Answer:
A (Atomic mass number or Nucleon number)
Explanation:
The mass number is the total number of protons and nucleons in an atomic nucleus.
Hope this helps.
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Given that H2(g)+F2(g)⟶2HF(g)ΔH∘rxn=−546.6 kJ 2H2(g)+O2(g)⟶2H2O(l)ΔH∘rxn=−571.6 kJ calculate the value of ΔH∘rxn for
Answer:
ΔH∘rxn of the reaction is -521.6kJ
Explanation:
Complete question: "Calculate the value of ΔH°rxn for 2F2(g)+2H2O(l)⟶4HF(g)+O2(g)"
You can find the ΔH of a reaction by the algebraic sum of similar reactions (Hess's law) as follows:
(1) H₂(g) + F₂(g) ⟶ 2HF(g) ΔH∘rxn=−546.6 kJ
(2) 2H₂(g)+O₂(g)⟶2H₂O(l) ΔH∘rxn=−571.6 kJ
Subtracting 2ₓ(1) - (2)
2ₓ(1) 2H₂(g) + 2F₂(g) ⟶ 4HF(g) ΔH∘rxn=2ₓ−546.6 kJ = -1093.2kJ
-(2) 2H₂O(l) ⟶ 2H₂(g)+O₂(g) ΔH∘rxn=- (-571.6 kJ) = 571.6kJ
2ₓ(1) - (2) 2F₂(g)+ 2H₂O(l) ⟶ 4HF(g) + O₂(g)
H₂(g) are cancelled because are the same in products and reactants
ΔH∘rxn = -1093.2kJ + 571.6kJ
ΔH∘rxn = -521.6
ΔH∘rxn of the reaction is -521.6kJA solution is known to contain only one type of cation. Addition of Cl1- ion to the solution had no apparent effect, but addition of (SO4)2- ion resulted in a precipitate. Which cation is present
Answer:
We can have: Calcium, strontium, or barium
Explanation:
In this case, we have to remember the solubility rules for sulfate [tex]SO_4~^-^2[/tex] and the chloride [tex]Cl^-[/tex]:
Sulfate
All sulfate salts are SOLUBLE-EXCEPT those also containing: Calcium, silver, mercury (I), strontium, barium or lead.([tex]Ca^+^2~,Ag^+~,Hg_2^+^2~,Sr^+2~,Ba^+^2~,Pb^+^2[/tex]), which are NOT soluble.
Chloride
All chloride salts as SOLUBLE-EXCEPT those also containing: lead, silver, or mercury (I). ([tex]Pb^+^2~,Ag^+~,Hg_2~^+^2[/tex]), which are NOT soluble.
If we the salt formed a precipitated with the sulfate anion, we will have as possibilities "Calcium, silver, mercury (I), strontium, barium or lead". If We dont have any precipitated with the Chloride anion we can discard "Silver, mercury (I), lead" and our possibilities are:
"Calcium, strontium, or barium".
I hope it helps!
Refer to the figure.
30. How many planes are shown in the figure?
31. How many planes contain points B, C, and E?
32. Name three collinear points.
3. Where could you add point G on plane N
so that A, B, and G would be collinear?
4. Name a point that is not coplanar with
A, B, and C.
5. Name four points that are coplanar.
BN
Answer:
30. 5 planes are shown
31. 1 plane
32. CEF
33. on line AB
34. E or F
35. ABCD or BCEF or CDEF or ACEF
Explanation:
30. Each of the surfaces of the rectangular pyramid is a plane. There are 5 planes.
__
31. 3 points define one plane only.
__
32. The only points shown on the same line segment are points E, F, and C.
__
33. If G is to be collinear with A and B, it must lie on line AB.
__
34. The only points shown that are not on plane N are points E and F. Either of those will do.
__
35. There are three planes that have 4 points shown on them. The four points that are on the same plane are any of ...
ABCDBCEFCDEFPlane ACEF is not shown on the diagram, but we know that those 4 points are also coplanar. (Any point not on line CE, together with the three points on that line, will define a plane with 4 coplanar points.)
