In the above question the probability the electron will tunnel through the barrier is 0.011%.
What do you mean by electron volt?An electron volt is the amount of energy required to move a charge equal to 1e⁻ across a potential difference of 1eV.
To calculate the probability the electron will tunnel through the barrier is calculated as -
Energy of electron
E=80eV
=80×1.6×10⁻¹⁹
=128×10⁻¹⁹
Height of the barrier U=100 eV
=100×1.6×10⁻¹⁹J
Thickness L=0.2×10⁻⁹m
Probability T=e⁻²cl
C=√2m(U-E)/h
=√[2×1.67×10⁻²⁷(160-128)×10⁻¹⁹] / 1.055×10⁻³⁴
=10.34×10⁻²³/1.055×10⁻³⁴
=9.8×10¹¹
2CL=2×9.8×10¹¹×0.2×10⁻⁹
=3.92×10²
T=e⁻²cl
= 1/e⁻³⁹²/¹⁰⁰⁰⁰
=0.0198%
=0.011%
Hence ,the probability the electron will tunnel through the barrier is 0.011%.
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Hypernatremia due to excess water loss: A. Diabetes insipidus B. Dialysis fluid excess C. Hyperaldosteronism D. Older persons
Answer:
Hypernantremia due to excess water loss
A. Diabetes insipidusA rare disorder that causes the body to make too much urine
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Hypernatremia due to excess water loss is a diabetes insipidus. Hence option A is correct.
What is hypernatremia?Hypernatremia is defined as an increase in serum sodium levels to a level greater than 145 mmol/L. Water leaks from the tissues into the bloodstream as a result of hypernatremia, which can induce cell shrinkage. Additionally, it affects the hormone levels that regulate salt levels, leading to an increase in thirst and more concentrated urine production.
Diabetes insipidus is defined as a rare illness that makes you almost insatiably thirsty and produces copious amounts of urine. A brain tumor that affects the hypothalamus or pituitary gland is one of the three most frequent causes of cranial diabetes insipidus. a severe head injury that damages the pituitary or hypothalamus. complications resulting from pituitary or brain surgery.
Thus, Hypernatremia due to excess water loss is a diabetes insipidus. Hence option A is correct.
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The volume of a rock weighing 1. 705 kg is 334. 5 ml. What is the density of the rock?
The density of rock weighing 1.705 kg is 3.213 gm/ml.
Explanation:
Given;
Volume of rock = 334.5 ml
Weight of rock = 1.075 kg = 1075 gm
By the formula,
Density = Weight in gm/Volume in ml
= 1075/334.5 gm/ml = 3.2137 gm/ml
Therefore, density of rock is 3.213 gm/ml.
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If you start with 227.8 grams of iron and 128 grams of oxygen to produce iron oxide, what is the limiting reagent? you will need to balance the equation first. don't forget that oxygen is diatomic (o 2 ) when finding the molar mass. fe o2 -> fe2o3
Fe is the limiting reactant.
The balanced chemical equation between iron and oxygen to produce iron (III) oxide is
4Fe(s) + 302(g) - ---> 2Fe2O3(s)
Mass of Fe = 227.8 g
Moles of Fe = 227.8gFe*Imol Fe/55.85g Fe = 4.079mol Fe
Mass of oxygen = 128 g
Moles of O2 = 128g02 * 1molo/32g02 = 4molO2
Calculating the limiting reactant: The reactant that produces the least amount of product will be the limiting reactant.
Mass of iron (III) oxide produced from Iron = 4.079mol Fe*2molFe2O3/4molFe*159.69g Fe2O3/1 mol Fe2O3 = 325.7gFe2O3
Mass of iron (III) oxide produced from oxygen = 4molO2 *2mol Fe2O3/3molO2*159.69gFe2O3/1mol Fe2O3 = 425.84gFe2O3
Iron (Fe) produces the least amount of the product iron (III) oxide. So, Fe is the limiting reactant.
