Answer:
B) 104 J/mol.K
Explanation:
Step 1: Given data
Standard enthalpy of vaporization (ΔH°vap): 35.2 kJ/molNormal boiling point (Tb): 64.6 °CStep 2: Convert "Tb" to Kelvin
We will use the following expression.
K = °C + 273.15
K = 64.6°C + 273.15
K = 337.8 K
Step 3: Calculate the standard change in entropy for the vaporization of methanol (ΔS°vap)
The vaporization is the phase transition from the liquid phase to vapor. We can calculate the standard change in entropy for the vaporization using the following expression.
ΔS°vap = ΔH°vap / Tb
ΔS°vap = (35.2 × 10³ J/mol) / 337.8 K
ΔS°vap = 104 J/mol.K
The standard change in entropy for the vaporization of methanol at its normal boiling point is 104 J/mol.K.
How do we calculate entropy of vaporization?Standard change in entropy for the vaporization will be calculated by using the below equation as:
ΔS°vap = ΔH°vap / Tb, where
ΔH°vap = standard enthalpy of vaporization of methanol = 35.2 kJ/mol
Tb = Boiling point of methanol = 64.6°C = 64.6°C + 273.15 = 337.8 K
On putting all these values on the above equation, we get
ΔS°vap = (35.2 × 10³ J/mol) / 337.8 K
ΔS°vap = 104 J/mol.K
Hence option (B) is correct.
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Two isotopes of hypothetical element X exist with abundances of 30.00% 100X and 70.00% 101X. What is the approximate atomic mass of X (in atomic units, amu)?
(A) 100.3
(B) 100.5
(C) 100.7
(D) 101.0
Answer:
C. 100.7 amu
Explanation:
Isotopes of an element are atoms of an element with the same atomic number but different atomic masses. Each atomic mass of an isotope is known as an isotopic mass. An element that exhibits isotope, that is, that have two or more isotopes has a relative atomic mass that is not a whole number.
Relative atomic mass of X is the sum of the products of the relative abundances of each isotope and its isotopic mass.
For Isotope ¹⁰⁰X: 30% × 100 = 30 amu
For Isotope ¹⁰¹X: 70% × 101 = 70.7 amu
Relative atomic mass of X = (30 + 70.7) amu = 100.7 amu
Therefore, the approximate atomic mass of X is 100.7 amu
Taking into account the definition of mass number, isotopes and atomic mass of an element, the average mass of hypothetical element X is 100.7.
First of all, all atoms are made up of subatomic particles: protons and neutrons, which are part of their nucleus, and electrons, which revolve around them. Protons are positively charged, neutrons are neutrally charged, and electrons are negatively charged (electrons).
On the other hand, the mass number tells us the total number of particles in the nucleus. That is, the mass number is the sum of the number of protons and the number of neutrons in the atomic nucleus.
The same chemical element can be made up of different atoms, that is, their atomic numbers are the same, but the number of neutrons is different. These atoms are called isotopes of the element.
Finally, the atomic mass of an element is the weighted average mass of its natural isotopes.
In other words, the atomic masses of chemical elements are usually calculated as the weighted average of the masses of the different isotopes of each element, taking into account the relative abundance of each of them.
In this case, two isotopes of hypothetical element X exist with abundances of 30.00% 100-X (the atomic mass is 100) and 70.00% 101-X (the atomic mass is 101). Then, the average mass of X can be calculated as:
100×0.30 + 101×0.70= 100.7
Finally, the average mass of hypothetical element X is 100.7.
Learn more about average mass:
brainly.com/question/14403750?referrer=searchResults brainly.com/question/10043246?referrer=searchResults brainly.com/question/15553207?referrer=searchResultsWhen 240 mg of a certain molecular compound X are dissolved in 35.0 g of dibenzyl ether ((C6H5CH2)2O), the freezing point of the solution is measured to be 1.0 °C. Calculate the molar mass of X If you need any additional information on dibenzyl ether, use only what you find in the ALEKS Data resource. Also, be sure your answer has a unit symbol, and is rounded to the correct number of significant digits.