Hãy cho biết giá trị và ý nghĩa của số lượng tử n, l, m, ms khi mô tả trạng thái của electron trong nguyên tử?
pls help!!! How can you prove the pennies are made of different material aside from cutting them in half?
Answer:
Most of our coins are metal sandwiches. The outside layers are three-quarters copper and one-quarter nickel, and the "filling" is solid copper. Pennies are made of zinc coated with copper. Only nickels are one solid material—that same 75% copper/25% nickel alloy
Explanation:
15. Calculate the critical angle of glass and water combination. Show your calculation. 16. What is the critical angle for the interface between Mystery A and glass
Answer:
15. Critical angle of glass and water combination, θ = 62.45°
16. Critical angle for the interface between Mystery A and glass, θ = 37.93°
Note; The question is incomplete. The complete question is as follows:
Medium Air Water Glass Mystery A Mystery B Table-2 Speed (m/s) 1.00 C 0.75 c 0.67 0.41 c 0.71 c n 1.00 1.33 1.50 Index of Refraction n of a given medium is defined as the ratio of speed of light in vacuum, c to the speed of light in a medium, v. n = c/v
Table-4: Incident Angle (degrees) Reflected Angle Refracted angle (degrees) (degrees) % Intensity of reflected ray 0 10 20 30 40 50 N/A N/A N/A 30 40 50 0 11.3 22.7 34.2 46.3 59.5 N/A N/A N/A 0.67 1.22 3.08 % Intensity of refracted ray 100 100 100 99.33 98.78 96.92
When rays travel from a denser medium to a less dense medium, we can define a critical angle of incidence θ such that refracted angle θ₂ = 90°. Applying Snell's law: Critical angle θ = sin-1(n₂/n₁).
When the angle of incidence is greater than the critical angle, 100% of the light intensity is reflected. This is called total internal reflection because all the light is reflected.
15. Calculate the critical angle of glass and water combination. Show your calculation.
16. What is the critical angle for the interface between Mystery A and glass?
Explanation:
15. Applying Snell's law; Critical angle θ = sin-1(n₂/n₁).
where n₂,refractive index of water = 1.33, n₁, refractive index of glass = 1.50 since glass is denser than water
θ = sin-1(1.33/1.50)
θ = 62.45°
Critical angle of glass and water combination, θ = 62.45°
16. Refractive index of mystery A , n = c/v
where v = 0.41 c
therefore, n = c / 0.41 c = 2.44
Critical angle for the interface between Mystery A and glass, θ = sin-1(n₂/n₁).
where n₂,refractive index of glass = 1.50, n₁, refractive index of mystery A = 2.44 since mystery A is denser than glass as seen from its refractive index
θ = sin-1(1.50/2.44)
θ = 37.93°
Critical angle for the interface between Mystery A and glass, θ = 37.93°
Determine the kinds of intermolecular forces that are present in each of the following. Part A Xe Check all that apply. dispersion forces dipole-dipole forces hydrogen bonding Request Answer Part B N2 Check all that apply. dispersion forces dipole-dipole forces hydrogen bonding Request Answer Part C CO Check all that apply. dispersion forces dipole-dipole forces hydrogen bonding Request Answer Part D HF Check all that apply. dispersion forces dipole-dipole forces hydrogen bonding
Answer:
Part A
dispersion forces
Part B
dispersion forces
Part C
dispersion forces
dipole-dipole forces
Part D
dispersion forces
dipole-dipole forces
hydrogen bonding
Explanation:
Dispersion forces occur in all molecules. They result from momentary shifts in the electron cloud of molecules which induces a dipole in another molecule. This induced dipole eventually spreads throughout the molecule.
For Xe which is a noble gas and N2 which is a diatomic molecule, dispersion forces is the only kind of intermolecular force present in the molecule.
CO is a polar molecule hence in addition to dispersion forces, dipole-dipole forces also exist in the molecule.
