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.
4. A taxi ride costs $5 plus .75 cents per mile. If I
ride for 120 miles, how much will be charged?
Answer:
$95
Explanation:
.75 x 120 = 90
90+5 = 95
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
Two identical light bulbs are connected to a battery in a series circuit.
An ammeter is wired into the circuit at measures a current of the
battery to be 0.5 Amps. The two light bulbs are then wired in parallel.
The ammeter shows that the current:
Answer:
0.10 amps
Explanation:
The glass of a lit 75-watt incandescent bulb is hotter to the touch than the glass of a 25-watt compact fluorescent (CFL) bulb that emits the same amount of light. What could be a reason for this
What mass of aluminum is produced by the decomposition of 5.0 kg? How many moles of oxygen are produced?
Answer:
2.6 × 10³ g Al
74 mol O₂
Explanation:
Aluminum oxide decomposes into aluminum and oxygen, according to the following balanced equation.
2 Al₂O₃ ⇒ 4 Al + 3 O₂
Step 1: Calculate the moles corresponding to 5.0 kg of aluminum oxide
The molar mass of aluminum oxide is 101.96 g/mol.
[tex]5.0 \times 10^{3} g \times \frac{1mol}{101.96g} = 49mol[/tex]
Step 2: Calculate the mass of aluminum formed
We will use the following relations.
The molar ratio of Al₂O₃ to Al is 2:4The molar mass of Al is 26.98 g/mol[tex]49molAl_2O_3 \times \frac{4molAl}{2molAl_2O_3} \times \frac{26.98gAl}{1molAl} = 2.6 \times 10^{3} gAl[/tex]
Step 3: Calculate the moles of oxygen produced
The molar ratio of Al₂O₃ to O₂ is 2:3. Then,
[tex]49molAl_2O_3 \times \frac{3molO_2}{2molAl_2O_3} =74molO_2[/tex]
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!
A sample of helium gas at room temperature is compressed from 100 cm3 to 20 cm3. Its new pressure is now 30 cm Hg. What was the original pressure of the gas?
Answer:
6 cm Hg
Explanation:
Boyles Law: P1V1=P2V2
(100 mL)(x)=(20 mL)(30 cm Hg)
x = 6 cm Hg
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A. An element with the valence electron configuration 5s1 would form a monatomic ion with a charge of ________. In order to form this ion, the element will _______ electron(s) from/into the _______ subshell(s).
B. An element with the valence electron configuration 2s22p4 would form a monatomic ion with a charge of ______. In order to form this ion, the element will ______ electron(s) from/into the _______ subshell(s)
Answer:
A) An element with the valence electron configuration 5s¹ would form a monatomic ion with a charge of +1. In order to form this ion, the element will lose electron(s) from/into the 5s subshell(s).
B) An element with the valence electron configuration 2s²2p⁴ would form a monatomic ion with a charge of +1. In order to form this ion, the element will lose electron(s) from/into the 2p (2pₓ specifically) subshell(s).
Explanation:
The secret to this task is to follow those rules for the stability of electronic structures of elements. The rules include
- Electrons are filled firstly into shells or subshells of lower energies first.
- While filling electronic structure or writing electronic structures for elements/ions, electrons are fed singly to the suborbital before pairing occurs, this is because the totally paired up electrons of a suborbital are more stable than the totally unpaired electrons of the same suborbital which is now in turn more stable than the combination of paired and unpaired electrons in the suborbitals.
A) For an element with its valence electron on 5s¹, this means that there is one valence electron on this atom's outermost shell and outermost suborbitals. So, to form a monoatomic ion, it would take between losing and gaining an electron. Gaining an electron leads to a 5s², which indicates empty 5p orbitals too and is therefore less stable than losing an electron which would lead to the loss of the shell 5 and focus on a completely filled 4-shell.
So, losing the electron from the 5s suborbital to become a monotonic ion makes it acquire a charge of +1.
B) Just like the explanation in (A), to form a monoatomic ion would require a loss or gain of an electron. With valence electrons 2s²2p⁴, gaining an electron would have led to a 2s²2p⁵ and a further breakdown as 2s²2pₓ²2pᵧ²2pz¹ which has unpaired and paired electrons in the 2p suborbital. This is evidently less stable than if an electron was lost, the valence electrons are 2s²2p³ and they are positioned in a totally unpaired fashion in the 2p suborbital as 2s²2pₓ¹2pᵧ¹2pz¹.
Hence, the more stable alternative is more likely to occur and the electron is lost from the 2pₓ suborbital to make the monoatomic ion of the element acquire a +1 charge status too because of lost electron too.
Hope this Helps!!!
The octet rule states that the atoms of the elements bond to each other in an attempt to complete their valence shell with eight electrons. In other words, the atoms will tend to give up or share electrons to complete eight electrons in the valence shell through an ionic, covalent or metallic bond.
In other words, the goal is to have the closest noble gas electron configuration, thus having the last complete electron shell and acquiring stability.
So, in this case, to comply with the octet rule:
A. An element with the valence electron configuration 5s¹ would form a monatomic ion with a charge of +1. In order to form this ion, the element will lose one electron from the 5s subshell.
For an element with its valence electron at 5s¹, this means that there is one valence electron in the outermost shell of this atom and in the outermost suborbitals. To form a monatomic ion, it would be necessary between losing or gaining an electron and that ion is stable. It takes less energy to lose the electron of the suborbital 5s and acquire a charge of of +1, than to acquire an electron, because it forms the 5s² suborbital, which indicates empty 5p orbitals too and is therefore less stable.
Also, in this way, the octet rule is fulfilled.
B. An element with the valence electron configuration 2s²2p⁴ would form a monatomic ion with a charge of -2. In order to form this ion, the element will gain two electron into the 2p subshell(s).
After gain two electron the atom has eight electrons in its valence shell, giving it the same electronic configuration as a noble gas (2s²2p⁶). In this way, the octet rule is fulfilled and the ion is stable.
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18.35 mL of an HCN solution were titrated with 35.4mL of a 0.268M NaOH solution to reach the equivalence point. What is the molarity of the HCN solution
Answer:
0.517
Explanation:
HCN + NaOH → NaCN + H2O [balanced as written]
(35.4 mL) x (0.268 M NaOH) x (1 mol HCN / 1 mol NaOH) / (18.35 mL HCN) = 0.517 M HCN
Answer: 0.517
Explanation:
At constant pressure, what generally happens to the solubility of solids and gases when the temperature of a solution is increased?
A. The solubility of solids and gases increases.
B. The solubility of solids and gases decreases.
C. The solubility of solids increases, and the solubility of gases decreases.
D. The solubility of solids decreases, and the solubility of gases increases.
Answer:
C)
Explanation:
JUST DID IT
Answer:
A D E
Explanation:
just did it
What are 3 stages of the water cycle are
Which of the following describes the change in atomic mass and atomic number during this reaction?
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.What is the mass defect of a mole of nuclei with 1.8 x 10^15 J/mol binding
energy?
Answer:
2.0 x 10^-2 kg/mol
Explanation:
PLEASE help! BRAINLIEST to correct answer!
Answer:
C
Explanation:
Answer:
I think its q
Explanation:
h is the Planck constant, c the speed of light
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
advhuosijoklxcmnjdabsuhggggabciaciudeifweingivg eygerigsygfe97rsghisdcvhbsduigwiugfu9uigdgiurfgyisdgfsdgfegiygewifgsdygfewusgfuyesigf7wgfiesgfiusgdfies
The largest contributed to water pollution is
Answer:
this si from google hope it helps
Explanation:
The Main Causes of Water Pollution in the U.S.
Runoff from Agricultural Operations. Agriculture represents one of the biggest sources of water pollution in the country. ...
Runoff and Nonpoint Source Pollution. ...
Industrial Activities. ...
Leakage from Underground Storage and Piping. ...
Leaking Sewers. ...
Vehicle Emissions. ...
Landfill Leakage. ...
Hazardous Waste.
Answer:
Runoff and Non-point Source Pollution.
Explanation:
it's caused by rainfall or snow-melt moving over and through the ground. As the runoff moves, it picks up and carries away natural and human-made pollutants, finally depositing them into lakes, rivers, wetlands, coastal waters and ground and NPS is it's abbreviation.
What is the correct IUPAC name for Ag₂S?
Answer:
Acanthite. MFCD00003406
Explanation:
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?
Pure water at 25°C ionizes as what?
Answer:
see explanation
Explanation:
Pure water (H₂O) at 25°C follows an autoionization mechanism. That is, water reacts with itself to yield Hydronium Ions (H₃O⁺) and Hydroxide Ions (OH⁻) according to the following proton transfer mechanism.
2H₂O(l) ⇄ H₃O⁺(aq) + OH⁻(aq) => H₂O(I) ⇄ H⁺(aq) + OH⁻(aq) as a shorthand form of the process primarily for convenience. The H⁺ ion is a proton and would not be found in solution as an independent free form particle, but the shorthand format is generally accepted in the chemical community because of it's ease of application.
Other related facts of water ionization include...
At 25°C/1atm => the molar concentrations of [H⁺(aq)] = 1 x 10⁻⁷M and [OH⁻(aq)] = 1 x 10⁻⁷M
Applying to the equilibrium ionization expression for water ...
H₂O(I) ⇄ H⁺(aq) + OH⁻(aq)
C(eq): ∞* 1 x 10⁻⁷M 1 x 10⁻⁷M
*The molar concentration of water is considered to be infinite [∞] as compared to concentration values of H⁺(aq) and OH⁻(aq) and is for practical purposes assumed to be constant. This leads to the classic Ionization Product constant expression for water (Kw = [H⁺(aq)][OH⁻(aq)].
The value for Kw at 25°C/1atm is then ...
Kw = [H⁺(aq)][OH⁻(aq)] = (1 x 10⁻⁷M)(1 x 10⁻⁷M) = 1 x 10⁻¹⁴M² (units are typically dropped and Kw listed simply as 1 x 10⁻¹⁴.
With this, the terms acidity, neutral and alkaline acid base systems are defined and related to pH. That is, if ...
[H⁺(aq)] > [OH⁻(aq)] => Acidic System => pH < 7
[H⁺(aq)] = [OH⁻(aq)] => Neutral System => pH = 7
[H⁺(aq)] < [OH⁻(aq)] => Alkaline System => pH < 7
pH = -log[H⁺] and pOH = -log[OH⁻] and pH + pOH = 14.
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.
5) Low iron concentration (as low as 0.02 nM) in the open ocean limits phytoplankton growth. Preconcentration is required to determine such low concentrations. Trace Fe3 from a large volume of seawater is concentrated onto a 1.2 mL chelating resin column, the column is then rinsed with 30 mL of high purity water and eluted with 10 mL of 1.5 M high purity HNO3. a.) For each sample, seawater is passed through the column of 17 h at 10 mL./min. How much is the concentration of Fe3 in the 10 mL of HNO3 eluate increased by this preconcentration procedure
Answer:
Check the explanation
Explanation:
Sample volume V= 10 mL/min x 17 h x 60 min/h / 1000 mL/L = 10.2 L
The concentration is increased
10200 mL (sample volum) / 10 mL (eluted sample) = 1020 times.
57x10-9 M / 1020 = 5.6x10-12 M
1.5 M HNO3 will contain ≤ 2ppm x (1.5M/15.7M ) ≤ 0.190 ppm ≤ 190 ppb
Ignoring this is reagent impurity and calculating for sea water
≤ 190 ppb /1020 = 0.186 ppb = 0.186 x 10-9g/mL = 0.186 x 10-6g/L =
0.186 x 10-6g/L / 56 g/mol = 0.003 x10-6 M = 3 nM
A student wants to examine a substance without changing its identity. Which of the following properties should the student examine?
Answer:
A. Ductility, because it can be observed by altering the shape of the substance
Explanation:
Changing the shape of a substance does not change its identity.
How many moles
are equal to
4.11x1023
molecules of
CO2?
Explanation:
6.02×1023 culture atoms have a mass of 63.5g. 12.0g. c +23.0g O2__44.0g CO2.(12.0+16.0+16.0=44.0g).1 mol 1 mol. 1 mol number molecules weight
The number of molecules in one mole of carbon dioxide is 6.02 × 10²³. Therefore, the number of moles of carbon dioxide which contains 4.11 × 10²³ molecules is 0.68.
What is Avogadro number ?The number of atoms that constitutes one mole of a substance is called Avogadro number. It is equal to 6.02 × 10²³. Thus, one mole of every elements contains Avogadro number of atoms.
Similarly, one mole of a compound contains 6.02 × 10²³ number of molecules. Thus, one mole of carbon dioxide contains these much molecules.
Given the number of molecules of carbon dioxide = 4.11 × 10²³
Then, no.of moles = number of molecules/ Avogadro number.
no.of moles = 4.11 × 10²³ /6.022 × 10²³ = 0.68.
Therefore, the number of moles of CO₂ that contains 4.11 × 10²³ molecules is 0.68.
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Which of the following statements about an S N1 reaction mechanism is true? The reaction involves two steps and occurs fastest with tertiary alkyl halides. The reaction involves one step and occurs fastest with tertiary alkyl halides. The reaction involves one step and occurs fastest with primary alkyl halides. The reaction involves two steps and occurs fastest with primary alkyl halides.
Answer:
The reaction involves two steps and occurs fastest with tertiary alkyl halides
Explanation:
To solve such this we must know the concept of nucleophilic substitution reaction. The reaction involves two steps and occurs fastest with tertiary alkyl halides. Therefore, the correct option is option A.
What is chemical reaction?Chemical reaction is a process in which two or more than two molecules collide in right orientation and energy to form a new chemical compound. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, double displacement reaction.
The characteristics of SN1 mechanism:
SN1 reaction is a nucleophilic substitution reaction.
Leaving group, a nucleophile, electrophile and a solvent are present
Two types of enantiomers can be formed in the reaction depending on the preference of the nucleophile.
The first step is the slowest because a bond is being broken.
SN1 reaction involves two steps and occurs fastest with tertiary alkyl halides
Therefore, the correct option is option A.
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The change in entropy, ΔS∘rxn , is related to the the change in the number of moles of gas molecules, Δngas . Determine the change in the moles of gas for each of the reactions and decide if the entropy increases, decreases, or has little or no change. A. 2H2(g)+O2(g) ⟶ 2H2O(l) Δngas= mol The entropy, ΔS∘rxn , increases. decreases. has little or no change.
Explanation:
Entropy of a reaction ΔS∘rxn is the degree of disoderliness in a system. Gases generally have a higher degree of disorder compared to liquids. Hence for the reaction 2H2(g)+O2(g) ⟶ 2H2O(l), the entropy decreases sice the reactants are in the gaseous state and the products is in the liquid state of matter
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.
Which of the following 0.5 M aqueous salt solutions will have a pH of 7.0 at
LiF RbBr NaClO4 NH4Cl
A) LiF only B) NaClO4 only C) LiF and RbBr D) RbBr and NaClO4
Answer:
LiF and RbBr
Explanation:
Salt is an ionic compound that is made from the reaction of an acid and a base solution. Salts dissolve in water to give solutions that are acidic, basic, or neutral.
Salt formed from a strong acid and a weak base will make an acidic solution when added to water. The reason this occurs is because when the salt dissociates, the conjugate acid of the weak base will donate a proton, or one hydrogen ion, to water and form hydronium ion.
If a salt is formed from a weak acid and a strong base, it dissolves in water and the conjugate base of the weak acid will accept a proton from water and yield the hydroxide ion. Hence the solution of the salt will be basic.
If the salt is formed from a strong acid and a strong base, the salt is neutral when dissolved in water. Both LiF and RbBr are formed from strong acids and strong bases hence they will have a pH of 7.0 in solution.
LiF RbBr NaClO4 NH4Cl is = LiF and RbBr The correction is 'C'.
What are the Salt solutions?
Salt is an ionic mixture that is made from the reaction of an acid and a base resolution. Salts liquefy in water to give solutions that are acidic, basic, or neutral.
Salt constructed from a strong acid and a breakable base will make an acidic solution when added to water. The reason this occurs is that when the salt dissociates, the conjugate acid of the weak base will donate a proton, or one hydrogen ion, to water and form a hydronium ion.
If a grain of salt is formed from a weak acid and a powerful ground, it liquefies in water and the conjugate bottom of the weak acid will accept a proton from water and yield the hydroxide ion. Therefore, the solution of the salt will be basic.
If the salt is formed from a strong acid and a strong bottom, the salt is neutral when liquefied in water. Both LiF and also RbBr are formed from strong acids and powerful bases hence they will have a pH of 7.0 in resolution.
Therefore, the Correct option is 'C'
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Which characteristic of a substance is considered a chemical property
Answer:
c
Explanation:
