Answer:
the wavelength of radiation emitted is [tex]\mathbf{\lambda= 2169.62 \ nm}[/tex]
Explanation:
The energy of the Bohr's hydrogen atom can be expressed with the formula:
[tex]\mathtt{E_n =- \dfrac{13.6\ ev}{n^2}}[/tex]
For n = 7:
[tex]\mathtt{E_7 =- \dfrac{13.6\ ev}{7^2}}[/tex]
[tex]\mathtt{E_7 =-0.27755 \ eV}[/tex]
For n = 4
[tex]\mathtt{E_4=- \dfrac{13.6\ ev}{4^2}}[/tex]
[tex]\mathtt{E_4 =- 0.85\ eV}[/tex]
The electron goes from the n = 7 to the n = 4, then :
[tex]\mathtt{E_7-E_4 = (-0.27755 - (-0.85) ) \ eV}[/tex]
[tex]\mathtt{= 0.57245\ eV}[/tex]
Wavelength of the radiation emitted:
[tex]\mathtt{\lambda= \dfrac{hc}{0.57245 \ eV}}[/tex]
where;
hc = 1242 eV.nm
[tex]\mathtt{\lambda= \dfrac{1242 \ eV.nm }{0.57245 \ eV}}[/tex]
[tex]\mathbf{\lambda= 2169.62 \ nm}[/tex]
Erica is bisecting an angle as shown. Which of the following should be her next step
Answer:
She should bisect from point M and then draw a line from the point where the arcs from M and N meet to point O
Which acid could not be prepared by treating a Grignard reagent with CO2?
a. p-methylbenzoic acid.
b. cyclopentane carboxylic acid.
c. 4-oxopentanoic acid.
d. 3-methylbutanoic acid.
Answer:
4-oxopentanoic acid.
Explanation:
In this case, we must remember that the Grignard reaction is a reaction in which carbanions are produced. Carboanions have the ability to react with CO2 to generate a new C-C bond and a carboxylate ion. Finally, the acid medium will protonate the carboxylate to produce the carboxylic acid group.
The molecules that can follow the mechanism described above are the molecules: p-methylbenzoic acid, cyclopentane carboxylic acid and 3-methylbutanoic acid. (See figure 1)
In the case of 4-oxopentanoic acid, the possible carbanion will attack the carbonyl group to generate a cyclic structure and an alcohol group (1-methylcyclopropan-1-ol). Therefore, this molecule cannot be produced by this reaction. (See figure 2)
Hydrangea is a flower that presents in a variety colors including blue, white and pink. The color of some varieties of
hydrangea flowers can be controlled by the gardener growing the plant in a container and carefully regulating the pH. In
some instances aluminum sulfate, Al2(SO4)3, must be added as well. Perform an on-line search to identify what pH range
favors pink and blue color petals on hydrangea flowers. Also comment on the role of aluminum sulfate in determining the
color of the flower.
Answer:
Bigleaf hydrangeas are blue if the pH is between 5.0 and 5.5. The flowers
turn pink when the pH gets around 6.0. The flower color is dependent on
the concentration of aluminum ions (Al+++) in the soil. Aluminum is more
available to the plant when the soil is acidic, less available when the soil is
alkaline.The color of the cultivar called “Endless Summer” of H. macrophylla depends
on soil pH. Red or pink blooms result from neutral or basic soil (pH 7 and
above), whereas blue blooms indicate acidic conditions (pH less than 7).
Which of the following is true about the scientific method?
a
Each step is related to the others.
b
It is an iterative process.
c
All of the answers are correct.
d
It is a step-by-step process.
e
It involves a logical flow.
Answer:
It is a step by step process
Explanation:
You cannot do the experiment and lab report without following the steps
Hope this is correct and helpful
HAVE A GOOD DAY!
If the initial concentrations of A and B are 0M each, and the initial concentrations of C and D are 1.6M each, and Kc=4.7, what is the equilibrium concentration of A?
Answer:
[tex][A]_{eq}=0.095M[/tex]
Explanation:
Hello,
In this case, for the reaction:
[tex]A+B\rightleftharpoons C+D[/tex]
It is clear that the equilibrium expression is:
[tex]Kc=\frac{[C][D]}{[A][B]}[/tex]
Nevertheless, since the initial concentrations of both A and B are 0 M and C and D 1.6 M, we should invert the reaction:
[tex]C+D\rightleftharpoons A+B[/tex]
Thereby the equilibrium expression is also inverted:
[tex]Kc=\frac{[A][B]}{[C][D]}[/tex]
Which can be written in terms of the reaction extent and initial concentrations as shown below:
[tex]\frac{1}{Kc} =\frac{x*x}{([C]_0-x)([D]_0-x)}\\\\\frac{1}{0.47}= \frac{x*x}{(1.6-x)(1.6-x)}[/tex]
Hence, solving for [tex]x[/tex] we obtain:
[tex]x=0.095M[/tex]
In such a way, the equilibrium concentration of A is:
[tex][A]_{eq}=x=0.095M[/tex]
Best regards.
The equilibrium concentration of A will be "0.095 M". To understand the calculation, check below.
EquilibriumAccording to the question,
Initial concentration for A and B = 0 M
For C and D = 1.6 M
Kc = 4.7
Here the reaction:
→ A + B [tex]\rightleftharpoons[/tex] C + D
We know the expression,
Kc = [tex]\frac{[C][D]}{[A][B]}[/tex]
By inverting the reaction,
→ C + D [tex]\rightleftharpoons[/tex] A + B
Kc = [tex]\frac{[A][B]}{[C][D]}[/tex]
By substituting the values,
[tex]\frac{1}{Kc}[/tex] = [tex]\frac{x\times x}{([C]_0 -x)([D]_0 -x)}[/tex]
= [tex]\frac{x\times x}{(1.6 - x)(1.6 -x)}[/tex]
x = 0.095 M ([tex][A]_{eq}[/tex])
Thus the above approach is correct.
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The element carbon would be expected to form covalent bond(s) in order to obey the octet rule. Use the octet rule to predict the formula of the compound that would form between carbon and bromine, if the molecule contains only one carbon atom and only single bonds are formed. Formula:
Answer and Explanation:
The octet rue depicts the overall trend of chemical bonding in which atoms of an elements would seek to attain stability by filling out their valence shell with eight (8) electrons, giving it the same electronic configuration as a noble gas (specifically Argon).
Hence Carbon with 4 valence electrons (2, 4 electronic configuration) would take on four bromine atoms with 7 valence electrons (2, 8, 4 electronic configuration) each, giving each Br atom the single electron it needs to achieve octet stability.
Carbon tetrabromide
Chemical formula: [tex]CBr_{4}[/tex]
I hope this is a clear explanation
Hydrophobic interactions help to stabilize the ________ structure(s) of a protein.
a. primary
b. secondary
c. secondary and tertiary
d. tertiary and quaternary
e. secondary and quaternary
Answer:
d. tertiary and quaternary
Explanation:
Form or shape of protein can be understood by its structure. The structure of protein encompasses four levels of protein :
Primary (Simplest layer of amino acids in polypeptide chain), Secondary (Atom - Backbone folding structure within polypeptide),Tertiary (R groups of amino acids), Quaternary (multiple polypeptide chain subunits).Hydrophobic Interactions refers to amino acids with non polar r group structure together on inside of protein, which leaves Hydrophobic amino acids outside to interact with surrounding water molecules.
These help to stabilise : D) Tertiary & Quaternary protein structures.
The purpose of the best-fit line on an experimental scatterplot is to:_______.
a. The best-fit line allows us to predict behavior between measured data using its slope.
b. Ignore data points that don't fit the line.
c. Determine individual slopes between each set of data points
Answer: a. The best-fit line allows us to predict behavior between measured data using its slope.
Explanation:
A line of best fit is drawn through a scatter-plot to determine the direction of an relation between two quantities.
The line of best fit can be used to make prediction for the dependent variables.
Hence, the purpose of the best-fit line on an experimental scatter-plot is to predict behavior between measured data using its slope.
Hence, the correct option is "a."
If the components of a solution are in the same state, which one is the solvent?
Answer:
Usually, the substance present in the greatest amount is considered the solvent.
which of the following molexules would you predict to be most polar? i. co2 ii. cf4 iii. both have the same molecular polarity why?
Answer:
iii. both have the same molecular polarity
Explanation:
Both CF4 and CO2 are nonpolar molecules.
CF4 is a tetrahedral molecule, the compound is highly symmetrical hence the individual dipole moments due to the four C-F bonds cancel out thereby making the molecule to be nonpolar.
Similarly, the direction of the two dipoles in CO2 cancel out since they are directed in opposite directions making the molecule nonpolar.
The specific spatial arrangement of amino acid residues that are close to each other in the polypeptide chain is called______the structure of a protein.
a. primary.
b. secondary.
c. tertiary.
d. quaternary .
Answer:
c. tertiary.
Explanation:
In this case, we can review the definition of each level of structuration in the proteins:
Primary structure
In the primary structure, the amino acids are linked by peptide bonds. That is, the order of the amino acids is the criterion that defines this type of structure.
Secondary structure
In the secondary structure, we have to look at the way in which the protein is folded. The options are:
-) Beta-laminar: A structure in which the protein has a planar shape.
-) Alpha-helix: A structure in which the protein has a cross-strand form.
Tertiary structure
In the tertiary structure, the R groups that the amino acids have in the primary structure can generate interactions with each other. Interactions such as hydrogen bridges, dipole-dipole, hydrophobic interactions. This makes the protein have a very specific three-dimensional structure, on which its function depends.
Quaternary structure
In the quaternary structure, several subunits may be attached, or there may be prostatic groups (metals that can help to attach various protein units).
With all these in mind, the deffinition that fits with the description in the question is the tertiary structure.
I hope it helps!
The specific spatial arrangement of amino acid residues that are close to each other in the polypeptide chain is called the tertiary structure of a protein.
What is Protein?Protein structure is three dimensional in shape, where the atoms are arranged in amino acid chain. The chain is polypeptide containing many amino acid sequences.
The tertiary structure have a single polypeptide chain which is called the backbone.
Therefore, the specific spatial arrangement of amino acid residues that are close to each other in the polypeptide chain is called the tertiary structure of a protein.
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At a given temperature, an unknown gas takes 10.0 minutes to travel the distance helium gas travels in 1.66 minutes. What is the approximate molar mass of the unknown gas
Answer:
The molar mass of the unknown is approximate 145g/mol
Explanation:
We can relate the speed of effusion of gases with the molar mass of the 2 compounds using Graham´s law:
[tex]\frac{v_a}{v_b} =\sqrt{ \frac{m_b}{m_a} }[/tex]
Where V is speed of the gas and m molar mass of a and b gases.
Molar mass of helium is 4g/mol. As the distance of the gases is the same, we can replace the speed of effusion with the time the gas takes to travel the distance. The equation will be:
[tex]\frac{t_b}{t_a} =\sqrt{ \frac{m_b}{m_a} }[/tex]
Replacing:
[tex]\frac{10.0min}{1.66} =\sqrt{ \frac{m_b}{4g/mol} }\\6.024 = \sqrt{ \frac{m_b}{4g/mol} }\\36.29 = \frac{m_b}{4g/mol}\\145 g/mol =m_b[/tex]
The molar mass of the unknown is approximate 145g/mol59.23
An atom contains one proton, one electron, and one neutron. Which two particles are most similar in mass?
O the neutron and the electron
O the proton and the electron
the proton and the neutron
O the neutron and the atom
Answer:
the proton and the neutron
Explanation:
mass of The proton is approximately 1.6726 × 10^-27 Kg
mass of the electron is approximately 9.109 × 10^-31 Kg
mass of the neutron is approximately 1.6749 × 10^-27 Kg
Here we see that mass of proton and neutron is approximately similar.
_____________________________________________
Lets see what is the mass of these particle IN atm unit
mass of these particles can also be described in form of amu(atomic mass unit)
1 atm is the mass defined as 1/12 th of mass of the carbon-12(c-12) atom.
In terms of unit atm
mass of proton = 1 amu
mass of electron = 5.45 × 10−4 amu
mass of neutron = 1 amu
hence we can say that mass of proton = mass of neutron.
mass of atom is sum of mass of all the neutron and proton in the atom.
Hence, mass of neturon and atom cannot be equal.
This makes option four the neutron and the atom , the wrong choice.
correct answer is the proton and the neutron
therefore, An atom contains one proton , one electron and one neutron then, mass of proton is similar in mass of neutron.
Answer:
proton and neutron
Explanation:
How many asymmetric centers are present in the open chain form of the aldohexose D-(-)-gulose?
A) 0
B) 1
C) 2
D) 4
E) 5
Answer:
D) 4
Explanation:
If we want to find the asymmetric centers, we must first remember that in an asymmetric center, in the carbon, we will have 4 different types of groups bonded to it.
Therefore we must look for carbons that have 4 different groups. With this in mind, we can look at each carbon.
Carbon 1
In this carbon, we have two bonds with the oxygen, therefore, we dont have 4 different groups. So, this is not an asymmetric center.
Carbon 2
In this carbon, we have an "OH" in the top, an hydrogen in the bottom a carbonyl group in the right, and a CHOH in the left. We have 4 different groups. So, this is an asymmetric center.
Carbon 3
In this carbon, we have an "OH" at the bottom, an hydrogen in the top, a CHOH group in the right (that is bonded to a carbonyl group), and a CHOH in the left. We have 4 different groups. So, this is an asymmetric center.
Carbon 4
In this carbon, we have an "OH" at the top, an hydrogen in the bottom a CHOH group in the right (that is bonded to a CHOH group), and a CHOH in the left. We have 4 different groups. So, this is an asymmetric center.
Carbon 5
In this carbon, we have an "OH" at the bottom, an hydrogen in the top, a CHOH group in the right (that is bonded to a CHOH), and a CH2OH in the left. We have 4 different groups. So, this is an asymmetric center.
Carbon 6
In this carbon, we have two bonds with hydrogens, therefore, we dont have 4 different groups. So, this is not an asymmetric center.
See figure 1
I hope it helps!
QUICK WILL MARK BRAINLIEST!!
Match each of the unknown ions to its appropriate description.
A− A) A nonmetal that gained one electron
B+ B) A metal that lost one electron
C2− C) A metal that lost two electrons
D2+ D) A nonmetal that gained two electrons
Answer:
Explanation:
1.A-
2.B+
3.D2+
4.C2-
Why are plastic containers preferred to glass containers for storing chemicals in the laboratory?
What information about a chemical solution can be inferred from knowing its pH value?
Answer:
See the answer below
Explanation:
The information than can be inferred from knowing the pH value of a chemical solution is the hydrogen or hydroxyl ion concentration of the solution.
The pH of a solution is the degree of acidity or alkalinity of the solution. Mathematically, the pH of a solution is expressed as:
pH = [tex]-log_{10}[H^+][/tex] where [tex][H^+][/tex] = hydrogen ion concentration.
Also,
pH = 14 - pOH, where pOH = [tex]-log_{10}[OH^-][/tex]
The more the [tex][H^+][/tex] of a solution, the lower the pH, and the more the [tex][OH^-][/tex] of a solution the higher the pH. The pH value ranges from 0 - 14 with 7 being a neutral pH.
Answer:
Explanation:
The hydrogen or hydroxyl ion concentration of the solution could be inferred from knowing its pH value.
When 36.5g Of NaCL(s) is added to enough water to make 550.0 ml of solution, what is the molarity of the solution?
Answer:
1.1442 moles| litre,NaCl
Explanation:
RAM:56g|mole
number of moles=36.5g÷58g|mole =0.6293moles
0.6293 is contained in 550ml
=1000ml
[1000×0.6293]÷550 =1.1442moles| litre,NaCl
While in Europe, if you drive 109 km per day, how much money would you spend on gas in one week if gas costs 1.10 euros per liter and your car's gas mileage is 22.0 mi/gal ? Assume that 1euro=1.26dollars.
Answer:
113.12 dollars
Explanation:
From the question we are told that you drive 109km/day and your gas milage = 22miles/gallon
Step 1
We convert 109km to miles
1 km = 0.6214 miles
109km =
109km × 0.6214miles/ 1 km
= 67.7326miles
Step 2
Since the gas mileage = 22miles per gallons, we calculated how many gallons of fuel you used in a day
22 miles = 1 gallon
67.7326 miles = x gallon
Cross Multiply
x gallon × 22 miles = 67.7326 × 1 gallon
x gallons = 67.7326 miles × 1 gallon/22 miles
x gallons = 3.0787545455 gallons
Approximately = 3.08 gallons of gas
Hence, in a day you use 3.08 gallons of gas.
Step 3
We are told that has cost 1.10 euros/ liter
Hence, we convert the amount of gas you used in gallons to liters
1 gallon = 3.785 liters
3.08 gallons = y liters
1 gallon × y liters = 3.08 gallons × 3.785 liters
y liters = 3.08 × 3.785/1
y = 11.6578 liters.
So in a day you use 11.6578 liters of gas.
Step 4
Assume that 1euro=1.26dollars.
We are also told that has = 1.10 euros per liters
We convert the amount in Euros to dollars
1 euro = 1.26 dollars
1.10 euros =
1.10 × 1.26
= 1.386 dollars
Hence gas costs 1.386 dollars per liter
Step 5
Since : 1 liter of gas = 1.386 dollars
11.6578 liters of gas =
= 11.6578 liters × 1.386 dollars/ 1 liter
= 16.1577108 dollars
Therefore, in 1 day, you spend approximately = 16.16 dollars on gas
Step 6
The final step:
We are asked to calculate how much you spent on gas in 1 week
1 week = 7 days
Therefore, if
In 1 day you spend = 16.16 dollars on gas
7 days =
= 7 × 16.16 dollars
= 113.12 dollars
Therefore, the amount money you would spend on gas in one week = 113.12 dollars.
During a titration, the solution with the unknown concentration is called the _____.
Answer:
Analyte.
Explanation:
Hello,
In this case, in a titration, an analyte is known as the the substance whose quantity or concentration is to be carefully determined (initially unknown) by using a titrant with a controlled volume and an accurately-known concentration which is also called a standard solution.
You can verify this by considering the attached picture.
Regards.
liquid water has the density of 1000.0kg/m^3. Calculate the volume occupied by 0.250kg of liquid water.
Answer:
[tex]V=2.5x10^{-4}m^3\\\\V=0.25L[/tex]
Explanation:
Hello,
In this case, since the density is defined as the degree of compactness a substance has and is mathematically defined as:
[tex]\rho =\frac{m}{V}[/tex]
Thus, for this problem, as we know both the density and mass of water we can compute the volume as shown below:
[tex]V=\frac{m}{\rho}=\frac{0.250kg}{1000.0kg/m^3}\\ \\V=2.5x10^{-4}m^3\\\\V=0.25L[/tex]
Best regards.
a chemist encounters an unknown metal. They drop the metal into a graduated cylinder containing water, and find the volume change is 3.2 mL. If the metal weighs 1.5g, what is the density in g/mL of the metal?
The density of metal will be "0.469 g/mL".
The given values in the question are:
Mass of metal = 1.5 gVolume of metal or Volume change = 3.2 mLNow,
The density of metal will be:
→ [tex]Density = \frac{Mass}{Volume}[/tex]
By substituting the given values, we get
→ [tex]= \frac{1.5}{3.2}[/tex]
→ [tex]=0.469 \ g/mL[/tex]
Thus the above is the appropriate answer.
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The density of the metal is 0.47 g/mL
The density of an object is defined as the mass of the object per unit volume of the object.
Density = mass / volumeWith the above formula, we can obtain the density of the metal. This is illustrated below:
Volume of metal = change in volume of water = 3.2 mL
Mass of metal = 1.5 g
Density of metal =?Density = mass / volume
Density = 1.5 / 3.2
Density of metal = 0.47 g/mLTherefore, the density of the metal is 0.47 g/mL
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Which of the following affects cell potential?
a. the standard cell potential value
b. the electronegativity of the elements in the electrodes
c. the volume of the solutions
d. all of the above
Answer:
the standard cell potential value
Explanation:
For every cell, we can calculate its standard electrode potential from the table of standard electrode potentials listed in many textbooks.
However, from Nernst's equation;
Ecell= E°cell - 0.0592/n log Q
Hence the standard cell potential (E°cell) affects the value of the calculated cell potential Ecell from Nernst's equation as stated above.
who discovered copper
Explanation:
The exact person is unkown cooper has been around for ages since 9000 BC in the Middle East are the earliest discoveries
Although various copper tools and decorative items dating back as early as 9000 BCE have been discovered, archaeological evidence suggests that it was the early Mesopotamians who, around 5000 to 6000 years ago, were the first to fully harness the ability to extract and work with copper
A C≡C triple bond contains-
A) 3 σ bonds
B) 2 σ bonds and one π bond
C) one σ bond and 2 π bonds
D) three π bonds
E) one-and-a-half σ bonds and one-and-a-half π bonds
Answer:
i think its D but im not really good with this calls tho
Substances that are composed of a network of atoms held together by covalent bonds are called
O A. ionic lattices
B. giant covalent structures
C. allotropes
D. diatomic networks
Answer:
giant covalent structures
Explanation:
Covalent solids are made up of atoms joined to one another by covalent bonds to form a giant lattice. The covalent bonds are very strong, this makes the giant covalent solids to be hard and possess high melting points. Covalent solids are nonconductors of electricity due to the absence of free electrons in the structure.
Diamond, graphite and boron nitride are all examples of giant covalent structures.
1. What does the atomic number of an element represent?
O A the number of neutrons
B the number of electrons
C the number of orbitals
D the number of protons
Answer:
D The number of protons
g Which ONE of the following ionic compounds is insoluble in water? A) MgCO3 B) Li2CO3 C) NH4Br D) K3PO4 E) Pb(NO3)2
Answer:
A) MgCO₃ is insoluble
Explanation:
Based on the rules of solubility:
All nitrates are soluble. That means Pb(NO₃)₂ is soluble.
All ammonium ions are soluble. NH₄Br is soluble.
All phosphate are insoluble except when combined with group I ions (Li, Na, K...) K₃PO₄ is soluble.
Also, all carbonates are insoluble except when combined with group I ions. That means Li₂CO₃ is soluble and:
A) MgCO₃ is insolubleWhat is the answer with the correct significant figures to the addition problem 1.2773 + 4.29
Answer:5.5673
Explanation: I searched it up for you
A mixture of glycine, alanine, aspartic acid, glutamic acid, leucine, lysine, histidine, asparagine, and phenylalanine are put into an electrophoresis apparatus, with the buffer pH=6.5. Sort each amino acid according to its charge in the buffer with a pH of 6.5.
a. Glycine
b. Alanine
c. Glutamic acid
d. Alanine aspartic acid
e. Leucine
f. Histidine asparagine
g. Phenylalanine
h. Lysine
Answer:
Positively charged: Lysine, Histidine
Negatively charged: Asparagine, Phenylalanine, Glutamatic acid, Alanine, Glycine, Leucine, Aspartic acid
Explanation:
The charge of an amino acid in solution is determined by its isoelectric point, pI, which is the characteristic pH in which the net electric charge of the amino acid is zero. In solutions of pH below the isoelectric point, the amino acid has a net positive charge whereas in solutions with pH above isoelectric point, the net charge on the amino acid is negative.
In a buffer solution of pH 6.5, the following charges are present in the amino acids given:
Positively charged: Lysine (pI = 9.74), Histidine (pI = 7.59)
Negatively charged: Asparagine (pI = 5.07), Phenylalanine (pI = 5.48), Glutamatic acid (pI = 3.22), Alanine (pI = 6.01), Glycine (pI = 5.97), Leucine (pI = 5.98), Aspartic acid (pI = 2.77)