Answer:
gold wire (Au)
Explanation:
A substance that cannot be separated or broken down into simpler substances by chemical means is an element.
Between the given options only gold wire is an element, Au.
A way of knowing that it is an element is noticing that its formula is a single symbol which corresponds to an element found in the periodic table, unlike a combination of said symbols (like NaCl or H₂O).
An absorption measurement with a 1 cm path length yields a reading of 0.002 absorbance units with a noise of 0.0005 absorbance units and a mean noise reading of 0 for 5 scans averaged together. Assuming the noise for a single scan does not change if the path length is increased to 5 cm and the number of scans is increase to 65, what is the signal to noise of the new measurement. Remember signal averaging
Answer:
Assuming the noise remains constant, the total noise for the longer path length, 65 scans should be 0.0005 x 65 = 0.0325 absorbance units. The new reading should be 0.01 absorbance units. The signal to noise ratio (SNR) of the new measurement will be 0.01/0.0325 = 3.08.
Signal averaging decreases the magnitude of the residual noise and increases the SNR. The total noise decreases by the square root of the number of scans, in this case √65 = 8, so for 65 scans, the noise level is 8 times lower than for a single scan.
Does anyone know these answers?
Correct me if I'm wrong but from my knowledge:
5, 6, 10, 11, 12, 15, 16, 17, 18, 19, and 20 would be a covalent bond
7, and 8 would be a metallic bond
9, 13, and 14 would be an ionic bond
By what factor is the rate of a reaction changed if an enzyme lowers the Ea by 9.0 kJ/mol at 37°C? O 2.2 times O 10.2 times
O 7.0 times
O 15.1 times
O 32.9 times
If an enzyme reduces the Ea, the given statement states that the reaction rate will alter seven times.
What does the term "reaction" in chemistry mean?In a chemical reaction, one or more substances—also known as reactants—are changed into one or more additional compounds are known as products. Chemical elements or chemical compounds make up substances.
K1 and K2 are the initial and end rate constants.
Given,
Ea1 - Ea2 = 5 KJ/mol
= 5000J/mol
T = 37 oC
= 310 k
Use,
ln(k2/k1) = (Ea1 - Ea2)/(R*T)
ln(k2/k1) = 5000/(8.314*310)
ln(k2/k1) = 1.94
k2/k1 = 6.96
= 7
Since the rate constant increased by seven.
As a result, the rate has increased by seven times from the beginning.
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For each pair of reactants below select the one that is more nucleophilic.
(1) (a) H2O or (b) CH3CO2-.
(2) (a) -NH2 or (b) NH3.
Draw the structure of the compound you would expect from E2 reaction of the molecule below with NaOH. In cases where there is a choice, draw the most substituted alkene product. Show the expected Z or E stereochemistry
(Light green = Cl, red-brown = Br)
The given compound undergoes an E2 elimination reaction to give an alkene.
Elimination by the E2 mechanism
We observed the following reaction between tert-butyl bromide and cyanide at the beginning of this lesson. This is definitely not a substitution reaction.
(CH3)3C-Br + CN(–) ——> (CH3)2C=CH2 + Br(–) + HCN
We are aware that an SN2 reaction for t-butyl bromide is not anticipated. The ethanol solvent is also insufficiently polar to support an SN1 reaction. Since it is around 10 times weaker than bicarbonate, the other reactant, cyanide anion, is both an excellent nucleophile and a respectable base. The only feasible reaction for this set of reactants, then, appears to be a base-induced elimination.
Methanethiolate is 100 times more nucleophilic than methoxide in the methanol solvent employed here. While methanethiolate is around 106 times more basic than methoxide. As a result, the reaction products exhibit a distinct difference that represents nucleophilicity (bonding to an electrophilic carbon) vs basicity (bonding to a proton).n).
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How can kinetic energy of motion be transformed into other kinds of energy thermal energy
Answer:
Answer Below ↓
Explanation:
If the moving sand hits an obstacle, it stops due to the friction created by the contact and its kinetic energy is then transformed into thermal energy, or heat.
which of the following has two equatorial alkyl substituents in its most stable conformation?
A.) 1,1-dimethylcyclohexane
B.) cis-1,2-dimethylcylcohexane
C.) cis-1,3-diethylcylcohexane
D.) cis-1,4-diethylcylcohexane
E.) trans-1,3-diethylcylcohexane
B.) cis-1,2-dimethylcylcohexane has two equatorial alkyl substituents in its most stable conformation
In cyclohexane ring, the most stable conformation is the one that has the lowest energy. The ring can adopt different conformations, such as the chair or the boat, depending on the position of the substituents. The most stable conformation of cyclohexane ring is the one that has maximum number of Substituents in equatorial position and minimum number of substituents in axial positions. The equatorial positions are more stable than the axial positions because they are farther apart and less crowded.In option B, cis-1,2-dimethylcylcohexane, the methyl groups are in equatorial positions, which makes it the most stable conformation among the options given.
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One disadvantage of coevolution is that:
if one of the two species becomes extinct, the other species may not be able to survive.
one species will likely evolve faster than the other.
only the species that have coevolved will survive if a natural disaster occurs.
the coevolved species will not be able to produce offspring.
Answer:
true
but it depends on their habitat and geographic location
Explanation:
hope this was helpful
After the rising phase, which ion channel is responsible for action potential returning to its
resting Vm and why?
A. Na+ channels, because positive Na* ions are at higher concentration outside the axon than inside, and so they enter the axon and raise Vm
B. Na+ channels, because positive Na+ ions are at higher concentration inside the axon than outside, and so they leave the axon and raise Vm
C. K* channels, because positive K+ ions are at higher concentration outside the axon than inside, and so they enter the axon and raise Vm
D. K channels, because positive K* ions are at higher concentration inside the axon than outside, and so they leave the axon and lower V m
Na+ channels enter the neuron and increase Vm because the positive Na+ ions are more abundant concentration outside the cell than inside.
The ratio of a constituent's abundance to the total volume of the mixture is its concentration. Mass concentration, molar concentration, number concentration, and volume concentration are a few of the various categories of mathematical description. Information is sent via neurons. Electrical impulses and chemical signals are used to transport information inside different brain areas as well as between the brain and the rest of the nervous system. The two primary subtypes of brain cells are neurons and glial cells. Although they play a supporting role in the brain, glial cells predominate over neurons in numerous areas of the organ.
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What mass in grams of hydrogen is produced by the reaction of 4.73 g of magnesium with 1.83 g of water? (Mg =24, H = 1, O = 16)
Mg (s) + 2H2O (l) → Mg(OH)2 (s) + H2 (g)
a) 0.204
b) 0.051
c) 0.0162
d) 0.219
At long last, change over moles to grams by increase it by the molar mass (0.1017 * 2)= 0.204 grams.
To begin with, you make a proportion between the reactants (H2O & Mg) to decide the restricting reactant so 2 mol H2O/ 1 mol Mg = 2 _calculate moles of Mg (mass/molar mass) = (4.73/24)= 0.197
moles _calculate moles of H2O (mass/molar mass) = (1.83/18)= 0.1017 moles make the proportion once more between H2O & Mg= (0.1017/0.197)= 0.5
So, H2O is the restricting reactant and as you would like the mass of H2 by comparing its moles with moles of H2O, you'll get 0.1017 moles.
Finally, change over moles to grams by duplicate it by the molar mass (0.1017 * 2)= 0.204 grams
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Which can conduct heat faster metal or air ( gas)? Explain your answer.
Metals conduct heat faster than air. Air or gas heats up by way of convection, whereas metals are closely packed with one another.
Which can conduct heat faster metal or air gas?substances that are poor conductors of thermal energy are called thermal insulators. Gases such as air and matter such as plastic Metal and wood are thermal insulators.
Metals and stones are examined as good conductors since they can rapidly transfer heat, whereas materials like wood, paper, air, and cloth are the poor maestros of heat. In particular, metals conduct heat better than non-metals, and solids conduct heat better than gases.
