Answer:
[tex]pOH=1.3[/tex]
Explanation:
Hello,
In this case, since pH is computed by knowing the concentration of hydrogen ions, one could compute the pOH by knowing the concentration of the hydroxyl ions as in this case which is 0.045M as shown below:
[tex]pOH=-log([OH^-])=-log([0.045])\\\\pOH=1.3[/tex]
Best regards.
Answer:
The pOH of the 0.045 M solution is 1.3
The second option (1.3) is correct
Explanation:
Step 1: Data given
Concentration [OH-] of KOH is 0.045 M
Step 2: Calculate pOH
pOH = -log[OH-]
pOH = -log (0.045)
pOH = 1.3
The answer:
The pOH of the 0.045 M solution is 1.3
The second option (1.3) is correct
What is the concentration of a solution if 0.450 mol of NaCl dissolved in 750 mL of water?
Answer:
.6mol/L
Explanation:
molarity = number of moles / volume of solvent (in L)
750mL / 1000mL/L = .75L
M = .450mol / .75L
M = .6mol/L
Question 13: Consider the strength of the Hβ absorption line in the spectra of stars of various surface temperatures. This is the amount of light that is missing from the spectra because Hydrogen electrons have absorbed the photons and jumped from level 2 to level 4. How do you think the strength of Hβ absorption varies with stellar surface temperature?
Answer:
The absorption and strength of the H-beta lines change with the temperature of the stellar surface, and because of this, one can find the temperature of the star from their absorption lines and strength. To better comprehend, let us look into the concept of the atom's atomic structure.
Atoms possess distinct energy levels and these levels of energy are constant, that is, the temperature has no influence on it. However, temperature possesses an influence on the electron numbers found within these levels of energy. Therefore, to generate an absorption line of hydrogen in the electromagnetic spectrum's visible band, the electrons are required to be present in the second energy level, that is when it captivates a photon.
Therefore, after captivating the photons the electrons jump from level 2 to level 4, which shows that there is an increase in the stellar surface temperature and at the same time one can witness a decline in the strength of the H-beta lines. In case, if the temperature of the surface increases too much, then one will witness no attachment of electron with the hydrogen atom and thus no H lines, and if the temperature of the surface becomes too low, then the electrons will stay in the ground state and no formation of H lines will take place in that condition too.
Hence, to generate a very robust H line, after captivating photons the majority of the electrons are required to stay in the second energy level.
Which diagram correctly describes the changes that occur as a small piece of rock falls from space and hits the earth
Answer:
the motion of gravity
Explanation:
Answer:
its c
Explanation
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Which factor would slow down a chemical reaction? (Choose all that apply)
A)Adding an inhibitor
B)Decreasing temperature
C)Decreasing particle size
D)Increasing particle size
Answer:
(decreasing particle size) C
Explanation: That is one of the answers, if there are more I am sorry.
How to make isopropyl alcohol
Answer:
.It is easily synthesized from the reaction of propylene with sulfuric acid, followed by hydrolysis. Isopropyl alcohol (2-propanol) is made by indirect hydration of propylene (CH2CHCH3).… In some cases the hydration of propylene is carried out in one step, using water and a catalyst at high pressure.
Hope it'll help!
stay safe:)
6.) (5 points) Assume you have a system with a fixed pH of 4.0. It is well buffered and therefore the pH will not change. What is the predominant state of a molecule with a dissociable proton with a pKa of 5.2 if it is introduced to that system (protonated or deprotonated)
Answer:
Dissociated state is the predominant one
Explanation:
When a molecule with pKa of 4.52 is in an aqueous solution at pH = 4.0, follows the H-H equation, thus:
pH = pKa + log₁₀ [A⁻] / [HA]
Where [A⁻] is the dissociated state and [HA] represents the protonated state
Replacing:
4.0 = 5.2 + log₁₀ [A⁻] / [HA]
-1.2 = log₁₀ [A⁻] / [HA]
0.063 = [A⁻] / [HA]
[HA] = 16 [A⁻]
That means you have 16 times more [HA] than [A⁻] and the dissociated state is the predominant one
When you add a controlled amount of substance known as an impurity to a pure semiconductor, its conductivity increases. This process is known as doping. The addition of an impurity can increase or decrease the number of available electrons. If the number of electrons is increased, the extra electrons conduct electricity. If the number of electrons is decreased, a vacant hole is created. The adjacent electron enters the vacant hole and conducts electricity. Thus, it seems like the holes act as charge carriers. They are considered to be positive charge carriers. Depending upon the charge carriers that conduct electricity, there are two types of semiconductors: p-type semiconductors and n-type semiconductors.Which of the following statements are correct with respect to semiconductors?
a) The addition of group 3A elements to group 4A semiconductors decreases the conductivity of the group 4A semiconductors.
b) The conductivity of semiconductors can be increased by the doping process.
c) As the temperature increases, the conductivity of semiconductors decreases.
d) The addition of group 5A elements to group 4A semiconductors increases the conductivity of the group 4A semiconductors.
e) Holes are charge carriers in p-type semiconductors.
f) Electrons are charge carriers in n-type semiconductors.
Answer:
See explaination
Explanation:
1. The addition of group 3A elements to group 4A semiconductors decreases the conductivity of the group 4A semiconductors: Wrong
The addition of 3A group elements inreases the conductivity and make them extrinsic semiconductors( p-type)
2. The conductivity of semiconductors can be increased by the doping process.: Correct
3.As the temperature increases, the conductivity of semiconductors decreases.. wrong
As the temperature increases, the conductivity of semiconductors increases.
4. The addition of group 5A elements to group 4A semiconductors increases the conductivity of the group 4A semiconductors: Correct : They will create n-type semicoductor.
5.Holes are charge carriers in p-type semiconductors: Correct
6. Electrons are charge carriers in n-type semiconductors: Correct
if a sample of gas at 25.2 c has a volume of 536mL at 637 torr, what will its volume be if the pressure is increased to 712 torr?
Which picture shows how the moon from earth when it’s in the position
Explanation:
This picture shows how the moon from earth when it is in position
Which statements describe inorganic compounds? Check all that apply
Inorganic compounds contain carbon
Inorganic compounds usually lack carbon
Inorganic compounds are not associated with or made from living things,
Inorganic compounds include fruits and vegetables,
Inorganic compounds include salt and water
Answer:
b, c, e
Explanation:
Inorganic compounds usually lack carbon.
Inorganic compounds are not associated with or made from living things.
Inorganic compounds include salt and water.
Answer:
yes the answer id bce
Explanation:
If an insufficient amount of liquid unknown had been used, how would this have effected the value of the experimental molar mass
Answer:
Actual yield reduces the more.
Explanation:
An actual yield of the course of a chemical reaction is the mass of a product actually obtained from the reaction.
In practice you see it and It is usually less than the theoretical yield.
Various reasons may come up to explain this away but here is one:
• incomplete reactions, simply put here some of the reactants do not react to form the product.
The same applies in the question about the actual yield will reduce significantly in molar mass now that insufficient amount of reagent are used.
What is the total amount of energy needed to heat 22.6 g of titanium from 1420oC to 1590oC in joules?
Answer:
[tex]Q=2091J=2.091kJ[/tex]
Explanation:
Hello,
In this case, the formula we use to compute the heat Q by increasing the temperature, in terms of the mass and the heat capacity is:
[tex]Q=mCp(T_2-T_1)[/tex]
Titanium's heat capacity is 0.544284 J/g°C, thus, the for such temperature increase, the heat results positive as shown below:
[tex]Q=22.6g*0.544284\frac{J}{g^oC}*(1590^oC-1420^oC) \\\\Q=2091J=2.091kJ[/tex]
Best regards.
In a different experiment, the student uses a calorimeter which is perfectly insulated. She fills the calorimeter with 100.0 g of 25.00°C dilute HCl solution and adds 0.594 g Mg metal (24.3 g/mol). The final temperature of the apparatus comes to 41.83°C. Remember, the solution is made-up of the solute and the solvent. The specific heat for magnesium is negligible compared to the aqueous solution. What is the Molar Heat of Enthalpy for this reaction?
Answer:
Explanation:
Mg + 2HCl = Mg Cl₂ + H₂
.594 g = .594 / 24.3
= .02444 mole
Heat evolved = msΔ T , m is mass of water ( solvant ) , s is specific heat of water , Δ T is rise in temperature
= 100 x 4.2 x ( 41.83 - 25 )
= 7068.6 J
.02444 mole of Mg evolves 7068.6 J of heat
1 mole of Mg evolves 7068.6 /.02444 J
= 289222.6 J
= 289 kJ .
Molar heat enthalpy = 289 kJ .
516 mL of a 3.82 M sodium sulfate (Na2SO4) solution is diluted ith .875 L of water. What is the new concentration in molarity?
Answer: 1.42
Explanation:
What is the molarity of sodium hydroxide solution made by combining 2.0 L of 0.60
NaOH With 495 mL 3.0 M NaOH? Assume the volumes of the two solutions to be additive___M
Answer:
[tex]M=1.1M[/tex]
Explanation:
Hello,
In this case, since we are mixing two NaOH solutions, the first step is to compute the total moles once the mixing is done, by using the volumes and concentrations of each solutions and subsequently adding them:
[tex]n_T=2.0L*0.60\frac{mol}{L}+495mL*\frac{1L}{1000mL}*3.0\frac{mol}{L}= 2.7molNaOH[/tex]
Next, we compute the total volume by adding the volume of each solution:
[tex]V_T=2.0L+495mL*\frac{1L}{1000mL}= 2.495L[/tex]
Finally, we compute the molarity of the resulting solution by the division between the total moles and the total volume:
[tex]M=\frac{2.7mol}{2.495L}\\ \\M=1.1M[/tex]
Best regards.
What is the hydronium ion concentration of a 0.100 M acetic acid solution with Ka = 1.8 × 10-5? The equation for the dissociation of acetic acid is: CH3CO2H(aq) + H2O(l) ⇌ H3O+(aq) + CH3CO2-(aq) What is the hydronium ion concentration of a 0.100 M acetic acid solution with Ka = 1.8 × 10-5? The equation for the dissociation of acetic acid is: CH3CO2H(aq) + H2O(l) ⇌ H3O+(aq) + CH3CO2-(aq) 1.3 × 10-2 M 4.2 × 10-2 M 1.3 × 10-3 M 4.2 × 10-3 M
Answer:
1.3×10⁻³ M
Explanation:
Hello,
In this case, given the dissociation reaction of acetic acid:
[tex]CH_3CO_2H(aq) + H_2O(l) \rightleftharpoons H_3O^+(aq) + CH_3CO_2^-(aq)[/tex]
We can write the law of mass action for it:
[tex]Ka=\frac{[H_3O^+][CH_3CO_2^-]}{[CH_3CO_2H]}[/tex]
Of course, excluding the water as heterogeneous substances are not included. Then, in terms of the change [tex]x[/tex] due to the dissociation extent, we are able to rewrite it as shown below:
[tex]1.8x10^{-5}=\frac{x*x}{0.100-x}[/tex]
Thus, via the quadratic equation or solve, we obtain the following solutions:
[tex]x_1=-0.00135M\\x_2=0.00133M[/tex]
Obviously, the solution is 0.00133M which match with the hydronium concentration, thus, answer is: 1.3×10⁻³ M in scientific notation.
Regards.
Answer:
1.3×10^-3 M
Explanation:
Step 1:
Data obtained from the question:
Equilibrium constant (Ka) = 1.8×10^-5
Concentration of acetic acid, [CH3COOH] = 0.100 M
Concentration of hydronium ion, [H3O+] =..?
Step 2:
The balanced equation for the reaction.
CH3CO2H(aq) + H2O(l) ⇌ H3O+(aq) + CH3CO2-(aq)
Step 3:
Determination of concentration of hydronium ion, [H3O+].
This can be obtained as follow:
Ka = [H3O+] [CH3CO2-] / [CH3CO2H]
Initial concentration:
[CH3COOH] = 0.100 M
[H3O+] = 0
[CH3CO2-] = 0
During reaction
[CH3COOH] = – y
[H3O+] = +y
[CH3CO2-] = +y
Equilibrium:
[CH3COOH] = 0.1 – y
[H3O+] = y
[CH3CO2-] = y
Ka = [H3O+] [CH3CO2-] / [CH3CO2H]
1.8×10^-5 = y × y / 0.1
Cross multiply
y^2 = 1.8×10^-5 x 0.1
Take the square root of both side
y = √(1.8×10^-5 x 0.1)
y = 1.3×10^-3 M
[H3O+] = y = 1.3×10^-3 M
Therefore, the concentration of the hydronium ion, [H3O+] is 1.3×10^-3 M
Dysphagia is the name of a disorder that disrupts
А
the swallowing reflex
B
the absorption of essential nutrients
acid levels in the stomach
C
D
the stomach lining
Answer:
A. The Swallowing reflex
Explanation:
Dysphagia Is a a condition that makes swallowing difficult.
please do this guys i need a lot of help please!
Answer:
the European countries grew together.
Explanation:
Europe saw human inflows from east and southeast.
the Roman Empire came to dominate the entire Mediterranean basin.
European politics from 1947 to 1989 made the European countries grew together.
If you start with 64g of a radioactive element how many half-lives would occur before 8g remain?
Answer:
3 half-lives
Explanation:
The half-life is the time that it takes to a radioactive element to decay to half of its initial amount.
Let's suppose we start with 64 g of the radioactive element.
After 1 half-life, the mass of the element will be 32 g.After 2 half-lives, the mass of the element will be 16 g.After 3 half-lives, the mass of the element will be 8 g.Helium occupies a volume of 3.8 L at –45°C. What was its initial temperature when it occupied 8.3 L?
Answer:
98.3 gradius Celsius
Explanation:
This problem is solved using the Ideal Gas Equation
pV = nRT
...
Please see the step-by-step solution in the picture attached below.
Hope this answer can help you. Have a nice day!
It takes 300 N to move a box 10 meters in 10 seconds. How much power is
required?
A. 30,000 W
B. 100 W
C. 3,000 J
D. 300 W
Plz help
Answer:
Power, P = 300 W
Explanation:
We have,
Force acting on the box to take it is 300 N
It is moved to a distance of 10 m in 10 seconds
It is required to find the power required to move the box. The rate at which work is done is called power required by an object. It can be given by the formula as follows :
[tex]P=\dfrac{W}{t}\\\\P=\dfrac{Fd}{t}\\\\P=\dfrac{300\times 10}{10}\\\\P=300\ W[/tex]
So, the power required is 300 W.
Describe an autopsy table
After the body is cleaned, the body is weighed and measured before being placed on the autopsy table for reexamination. The autopsy table is typically a slanted, aluminum table with raised edges that has several faucets and drains used to wash away collecting blood during the internal investigation.
Answer:
A table used to scientifically determine the cause of death of a human or animal
Explanation:
Based on the diagram below, how much of the excess reactant is left over? *
2 slices of bread and 3 pieces of lunchmeat
2 slices of bread and 2 slices of cheese
2 of lunchmeat and 3 slices of cheese
3 of lunchmeat and 2 slices of cheese
Answer:
3 pieces of lunch-meat and 2 slices of cheese
Explanation:
You have enough bread to make 3 sandwiches
You have enough lunch-meat to make 4 sandwiches
You have enough cheese to make 5 sandwiches
In all you have enough material to make 3 sandwiches
so if you subtract three from each number above you will have no bread, enough lunch-meat to make one sandwich and enough cheese to make two sandwiches
luch-meat for one sandwich is: 3 pieces
Cheese for two sandwiches is: 2 pieces
Claims • Evidence • Reasoning Make
a claim about ways people can stay safe
during storms with high wind and heavy
rains. Summarize evidence to support the
claim and explain your reasoning.
Answer:
the claim is that when people avoid storms they hide in any secret place in there house
Explanation:
when people do that they don't even have to worry about a single thing that will happen to them
What is the symbol for the entity that has 17 protons, 20 neutrons, and 18 electrons?
hEy!!!
Chlorine(CL) is the symbol for the entity that has 17 protons,20 neutrons and 18 electrons.
Hope it will be helpful to you...
Answer:chlorine
Explanation:
If I add 50 mls of water to 300 mls of 0.6M KNO3 solution, what will be the molarity of the diluted solution?
Answer:
[tex]M_2=0.51M[/tex]
Explanation:
Hello,
In this case, for this dilution process, we understand that the moles of the solute (potassium nitrate) remain unchanged upon the addition of diluting water. However, the resulting or final volume includes the added water as shown below:
[tex]V_2=300mL+50mL=350mL[/tex]
In such a way, we are able to relate the solution before and after the dilution by:
[tex]V_1M_1=V_2M_2[/tex]
Hence, we solve for the final molarity as:
[tex]M_2=\frac{M_1V_1}{V_2}=\frac{0.6M*300mL}{350mL}[/tex]
Best regards.
[tex]M_2=0.51M[/tex]
Describe the catenation property of carbon by illustrating the formation of a straight chain and branched chain compounds
Answer:
Catenation refers to the ability of an atom to link to other atoms of the same kind to form a chain.
Explanation:
Catenation is the binding of an element to itself through covalent bonds to form chain or ring .Catenation can also be defined as the self-linking of atoms of an element to form chains and rings. This definition can be extended to include the formation of layers like two-dimensional catenation and space lattices like three-dimensional catenation. Thus, we can boldly say that, Catenation occurs when atoms of the same element covalently bond to one another to create a chain or ring.
Catenation occurs most readily in carbon, forming covalent bonds to and longer chains and structures with other carbon atoms. This is why the vast number of organic compounds are found in nature. Carbon is best known for its catenation properties, with the analysis of catenated carbon structures in organic chemistry.
Carbon is by no means the only element capable of forming such catenae, however, and several other main group elements are capable of forming a wide range of catenae, including silicon, sulfur, and boron. In group 14, the high bond energy of carbon makes it able to self-link almost indefinitely when compared with other members of the group which form only a few bonds to other atoms of the same element.
Use the graph to determine which is greater, the heat of fusion or the heat of vaporization. Explain how you used the graph to determine that.
(The substance is water)
Answer:
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3. Infer A forgotten ice pop lies melting on a deck on a hot summer day. What is the direction of heat flow as the ice pop melts?
Is the process endothermic or exothermic? Explain.
Answer:
Endothermic. The energy is flowing into the molecules causing them to break apart and the ice pop change state.
Answer:
Yes, an autumn day isn’t cold enough to keep an ice pop at freezing temperatures.
The roles of hydrochloric acid (HCl) in the digestive system?
Answer:
There are several roles of HCl in the digestive system. Some of them are as follows:
There is HCl present in the gastric juice of your stomach, otherwise known as stomach acid. The acidic nature of the HCl in the stomach acid make it useful for quickly breaking down food.HCl's acidic nature also allows it to kill bacteria and other pathogens that you may have ingested, keeping you safe from their dangerous effects.HCl can also contribute Hydrogen ions, which helps to activate pepsinogen, a substance secreted by the stomach wall. The activated pepsinogen is then converted into pepsin, which aids in the digestion of proteins. Because of this, HCl essentially keeps the systems of protein digestion in check. Too much or too little of it can be dangerous.HCl also makes sure that vitamins are properly absorbed and acts as a communicator to other organs in the digestive system.