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The number of π molecular orbitals in a molecule is always equal to the number of ________. a. p orbitals used to construct the π bonds b. hydrogen atoms in the molecule c. π bonds
The number of π molecular orbitals in a molecule is always equal to the number of p orbitals used to construct the π bonds.
An electron's position and wave-like behavior within a molecule are described by a mathematical function called a molecular orbital. Chemical, as well as physical properties like the probability of locating an electron in a particular area, can be determined using this function.
A molecular orbital would be created when two atomic orbitals cross one other along the internuclear axis. A molecular orbital is created when two atomic orbitals cross each other sideways.
Therefore, the number of π molecular orbitals in a molecule is always equal to the number of p orbitals used to construct the π bonds.
Hence, the correct answer will be option (a).
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Heliox is a mixture of helium and oxygen gas used to help patients with breathing difficulties. It is also used for scuba diving. The total pressure in a tank of heliox is 208 atm. If the mole fraction of o2 is 0. 220, what is the partial pressure of he in the tank?.
It should be noticed that the mole fraction of all the system's components is 1.
Describe a mole fraction.the proportion between the moles of one component in a solution or other combination and the total moles of all the components.
What is a mole fraction and an illustration of one?In a mixture, a mole fraction is the ratio of molecules of one component. By way of illustration, if the mole fraction of methane in a gas is 0.90, then this implies that 90% of the molecules are methane. Since the amount fractions resemble mole fractions, methane makes up an additional 90% of the mixture.
The mole fraction is calculated in what way?By dividing the solute's moles by all the other molecules in solution, you may determine the solute's mole fraction.
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Suppose that 0.50 grams of barium-131 are administered orally to a patient. Approximately how many milligrams of the barium would still be radioactive two months later?
Two months later 13.8 milligrams of the barium-131 still be radioactive.
How is the decay rate of a radioactive substance expressed ?It is expressed as:
[tex]A = A_{0} \times (\frac{1}{2})^{t/T}[/tex]
where,
A = Amount remaining
A₀ = Initial Amount
t = time
T = Half life
Here
A₀ = 0.50g
t = 2 months = 60 days
T = 11.6 days
Now put the values in above expression we get
[tex]A = A_{0} \times (\frac{1}{2})^{t/T}[/tex]
[tex]= 0.50 \times (\frac{1}{2})^{60/11.6}[/tex]
[tex]= 0.50 \times (\frac{1}{2})^{5.17}[/tex]
= 0.50 × 0.0277
= 0.0138 g
= 13.8 mg [1 mg = 1000 g]
Thus from the above conclusion we can say that Two months later 13.8 milligrams of the barium-131 still be radioactive.
Disclaimer: The question was given incomplete on the portal. Here is the complete question.
Question: Suppose that 0.50 grams of ban that 0.50 grams of barium-131 are administered orally to a patient. Approximately many milligrams of the barium would still be radioactive two months later? The half-life of barium-131 is 11.6 days.
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What mass of cu(s)cu(s) is electroplated by running 14. 5 aa of current through a cu2 (aq)cu2 (aq) solution for 4. 00 hh?
Mass of copper would be=92.46 g
I = Current = 19.5 A
t = 4 hours =4×60×60=14400 s
F = Faraday constant = 96485.33 C/mol
Molar mass of copper = 63.546 g/mol
A charge is given by
Q=19.5×14400=280880 C
Moles of electrons are given by Q/F=280880/96485.33=2.91 mol
Moles of copper is=1/2×2.91=1.455 mol
Mass of copper would be=1.455×63.546=92.46 g
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The mass of Copper electroplated is 68.76 g
What is electroplating?The process of plating a metal onto another is known as electroplating.
It is often used to prevent corrosion of metal or for the decorative purposes
In this process, electric current is passed through an aqueous solution containing dissolved cations.
The dissolved cations are reduced developing a thin metal coating on the electrode.
At cathode,
[tex]Cu^{2+}(aq) + 2e^-\rightarrow Cu(s)[/tex]
Current, I = 14.5 A
Time, t = 4 hrs = 4×60×60 = 14400 sec
Charge, q = It = 14.5×14400= 208800 C
Copper metal deposited by 2×96487 C = 63.55 g
Copper metal deposited by 208800 C = [tex]\frac{63.55 \times208800}{2\times96487}[/tex]
= 68.76g
Hence, The mass of Copper electroplated is 68.76 g
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Enter your answer in the provided box. what is the original molarity of an aqueous solution of ammonia (nh3) whose ph is 11. 02 at 25°c? (kb for nh3 = 1. 8 × 10−5) m
The original molarity of an aqueous solution of ammonia whose pH is 11. 02 at 25°C is 0.556 M
Calculation ,
Given : pH = 11.5
[tex][H^{+} ][/tex] = [tex]10^{-11.5}[/tex]
[tex][OH^{-} ][/tex] = [tex]K_{w} /[H^{+} ][/tex] = [tex]10^{-14}[/tex]/ [tex]10^{-11.5}[/tex] = [tex]10^{-2.5}[/tex] M
Kb = [tex][NH_{4}^{+} ][OH^{-} ]/[NH_{4} OH][/tex] = [tex](10^{-2.5})^{2} /C[/tex] = 1.8×[tex]10^{-5}[/tex] M
C = 1/1.8 = 0.566 M
So, molarity of an aqueous solution of ammonia is 0.566 M
pH ia a measure of hydrogen ion concentration , a measure of acidity or alkalinity of the solution .pH scale usually range from 0 to 14 Aqueous solutions at 25°C witha pH less rhan 7 are acidic , whereas , those with pH greater than 7 are basic or alkaline. pOH ia a measure of hydroxide ion concentration , a measure of alkalinity of the solution .
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What is the equilibrium expression for
2SO3(g) 0₂(g) +2SO₂(g)
Answer:
[tex]K_{c} =\frac{[O_{2} ] [SO_{2} ]^{2} }{[SO_{3} ]^{2} }[/tex]
Explanation:
To construct the equilibrium constant, you need the balanced equation:
2 SO₃(g) -----> O₂(g) + 2 SO₂(g)
The equilibrium constant compares the concentrations of the products and the reactants.
The given expression follows this structure:
aA(g) ----> bB(g) + cC(g)
In this equation, the uppercase letters symbolize the molecules and the lowercase letters symbolize their corresponding coefficients in the balanced equation.
The general equilibrium expression looks like this:
[tex]K_{c} =\frac{[B]^{b} [C]^{c} }{[A]^{a} }[/tex]
To be clear, the concentrations in the numerator represent the gaseous products and the concentrations in the denominator represent the gaseous reactants.
Therefore, the equilibrium expression for this equation is:
[tex]K_{c} =\frac{[O_{2} ] [SO_{2} ]^{2} }{[SO_{3} ]^{2} }[/tex]
Nh4cl is sometimes preferred instead of hcl or h2so4 for "acid" work-up after grignard reactions, particularly when the expected and desired product is a tertiary alcohol. Why?
Nh4cl is sometimes preferred instead of hcl or h2so4 for "acid" work-up after grignard reactions, particularly when the expected and desired product is a tertiary alcohol because NH4+ is a much milder acid than HCl or H2SO4, which achieve the protonation of
the oxyanion to yield the alcohol while minimizing the risk of dehydration.
Ammonium chloride (NH4Cl) is the used as reagent that quenches the magnesium alkoxide product of the Grignard addition.
It is a proton source without being acidic as in acidic medium the protonation of the tertiary alcohol product and elimination to the alkene.
In the presence of HCl or any other strong acid protonation proceed and form alkene but not with ammonium chloride.
Thus from above we concluded that Nh4cl is preferred instead of hcl or h2so4 for "acid" work-up after grignard reactions.
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A housewife purchases a 3.0 lb. roast, what is its weight in grams
The weight of the 3 lb roast purchased by the housewife is 1,360.78 grams.
What is weight?The weight of an object is the force acting on the object due to gravity.