Answer: MM = 16.55 g/mol
Explanation: Freezing point depression is a phenomena that explains why adding a solute to a solvent decreases the solvent freezing point: when a substance begins to freeze, its molecules slows down and rearrange itself forming a solid. If a solute is added, the molecules from the solvent interfere in the formation of the solid. To guarantee the transformation, the solution has to cooled down even more.
Freezing point and molality concentration is related by
[tex]\Delta T=T_{f}_{(solvent)}-T_{f}_{(solution)}=K_{f}.m[/tex]
where
ΔT is freezing point depression
[tex]T_{f}_{(solvent)}[/tex] and [tex]T_{f}_{(solution)}[/tex] are freezing point of solvent and solution, respectively
[tex]K_{f}[/tex] is freezing point depression constant
m is molality concentration
Dibenzyl ether is the solvent and has the following properties: [tex]K_{f}=[/tex] 6.27 and [tex]T_{f}[/tex] = 3.6°C.
Molality concentration is
[tex]m=\frac{T_{(solvent)}-T_{(solution)}}{K_{f}}[/tex]
[tex]m=\frac{3.6-1}{6.27}[/tex]
m = 0.415
Molality concentration is moles (n) of solute dissolved in a mass, in kilogram, of solvent.
[tex]m=\frac{moles}{mass(kg)}[/tex]
n = m(mass of solvent in kg)
n = 0.415(0.035)
n = 0.0145
Molar mass (M) is the weight of one sample mole and can be calculated as
[tex]n=\frac{m}{M}[/tex]
M = [tex]\frac{m}{n}[/tex]
m in grams
Molar mass of compound X is
[tex]M=\frac{0.24}{0.0145}[/tex]
M = 16.55
Molar mass of molecular compound X is 16.55g/mol
What is required to cause change in matter
Answer:
Adding or removing energy from matter causes a physical change as matter moves from one state to another. For example, adding thermal energy (heat) to liquid water causes it to become steam or vapor (a gas). And removing energy from liquid water causes it to become ice (a solid). ... Most liquids contract as they freeze.
Explanation:
have a nice day
8)
C(diamond) → C(graphite)
delta G° = -2.9 kJ/molrxn
Which of the following best explains why the reaction represented above is not observed to occur at
room temperature?
(A) The rate of the reaction is extremely slow because of the relatively small value of AGº for
the reaction.
(B) The entropy of the system decreases because the carbon atoms in graphite are less ordered
than those in diamond.
(C) The reaction has an extremely large activation energy due to strong three-dimensional
bonding among carbon atoms in diamond.
(D) The reaction does not occur because it is not thermodynamically favorable.
Answer: its b hope this helps.
Explanation:
Which set of terms best defines what affects kinetic energy and potential energy, respecrively
Please I have a D in chem and grades close tomorrow ;-;
Which of the following polyatomic lons will form an lonic compound with a single sodium lon?
co₂2-
нсо3^1-
S04^2-
S03^2-
Argon (Ar) is an element in group 18. Argon is _____.
a gas highly reactive
a metalloid
a good conductor of heat
Answer:
c
Explanation:c
it is a good conducter
Someone took the last cookie from the cookie jar last night. The last person to leave the scene is the culprit. Who was it? Highlight the guilty culprit based on the clues provided.
Need help please? Thanks youu
Answer:
A
B
E
Explanation:
"Fission is the splitting of a heavy, unstable nucleus into two lighter nuclei
and fusion is the process where two light nuclei combine together releasing vast amounts of energy"
a process that releases energy is respiration
In a laboratory experiment, students synthesized a new compound and found that when 11.01 grams of the compound were dissolved to make 158.1 mL of a ethanol solution, the osmotic pressure generated was 1.91 atm at 298 K. The compound was also found to be nonvolatile and a non-electrolyte. What is the molecular weight they determined for this compound?