HF is a polar molecule hence it possesses dipole-dipole forces in addition to dispersion forces. In this molecule, hydrogen is bonded to a highly electronegative atom (fluorine). Hence, hydrogen bonding is a dominant intermolecular interaction in the molecule.
Which of the following chemical equations corresponds to the standard molar enthalpy of formation of Na_2CO_3(s)?
a. 2 NA(s) + C(s) + 3 O(g) ------------> Na_2CO_3(s)
b. Na_2O(s) + CO_2(g) --------------->Na_2CO_3 (s)
c. Na_2(s) + C(s) + 3 O(g) -------------> Na_2CO_3 (s)
d. Na_2O(s) + CO(g) ---------------> Na_2CO_3(s)
e. 2 Na(s)+ C(s) + 3/2 O_2(g) ------------> Na_2CO_3(s)
Answer:
2 Na(s) + C(s) + 3/2 O₂(g) → Na₂CO₃(s)
Explanation:
The molar enthalpy of formation of a chemical is defined as the change in enthalpy during the formation of 1 mole of the substance from its constituent elements (Constituent elements are pure elements you have in the periodic table)
For Na₂CO₃ constituent elements are Na(s), C(s) and O₂(g) and the chemical equation that represents the molar enthalpy is:
2 Na(s) + C(s) + 3/2 O₂(g) → Na₂CO₃(s)Match each term to an appropriate example. (4 points) Column A 1. Gravitational energy : Gravitational energy 2. Nuclear energy : Nuclear energy 3. Radiant energy : Radiant energy 4. Stored mechanical energy : Stored mechanical energy Column B a. Fission and fusion b. A ball at the top of a hill c. A compressed spring d. X-rays and light
Answer:
Explanation:
Before proceeding to answering the questions, let's try and understand each term.
Gravitational energy can be defined as the potential energy an object has when placed in a high position (compared to been placed in a low position). Examples include; a knife been placed at the top of the cupboard, a ball at the top of a hill.
Nuclear energy can be defined as the energy released or consumed as a result of splitting or joining together of the nuclei (plural of nucleus) of atom(s). The process of splitting an atomic nucleus is called nuclear fission while the process of joining two nuclei of atoms is called nuclear fusion.
Radiant energy can be defined as the energy of electromagnetic wave. One of the properties of electromagnetic waves is that they travel through space. Examples include X-rays and light
Stored mechanical energy can be defined as the potential energy an object has as a result of the application of force. Examples include; a stretched rubber band, a compressed spring
Assuming a mixture of equal volumes of o xylene and cyclohexane,which of these will distill off first?
Convert the concentration of 0.700 M Na2SO4 to g/mol
To convert from mass concentration to molar concentration we use the formula;
Mass concentration = molar concentration * molar mass
Molar concentration of Na2SO4 = 0.700 M
Molar mass of Na2SO4 = 2(23) + 32 + 4(16) = 142 gmol-1
Hence;
Mass concentration = 0.700 M * 142 gmol-1
Mass concentration = 99.4 g/mol
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Compare the modern (electron cloud) model of the atom with Bohr’s atomic model. Which of these statements describe the two models correctly? Check all of the boxes that apply.
A. Bohr’s model was replaced only because of its age.
B. Bohr’s model electrons cannot exist between orbits, but in the electron cloud model the location of the electrons cannot be predicted.
C. The modern model explains all available data about atoms; Bohr’s model does not.
D. The modern model is more widely accepted because it was proposed by more well known scientists.
Answer:
B. Bohr’s model electrons cannot exist between orbits, but in the electron cloud model, the location of the electrons cannot be predicted.
AND
C. The modern model explains all available data about atoms; Bohr’s model does not.
Explanation:
The answers are right on Edge. :)
Answer:
b and c
Explanation:
my assignment was 100% 2022
2.5
Nakula investigated the effect of heat on amylase. Amylase is an enzyme
that makes starch molecules break down into sugar molecules.
P
• Nakula put some amylase solution into two boiling tubes,
P and Q
• He boiled the solution in tube P. He did not heat tube Q.