The weight of an object varies from place to place across the globe due to difference in acceleration due to gravity.
Weight of the roast in grams1 lb ------------> 453.592 grams
3 lb ------------> ?
= (3 x 453.592)
= 1,360.78 grams
Thus, the weight of the 3 lb roast purchased by the housewife is 1,360.78 grams.
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What happened to the molecule when the electron was promoted to the antibonding orbital?.
the bond will break
The bond will dissolve (break) if the electron absorbs a photon and is moved from a bonding molecular orbital to an antibonding orbital since there is no longer an overall stabilizing interaction.
What is an antibonding orbital?An antibonding molecular orbital is the molecular orbital created by the destructive overlapping of atomic orbitals.
Why is it called antibonding orbital?Every atom will add one electron to the bond that makes up the lower energy bond. To prevent interacting with the other two electrons, the additional electron will occupy a higher energy state. The antibonding orbital is the name of this higher energy orbital.What orbitals form an antibond?The bonding orbitals are home to electrons that spend the majority of their time between the nuclei of two atoms, whereas the antibonding orbitals are home to electrons that spend the majority of their time outside the nuclei of two atoms.When an electron was elevated to the antibonding orbital, what happened?In contrast, putting electrons in antibonding orbitals will make the molecule less stable. The energy levels of the orbitals will determine how many electrons are filled. The lower energy orbitals will be filled first, and then the higher energy orbitals.To learn more about antibonding orbitals visit:
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Gallium exists naturally as a mixture of two isotopes, Gallium - 69 & Gallium - 71. The atomic mass number of gallium is 31.
Relative Atomic Mass of Gallium is 69.8 . Calculate % composition of each isotope
Considering the definition of atomic mass, isotopes and atomic mass of an element, the % composition of each isotope is:
Gallium - 69: 60% Gallium - 71: 40%Definition of atomic massFirst of all, the atomic mass (A) is obtained by adding the number of protons and neutrons in a given nucleus of a chemical element.
Definition of isotopeThe same chemical element can be made up of different atoms, that is, their atomic numbers are the same, but the number of neutrons is different. These atoms are called isotopes of the element.
Definition of atomic massOn the other hand, the atomic mass of an element is the weighted average mass of its natural isotopes. In other words, the atomic masses of chemical elements are usually calculated as the weighted average of the masses of the different isotopes of each element, taking into account the relative abundance of each of them.
% composition of each isotopeIn this case, the first isotope Gallium - 69 has an atomic mass of 69 and a percent natural abundance of X%. The second isotope Gallium - 71 has an atomic mass of 71 and a percent natural abundance of (100-X)%.
On the other hand, the Relative Atomic Mass of Gallium is 69.8 .
Then, the value of X can be calculated as:
69× X+ 71× (1-X)= 69.8
Solving
69× X+ 71× 1- 71× X= 69.8
69× X+ 71- 71× X= 69.8
69× X- 71× X= 69.8 - 71
- 2× X= -1.2
X= (-1.2)÷ (-2)
X=0.6 which expressed as a percentage is X%= 60%.
So, the % compositon of Gallium - 71 is calculated as (100-X)%=(100 -60)%= 40%
Finally, the % composition of each isotope is:
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The ________ of a liquid is the temperature at which its equilibrium vapor pressure is equal to the pressure exerted on the liquid by its gaseous surroundings.
The temperature at which a liquid's vapor pressure equals the pressure of the gas above it is known as the boiling point of the liquid. The temperature at which a liquid's vapor pressure equals one atmosphere is considered the liquid's typical boiling point (760).
When the vapor pressure of a liquid equals the pressure of the gas above it, the liquid boils. The temperature at which a liquid will boil decreases with decreasing gas pressure above the liquid.
The Macro Perspective.A liquid's vapor pressure rises as it warms until it reaches the same level as the gas above it. Within the bulk liquid, vaporize liquid (i.e., gas) bubbles form, rise to the surface, burst, and release the gas. (A bubble's internal vapor pressure is sufficient to prevent the bubble from collapsing at boiling temperature.)The liquid's molecules must overcome their forces of attraction in order to create vapor.
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Predict the nature of the indicated covalent bond. polar or non-polar
The given bond is polar covalent bond.
Polar covalent bonds are covalent bonds in which the electrons are shared unequally. Nonpolar covalent bonds are covalent bonds with an equal distribution of electrons. Chemists utilise electronegativity, a relative measurement of how strongly an atom attracts electrons as it forms a covalent connection, to assess the relative polarity of a covalent bond.
Polarity characterises io3-. If a molecule's dipole moment is greater than 0, it is considered to be polar. The three I-O bonds in this combination are polar due to the difference in electronegativity between the I and O atoms. The three I-O bond moments point toward I atom because I is more electronegative than O atom.
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2.5 moles of a gas is enclosed in a 87.2 L cylinder with a moveable piston at 425 K and 1.0 atm. An additional 2.5 moles of gas is added to the system and it is cooled to 273 K. The cylinder changes volume to maintain the pressure. What is the volume in the final system?
Answer:
112 L
Explanation:
Since the pressure is being held constant, you can use the following variation of the Ideal Gas Law to find the new volume:
[tex]\frac{V_1}{T_1N_1}=\frac{V_2}{T_2N_2}[/tex]
In this equation, "V₁", "T₁", and "N₁" represent the initial volume, temperature, and moles. "V₂", "T₂", and "N₂" represent the final volume, temperature, and moles.
V₁ = 87.2 L V₂ = ? L
T₁ = 425 K T₂ = 273 K
N₁ = 2.5 moles N₂ = 2.5 + 2.5 = 5.0 moles
[tex]\frac{V_1}{T_1N_1}=\frac{V_2}{T_2N_2}[/tex] <----- Formula
[tex]\frac{87.2 L}{(425K)(2.5 moles)}=\frac{V_2}{(273 K)(5.0 moles)}[/tex] <----- Insert values
[tex]\frac{87.2 L}{1062.5}=\frac{V_2}{1365}[/tex] <----- Simplify denominators
[tex]0.08207=\frac{V_2}{1365}[/tex] <----- Simplify left side
[tex]112L={V_2}[/tex] <----- Multiply both sides by 1365
In state n = 1, the energy of the hydrogen atom is -13. 58 ev. what is its energy in state n = 2?
In state n = 1, the energy of the hydrogen atom is -13. 58 ev, then the energy in state n = 2 is -3.40eV.
For an electron located in an inner orbit to jump an upper orbit, it needs an energy equal to the difference between the two quantized orbits. This energy comes from the absorption of a photon with the same energy required. The formula for the energy levels of a Hydrogen atom is:
En = E/(n×n)
where E is the energy of the ground state and n is the energy level or state. Then the energy in n= 1 is
En = -13. 58/ 4
En = -3. 40eV
Thus, we find the value of energy of hydrogen atom in n=2 is -3. 40eV.
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An organic compound was analyzed and found to contain 70. 6% carbon, 5. 9% hydrogen, and 23. 5% oxygen by mass. Additionally, the molar mass of the compound was experimentally determined to be 136 g/mole. What is the molecular formula for the compound? how many grams of mgcl 2 would be required to prepare 250 ml of a 0. 8 m solution of that solute in water? please report your answer to two digits after the decimal place.
The correct answer is C8H8O2.
What is organic compound?Organic combinations are a substance that contains covalently- bonded carbon and hydrogen and often with other ingredients. Organic compounds examples are benzoic Acid, aromatic mixtures, benzoic aldehyde, propanoic acid, butanoic acid, malonic acid, amines, heterocyclic compounds, VOC, benzoic acid, and diethyl malonate.organic compound, any of a large class of chemical combinations in which one or more atoms of carbon are covalently linked to atoms of other elements, most generally hydrogen, oxygen, or nitrogen. The few carbon-containing combinations not categorized as organic comprise carbides, carbonates, and cyanides.Organic compounds important to human functioning include carbohydrates, lipids, proteins, and nucleotides. These mixtures are said to be organic because they include both carbon and hydrogen.To learn more about organic compound, refer to:
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For the reaction: n2(g) 2 o2(g) ⇌ 2 no2(g), kc = 8. 3 × 10-10 at 25°c. what is the concentration of n2 gas at equilibrium when the concentration of no2 is twice the concentration of o2 gas?
4.8 × 10^9 M is the concentration of n2 gas at equilibrium when the concentration of no2 is twice the concentration of o2 gas.
In some gas-producing fields, such as those in the US Midwest, North Sea, Eastern Europe, and South East Asia, nitrogen (N2) may naturally present in significant concentrations. Around 15% of the world's non-associated gas deposits have nitrogen content levels that are too high to be considered pipeline-quality gas (usually 3–4 mol%). Because it is an inert gas, nitrogen cannot support burning. Consequently, unstable combustion could result from burning a gas that contains too much nitrogen. The recovery of NGL content will be lowered when high nitrogen gas is treated in a gas plant because nitrogen acts as stripping gas. The compression technology and size of the transmission pipeline will rise with increased nitrogen concentration. High nitrogen levels are undesirable in an LNG plant because they lower the LNG temperature, which increases the energy required to liquefy natural gas and also increases the amount of boil-off gas from the LNG storage tanks.
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To prevent the system refrigerant from quickly dropping in temperature and pressure, refrigerant recovery should?
To prevent the system refrigerant from quickly dropping in temperature and pressure, refrigerant recovery should Begin with a liquid
In the refrigeration cycle of air conditioners and heat pumps, refrigerants are working fluids that typically go through numerous phase changes from a liquid to a gas and back again.
In the refrigeration cycle, which cools a place, a refrigerant is a material, frequently a fluid. Refrigerants use the thermodynamic phenomenon of phase transitions, in which a fluid transforms into a gas or vice versa, to absorb heat and then release it to another area.
At room temperature, it is often a gas. Ammonia, sulfur dioxide, and non-halogenated hydrocarbons like propane are further typical refrigerants that are employed in a variety of applications.
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What type of reactive intermediate is formed in the reaction of an alkene with br2 and water?
Cyclic bromonium ion is the reactive intermediate that is formed in the reaction of an alkene with br2 and water. the correct answer is option(d).
A reactive intermediate is a highly reactive, high-energy, brief-lived molecule that, when produced in a chemical reaction, will swiftly transform into a stable molecule. They may occasionally be divided and stored. For instance, low temperatures and Matrix Isolation. Carbocations, carbanions, free radicals, carbenes, nitrenes, and benzyne are six different categories of reaction intermediates. These intermediaries are frequently produced when a chemical substance is chemically broken down.
Reactive intermediates can be used to explain the process of a chemical reaction. Reactive intermediates are high-energy, stable products that are present only in one of the intermediate phases of most chemical reactions, which typically involve more than one elementary step.
The complete question is:
What type of reactive intermediate is formed in the reaction of an alkene with Br2 and water to give a bromohydrin?
a.carbocation
b.carbanion
c.radical
d.cyclic bromonium ion
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A radioactive isotope of potassium (K) has a half-life of 20 minutes. If a 255 gram sample of this isotope is allowed to decay for 80 minutes, how many grams of the radioactive isotope will remain? nd the O a. 8.0 0 b. 63.8 O c. 15.9 0 d 319
Answer:
15.94 g
Explanation:
80 mins is 4 half lives ( 20 min each)
255 * 1/2 * 1/2 * 1/2 * 1/2 = 255 * 1/2^4 = 15.94 g
The average rate of a reaction is a good approximation of an instantaneous rate when?
The average rate of a reaction is a good approximation of an instantaneous rate when the concentration is measured during relatively brief time intervals.
At any point during such a little period, the average rate will be extremely near to the instantaneous rate. The average rate will differ from the instantaneous rates inside the period more when time intervals are longer.
The concentration change during a chosen time period is the average rate. When you take the measurements makes a difference.
The rate at a specific moment is known as the instantaneous rate. Finding the slope of the tangent to the concentration vs. time curve at that point yields the answer.
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Enter your answer in the provided box. calculate the ph at 25°c of a 0. 0077 m solution of a weak base with a kb of 6. 2 × 10−9. ph =
The pH at 25°c of a 0. 0077 m solution of a weak base with a kb of 6. 2 × 10−9 is 8.8.
What is base dissociation constant?The base dissociation constant is termed as Kb. Throughout a base split into ts constituent ions in water is determined by its base dissociation constant.
Kb = [B+] [OH-]/[BOH]
Now, let the concentration of [B+] = [OH-] = x
Given,
Kb = 6. 2 × 10^-9
6. 2 × 10^-9 = x^2/(0.0077-x)
x = 6.909 × 10^(-6)
[B+] = [OH-] = 6.909 × 10^(-6)
As we know that,
pOH = -log [OH-]
pOH = -log( 6.909 × 10^(-6))
pOH = 5.2
As we also know that,
pOH + pH = 14
pH = 14 - pOH
pH = 14 - 5.2
pH = 8.8
Thus we calculated that the pH of the solution is 8.8.
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What is the molality of ethylene glycol, c2h4(oh)2, in a solution prepared from 2. 331×103 g of ethylene glycol and 2. 00×103 g of water, h2o?
Molality of ethylene glycol, C₂H₄(OH)₂, in a solution prepared from 2. 331×10³ g of ethylene glycol and 2.00×10³ g of water, H₂O is 47.6m
Ethylene Glycol is known as C₂H₄(OH)₂. It is added in water to prepare an Antifreeze solution.
Given,
Mass of Ethylene Glycol = 2.331 × 10³ g = 2.331kg
Mass of Water = 2.00 × 10³ g
Since, Ethylene Glycol is in excess. Hence, it acts as a solvent and water acts as a solute.
We know, Molar Mass of Water = 18g
Hence, Moles of Water = Given mass of water / Molar Mass of Water
⇒ Moles of Water = 2000 / 18
⇒ Moles of Water = 111.1
Molality is defined as the moles of solute present in a given solvent in kg.
∴ Molality = Moles of Solute / Mass of Solvent (in kg)
Molality = Moles of Water / Mass of Ethylene Glycol
⇒ Molality = 111.1 / 2.331
⇒ Molality = 47.6m
Molality of ethylene glycol, C₂H₄(OH)₂, in a solution prepared from 2. 331×10³ g of ethylene glycol and 2.00×10³ g of water, H₂O is 47.6m
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A solution containing a buffer has an initial ph of 8.78. If a student adds 5 drops of hcl(aq) to this solution. What would be a reasonable ph for the resulting solution?
Buffer is a solution that has been known to have an acid and base dissolved with constant hydrogen concentration. If 5 drops of HCl are added to the buffer then the final pH will be 8.64. Thus, option a is correct.
What is pH?pH has been the concentration that is made of hydrogen or proton ions. The ions have been known to be released from the acids while the bases release the hydroxide ions.
The given buffer has a pH of 8.78, and hence, it is a basic buffer. If the solution of HCl (strong acid) is added to this buffer then the pH will decrease definitely. As only 5 drops are added there will be not much decrease in the pH.
Therefore, option a. the pH of the buffer after addition to HCl will be 8.64.
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Your question is incomplete, but most probably your full question was, A solution containing a buffer has an initial pH of 8.78. If a student adds 5 drops of HCl(aq) to this solution. What would be a reasonable pH for the resulting solution?
8.648.787.008.895.22For the energy diagram of the chemical reaction depicted here, which statement is the best conclusion?
The reaction is endothermic.
The reaction is endothermic.
The reaction will proceed without the input of energy.
The reaction will proceed without the input of energy.
The reaction is exothermic.
The reaction is exothermic.
The activation energy is not represented on the graph.
The reaction shown here is an exothermic reaction.