So we can conclude that All metals 'can' flatter a gas. If you heat them in a vacuum, all elemental metals can become a gas
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Rank absorption of the indicated bonds in decreasing (highest to lowest) order of wavenumber. A. I > V > II > IV > III B. IV > II > I > V > III C. II > I > V> III > IV D. IV > I > V > II > III E. IV > II > V > I > III
The indicated bonds in decreasing order of wavenumber is E. IV > II > V > I > III
What is absorption?Atoms, molecules, or ions can enter a liquid or solid material by a process known as absorption, which can be physical or chemical in nature.
The order of absorption of the indicated bonds in decreasing order of wavenumber is IV > II > V > I > III.
This order is based on the strength of the bond and the functional group associated with it.
The order of the absorption of functional groups are typically based on the polarity and electron density of the bond.
In general, the more polar and electron-rich the bond, the higher the wavenumber of its absorption.
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A 100.-milliliter sample of helium gas is placed in a sealed container of fixed volume. As the temp of the confined gas increases from 10°c to 30°c, the internal pressure
The internal pressure of the container will increase, given that the temperature of the confined gas increases from 10 °C to 30 °C (Option B)
How do I know if the pressure will decrease, increase or remain the same?To determine if the pressure will decrease, increase or remain the same, we shall obtain the new pressure of the container. Details below
The following data were obtained from the question:
Volume = 100 mL = ConstantInitial temperature (T₁) = 10 °C = 10 + 273 = 283 K New temperature (T₂) = 30 °C = 30 + 273 = 202 KInitial pressure (P₁) = PNew pressure (P₂) = ?P₁V₁ / T₁ = P₂V₂ / T₂
Volume = contant
P₁ / T₁ = P₂ / T₂
P / 283 = P₂ / 303
Cross multiply
P₂ × 283 = P × 303
Divide both sides by 283
P₂ = (P × 303) / 283
P₂ = 1.07 × P
From the above calculation, we can see that the new pressure is 1.07 times the initial pressure.
Thus, we can conclude that the internal pressure will increase (Option B)
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Complete question:
A 100.-milliliter sample of helium gas is placed in a sealed container of fixed volume. As the temp of the confined gas increases from 10°c to 30°c, the internal pressure
A. Decreases
B. Increases
C. Remain the same
Predict the product, if any, of reaction between propanamide and 2 CH3MgBr, then H3O+. Draw only the product derived from the acyl portion of propanamide. You do not have to consider stereochemistry. If no reaction occurs, draw the organic starting material.
The product derived from the acyl portion of propanamide is attached below.
What is stereochemistry, and how does it work?The study of the various spatial arrangements of atoms in molecules is the focus of the branch of chemistry known as stereochemistry. Stereochemistry is the systematic presentation of a particular area of science and technology that customarily necessitates a brief prelude into history.
Because propanamide contains a primary amine group, the carbon centre will become less electrophilic as a result. As a result, resonance structure will form, which will reduce the reactivity of the electrophilic carbon and eliminate the possibility of a high-yield product formation.
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Show how the following compounds can be prepared, using ethyne as one of the starting materials: 1. 1-pentyn-3-ol 2. 1-phenyl-2-butyn-1-ol 3. 2-methyl-3-hexyn-2-ol
Ethyne (acetylene) was first discovered in 1836 by the Irish chemist Edmund Davy as a by-product during the medication of metallic potassium by heating an intermixture of calcined potassium tartrate with charcoal.
How is ethyne formed?Carbon dioxide, water, and heat are produced when ethanol burns in the atmosphere with a sooty flame. Together with hydrogen, ethyne first produces ethene and then ethane. 1,2-Tetra halo ethanes are created when ethyne interacts with halogen acids.
Ethyne has the chemical formula C2H2. This substance is an unsaturated hydrocarbon, and in its pure form, it is incredibly unstable. Due to its two carbon atoms, which are triple linked to one another, ethyne is referred to as the most basic alkyne.
All four atoms in the ethyne molecule are aligned in a straight line because it is a linear molecule. The triple bond between carbons is just 1.20 long. In the acetylene hybrid orbital, both carbons are sp- hybridised.
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A 25.0 g block of copper (specific heat capacity 0.380 J/g･ °C) at 57.8 °C is placed into 500.0 g of water initially at 20.0 °C. What is the change in temperature (in °C) of the copper block? (The specific heat capacity of water is 4.184 J/g･ °C).
In order to make the heat values obtained from the equation q=mCsT equal to one another, we set them to that value. (Specific heat capacity: 0.380 J/g) 57.8 block of copper
How do you define "at capacity"?Your capacity or the quantity something can hold are both described by the word capacity. You cannot squeeze another feathery companion into a cage that is already overcrowded without risking the claustrophobia of the birds.
How come capacity is so crucial?Capacity, particularly corporate expansion, unquestionably has a quantifiable impact on every firm. Because it directly affects a company's capacity to expand, compete, and create and maintain a pleasant customer experience, capacity planning is extremely important to business success.
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Determine the solubility of the ions that is calculated from the Ksp for Na3PO4.
Answer choices:
9S4
S4
27S3
3S2
27S4
From the Ksp for Na3PO4, the solubility of the ions is determined to be 27S4. Solubility is a term used in chemistry to describe a substance's capacity to mix with another substance, the solvent.
Na+ and PO4-3 are the ions found in Na3PO4. Since sodium is listed on the periodic table as an alkali metal, it will create a positive charge in solution. A polyatomic ion is one that requires its charge to be remembered, such as the phosphate ion. Therefore, each unit of sodium phosphate that dissolves produces 4 ions. As a result, each molecule of Na3PO4 has a total of four ions in the solution.
Na3PO4 -> 3Na+ + [PO4 3-]
Let the solubility of each ion be S such that
Ksp = [Na+]^3 [(PO4)3-]
Ksp = (3S)^3 (S) = 27S^4 as there are 3 sodium ions and 1 phosphate ion.
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The reaction between strontium hydroxide and chloric acid produces __________.A) a molecular compound and a weak electrolyteB) two weak electrolytesC) two strong electrolytesD) a molecular compound and a strong electrolyteE) two molecular compounds
The reaction between strontium hydroxide and chloric acid produces: D) a molecular compound and a strong electrolyte. It is solved using the concept of acid-base.
What is acid-base reaction?The neutralization process, which produces a salt and water molecule, occurs when an acid and a base interact. Here, the reaction between the acids chloric acid and strontium hydroxide produces strontium perchlorate and two moles of water. The strong electrolyte strontium perchlorate entirely dissociates in one direction, similar to sodium chloride. Both strontium hydroxide and chloric acid are powerful acids and bases. According to Pearson's Hard Soft Acid Base Concept, ionic complexes are created when hard acid and hard base mix. Ionic complexes often completely dissociate and are thus regarded as strong electrolytes (in the present case Strontium perchlorate).
As far as we are aware, Sr is a group 2 alkaline earth metal. Because it produces basic oxides, when it reacts with acid, salt and water are produced. Since SrO is also a basic oxide in this instance, it may react with acids like HClO₄ (chloric acid) to produce salt and water.
Thus, it will form one molecular compound that is H₂O and one strong electrolyte that is Sr(ClO₄)₂.
The reaction is as follows:
SrO + 2HClO₄ → Sr(ClO₄)₂ + H₂O
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Draw the two enantiomers that are obtained upon bromination of (S)-3-methylhexane.
Radical bromination of (S)-3-methylhexane results in 3-bromo-3-methylhexane as the main byproduct, which is optically inactive. The branching hydrocarbon 3-methylhexane has two enantiomers. It belongs to the family of heptane isomers.
One of heptane's two structural isomers, 2,3-dimethylpentane, and this particular molecule both possess the chirality property. They are (R)-3 methylhexane and (S)-3 methylhexane, respectively. Bromomethane is the natural product. This is a substitution process because one of the hydrogen atoms in the methane has been swapped out for a bromine atom. Enantiomers are stereoisomers that cannot be superimposed mirror images of one another. Depending on how each stereocenter is set up, enantiomers are different. In terms of handedness, they can be compared to gloves for the right or left hand.
