a 67.5 L sample of gas at 27.6 °c and 383.1mm hg expands to 244.2 L at 4.7 °c. what is the new gas pressure.
a 97.8
b 18.0
c 115
d 1.65
Answer:
a well well well all el well eto eto rup wp will rup ei well dll alsof well po team app app app well piz wmv epic enz
An ionic bond is a bond
Answer:
That involve the complete transfer of an electron from one atom of an element to another
The sugars can be classified as either aldoses or ketoses.
a. True
b. Fasle
Could someone help with this? Much appreciated!
Answer:
The 3rd answer down.
Na²O (sodium oxide) will be a base when exposed to water H²O
Explanation:
Sodium Oxide Na²O, will become Sodium Hydroxide after being exposed to water (at 80% I believe).
The oxygen ion in Na²O has 2 extra electrons which makes it highly charged and very attractive to hydrogen ions. The attraction is so strong that when Na²O comes in contact with H²O, the O(-2) strips off a hydrogen from water, forming 2 x OH ions which of course are still strongly basic.
Discuss the action of sodium with a) Ammonia b) non-metals
Answer:
i hope ammonia is the correct answer
what is the zeff of carbon
Answer:
Explanation:
The steps to calculate the Zeff is :
1) Write the electronic configuration.
Carbon: 1s2 2s2 2p2
Oxygen: 1s2 2s2 2p4
2) there are two core electrons in each atom and four in carbon and six in oxygen.
1s) (2s2p)
3) as mentioned the shielding of electrons within the same shell is negligible.
4) for electron of s or p orbital the shielding contribution by the electrons having a principal quantum number less by one would be 0.85 each. And all electrons further left would contribute an amount of 1.0 each.
5) For oxygen:
Zeff = Z - S
S = 2X0.85 = 1.7
Zeff = 8- 1.7 = 6.3
For carbon
Zeff = Z - S
S = 2X0.85 = 1.7
Zeff = 6- 1.7 = 4.3
Which electron configuration matches this model?
0 1s22s2p2
0 1s²2s2p3
O 1s²2s²2p4
1s22s²2p5
Answer:
1s2 2s2 2p5
is the correct answer
Explanation:
Hi there!
From the figure;
We can figure out that the atomic number is 7.
So;
Option A: 1s² 2s² 2p²
Sum of the powers of variable is just 6. So, it's not answer.
Option B: 1s²2s²2p³
Sum of the powers of variable is 7. So it's the answer
Option C: 1s²2s²2p⁴
Sum of the powers of variable is 8. So, it's not answer.
Option D: 1s²2s²2p⁵
Sum of the powers of variable is 9. So, it's not the correct answer.
Therefore, answer is option B.
Hope it helps!
If the starting material has no stereogenic centers, when carbonyl compounds are reduced with a reagent such as LiAlH4 or NaBH4 and a new stereogenic center is formed, what will the composition of the product mixture be?
A) Forms a racemic mixture of the two possible enantiomers.
B) Forms more of one enantiomer than another because of steric reasons around the carbonyl.
C) Forms more of one enantiomer than another depending on the temperature of the reaction.
D) Forms different products depending on the solvent used.
Answer:
A) Forms a racemic mixture of the two possible enantiomers
When carbonyl compounds are reduced with a reagent such as LiAlH₄ or NaBH₄ and new stereogenic center is formed chemical change will lead to products that form a racemic mixture of the two possible enantiomers.
What is a chemical change?
Chemical changes are defined as changes which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical change.
There are several characteristics of chemical changes like change in color, change in state , change in odor and change in composition . During chemical change there is also formation of precipitate an insoluble mass of substance or even evolution of gases.
There are three types of chemical changes:
1) inorganic changes
2)organic changes
3) biochemical changes
During chemical changes atoms are rearranged and changes are accompanied by an energy change as new substances are formed.
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5. Calcule las concentraciones cuando se alcanza el equilibrio si partimos de unas concentraciones iniciales [A]=[B]=1M ; [C]=[D]=0M y una constante de equilibrio de 5.
Las concentraciones en el equilibrio para la reacción química presentada son:
[tex][A] = [B] = 1-x = 1-0.69 = 0.31 M\\[C] = [D] = x = 0.69 M[/tex]
Consideremos la siguiente reacción química genérica:
A + B ⇄ C + D
Para calcular las concentraciones en el equilibrio, debemos construir una Tabla ICE. Cada fila representa una instancia (Inicial, Cambio, Equilibrio) y la completamos con la concentración o cambio de concentración ("x" para concentraciones desconocidas). Como inicialmente no hay productos, la reacción se desplazará hacia la derecha para alcanzar el equilibrio.
A + B ⇄ C + D
I 1 1 0 0
C -x -x +x +x
E 1-x 1-x x x
La constante de equilibrio, Kc, es:
[tex]Kc = 5 = \frac{[C][D]}{[A][B]} = \frac{x^{2} }{(1-x)^{2} } \\\sqrt{5} = x/1-x\\x = 0.69[/tex]
Las concentraciones en el equilibrio son:
[tex][A] = [B] = 1-x = 1-0.69 = 0.31 M\\[C] = [D] = x = 0.69 M[/tex]
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A nitrogen ion has a mass of 14 and a charge of +2. Which subatomic particles does it contain? (1 point)
O 2 protons, 6 neutrons, and 6 electrons
O 7 protons, 7 neutrons, and 5 electrons
O 4 protons, 4 neutrons, and 6 electrons
o 7 protons, 7 neutrons, and 9 electrons
Answer:
7 protons, 7 neutrons, and 5 electrons
Explanation:
the formula for atomic weight=no.of protons + no. of electrons this shortens the options into b or d and second part says that the ion has charge +2 which means it has lost two electrons. so no. of electrons=no.of electrons in nitrogen atom - 2=5.
Nitrogen ion with a charge of +2 has 7 protons, 7 neutrons, and 5 electrons
Explanation:
To obtain the right answer to the question, we must determine the number of proton, neutron and electron of nitrogen ion. This can be obtained as illustrated follow.
Step 1:Data obtained from the question.
Mass number = 14
Charge = +2
Step 2:Determination of the number of proton.
The atomic number of an element is simply the number of protons in the atom of the element.
Atomic number of nitrogen = 7
Thus, the proton number of nitrogen is 7.
NOTE: The atomic number of an element does not change be it atom or ion, it remains the same.
Therefore the proton number of nitrogen ion is 7
Step 3:Determination of the number of neutron
Mass number = 14
Proton number = 7
Neutron number =?Mass number = Proton + Neutron
14 = 7 + Neutron
Collect like terms
14 – 7 = Neutron
Neutron = 7Step 4Determination of the number of electrons.
Charge = +2
Proton number = 7
Electron number =?Charge = Proton – Electron
+2 = 7 – Electron
Collect like terms
2 – 7 = – Electron
–5 = – Electron
Multiply through by –1
Electron = 5SUMMARY:Nitrogen ion with a charge of +2 has:
1. 7 protons
2. 7 neutrons
3. 5 electrons.
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PLEASE HELP!!
this is on USAtestprep
a)
b)
c)
d)
Answer:
silicon dioxide /C
Explanation:
it can form thousands of covalent bonds between it's silicon and Oxygen due to it's macromolecular structure
milk has a pH of 6.0 and household ammonia has a pH of 12.0. How much more acidic is milk than ammonia
60 I think bcz if there is 1&2 they differ 10 times
The milk has a pH of 6.0 and household ammonia has a pH of 12.0. then milk will be 6 times milk acidic than ammonia.
What is pH?The pH scale, which previously stood for "potential of hydrogen," would be used to describe how acidic or basic an aqueous solution is.
What is an acidic solution?More hydrogen ions are present in an acidic solution than it was in pure water.
It is given then,
[tex](milk)pH_{1} = 6\\(ammonia)pH_{2} = 12[/tex]
The concentration of hydrogen ions can be calculated by using the formula:
[tex][H^{+}] = 10^{-pH}[/tex]
By putting the value of given data in the above equation.
[tex][H^{+}_{milk} ] / H^{+}_{ammonia}= 10^{-6}/10^{-12}\\ = 10^{6} = 6[/tex]
We get that, milk will be 6 times more acidic than ammonia.
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Draw all four products when the following compound undergoes dehydrohalogenation and rank them in terms of stability. Which product do you expect to be the major product?
Answer:
2 Methyl pent 2 ene
9.7300x10^2 + 9.8700x10^3
? × 10^?
Answer:
19.6 x 10⁵
1.96 x 10⁶
I hope it's helps you
Describe ask a question in in sincence
Answer:
why do we dream
Explanation:
Which of the following represents a physical change?
Answer:
» Water evaporating to gas.
» Solid subliming to gas.
» Water freezing to solid.
» Solid melting to liquid.
Explanation:
[tex]{ \underline{ \blue{ \sf{christ \:† \: alone }}}}[/tex]
18. What is the density of a substance with a mass of 0.90 kg and a volume of 1.2 mL?
21. An oxygen tank in the lab has a pressure of 12 atm at 250C. If the pressure inside the gas tank exceeds 25 atm, the tank will explode. If a fire occurs in the lab, raising the temperature of the gas inside the cylinder to 398oC, will the tank explode?
Answer:
fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
Explanation:
Which one of the following is not matches the organelle with its function
Answer:
rip there isnt a photo
Explanation:
i do know a lot about cells tho lol
A 1.45 L buffer solution consists of 0.111 M butanoic acid and 0.281 M sodium butanoate. Calculate the pH of the solution following the addition of 0.078 moles of NaOH. Assumr that any contribution of the NaOH to the volume of the solution negligble. The ka of butanoic acid is 1.52x10^-5.
Ph= __________-
Answer: -5
Explanation:
What is the state of water at room temperature? Please someone help thank you
it is in a liquid state
in room temperature
Answer:
liquid state
Explanation:
water is liquid at room temperature because of the many weak hydrogen bonds that holds its molecules together in small fractions of second
If sodium chloride (NaCl) is dissolved in water, how will the vapor pressure of the water be affected?
A. The vapor pressure will be raised, making it more easier to boil.
B. The vapor pressure will be raised, making it more difficult to boil.
C. The vapor pressure will be lowered, making it easier to boil.
D. The vapor pressure will be lowered, making it more difficult to boil.
The vapor pressure will be lowered, making it more difficult to boil If sodium chloride (NaCl) is dissolved in water. Hence, option D is correct.
What is vapor pressure?It can be defined as the pressure exerted by a vapor with its condensed phases in a closed system at a given temperature show the equilibrium vapor is a well-known measure of a liquid evaporation rate.
The vapor pressure of a liquid is the point at which equilibrium pressure is reached in a closed container. The molecules leaving the liquid and going into the gaseous phase and molecules leaving the gaseous phase and entering the liquid phase.
It is measured in the standard units of pressure the international system of units. Pressure as a derived unit with the dimension of force per area and designate the Pascal (Pa) as its standard unit.
When common salt is dissolved in water boiling point of a solution increases the boiling point of a substance is the temperature at which it will be lowered, making it more difficult to boil If sodium chloride (NaCl) is dissolved in water. Hence, option D is correct.
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Determine which choice is an example of an endothermic process.
O A. Lighting a match
B. Respiration
C. Running a gas engine
D. Baking bread
Answer:
D. Baking bread
Explanation:
In this process, energy is absorbed and in an endothermic process energy is absorbed too.
Baking bread is an example of an endothermic process, therefore option (d) is correct .
What do you mean by endothermic process ?Endothermic reactions are chemical processes in which the reactants absorb heat from the environment to produce products.
An endothermic reaction is accompanied by an absorption of heat.
Endothermic reactions cause a cooling effect by lowering the temperature of the surrounding environment.
A decrease in temperature can be observed with the progression of the reaction. The reaction is non-spontaneous in endothermic reactions .
Baking bread is an example of an endothermic process, hence option (d) is correct .
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what is the bond energy required to break one mole of carbon-carbon bonds
Answer:
100 kcal of bond energy
A gas within a piston–cylinder assembly undergoes an isothermal process at 400 K during which the change in entropy is −0.3 kJ/K. Assuming the ideal gas model for the gas and negligible kinetic and potential energy effects, evaluate the work, in kJ.
Answer:
W = -120 KJ
Explanation:
Since the piston–cylinder assembly undergoes an isothermal process, then the temperature is constant.
Thus; T1 = T2 = 400K
change in entropy; ΔS = −0.3 kJ/K
Formula for change in entropy is written as;
ΔS = Q/T
Where Q is amount of heat transferred.
Thus;
Q = ΔS × T
Q = -0.3 × 400
Q = -120 KJ
From the first law of thermodynamics, we can find the workdone from;
Q = ΔU + W
Where;
ΔU is Change in the internal energy
W = Work done
Now, since it's an ideal gas model, the change in internal energy is expressed as;
ΔU = m•C_v•ΔT
Where;
m is mass
C_v is heat capacity at constant volume
ΔT is change in temperature
Now, since it's an isothermal process where temperature is constant, then;
ΔT = T2 - T1 = 0
Thus;
ΔU = m•C_v•ΔT = 0
ΔU = 0
From earlier;
Q = ΔU + W
Thus;
-120 = 0+ W
W = -120 KJ
a. You have a stock solution of 14.8 M NH3. How many milliliters of this solution should you dilute to make 1000.0 mL of 0.250 M NH3?
b. If you take a 10.0 mL portion of the stock solution and dilute it to a total volume of 0.500 L, what will be the concentration of the final solution?
Answer:A) V = 16.892 ml
Explanation:
M1 * V1 = M2 * V2
14.8 M * V1 =0.250 M * 1000 ml
V1 = 16.892 ml
a. The volume of 16.89 milliliters of the stock solution of 14.8 M should be diluted to make 1000.0 mL of 0.250 M.
b. The concentration of the final solution is 0.296 M.
What is the dilution law?The concentration or the volume of the concentrated or dilute solution can be calculated by using the equation:
M₁V₁ = M₂V₂
where M₁ and V₁ are the concentration and volume of the concentrated solution respectively and M₂ and V₂ are the concentration and volume of the dilute solution.
A stock solution is a solution that has a high concentration and that will be diluted to a low concentration by the addition of water in it.
Given, a stock solution of concentration, M₁ = 14.8 M
The concentration of the diluted solution, M₂ = 0.250 M
The volume of diluted solution, V₂ = 1000ml
Substitute the value of the molarity and volume in equation (1):
(14.8)× (V₁) = (1000) × (0.250)
V₁ = 16.89 ml
Similarly, for part (b): M₁ = 14.8 M, V₁ = 10 ml and V₂ = 0.5L = 500 ml
(14.8)× (10) = (500) × (M₂)
M₂ = 0.296 M
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Three bonding pairs around a central atom results in a ________. A. octahedral B. trigonal planar compound C. tetrahedral compound D. linear compound
Answer:
B
Explanation:
because it is a trigonal planar compound
Three bonding pairs around a central atom results in a trigonal planar compound. Option B is correct.
In a trigonal planar arrangement, the central atom is surrounded by three bonding pairs of electrons, forming a flat, triangular shape. The bond angles between the bonding pairs are approximately 120 degrees.
This molecular geometry is observed when a molecule has a central atom with three bonded pairs and no lone pairs. Examples of compounds with trigonal planar geometry include boron trifluoride (BF₃) as well as formaldehyde (H₂CO).
The other options are not correct for a molecule with three bonding pairs;
Octahedral refers to a molecular geometry with six bonding pairs around a central atom.
Tetrahedral corresponds to a molecular geometry with four bonding pairs around a central atom.
Linear represents a molecular geometry with two bonding pairs around a central atom.
Hence, B. is the correct option.
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a=bcd in order to solve the equation above for b you must multiply both sides of the equation by the same expression
a x _ = bcd x _
the results equation is:
b=
Both sides of the equation must be multiplied by 1/cd to give the following equation: b = a/cd
The following equation was given in this question: a = bcd. This means that a = b × c × d. Hence, to make "b" the subject of the formula, we have to eliminate "cd" from the side of the equation with "b". To do that, we multiply both sides of the equation with the same expression as follows:a x 1/cd = bcd x 1/cd
"cd" cancels out "cd" in the right side of the equation to result to:a/cd = b
Therefore, b = a/cd
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What volume of 6.9 M NaOH is needed to completely titrate 0.42 L of 2.39 M phosphoric acid according to
the equation:
H3PO4(aq) + 3NaOH(aq) + Na3PO4(aq) + 3H2O(aq)
A) O 0.05 L
B) O6.93 L
C) O0.44 L
D) 03.01 L
E) 436.43 L
Taking into account the definition of molarity and the stoichiometry of the reaction, the correct option is option C) 0.44 L of 6.9 M NaOH is needed to completely titrate 0.42 L of 2.39 M phosphoric acid.
The balanced reaction is:
H₃PO₄ (aq) + 3 NaOH (aq) → Na₃PO₄ (aq) + 3 H₂O(aq)
Then, by stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:
H₃PO₄: 1 mole NaOH: 3 moles Na₃PO₄: 1 mole H₂O: 3 molesMolarity is the number of moles of solute that are dissolved in a given volume.
Molarity is determined by:
[tex]Molarity=\frac{number of moles of solute}{volume}[/tex]
Molarity is expressed in units [tex]\frac{moles}{liter}[/tex].
In this case, 0.42 L of 2.39 M phosphoric acid reacts. So, by definition of molarity, the number of moles that participate in the reaction is calculated as:
[tex]2.39 \frac{moles}{liter}=\frac{number of moles of phosphiric acid}{0.42 liters}[/tex]
Solving:
number of moles of phosphiric acid= 2.39 [tex]\frac{moles}{liter}[/tex]* 0.42 liters
number of moles of phosphiric acid= 1.0038 moles ≅ 1 mole
Approaching 1 mole of the amount of phosphoric acid required, then by stoichiometry of the reaction, 3 moles of NaOH are necessary to react with 1 mole of the acid.
Then by definition of molarity and knowing that 6.9 M NaOH is needed, you can calculate the necessary volume amount of NaOH by:
[tex]6.9 \frac{moles}{liter} =\frac{3 moles}{volume}[/tex]
Solving:
6.9 [tex]\frac{moles}{liter}[/tex]* volume= 3 moles
[tex]volume=\frac{3 moles}{6.9\frac{moles}{liter} }[/tex]
volume= 0.44 L
The correct option is option C) 0.44 L of 6.9 M NaOH is needed to completely titrate 0.42 L of 2.39 M phosphoric acid.
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Isotopes are: A. are only theoretical. B. only formed in laboratories. C. found in nature. D. found in the nuclear reactions in stars but not on Earth.
Answer:
B. only formed in laboratories
Explanation:
i know
Isotopes are only formed in Laboratories. hence, Option (B) is correct.
What are Isotopes ?
Each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties; in particular, a radioactive form of an element is known as Isotope.
Isotopes are two or more types of atoms that have the same atomic number and position in the periodic table, and that differ in nucleon numbers due to different numbers of neutrons in their nuclei.
Therefore, Isotopes are only formed in Laboratories. hence, Option (B) is correct.
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Which phenomenon explained below is an example of deposition?
Select the correct answer below:
A) Hail is formed from water droplets lifted by air currents to an altitude where they turn into pellets of ice.
B) Frost forms when cold evening temperatures convert the humidity in the air to thin layers of ice on the ground.
C) In the winter, the top few inches of a pond turn to ice.
D) The visible cloud arising from a boiling tea kettle is not actually steam, but droplets of liquid water that form as the
steam cools in the air.
Answer:
b
Explanation:
deposition is when water turns from gas to solid. b is the only one that fits
Deposition is frost forms when cold evening temperatures convert the humidity in the air to thin layers of ice on the ground.
What is deposition?Deposition is a process that involves collection of large mass or when mean distance between molecules are reduced. It can also be explained as gathering of substances together to form a larger mass.
Therefore, the phenomenon explained in the given example about deposition is frost forms when cold evening temperatures convert the humidity in the air to thin layers of ice on the ground.
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