What is an exothermic reaction?An exothermic reaction is one in which the energy of the reactants is greater than the energy of the products. This implies that energy is given out in the process. Whether a reaction is endothermic or exothermic shows in the nature of the reaction profile curve.
For an endothermic reaction, the part of the diagram that represents the energy of the products is higher than the part that represents the energy of the reactants. This is clear from the image attached here.
If we look at the reaction graph very well, we will observe that the energy of the reactants is far above that of the products. Thus it follows that the reaction shown here is an exothermic reaction.
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How many fe(ii) ions are there in 20. 0 g of feso4 (molar mass=151. 9 g/mol) ? avogadro number=6. 0225x 1023
20 g of [tex]FeSO_4[/tex] contains [tex]7.94 \times 10^{22}[/tex] ions of [tex]Fe^2^+[/tex]
What is Mole?A mole is a unit to measure an amount of any substance which contains as many elementary particles as there in 12 g of Carbon 12.
A mole contains [tex]6.02214 \times 10^{23}[/tex] particles and this fixed number is called Avogadro’s number.
No. of moles is given by,
[tex]n =\frac{m}{M}[/tex]
where m = Given mass in grams
M = Molar mass
Here,
[tex]FeSO_4 \rightarrow Fe^2^+ + SO_4^2^-[/tex]
No. of moles of [tex]FeSO_4[/tex] = [tex]\frac{20g}{151.9gmol^-^1}[/tex] = 0.132 moles
No. of molecules of [tex]FeSO_4[/tex] = 0.132 x 6.022 x [tex]10^2^3[/tex] = 7.94 x [tex]10^2^2[/tex]
No. of molecules of [tex]FeSO_4[/tex] = no. of ions of [tex]Fe^2^+[/tex] = no of ions of [tex]SO_4^2^-[/tex]
Thus, no. of ions [tex]Fe^2^+[/tex] in 20 g of [tex]FeSO_4[/tex] is 7.94 x [tex]10^2^2[/tex]
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5.04 Discussion: Reaction-Rate Factors
Discuss with your classmates your investigation about reaction-rate factors.
Describe how you conducted your experiment, and explain how you reached your conclusion.
Evaluate your investigation, and describe some ways that you could modify your investigation.
Respond to your classmates' experimental designs and conclusions. Do they support their conclusions with evidence?
Increasing the surface area of the reactant by pelletizing the calcium carbonate, and increasing the concentration of hydrochloric acid resulted in increase in the rate of reaction.
What is reaction rate?Reaction rate refers to the rate at which reactant molecules are consumed or the rate at which product molecules are formed.
The factors that affect reaction rate include:
TemperatureConcentrationSurface area of reactantsNature of reactantsPresence of catalystsGiven an experiment to determine effect of surface area of reactants and concentration on reaction rate of dilute hydrochloric acid and calcium carbonate:
It was observed that increasing the surface area of the reactant by pelletizing the calcium carbonate and increasing the concentration of hydrochloric acid made the reaction proceed faster.
In conclusion, reaction rate increases with increase in surface area.
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Types of dissolved substances that may be present in water
A polar molecule is a water. As a result, polar solutes such as ionic compounds and polar molecular compounds will dissolve in them.
What are the dissolved substances in water?Coffee, sugar, and salt all dissolve in water. They dissolve easily. In warm or hot water, they usually dissolve more quickly and effectively. Sand and pepper are insoluble; even hot water won't make them dissolve.There are three ways that substances can dissolve in water: dissociation, dispersion, and ionization.Types of dissolved substances that may be present in water:
Ionic chemicals and polar molecular compounds, for example, will dissolve in water since it is a polar molecules.
When it comes to organic compounds, water will dissolve any that have a carbon to oxygen atom ratio of less than or equal to 5.
[tex]$\frac{C}{O} \leq 5$[/tex]
Because of this, vitamin A is not water-soluble. Vitamin C is soluble, though.
A polar molecule is a water. As a result, polar solutes such as ionic compounds and polar molecular compounds will dissolve in them.
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