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how many moles are contained in 4.131 x 10^24 particles?
To find the number of moles contained in 4.131 x 10^24 particles, we need to use Avogadro's number. Avogadro's number, denoted by N, is the number of atoms, molecules, or other entities in one mole of a substance. It is approximately equal to 6.022 x 10^23.
So, we can use this formula to find the number of moles:
moles = (number of particles) / N
Where N = 6.022 x 10^23
Substituting the given value of particles:
moles = (4.131 x 10^24 particles) / (6.022 x 10^23)
moles = (4.131 x 10^24) / (6.022 x 10^23)
moles = 0.6869
So, 4.131 x 10^24 particles contains approximately 0.6869 moles.
Consider the enzyme-catalyzed reaction with Vmax=164 (μmol/L)min−1 and KM=32 μmol/L.
Part A
If the total enzyme concentration was 1 nmol/L, how many molecules of substrate can a molecule of enzyme process in each minute?
Part B
Calculate kcat/KM for the enzyme reaction.
Part - A 164000 molecules of substrate can a molecule of enzyme process in each minute.
Part - B The kcat/KM for the enzyme reaction is 85.416×10⁶ (M.s)⁻¹
An enzyme-catalyzed reaction is what?An enzyme will attach itself to one or more reactant molecules and start the reaction by catalyzing it. These molecules are the substrates for the enzyme. One substrate may undergo several product breakdowns in some reactions. Others involve the fusion of two substrates into a single larger molecule or the exchange of individual molecules.
The place on an enzyme's surface where substrates bind and the chemical reaction it catalyzes take place is called the active site of the enzyme.
(A)kcat = turnover number
kcat = Vmax/[Etotal] = ( 164×10⁻⁶ (mol/L)min⁻¹ )/(1×10⁻⁹ mol/L)
kcat = 164000 min⁻¹
(B) kcat/kM = ( 164000 min⁻¹ / 32×10⁻⁶M )
kcat/kM = 5125×10⁶ (M.min)⁻¹
kcat/kM = 85.416×10⁶ (M.s)⁻¹.
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design a synthesis of 2-methyl-2-propanol from 2-methylpropane.
Synthesis is an analysis method that includes the steps of comparing and contrasting, categorising, and dividing.
What is the meaning of synthesis?
Comparing and contrasting, categorising, and dividing are all aspects of the analysis technique known as synthesis. Synthesis, at its most fundamental level, is the combination of two or more sources while searching for common themes. Finding connections between disparate materials to support your argument is the goal of synthesis.
2-Methylpropene must be changed into 2-Methyl-2-Propanol using a. H2 O/H+. Using an addition reaction, the alkene will be transformed into the necessary alcohol.
Alkene and water react with an acidic medium to produce alcohols in a process known as acid catalysed hydration. As dictated by Markovnikov's rule, this reaction occurs. An acid catalyst and water combine to generate 2-methylpropan-2-ol from 2-methylpropene.
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.pls ans my question interested girl come 15++ come fast
Answer:
wait so do you need help with
Explanation:
Maria is studying fungi in a forest. She makes some observations and takes some notes on a variety of fungi found on the forest floor. If Maria returned to the forest a year later and discovered that all the fungi were gone, what would she most likely observe as a result of this?
Answer:
Without fungi in the forest, dead and rotting materials would not be broken down, which would cause dead plants and animals to pile up in the forest.
Without fungi in the forest, dead and rotting materials would not be broken down. Fungi breaks down materials, and if fungi was not in the forest, the forest would have dead and rotting, plants and animals piled up everywhere.
Explanation: My frog taught me
Doing the test rn and says its right btw!
Hope I helped yall!
which amino acid has the greatest amount of negative charge at ph = 6.20?
Answer:
Amino acid alanine
Explanation:
because it is.
Ozone layer sentence
Answer:
The ozone layer is a layer of the Earth's atmosphere that protects us from the sun's harmful UV radiation.
The "alum" used in cooking is potassium aluminum sulfate hydrate, KAl(SO4)2·x H2O. To find the value of x, you can heat a sample of the compound to drive off all of the water and leave only KAl(SO4)2. Assume you heat 4.74 g of the hydrated compound and that the sample loses 2.16 g of water. What is the value of x?
The "alum" used in cooking is potassium aluminum sulfate hydrate, KAl(SO4)2·x H2O and the value of x calculated is 12.
What is meant by alum?Alum is a type of chemical compound, usually hydrated double sulfate salt of aluminum having general formula X Al ₂·12 H ₂O, where X is monovalent cation such as potassium or ammonium.
Given mass of KAl(SO₄)₂.XH₂O = 4.74 g
and mass of water = 2.16 g
So, mass of KAl(SO₄)₂ = 4.74 – 2.16 = 2.58 g
Molar mass of KAl(SO₄)₂ ;
= 39 + 27 + 2[32 + (4×26)]
Now, molar mass of KAl(SO₄)₂ = 258 g/mol
Molar mass of H₂O ;
= (2×1) + 16
Now, molar mass of H₂O = 18 g/mol
Hence, KAl(SO₄)₂ = 2.58 / 258 = 0.01
and H₂O = 2.16 / 18 = 0.12
KAl(SO₄)₂ = 0.01 / 0.01 = 1
H₂O = 0.12 / 0.01 = 12
The formula of the compound is obtained as KAl(SO₄)₂.12H₂O
Comparing KAl(SO₄)₂.12H₂O with KAl(SO₄)₂.XH₂O, value of X is 12.
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Nitrogen fixation requires the hydrolysis of 8 ATPs to produce 2 NH3 molecules from 1N2.
True or False?
Nitrogen fixation does result in the release of energy, but the activation of this reaction takes energy in the form of ATP hydrolysis.
Does nitrogen fixation require ATP hydrolysis?Energy is released during the nitrogen fixation process, although ATP hydrolysis is required to start the reaction. Metallocenzymes, or proteins with metallic molecules as subunits, include nitrogenases.
This type of reaction is known as a reduction reaction because it causes N2 to gain electrons (see equation above). Due to technological challenges biochemists face in actually viewing this reaction in vitro, the precise mechanism of catalysis is unknown, and the precise order of the steps of this reaction is not fully understood.
Despite this, a lot is understood about the process. The equilibrium synthesis of ammonia from molecules of hydrogen and nitrogen has a negative enthalpy of reaction overall, which means it releases energy, but the energy barrier.
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Calculate the pH and [S2− ] in a 0.24 M H2S solution. Assume Ka1 = 1.0 ✕ 10−7; Ka2 = 1.0 ✕ 10−19.
pH _________
[S2− ] __________ M
The supplied statement states that the pH and S²⁻ in a 0.24M H₂S solution are 3.81 & 3.92 * 10⁻¹², respectively.
What does chemistry mean by defining a solution?A continuous variation of a continuous phase of two and more chemicals in relative proportions up the point that is known as the boundary of solubility. Although concentrations of gases other solids are possible, the term "solution" is most frequently used to refer to the liquid condition of matter. There are many different types of solutions, such as soda water, salt-and-sugar solutions, and others. In a solution, each component resembles a single phase.
Firstly, we have
[tex]$$\begin{aligned}& \mathrm{K} a_1=1.0 \times 10^{-7}=\frac{\left[\mathrm{H}^{+}\right]\left[\mathrm{HS}^{-}\right]}{\left[\mathrm{H}_2 \mathrm{~S}\right]}=\frac{\times_1^2}{0.24} \\& \text { or, } x_1^2=0.24 \times 1.0 \times 10^{-7}=2.4 \times 10^{-8} \\& \text { or, } x_1=1.54 \times 10^{-4} \mathrm{M} \\& \text { i.e, }\left[\mathrm{H}^{+}\right]=\left[\mathrm{HS}^{-}\right]=1.54 \times 10^{-4} \mathrm{~m}\end{aligned}$$[/tex]
Again,
[tex]$$\begin{aligned}& \begin{aligned}k_{a_2}=1.0 \times 10^{-19}= & \frac{\left[\mathrm{H}^{+}\right]\left[\mathrm{S}^{2-}\right]}{\left[\mathrm{HS}^{-}\right]}=\frac{x_2^2}{1.54 \times 10^{-4}} \\\text { or, } x_2^2 & =1.54 \times 10^{-4} \times 1.0 \times 10^{-19} \\& =1.54 \times 10^{-23}=15.4 \times 10^{-24} \\\text { or, } \quad x_2 & =3.92 \times 10^{-12} \\\text { i.e., }\left[\mathrm{H}^{+}\right] & =\left[\mathrm{S}^{2-}\right]=3.92 \times 10^{-12} \mathrm{M}\end{aligned}\end{aligned}$$[/tex]
[tex]$$\text { Total } \begin{aligned}{\left[H^{+}\right] } & =1.54 \times 10^{-4}+3.92 \times 10^{-12} \\& =1.54 \times 10^{-4} \mathrm{~m} \text { (approximated) }\end{aligned}$$[/tex]
Thus, [tex]$p^H=-\log \left(1.54 \times 10^{-4}\right)=3.81$[/tex]
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FILL IN THE BLANK. The _______ fluid is the substance to and from which heat is transferred in a heat engine or other cyclic device
The working fluid is the substance to and from which heat is transferred in a heat engine or other cyclic device.
A heat engine is a device that converts heat energy into mechanical energy, and a key component of a heat engine is the working fluid. The working fluid is the substance that is used to transfer heat in and out of the engine.
It is the fluid that is heated and cooled during the process of converting heat into mechanical energy. The working fluid is typically a liquid or gas, and it is chosen based on its ability to efficiently transfer heat, its cost, and its availability.
The working fluid is cycled through the engine, absorbing heat from a high-temperature source, then losing heat to a low-temperature sink, and the process repeats. The working fluid plays a crucial role in the efficiency and performance of the heat engine.
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Predict the normal boiling point of hydrogen peroxide (H2O2) from the following data: ΔHºf, kJ/mol Sº, J/(mol • K) H2O2(ℓ) –187.8 110 H2O2(g) –136.3 233 Tb = Based on the estimated boiling point, is H2O2 a liquid or a gas at room temperature (25°C)? Why?
Choose one:
A liquid, because its estimated boiling point is less than 25°C.
A gas, because its estimated boiling point is less than 25°C.
A liquid, because its estimated boiling point is greater than 25°C.
A gas, because its estimated boiling point is greater than 25°C.
The correct option is: A liquid, because its estimated boiling point is greater than 25°C
What is boiling point?A liquid's boiling point is determined by the temperature at which its vapour pressure equals that of the gas above it. The temperature at which a liquid's vapour pressure equals one atmosphere is known as the normal boiling point of that liquid (760 torr).
When a substance's vapour pressure reaches parity with outside pressure, that point is known as its boiling point.
H₂O₂(l) ↔ H₂O₂(g)
ΔH⁰rxn = (ΔH⁰f, H₂O₂(g) - ΔH⁰f, H₂O₂(l))
or, ΔH⁰rxn = (-136.3-(-187.8))
or, ΔH⁰rxn = 51.5 KJ/mol
or, ΔH⁰rxn = (Δs⁰f, H₂O₂(g) - Δs⁰f, H₂O₂(l))
or, ΔH⁰rxn = (233 - 110)
or, ΔH⁰rxn = 123 J/mol.k
at the boiling point (Tb), ΔG⁰ = 0 (due to equilibrium)
As we know,
ΔG⁰ = ΔH⁰- TΔs⁰
or, 0 = 51.5*10^3 - (T*123)
or, T = boiling point of H₂O₂
or, T = 418.7 K
or, T = 418.7 - 273.15 K
or, T = 145.55 °C
As, boiling point of H₂O₂ is higher than room temperature (25°c). it is liquid.
Thus, a liquid, because its estimated boiling point is greater than 25°C.
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