• He waited until the solution in tube P had cooled down to
room temperature.
• He added equal volumes of starch solution to tube P and
boiled amylase amylase
• After 10 minutes, he tested both tubes for sugar.
and starch and starch
• Nakula found that there was sugar in tube Q. but not in tube P.
The structure of amylase deteriorates due to high temperature of the solution.
This experiment shows that the structure of amylase deteriorates due to high temperature which prevents this amylase from performing its function properly.
At high temperatures the amylase will break starch down very slowly or not at all due to denaturation of the enzyme's active site due to which it can't perform its function properly so we can conclude that high temperature denatures amylase enzyme.
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Nakula's conclusion was- "My results show that boiling destroys amylase"
Amylase is an enzyme that breaks down starch molecules into sugar molecules. He boiled the solution in tube P, and when he checked tube P for sugar, there wasn't any. He didn't boil the solution in tube Q and he found sugar in it.
Amylase had broken down starch molecules to sugar molecules in tube Q. Tube P's solution had been boiled, and this showed that when he boiled it, it destroyed the amylase, that is why the starch molecules hadn't been broken down into sugar molecules.
A/An is a type of blood cell that's also called a red blood cell. a) Jeukocyte O b) thrombocyte c) plasma d) erythrocyte
Answer:
option a
Explanation:
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which of the following compounds are polar: CH2Cl2, HBr?
Answer:
CH2Cl2 is polar
Explanation:
What is the mass grams that are in 3.52 × 10²⁵ molecules of I₂
Answer:
As you know, one mole of any substance contains exactly
6.022
⋅
10
23
molecules of that substance - this is known as Avogadro's number.
Notice that you're dealing with more than
6.022
⋅
10
23
molecules of carbon dioxide, which means that you'll also be dealing with more than one mole of the compound.
More specifically, you'll have
1.5
⋅
10
26
molecules
⋅
1 mole CO
2
6.022
⋅
10
23
molecules
=
2.491
⋅
10
2
moles CO
2
Now, a substance's molar mass tells what the mass of one mole of that substance is. In carbon dioxide's case, its molar mass is equal to
44.01 g/mol
, which means that every mole of
CO
2
will have a mass of
44.01 g
.
In your case,
2.491
⋅
10
2
moles of
CO
2
would have a mass of
2.491
⋅
10
2
moles CO
2
⋅
44.01 g
1
mole CO
2
=
109.63 g
Rounded to two sig figs, the number of sig figs you have for the number of molecules of
CO
2
, the answer will be
m
C
O
2
=
110 g
Based on the crystal- field strength cl-
1) Based on the crystal field strength, Cl ligand would give the longest d-d transition when complexed with Ti(III). as this is the weak field igand and would cause minimum splitting of d orbitals.
Which is the best interpretation of the two flat portions of the graph?
In those portions, the heat supplied to the substance by the heater does not lead to a temperature rise as intermolecular forces are broken.
When a substance is heated, we normally expect that its temperature will rise as a consequence.
However, heat may be supplied to a substance but its temperature does not rise owing to the fact that the heat energy supplied is used to break intermolecular bonds.
This occurs during fusion and boiling. The heat supplied at these point does not result in temperature rise since it is used to break intermolecular bonds. The temperature remains steady during these processes as shown by the two flat portions on the graph in the image attached to the question. This heat supplied is known as the latent heat.
For more about latent heat, see:
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Answer:
The answer for me was "These show where changes of state are occuring"
Explanation:
I got it right
There are 454 grams in one pound. How many pounds are in 700 grams
Answer:
1.543 pounds = 700 grams
Typical "hard" water contains about 2.0 x 10–3 mol of Ca2+ per liter. Calculate the maximum concentration of fluoride ion that could be present in hard water. Assume fluoride is the only anion present that will precipitate calcium ion.
Answer:
[tex][F^-]_{max}=4x10{-3}\frac{molF^-}{L}[/tex]
Explanation:
Hello,
In this case, for the described situation, we infer that calcium reacts with fluoride ions to yield insoluble calcium fluoride as shown below:
[tex]Ca^{+2}(aq)+2F^-(aq)\rightleftharpoons CaF_2(s)[/tex]
Which is typically an equilibrium reaction, since calcium fluoride is able to come back to the ions. In such a way, since the maximum amount is computed via stoichiometry, we can see a 1:2 mole ratio between the ions, therefore, the required maximum amount of fluoride ions in the "hard" water (assuming no other ions) turns out:
[tex][F^-]_{max}=2.0x10^{-3}\frac{molCa^{2+}}{L}*\frac{2molF^-}{1molCa^{2+}} \\[/tex]
[tex][F^-]_{max}=4x10{-3}\frac{molF^-}{L}[/tex]
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The surface temperature on Venus may approach 753 K. What is this temperature in degrees Celsius?
Answer:
461.85 degrees Celsius
Using the data: C2H4(g), = +51.9 kJ mol-1, S° = 219.8 J mol-1 K-1 CO2(g), = ‑394 kJ mol-1, S° = 213.6 J mol-1 K-1 H2O(l), = ‑286.0 kJ mol-1, S° = 69.96 J mol-1 K-1 O2(g), = 0.00 kJ mol-1, S° = 205 J mol-1 K-1 calculate the maximum amount of work that can be obtained, at 25.0 °C, from the process: C2H4(g) + 3 O2(g) → 2 CO2(g) + 2 H2O(l)
Answer:
The correct answer is 1332 KJ.
Explanation:
Based on the given information,
ΔH°f of C2H4 is 51.9 KJ/mol, ΔH°O2 is 0.0 KJ/mol, ΔH°f of CO2 is -394 KJ/mol, and ΔH°f of H2O is -286 KJ/mol.
Now the balanced equation is:
C2H4 (g) + 3O2 (g) ⇔ 2CO2 (g) + 2H2O (l)
ΔH°rxn = 2 × ΔH°f CO2 + 2 × ΔH°fH2O - 1 × ΔH°fC2H4 - 3×ΔH°fO2
ΔH°rxn = 2 (-394) + 2(-286) - 1(51.9) - 3(0)
ΔH°rxn = -1411.9 KJ
Now, the given ΔS°f of C2H4 is 219.8 J/mol.K, ΔS°f of O2 is 205 J/mol.K, ΔS°f of CO2 is 213.6 J/mol.K, and ΔS°f of H2O is 69.96 J/mol.K.
Now based on the balanced chemical reaction,
ΔS°rxn = 2 × ΔS°fCO2 + 2 ΔS°fH2O - 1 × ΔS°f C2H4 - 3 ΔS°fO2
ΔS°rxn = 2 (213.6) + 2(69.96) - 1(219.8) -3(205)
ΔS°rxn = -267.68 J/K or -0.26768 KJ/K
T = 25 °C or 298 K
Now putting the values of ΔH, ΔS and T in the equation ΔG = ΔH-TΔS, we get
ΔG = -1411.9 - 298.0 × (-0.2677)
ΔG = -1332 KJ.
Thus, the maximum work, which can obtained is 1332 kJ.
Heterocyclic aromatic compounds undergo electrophilic aromatic substitution in a similar fashion to that undergone by benzene with the formation of a resonance-stabilized intermediate. Draw all of the resonance contributors expected when the above compound undergoes bromination
Answer:
See explanation
Explanation:
When we talk about electrophilic substitution, we are talking about a substitution reaction in which the attacking agent is an electrophile. The electrophile attacks an electron rich area of a compound during the reaction.
The five membered furan ring is aromatic just as benzene. This aromatic structure is maintained during electrophilic substitution reaction. The attack of the electrophile generates a resonance stabilized intermediate whose canonical structures have been shown in the image attached.
the water in a glass does not contain any other substance.what kind of water is it
Answer:
natural mineral water.