Answer:
892 g/mol
Explanation:
Step 1: Given and required data
Mass of the nonvolatile and a non-electrolyte solute: 11.01 gVolume of solution: 158.1 mL = 0.1581 LOsmotic pressure (π): 1.91 atmIdeal gas constant (R): 0.0821 atm.L/mol.KAbsolute temperature (T): 298 KStep 2: Calculate the molarity (M) of the solution
The osmotic pressure is a colligative property that can be calculated using the following expression.
π = M × R × T
M = π / R × T
M = 1.91 atm / (0.0821 atm.L/mol.K) × 298 K
M = 0.0781 M
Step 3: Calculate the molecular weight of the solute
We will use the following expression for molarity.
M = mass of solute / molecular weight of solute × liters of solution
molecular weight of solute = mass of solute / M × liters of solution
molecular weight of solute = 11.01 g / (0.0781 mol/L) × 0.1581 L
molecular weight of solute = 892 g/mol
1 carbon atom mixed with 1 oxygen atom what is the formula
Answer:
carbon mono oxide CO
Explanation:
as both are in 1:1 ratio so CO is formed
Cl2 +
NaBr
-
NaCl +
Br2
Answer:
hope this helps :)
Explanation:
Cl2 + NaBr = NaCl + Br2
NaCl + Br2 = NaBr + Cl2
What is a solute?
A material that is dissolved in another material.
O A material in which another material is dissolved.
An area of space surrounding the nucleus.
O Chemical formulas on the left side of an equation.
Which reaction takes place in a nuclear fission reactor?
C+HN
2 Put He → Cm
OCO+ He-Cot 'n
o U+ nKr+Ba+3'n
Answer:
The reaction that takes place in a nuclear fission reactor is answer D.
Explanation:
Step-by-step explanation:
Nuclear fission reactions involves the process by which large atomic nuclei are bombarded with energetic particles and release of an enormous amount of nuclear energy, which mainly ends up as heat energy.
So now, consider the nuclear reaction from D, after the uranium nucleus absorbs the neutron its split into two smaller nuclei (often radioactive themselves), Krypton and Barium and releases more neutrons (or energy).
Explain how atoms organize to create larger structures?
Answer:
First of all they are super tiny particles of neutrons, electrons and protons. Then they come together to organize a structure of atom. Atoms come together to form a molecule and smaller molecules work together to form macromolecules. Thus, how they organize and form building blocks of a substance.
Hope it helps!<3
19.
Caustic soda is 20 M NaOH and is olluted for household use. What is the household concentration of 10
mL of the concentrated solution is diluted to 500 ml?
(A) 0.4 M N OH
(B) 400 M NaOH
(C) 4 M NaOH
(D) 20M NaO
Answer:
(A) 0.4M NaOH
Explanation:
The 20M NaOH caustic soda is diluted from 10mL to 500mL, that is:
500mL / 10mL = Is diluted 50 times.
That means we can solve the new concentration of the diluted solution dividing the stock concentration (20M) 50 times:
20M / 50 = 0.4M NaOH is the concentration of the diluted NaOH solution.
Right answer is:
(A) 0.4M NaOHA system performed 145 kJ of work on the surroundings and absorbed 105 kJ of heat from the surroundings. What is the change in energy of the system?
Answer:
250 kJ
Explanation:
Step 1: Given data
Work performed by the system (w): 145 kJ (By convention, when the system performs work on the surroundings, w > 0)Heat absorbed by the system (q): 105 kJ (By convention, when the system absorbs heat from the surroundings, q > 0)Step 2: Calculate the change in the internal energy of the system
The internal energy of a thermodynamic system is the energy contained within it. We can calculate the change in the internal energy (ΔE°) using the following expression.
ΔE° = q + w
ΔE° = 105 kJ + 145 kJ = 250 kJ
Which of the following statements is true?
Electrons have a positive charge.
Protons and neutrons are found in the nucleus.
Electrons and protons are found in the nucleus.
All shells can hold up to eight electrons.
Answer:
2/ Protons and neutrons are found in the nucleus.
Explanation:
what is protein denaturation
Answer:
Denaturation is a process in which proteins or nucleic acids lose the quaternary structure, tertiary structure, and secondary structure which is present in their native state, by application of some
Explanation:
Phosphorus trichloride, PCl3, is commonly used in the chemical industry as a source of phosphorus in various reactions. Indicate the electron pair geometry and the molecular geometry of the PCl3 molecule. Electron pair geometry: T-shaped tetrahedral trigonal planar trigonal pyramidal trigonal bipyramidal Molecular geometry: tetrahedral trigonal pyramidal trigonal bipyramidal trigonal planar T-shaped
Answer:
Electron pair geometry - tetrahedral
molecular geometry- trigonal pyramidal
Explanation:
According to Valence Shell Electron Pair Repulsion Theory, the shape of a molecule is determined by the number of electron pairs around the central atom in the molecule. Lone pairs distort a molecule away from its expected geometry based on VSEPR. This is why the electron pair geometry differs from the actual molecular geometry.
PCl3 has four regions of electron density, three substituents and one lone pair hence its electron pair geometry is tetrahedral. However, the three substituents are arranged in a trigonal pyramidal geometry(its molecular geometry).
What happens after condensation to cause precipitation?
A
The sun heats water on the Earth's surface.
B
Water is absorbed into the ground.
C
Clouds fill with moisture and get too heavy.
D
Excess water runs downhill.
Answer:
The answer is c, Clouds fill with moisture and get too hravy
What is the structural formula of CF2Br2
Answer:
Dibromodifluoromethane
Explanation:
A compound is an example of pure substance
True
False
Which isomer of 1-bromo-2-tert-butylcyclohexane reacts faster when refluxed with potassium tert-butoxide?Draw the structure of the expected major product from the faster reacting compound.
Answer:
See explanation and image attached
Explanation:
The reaction of 1-bromo-2-tert-butylcyclohexane with potassium tert-butoxide is an elimination reaction that occurs by E2 mechanism.
The E2 reaction proceeds faster when the hydrogens are in an antiperiplanar position at an angle of 180 degrees.
This is only attainable in the trans isomer of 1-bromo-2-tert-butylcyclohexane. Hence trans 1-bromo-2-tert-butylcyclohexane reacts faster with potassium tert-butoxide
Justin is making a snack. He toasts a piece of bread and first peanut butter and jelly on it. Then he cut an apple into several slices and adds these to his plate. Next Justin mixes a scoop of lemonade powder into a glass of water mixes it in Dad's ice. How many chemical changes occurred in this scenario? 1 2 three or four
Answer:
2
Explanation:
Toasting bread and lemonade powder in water are chemical changes. Pb&j on bread and cutting apple are physical changes.
Answer:
b
Explanation:
Which terms describe a substance that has a low melting point and poor electrical conductivity?
(1) Metallic and lustrous
(2) Dull and brittle
(3) Brittle and lustrous
(4) Metallic and dull
which of the following is an isotope of hydrogen
What is the degree of oxidation of a simple substance
Answer:
The oxidation state of a free element (uncombined element) is zero. For a simple (monoatomic) ion, the oxidation state is equal to the net charge on the ion. For example, Cl– has an oxidation state of -1. When present in most compounds, hydrogen has an oxidation state of +1 and oxygen an oxidation state of -2
HELP ASAPPPP BRAINLIEST
Answer:
2nd option
Explanation:
15 points! Answer only if you can please!
1. Have you ever grabbed the handle of a hot metal pan? Why did it feel hot to you?
2. What would happen if a person who is wearing a heavy winter jacket were to place a thermometer inside the jacket next to his or her skin? What would happen if we took the same jacket, after it had been hanging in a closet, and placed a thermometer inside?
3. How do you think the transfer of thermal energy causes unpopped popcorn kernels to pop?
Answer:
1. Yes
2. it would be the same i guess
3. because it travels to popcorn kernels with its heat and makes it pop'
did i get it right?
Explanation: