) is added. It becomes yellow when an acid is added. A neutral color is green (like water).

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10 milliliters of a stock solution of 10.0 M HNO3 would be used to prepare 0.500 L of 0.200 M HNO3

Let M1 and V1 represent the concentration and volume of the stock solution, M2 and V2, respectively, and M1 and V1 represent M2 and V1, the concentration and volume of the diluted solution.

As a result, using the dilution formula, we get:

M1V1=M2V2.

Given information: M1=10 M.

V1=?

M2=0.2 M.

V2=500 ml.

To find V1 as shown below, we replace all the values in the formula above.

V1=M2V2/M1

V1=(0.2)(500)/10

=10 ml.

Hence To obtain the aforementioned concentration, the stock solution must be diluted by 10 ml.

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All the masses of the elements are determined relative to 12C. Since many elements have a number of isotopes, chemists use average atomic mass. On the periodic table the mass of carbon is reported as 12.011 amu.

The triple-alpha process, which creates carbon-12 in stars, accounts for its abundance, which accounts for 98.93% of the element carbon on Earth. Carbon-12 (12C) is the more abundant of the two stable isotopes of carbon (carbon-13 is the other). Since carbon-12 is used as the reference point to calculate the atomic masses of all other nuclides, its atomic mass is 12 daltons by definition, which makes it particularly significant. Six protons, six neutrons, and six electrons are found in carbon-12.

A resonant, excited, spinless form of carbon-12 is known as the Hoyle state. In 1954, Fred Hoyle predicted that it would exist. It is created using the triple-alpha process.

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535 mL of 0.7 M SrCl2 solution needs 2.77 liters of 0.270 m NaF solution to react completely.

The amount of a solute per unit volume of a solution, or the concentration of a chemical species in a solution, is expressed as a solute's molar concentration. The number of moles per liter, denoted by the unit symbol mol/L or mol/dm³ in SI units, is the most often used unit denoting molarity in chemistry.

The balanced equation:

SrCl₂ (aq) + 2NaF (aq) ⟶ SrF₂ (s) + 2NaCl (aq)

The number of moles of SrCl₂ present is:

= 0.535 L × 0.700 mol L⁻¹

= 0.3745 moles

The number of moles NaF needed to react is:

[tex]=0.3745 {~} \text{mol} {~}SrCl_{2} \times \frac{2{~}\text{mol}{~}NaF}{\text{mol}{~}SrCl_{2}}[/tex]

= 0.749 mol NaF

Therefore, the volume of NaF is:

[tex]( x {~}\text{L} ) \times 0.270 {~}mol {~}L^{-1} = 0.749{~} moles[/tex]

[tex]x=\frac{0.749 \text{mol}}{0.270{~} \text{mol}{~}L^{-1}}[/tex]

[tex]x=2.77{~}\text{L}[/tex]

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option (b) is correct .

The ph at the equivalence point is 7 for a weak acid-strong base titration.

There is no hydrolysis in the case of titration of a strong acid with a strong base (or strong base with strong acid), and the solution pH is neutral - 7.00 (at 25°C). The weak acid salt hydrolysis determines the pH at the equivalence point in the case of titration of a weak acid with a strong base.

The weak acid salt hydrolysis determines the pH at the equivalence point in the case of titration of a weak acid with a strong base. That means we must first determine the pK b of the conjugated base and calculate the concentration of OH, and then apply the pH=14-pOH formula.

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Liquid sodium is being considered as an engine coolant.  709,415.58 g.

The chemical element sodium has the atomic number 11 and the letter Na, which derives from the Latin natrium. It is a malleable, silvery-white, and extremely reactive metal. In group 1 of the periodic table, sodium is an alkali metal. Only 23Na is a stable isotope of it. It is necessary to prepare the free metal from compounds because it does not exist in nature.

Numerous minerals, including feldspars, sodalite, and halite, include sodium, which is the sixth most prevalent element in the Earth's crust (NaCl). Since the Earth's minerals have been slowly leached of their sodium ions over eons by the action of water, many salts of sodium are very water soluble. As a result, sodium and chlorine are the most prevalent dissolved elements by weight in the oceans.

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Some compounds can be seen under uv light becasue they are inherently fluorescent and usually glow brightly.

What are fluorescent compounds?

the light that a material emits when exposed to photons of a different wavelength. When exposed to UV radiation, a fluorescent object frequently emits visible light. The fluorescent properties of some deep sea fish and fireflies are examples of fluorescence in nature.

When a substance passes through fluorescence, it emits light after having absorbed light or other electromagnetic radiation. B2 emits a yellow colour while fluorescing. Tonic water glows blue because it contains quinine. Benzimidazoles, benzothiazoles, coumarins, vitamins like cyanocobalamine, fluorene, and pentacene are examples of fluorescent materials.

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When an electrical utility charges higher prices during the day than at night, it is practicing is peak load pricing.

The demand for the many goods is larger during certain times of the day or week. For example, the roads are congested during rush hours during the morning and evening commutes. Electricity has larger demand during day than at night. Ski resorts have large (peak) demands during weekends, and smaller demand during the week.

Economic efficiency is greatly improved by charging the higher prices during peak times. If utility were required to charge a single price at all times, it would lose ability to charge consumers an appropriate price during peak demand periods. Charging higher price during peak hours provides an incentive for consumers to switch consumption to off-peak hours. This saves the society resources, since costs are lower during those times.

An example is an electricity consumption. If consumers are charged higher prices during the peak hours, they are able to shift some electricity demand to night, the off-peak hours. Dishwashers, laundry, and the bathing can be shifted to off-peak hours, saving the consumer money and saving society resources. Electricity companies also promote the “smart grid” technology that automatically turns thermostats down when individuals and families are not at home… saving the consumer and society money.

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The chemical structure of the ammonium ion, NH4, resembles that of CH4 the most.

What is tetrahedral geometry?

When there are four bonds and no lone pairs in the core atom of the molecule, the molecule is said to be tetrahedral. With 109.5° angles between them, the atoms that are bound to the core atom are positioned at its four corners.

A central atom in tetrahedral molecular geometry is situated in the middle of the four substituents that make up the corners of the tetrahedron. Complexes with metals in the d0 or d10 electron configuration frequently have tetrahedral shape.

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Answer:

D

Explanation:

They have same number ofnprotons in their shells.

Answer:

See below.

Explanation:

Since energy is released when bonds form, the process of burning food can be explained through exothermic reactions. We use food as a resource to obtain energy through calories, where the chemicals that makeup food result in endothermic reactions to fulfill our dietary needs. As a result, that energy MUST be released since energy can neither be created nor destroyed. Therefore, it must come out as the bonds are broken (usually hydrogen bonds during the process of cellular respiration). While calories are being burned, energy is released, causing bonds to break and resulting in exothermic reactions.

If the final temperature of the water is 28.1 °c, then the identity of metal is Ag.

What is Ag metal?

With the atomic number 47 and the symbol Ag (from the Latin argentum, which is derived from the Proto-Indo-European h2er: "bright" or "white"), silver is a chemical element. It is the highest electrical, thermal, and reflectivity of all metals, and it is a soft, white, lustrous transition metal.

The Latin argentum and Sanskrit argunas, both meaning "bright," are where the word "Ag" originates. Even in the Stone Age, silver was used. Silver use dates back at least 5000 years, according to archeological findings.

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Catalytic converters reduce the engine's tailpipe emissions of unburned hydrocarbons and carbon monoxide and can be recycled. The above statement is true.

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Effects of carbon monoxide partial pressures on the synthesis of medium chain fatty acids and methanogenesis during the fermentation of ethanol is to sustained electron and carbon donor for fatty acid elongation.

What is methanogenesis?

Methane is the end product of metabolism and is produced by methanogenesis, an anaerobic respiration. Organic matter, such as glucose, is oxidized to CO2 in aerobic respiration, and O2 is reduced to H2O. H2 is oxidized to H+ while CO2 is converted to CH4 during hydrogenotrophic methanogenesis, in contrast.

The major goal of this research was to ascertain whether increasing the formation of acetate or MCFA during the fermentation of ethanol would result from inhibiting methanogenesis by adding CO continuously.

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Answer: thermal radiation

Explanation: