It is B. What I found is when water freezes it's entropy decrease. If water freezing that means the temperature is decreasing and that is B.
The muscles of the body are part of the muscular system but would not operate without the _______ system providing the impulses that cause the muscles to act.
Answer:
The nervous system
Explanation:
The nervous system send messages from the brain to the muscles to move.
The nervous system, particularly the somatic nervous system, provides the impulses that enable the muscular system to function, allowing for a wide range of both voluntary and involuntary movements.
Explanation:The muscles of the body, part of the muscular system, would not function without the nervous system providing the impulses that cause the muscles to act. This is particularly true for the skeletal muscles, which completely depend on signaling from the nervous system to work properly.
Our nervous system is divided into the somatic nervous system (SNS) and the autonomic nervous system, with the SNS responsible for the contraction of our skeletal muscles. This mechanism enables a wide range of voluntary and involuntary movements, like standing, walking, running, grasping items, and reflex actions; some of which happen automatically due to habit learning or procedural memory.
Responses can be voluntary, such as the contraction of skeletal muscles, or involuntary like the contraction of smooth muscles, regulation of cardiac muscles, and activation of glands.
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iodine sublimes by turning from a solid to a vapor when heated. a 100g sample of solid i2 is put in an empty rigid 10 l container and heated to 325k. when al the solid i2 vaporizes what is the pressure(in atm) in the container
Answer:
[tex]\boxed{\text{1.05 atm}}[/tex]
Explanation:
We can use the Ideal Gas Law to calculate the pressure.
pV = nRT Divide both sides by V
p = (nRT)/V
p = (m/M)(RT/V) = (mRT)/(MV)
Data:
m = 100 g
R = 0.082 06 L·atm·K⁻¹mol⁻¹
T = 325 K
M = 253.81 g·mol⁻¹
V = 10 L
Calculations:
p = (100 × 0.082 06× 325)/(253.81 × 10) = 1.05 atm
The pressure in the container is [tex]\boxed{\text{1.05 atm}}[/tex].
Rank the following elements in order of decreasing atomic radius.
Rank from largest to smallest radius. Si, Mg, Na, Al
In the periodic table, atomic radius decreases as we move left to right across a period. In period 3, this results in the elements Si, Mg, Na, and Al being ranked in decreasing atomic radius as follows: Na, Mg, Al, and Si.
Explanation:The atomic radius of an element is generally defined as the total distance from the center of an atom's nucleus to its outermost shell of electrons. In the periodic table, the atomic radius tends to decrease as we move across a period from left to right, and it increases as we move down a group.
Considering the elements Si, Mg, Na, and Al, all these elements are located in the same period in the periodic table, period 3. Therefore, as we move across this period from left to right, the atomic radius should decrease.
And following this rule, the elements should rank in this order from largest to smallest atomic radius: Na > Mg > Al > Si.
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The elements Si, Mg, Na, Al in order from largest to smallest atomic radius would be Na, Mg, Al, Si. This is based on the general trend in the periodic table where atomic radius decreases as you move from left to right across a period and increases as you move down a group.
Explanation:In the periodic table, atomic radius generally decreases as you move from left to right across a period and increases as you move down a group. So, considering this, Si, Mg, Na, Al are positioned in the periodic table as follows: Na (period 3, group 1), Mg (period 3, group 2), Al (period 3, group 13), and Si (period 3, group 14). Following the trend in the periodic table, the order from largest to smallest atomic radius would be Na, Mg, Al, Si.
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What would be the composition and ph of an ideal buffer prepared from lactic acid (ch3chohco2h), where the hydrogen atom highlighted in boldface is the acidic hydrogen atom? the ka value for lactic acid is 1.38 ?? 10???4.\?
c= 1.4 X [tex]10^-^4[/tex] is the composition and ph of an ideal buffer prepared from lactic acid ([tex]CH_3CHOHCO_2H[/tex]), where the hydrogen atom highlighted in boldface is the acidic hydrogen atom.
What is a buffer solution?A buffer is a solution that can resist pH change upon the addition of an acidic or basic components.
Equilibrium equation
[tex]C_3H_6O_3[/tex] ⇄[tex]C_3H_5O_3^-[/tex] +[tex]H^+[/tex]
Assuming a degree of dissociation [tex]\alpha[/tex] =[tex]\frac{1}{10}[/tex]
And the initial concentration of [tex]C_3H_6O_3[/tex] =c
At equlibrium ;
Concentration of [tex]C_3H_6O_3[/tex] = [tex]c - c\alpha[/tex]
[tex]C_3H_5O_3^-[/tex] = [tex]c\alpha[/tex]
[[tex]H^+[/tex]] = [tex]c\alpha[/tex]
[tex]Ka =\frac{c\alpha X c\alpha }{c-c\alpha }[/tex]
[tex]\alpha[/tex] is very small so 1-[tex]\alpha[/tex] can be neglected and the equation is;
[tex]Ka = c\alpha X \alpha[/tex]
[H^+] = [tex]c\alpha[/tex] =[tex]\frac{k\alpha }{\alpha }[/tex]
pH = -log [[tex]H^+[/tex]]
pH = -log[tex]Ka[/tex] +log [tex]\alpha[/tex]
[tex]Ka[/tex] = 1.38 X [tex]10^{-4}[/tex]
[tex]\alpha[/tex] = [tex]\frac{1}{10}[/tex]
pH = 3.86 -1
pH =2.86
Composition ;
C=[tex]\frac{1}{\alpha }[/tex] X [tex][H^+][/tex]
[tex][H^+][/tex] =0.0014
c= 0.0014 X [tex]\frac{1}{10}[/tex]
c= 1.4 X [tex]10^-^4[/tex]
Hence, c= 1.4 X [tex]10^-^4[/tex] is the composition and ph of an ideal buffer prepared from lactic acid ([tex]CH_3CHOHCO_2H[/tex]), where the hydrogen atom highlighted in boldface is the acidic hydrogen atom.
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An ideal buffer composed of lactic acid involves a mixture of lactic acid and its conjugate base, usually in equal molar amounts. Using the Henderson-Hasselbalch equation, the resulting pH will be close to 3.86, which is the pKa value of lactic acid.
The composition and pH of an ideal buffer prepared from lactic acid (CH3CHOHCO2H), would involve a mixture of lactic acid and its conjugate base, sodium lactate (CH3CHOHCO2Na). By using the Henderson-Hasselbalch equation, pH = pKa + log([A-]/[HA]), where pKa is the negative logarithm of Ka and [A-]/[HA] represents the ratio of the concentration of the conjugate base to the acid, we can determine the pH. For an ideal buffer, the ratio should be close to 1:1 to maintain a pH close to the pKa of lactic acid.
As an example, assume a student has mixed an equal number of moles (not necessary for equal weights as molar masses differ) of lactic acid and sodium lactate. In this case, since the pKa of lactic acid is 3.86, the resulting buffer would ideally have a pH close to 3.86, given that the concentrations of lactic acid and sodium lactate are similar after mixing.
Which of the following is true regarding the inner transition elements? (PF)
A. These include the lanthanides and actinides and do not have f sublevels.
B. They occupy the d block of the periodic table.
C. These include all elements in groups 3-12.
D. Their valence electrons can be located in both s and f sublevels.
Answer:The answer is D
Explanation:
The inner transition elements are those in the two long rows at the bottom of the Periodic Table.
The lanthanide series starts after Ba in Period 6, and the actinide series starts after Ra in Period 7.
Thus, we would predict their electron configurations to be of the form
However, the energy levels of the ns, (n-1)d, and (n-2)f orbitals are so close in energy that there are many exceptions to our predictions
For example, here are some electron configurations.
La = [Xe]6s²5d (not [Xe]6s²4f)
Ce = [Xe]6s²4f5d (not [Xe]6s²4f²)
Pr = [Xe]6s²4f³ (as predicted)
Thus, their valence electrons can be in both s and f (and sometimes d) sublevels.
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The answer should be d
What is emitted during gamma emission?
Electrons
Light
Alpha particles
Beta particles
Answer:c
Explanation:
Answer
Light
Explanation:
The gamma emission is an electromagnetic radiation, this kind of radiation come from the light.
In gamma ray emission, a gamma ray is photon of light. Given that light does not have mass or charge, the symbol we use to identify it is: 00γ. With two zeroes.
hope i helped
-lvr
Why are emission spectra referred to as the fingerprints of the elements?
They are referred to as the finger prints of the element because they show the particular properties of the elements which differentiates one element from other elements
The emission spectrum or emission spectra is characteristic for each element as it provides information which is unique to each element.
What is emission spectrum?
Emission spectrum is defined as a spectrum of a chemical compound or substance composed of frequencies of electromagnetic radiation. Radiations which are emitted while electron make transition from higher to lower energy level.
Energy of photon is equal to the difference between the two energy states . There are many possible electronic transitions in an atom and every transition has a specific wavelength.
Collection of different transitions with respect to different wavelengths makes up an emission spectrum.Emission spectrum of each element is unique and therefore spectroscopy is used to identify elements which are present in different substances.
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Which description correctly characterizes the acidity or basicity of a solution? The higher the pH is, the more the hydroxide ion concentration decreases and the more acidic the solution becomes. The higher the pH is, the more the hydroxide ion concentration increases and the more basic the solution becomes. The lower the pH is, the more the hydronium ion concentration decreases and the more acidic the solution becomes. The lower the pH is, the more the hydronium ion concentration increases and the more basic the solution becomes.
Answer:
The higher the pH is, the more the hydroxide ion concentration increases and the more basic the solution becomes.
Explanation:
When the pH of a solution is less than 7, then solution is called acidic and as the pH decreases the concentration of Hydronium ion increases.When the pH is about 7, then the solution is said to be neutral. On the other hand, when the pH is greater than 7, the solution is is said to be basic and as the pH increases the concentration of Hydroxide ions increases.Therefore, An acidic solution has a higher concentration of hydrogen ions compared to the concentration of hydroxide ions.Answer:
B
Explanation:
What is the wavelength of light that has a frequency of 2.85 x 10^14 Hz [c=3.00 x 10^8]
Answer:
1.05 x 10^-6
Explanation:
Lambda = c / f
f if frequency
c is intensity of light
lambda = 3 x 10^8 / 2.85 x 10^14
= 1.05 x 10 ^-6
What is the expected change in the freezing point of water for a 0.015 m aqueous solution of alcl3?
Answer:
- 0.028 °C
Explanation:
The depression in freezing point of water (ΔTf) due to adding a solute to it is given by: ΔTf = Kf.m.Where, ΔTf is the depression in water freezing point (ΔTf = ???°C).
Kf is the molal freezing point depression constant of the solvent (Kf = 1.86 °C/m).
m is the molality of AlCl₃ (m = 0.015 m).
∴ ΔTf = Kf.m = (1.86 °C/m)(0.015 m) = 0.0279 °C ≅ 0.028 °C.
∵ ΔTf = freezing point of pure water - freezing point of the solution in presence of AlCl₃.
∴ freezing point of the solution in presence of AlCl₃ = freezing point of pure water - ΔTf = 0.0 °C - 0.028 °C = - 0.028 °C.
which of the following bases could you write an equilibrium expression for?
A)NaOH
B)KOH
C)NH3
D)Ba(OH)2
D. I hope you have a good morning
- Josie Annette
Rutherford created a planetary model for atoms after his experiments. Imagine if Rutherford's idea that electrons radiate energy while orbiting around a nucleus was true. Which other model or scientific idea would have been strengthened by this? Bohr's model of the atom would have been strengthened because Bohr proposed that the energy of electrons is continuous. Bohr's model of the atom would have been strengthened because Bohr proposed that electrons can have only certain energy values. The idea that atoms are unstable would have been strengthened because the orbiting electron would lose energy and fall into the nucleus. The idea that atoms are unstable would be strengthened because the orbiting electron would absorb energy while moving and escape the pull from the nucleus.
The idea that atoms are unstable would have been strengthened because the orbiting electron would lose energy and fall into the nucleus.
Answer:
The idea that atoms are unstable would have been strengthened because the orbiting electron would lose energy and fall into the nucleus.
Explanation:
Based on classical mechanics an electron would spiral and fall on the nucleus thus collapsing the atom. But it was quantum mechanics that proposed that electrons move in definite orbits around the nucleus. Electrons absorb a definite quantum of energy and move from a lower state to an excited state. Also electrons release a definite quantum of energy and move from excited to more stable state.
Fluorine-18, which has a half-life of 110 min, is used in PET scans.
a. If 100. mg of fluorine-18 is shipped at 8:00 a.m., how many milligrams of the radioisotope are still active after 110 min?
b. If 100. mg of fluorine-18 is shipped at 8:00 a.m., how many milligrams of the radioisotope are still active when the sample arrives at the radiology laboratory at 1:30 p.m.?
Answer:
Part a. 50.0 mgPart b. 12.5 mgExplanation:
For every hal-life time the amount of the radioisotope (fluorine-18) will be cut to half.
Part a.
Since the half-life of fluorine-18 is 110 min, ater this very time, half of the fluorine-18 is still alive, i.e 100. mg / 2 = 50.0 mg. ← answer
Part b.
Compute the time elapsed from 8:00 am, when the fluorine-18 is shipped, to 1:30 pm, when the sample arrives at teh radiology laboratory.
1:30 pm - 8:00 am = 5 hours and 30 minutesConvert to minutes+ 5×60 + 30 = 330 minCompute the number of half-lives in 330 min:
330 min / 110 min per half-life = 3 half-lives.Conclusion:
the radiosotope has been reduced to half 3 times 100.0 mg × (1/2) × (1/2) × (1/2) = 100.0 mg × (1/2)³ = 100.0 mg / 8 = 12.5 mgHence, 12.5 mg of the radioisotope are still alive ← answerAfter one half-life of 110 minutes, 50mg of the 100mg of Fluorine-18 would remain. After the time interval of 5 hours and 30 minutes or 330 minutes, which constitutes three half-lives, the remaining active Fluorine-18 would be 12.5mg.
Explanation:In the case of Fluorine-18, the half-life is 110 minutes. This essentially means that half of the original amount of the radioisotope will decay and become inactive in 110 minutes.
a. If 100mg of Fluorine-18 is shipped at 8:00 a.m., after 110 minutes (or 1 hour and 50 minutes), at 9:50 a.m., half of the original amount, 50mg, will still be active.
b. If 100mg of Fluorine-18 is shipped at 8:00 a.m., and it arrives at the radiology laboratory at 1:30 p.m., this is 5 hours and 30 minutes, or 330 minutes later. As the half-life is 110 minutes, this period encompasses three half-lives (330/110). Starting with 100mg, after one half-life it would be 50mg, after the next it would be halved to 25mg, and after the third it would be 12.5mg remaining active.
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If 200 mL of water is evaporated from 400 mL of 0.5 M aqueous salt solution, what is the resulting concentration? 1. 2.5 × 10−1 M 2. 2.5 × 101 M 3. 2.5 × 100 M 4. 2.5 × 10−2 M 5. None of these
Answer:
None of these
Explanation:
Using the dilution formula;
M1V1 = M2V2
where M1 is the initial concentration, V1 is the initial volume, M2 is the concentration attained while V2 is the new volume.
Therefore;
M2 = M1V1/V2
= (400 mL × 0.5) / 200 mL
= 1 M
Therefore, the resulting concentration is 1M
Thus, the correct answer is "none of these"
If 200 mL of water is evaporated from 400 mL of 0.5 M aqueous salt solution, the resulting concentration is 1.0 M.
What is evaporation?Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase.
A 400 mL solution has a concentration of 0.5 M. After 200 mL of water evaporate, 200 mL of solution remain. We can calculate the final concentration using the following expression.
C1 . V1 = C2 . V2
C2 = C1 . V1 / V2
C2 = 0.5 M . 400 mL / 200 mL = 1.0 M
where,
C1 and V1 are the initial concentration and volume.C2 and V2 are the final concentration and volume.If 200 mL of water is evaporated from 400 mL of 0.5 M aqueous salt solution, the resulting concentration is 1.0 M.
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How do you do 35 and 36?
Answer:
Q35 (C); Q36 (B)
Explanation:
Li₃N + 2H₂ ⇌ 2LiNH₂ + 2LiH; ΔH° = -192 kJ·mol⁻¹
Q35. Reaction rate
The reaction is slow below because it has a high activation energy.
ΔH, ΔS, and ΔG determine the position of equilibrium and the spontaneity of the reaction, not its rate.
Q36. Maximizing amount of H₂
The reaction is exothermic. According to Le Châtelier's Principle, increasing the temperature will shift the position of equilibrium to the left and increase the amount of hydrogen.
Increasing the pressure will shift the position of equilibrium to the side with fewer moles of hydrogen.
Decreasing the pressure will shift the position of equilibrium to the side with more moles of hydrogen.
The correct answer is (B) increasing the temperature and decreasing the pressure .
For the baeyer–villiger oxidation of cyclohexyl methyl ketone
just be postice and you will find the answer
How do atoms achieve noble-gas electron configurations in single covalent bonds?
Answer:
Noble gases are the only type of element that are chemically inert, that is, they do not normally undergo chemical reactions with other elements under normal circumstances, this is because they are chemically stable. Their stability is as a result of the eight valence electrons that they have in their outermost shells.
Other elements usually try to attain the stability found in noble gases by undergoing chemical reactions and by forming different types of bonds with other elements. One of the chemical bonds that are usually formed is covalent bond. In simple covalent bond, two elements usually donate one electron each, the two electrons donated are then shared equally by the two of them in order to ensure that each one has eight electrons in its outermost shell.
Atoms achieve noble-gas electron configurations in single covalent bonds through the sharing of electrons between atoms.
Explanation:Atoms achieve noble-gas electron configurations in single covalent bonds through the sharing of electrons between atoms.
In a covalent bond, electrons are shared between atoms, and generally, each atom contributes one or more electrons to the bond. The shared electrons are attracted by the nuclei of both atoms, resulting in a stable electron configuration.
For example, in a double covalent bond between two oxygen atoms (O=O), each oxygen atom contributes two electrons, resulting in a shared configuration that resembles the noble gas, neon.
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Element named for a university on the west coast of the us
Answer is hope this helps
Answer:
Cf
Explanation:
californium
Which sources are reliable? Check all that apply.
an article discussing mineral resources written by the United States Geological Survey
a blog discussing sources of alternate energy written by a high school student
an advertisement for guided hikes and tours in Camping magazine
a study describing clinical trials of a new medication in the Journal of Medicinal Chemistry
an entry about common uses of metals in an encyclopedia that can be edited by the general public
Answer:
an article discussing mineral resources written by the United States Geological Surveya study describing clinical trials of a new medication in the Journal of Medicinal Chemistry
Answer:
An article discussing mineral resources written by the United States Geological Survey.
A study describing clinical trials of a new medication in the Journal of Medicinal Chemistry.
Explanation:
A reliable source can be define as the source of information which can be used for the purpose of research. The reliable source should be thorough, well reasoned and must be supported by the evidences. It can be based on experimental trials and outcomes of the previous research. It can be proved by the authentic organization and institution.
The following are the examples of reliable sources:
An article discussing mineral resources written by the United States Geological Survey.: This is the authentic reliable source as the information is provided by recognized survey organization.
A study describing clinical trials of a new medication in the Journal of Medicinal Chemistry.: This is reliable source because the information is provided on the basis of the clinical trials the results of which will be reliable as in journals only the reliable information is presented.
It is generally seen that, when a substance absorbs heat energy, its heating curve shows two plateaus. which phenomenon is indicated by these plateaus? select one:
a. melting
b. boiling
c. phase change
d. crystallization
The answer is a. Melting
If a solid line represents a covalent bond and a dotted line represents intermolecular attraction, which of these choices shows a hydrogen bond? check all that apply
Answer:
the dotted line showing the intermolecular attraction
Explanation:
how does photosynthesis in the biosphere impact the atmosphere
Answer:The biosphere is all life on our planet. ... The impact on climate is mainly due to the connection between the biosphere and the atmosphere. Processes such as photosynthesis and respiration naturally affect the concentrations of gases such as oxygen and carbon dioxide in the atmosphere.
Explanation:
In photosynthesis, plants constantly absorb and release atmospheric gases in a way that creates sugar for food. Carbon dioxide goes in the plant's cells; oxygen comes out. Without sunlight and plants, the Earth would become an inhospitable place unable to support air-breathing animals and people.
The humidity in a local area is high and the temperature drops. These conditions might cause A. dry weather. B. ocean currents. C. rainy weather. D. colder winters.
Answer:
C. rainy weather
Explanation:
Rainy weather or other precipitation occurs when moist (humid) air is cooled below its dew point.
Cold winters are part of the long term climate of an area.
These conditions might cause a rainy weather. Therefore, the correct option is option C among all the given options
What is humidity?Humidity refers to the quantity of air that contains water vapor. Water vapor, the gaseous component of water, is frequently invisible to the eye. The humidity predicts the presence for precipitation, dew, and fog. Humidity is affected by the pressure as well as temperature of the system in issue.
When a corresponding quantity of vaporized water is present, cold air has a higher relative humidity than warm air. Another important variable is the dew point. More water vapor is necessary as the temperature rises until saturation is attained. The humidity in a local area is high and the temperature drops. These conditions might cause a rainy weather.
Therefore, the correct option is option C.
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Which is the best description of hydrogen bonding? Which is the best description of hydrogen bonding? the association between a hydrogen atom which is somewhat positive because it is bonded to a small electronegative atom and an atom of O, N or F on another molecule the association between hydrogen of one molecule and a region of another molecule which has become negative due to temporary shifts in electron density the unique chemical bonds between hydrogen and any other atom in the same molecule the temporary attraction between hydrogen atoms on different molecules resulting from shifts in electron density the polarity associated with a bond between hydrogen and a small electronegative atom to which it is bonded
Answer:
The best description of hydrogen bonding is the association between a hydrogen atom which is somewhat positive because it is bonded to a small electronegative atom and an atom of O, N or F on another molecule. (this is the first choice)Explanation:
Hydrogen bonding is a special type of intermolecular force due to dipole - dipole atraction.
In order to the hydrogen bonding can be formed, the hydrogen atom in a molecule must be covalently bonded to an atom of oxygen (O), nitrogen (N), or fluor (F).
The most common example of hydrogen bonding is that of water molecules (H₂0).
Due to the relatively high electronegativity difference between hydrogen (H) and oxygen (O) atoms, each H will bear a high partial positive charge (δ+) and each O will have a high partial negative charge (δ-). Thus, the negative end of each H₂O molecule will be attracted to the negative part of other (neighbor) H₂O molecule. This attraction is the hydrogen bonding and is responsible for many important special properties of water.
Hydrogen bonding is the association between a weakly positive hydrogen atom already bonded to one electronegative atom and an atom of O, N or F on another molecule. It is a weak interaction that occurs due to the attraction between opposite partial charges.
Explanation:The best description of hydrogen bonding is the association between a hydrogen atom which is somewhat positive because it is bonded to a small electronegative atom and an atom of O, N or F on another molecule. This occurs when a weakly positive hydrogen atom already bonded to one electronegative atom is attracted to another electronegative atom from another molecule. Hydrogen bonding is a weak interaction, but it plays a significant role in many chemical and biological processes.
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Which of the following is an example of a combustion reaction?
A. Mixing of acid and base
B. Photosynthesis in plants
C. Lighting of a matchstick
D. Reacting sodium and chlorine
Answer:
Option c = Lighting of matchstick
Explanation:
The lightning of match stick is combustion reaction. The chemical potassium chlorate, glue, sulfur and starch is present on the tip of match stick. When the match stick catch the fire combustion process occur and heat is released.
Photosynthesis in plant:
It is the reaction in which plants used the carbon dioxide and water and convert it into sugar and oxygen in the presence of light.
6CO₂ + 6H₂O + light → C₆H₁₂O₆ + 6O₂
Mixing of acid and base:
When an acid react with base it form the salt and water. The reaction is also called neutralization reaction because both neutralize each other.
In neutralization reaction equal amount of acid and base react to neutralize each other and equal amount of water and salt are formed. When pH does not reach to 7 its means there is less amount of one of reactant which is not fully neutralize.
Reacting of sodium and chlorine
The reaction of sodium and chlorine is the formation of ionic compound. It is formed by the complete transfer of electron from sodium to chlorine atom and form ionic bond. In this ionic compound sodium carry positive charge and chlorine carry negative charge there is attraction between these oppositely charged atoms.
Answer:
lighting of a match stick
Explanation:
A type of spectroscopy used to analyze pigments in a painting is:
a. ultraviolet absorption
b. microwave emission
c. X-ray fluorescence
d. Infrared absorption
e. color phosphorescence
I would say the answer is D
Paint samples received by forensic laboratories are usually in the form of small chips or smears. Infrared (IR) spectroscopy is one of the most commonly used tools available for the analysis of these types of samples and serves as a staple comparative technique in the assessment of whether or not a questioned sample could have come from a suspected object
The most direct way to probe the vibrational frequencies of a molecule is through infrared spectroscopy. This is because vibrational transitions typically require an amount of energy that corresponds to the infrared region of the spectrum. Raman spectroscopy, which typically uses visible light, can also be used to directly measure vibration frequencies.
Answer:
d) Infrared absorption
Explanation:
Spectroscopy involves the study of the interaction of electromagnetic radiation with matter. The electromagnetic spectrum is essentially a composite of photons of different wavelengths and frequencies; from the low wavelength gamma rays to the high wavelength radio waves.
The pigments in a painting are organic compounds which can be easily identified via Infrared spectroscopy. When a beam of infrared light (photons in the 700 nm-1000 nm of the electromagnetic spectrum) is passed through the painting, photons of particular wavelengths or energy which are in resonance with the molecular vibrations of the pigment molecules get absorbed whereas the rest of the IR radiation is reflected and directed onto a detector. A plot intensity of the reflected IR light vs wavelength corresponds to the IR spectrum which is unique to a particular chemical substance. Thus, various pigments in a painting that have IR active features can be identified by this method.
How do you do this question?
Answer:
[tex]\boxed{\text{(D) 2 HCHO}_{2}}[/tex]
Explanation:
HCOOH + H₂O ⇌ H₃O⁺ + HCOO⁻
HCHO₂ is a weak acid. It dissociates only to a few percent, so there will be more HCHO₂ than H₃O⁺ present.
After H₂O, the most abundant species will be undissociated HCHO₂, so the answer will be either (B) or (D).
We can use an ICE table to organize the calculation of the pH.
HCOOH +H₂O ⇌ H₃O⁺ + HCOO⁻
I/mol·L⁻¹: 0.5 0 0
C/mol·L⁻¹: -x +x +x
E/mol·L⁻¹: 0.5 - x x x
[tex]K_{\text{a}} = \dfrac{\text{[H}_{3}\text{O}^{+}]\text{HCOO}^{-}]} {\text{[HCOOH]}} = 2 \times 10^{-4}\\\\\dfrac{x^{2}}{0.5-x} = 2 \times 10^{-4}[/tex]
Check for negligibility of x
[tex]\dfrac{ 0.5 }{2 \times 10^{-4}} = 2500 > 400.[/tex]
∴ x ≪ 0.5
[tex]\dfrac{x^{2}}{0.5} = 2 \times 10^{-4}[/tex]
x² = 0.5 × 2 × 10⁴ = 1 × 10⁻⁴
x = √(1 × 10⁻⁴) = 1 × 10⁻²
[H₃O⁺] = x mol·L⁻¹ = 1 × 10⁻² mol·L⁻¹
pH = -log[H₃O⁺] = -log(1 × 10⁻²) = 2
The correct answer is [tex]\boxed{\textbf{(D) 2 HCHO}_{2}}[/tex].
When production first began some eighty years ago, ammonia production relied upon the direct reaction between gaseous hydrogen and nitrogen called the Haber process: 3 H2(g) + N2(g) ⇀↽ 2 NH3(g) ∆H = −92.2 kJ Decreasing the temperature of an equilibrated reaction between hydrogen and nitrogen will 1. increase the velocity of the gas molecules. 2. produce more ammonia. 3. increase the kinetic energy of the gas molecules. 4. produce less ammonia. 5. have no effect.
Answer:
Option 2. Produce more ammonia.Explanation:
The influence of temperature in equilibrium reactions can be predicted from the heat (enthalpy) information.
This is the chemical reaction:
3 H₂ (g) + N₂(g) ⇄ 2 NH₃(g) ∆H = −92.2 kJThe information about the enthalpy of the reaction, ∆H = − 92.2 kJ, indicates that energy (heat) has been released to the surroundings (the products of the forward reaction have less energy than the reactants), which is defined as an exothermic reaction.
Then, you can rewrite the equaition in the form:
3 H₂ (g) + N₂(g) ⇄ 2 NH₃(g) + 92.2 kJThis is, the heat can be seen as a product of the direct reaction (or a reactant of the reverse reaction).
Now, it is quite straight to apply Le Chatelier's principle:
a) Decreasing temperature is equivalent to extract heat or having less heat on the left side.
b) Then, the equilibrium must shift in a way that this lack of heat is compensated. Then, the reaction will shift to the right to produce more heat.
As conclusion, you can tell that in exothermic reactions, a decrase in temperature will cause the equilibrium to shift to the right.
This shift, of course, means the production of more ammonia.
The other choices are discarded following this brief reasoning:
1. increase the velocity of the gas molecules: the average velocity of the particles increases when the average kinetic energy increases, and the average kinetic energy will decrease if the temperature decreases. So, this statement is false.
3. increase the kinetic energy of the gas molecules: no, the average kinetic energy is proportional to the temperature, then reducing the temperature decreasese the average kinetic energy.
4. produce less ammonia: it was shown that reducing the temperature will produce more ammonia.
5. have no effect: no, it does have effect, as shown.
In the Haber process of ammonia production, when the reaction temperature is decreased, more ammonia is produced due to the exothermic nature of the reaction following Le Chatelier's Principle. The velocity and kinetic energy of the gas molecules decrease. Real-world ammonia production also accounts for pressure and catalyst factors.
Explanation:The reaction of nitrogen and hydrogen to form ammonia, otherwise known as the Haber process, is an exothermic process, meaning it releases heat. As per Le Chatelier's principle, lowering the temperature of an exothermic reaction at equilibrium favors the production of more products. Therefore, decreasing the temperature of the hydrogen and nitrogen reaction will produce more ammonia (option 2).
Simultaneously, as we decrease the temperature, the average kinetic energy of the gas molecules decreases and, hence, the speed of the gas molecules also decreases. Therefore, the statement that decreasing the temperature will increase the velocity of the gas molecules (option 1) and increase the kinetic energy of the gas molecules (option 3) are incorrect. The option that decreasing the temperature will have no effect (option 5) is also incorrect in this scenario.
In real-world applications, the production of ammonia via the Haber process is influenced by pressure and temperature changes, and also by the usage of a catalyst to overcome the reaction's slow rate at lower temperatures.
Learn more about Haber Process here:https://brainly.com/question/26667299
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What is the nucleon a number of carbon-14?
Answer:
The nucleon number of carbon-14 is 14Explanation:
Nucleons are the particles that are in the nucleus of the atom, i.e. protons and neutrons.
So, the nucleon number is the number of protons and neutrons.
Other name for nucleon number is mass number, and it is represented by the letter A:
nucleon number = mass number = A = protons + neutrons.
Carbon-14 is the particular name, indicating the mass number, of the isotope of carbon with mass number 14.
So, the nucleon number of carbon-14 is indicated in its name, and it is 14.
The name carbon-14 identifies completely the isotope because, the atomic number of carbon is the same for every atom (isotope) of carbon:
Atomic number = number of protons = Z = 6Mass number = A = 14Number of neutrons = N = Z - A = 14 - 6 = 8What is the molarity of a solution prepared by mixing 12.5 G of FeCl3 in enough water to make 300 mL of solution?
Answer:0.256 M
Explanation: Molarity (M)= (mass/molar mass)(1000/Volume in mL)
M= 12.5x1000/162.2x300=0.256 M
The molarity of the FeCl₃ solution, convert the mass of FeCl₃ to moles, convert the solution volume to liters, and then divide the moles by the volume. The molarity of the FeCl₃ solution is 0.257 M.
The molarity of a solution is calculated by dividing the number of moles of the solute by the volume of the solution in liters. First, we need to convert the mass of FeCl₃ to moles by using its molar mass. Once we have the moles, we can divide by the volume of the solution in liters to find the molarity.
Steps to Calculate Molarity:
Calculate the molar mass of FeCl₃: (55.845 g/mol Fe) + (3 times 35.453 g/mol Cl) = 162.204 g/mol.
Convert the mass of FeCl₃ to moles: 12.5 g \/ 162.204 g/mol = 0.07710 moles.
Convert the volume of the solution to liters: 300 mL = 0.300 L.
Divide the moles of solute by the volume of the solution in liters to find the molarity: 0.07710 moles \/ 0.300 L = 0.257 M.
Therefore, the molarity of the FeCl₃ solution is 0.257 M.