Gas is contained in a 9.00-L vessel at a temperature of 24.0°C and a pressure of 5.00 atm. (a) Determine the number of moles of gas in the vessel. mol (b) How many molecules are in the vessel? molecules
Answer:
a. Moles in the vessel = 1.85 moles of the gas
b. 1.11x10²⁴ molecules are in the vessel
Explanation:
a.It is possible to determine moles of a gas using the general law of gases:
PV = nRT
Where P is pressure: 5.00atm; V is volume = 9.00L; R is gas constant: 0.082atmL/molK; T is absolute temperature: 273.15K +24.0 = 297.15K
Computing the values:
PV / RT = n
5.00atm* 9.00L / 0.082atmL/molK*297.15K = n
Moles in the vessel = 1.85 moles of the gasb. With Avogadro's number we can convert moles of any compound to molecules thus:
Avogadro's number = 6.022x10²³ molecules / mole
1.85moles ₓ (6.022x10²³ molecules / mole) =
1.11x10²⁴ molecules are in the vesselwhat substances will make salt when combined?
vinegar and soda
soda and wine
detergent and ammonia
fertilizer and vinegar
Answer:
vinegr and soda ..................
........
Answer:
acid + base = salt
so the answer is vinegar and soda
Explanation:
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When the nuclide carbon-14 undergoes beta decay: The name of the product nuclide is . The symbol for the product nuclide is
Answer:
Explanation:
The equation for the decay is given as;
¹⁴₆C --> X + ⁰₋₁e
For conservation of matter, the mass number and atomic number has to be the same in both the reactant and product side f he equation;
Mass number;
14 = x + 0
x = 14
Atomic Number;
6 = x + (-1)
x = 6 + 1 =7
¹⁴₆C --> ¹⁴₇N + ⁰₋₁e
The name of the product nuclide with atomic number of 7 is Nitrogen. The symbol is; ¹⁴₇N
Will a precipitate (ppt) form when 300. mL of 2.0 × 10 –5 M AgNO 3 are added to 200. mL of 2.5 × 10 –9 M NaI? Answer yes or no, and identify the precipitate if there is one
Answer:
A precipitate will form, AgI
Explanation:
When Ag⁺ and I⁻ ions are in an aqueous media, AgI(s), a precipitate, is produced or not based on its Ksp expression:
Ksp = 8.3x10⁻¹⁷ = [Ag⁺] [I⁻]
Where the concentrations of the ions are the concentrations in equilibrium
For actual concentrations of a solution, you can define Q, reaction quotient, as:
Q = [Ag⁺] [I⁻]
If Q > Ksp, the ions will react producing BaCO₃, if not, no precipitate will form.
Actual concentrations of Ag⁺ and I⁻ are:
[Ag⁺] = [AgNO₃] = 2.0x10⁻⁵ × (300mL / 500.0mL) = 1.2x10⁻⁵M
[I⁻] = [NaI] = 2.5x10⁻⁹ × (200mL / 500.0mL) = 1.0x10⁻⁹M
500.0mL is the volume of the mixture of the solutions
Replacing in Q expression:
Q = [Ag⁺] [I⁻]
Q = [1.2x10⁻⁵M] [1.0x10⁻⁹M]
Q = 1.2x10⁻¹⁴
As Q > Ksp
A precipitate will form, AgICho biết độ tan của NH4Cl trong nước ở 20oC và 70oC lần lượt là 37,2 g/100 gam nước và 60,2 gam/100 g nước. Hòa tan 166,8 gam NH4Cl vào 400 gam nước ở 70oC thu được dung dịch X. Sau đó, hạ nhiệt độ dung dịch X xuống 20oC. Tính khối lượng (gam) NH4Cl kết tinh lại trong X?
Answer: Hợp chất CTHH 0 °C 10 °C 20 °C 30 °C 40 °C 50 °C 70 °C
Actini(III) hydroxide Ac(OH)3 0,0022
Amonia NH3 1176 900 702 565 428 333 188
Amoni azua NH4N3 16 25,3 37,1
View 42 more rows
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Use the periodic table, to determine which element the following spin diagram represents