Answer:
Synthesis
The first reported synthesis of selenium tetrafluoride was by Paul Lebeau in 1907, who treated selenium with fluorine:[1]
Se + 2 F2 → SeF4
A synthesis involving more easily handled reagents entails the fluorination of selenium dioxide with sulfur tetrafluoride:[2]
SF4 + SeO2 → SeF4 + SO2
An intermediate in this reaction is seleninyl fluoride (SeOF2).
Other methods of preparation include fluorinating elemental selenium with chlorine trifluoride:
3 Se + 4 ClF3 → 3 SeF4 + 2 Cl2
Structure and bonding
Selenium in SeF4 has an oxidation state of +4. Its shape in the gaseous phase is similar to that of SF4, having a see-saw shape. VSEPR theory predicts a pseudo-trigonal pyramidal disposition of the five electron pairs around the selenium atom. The axial Se-F bonds are 177 pm with an F-Se-F bond angle of 169.2°. The two other fluorine atoms are attached by shorter bonds (168 pm), with an F-Se-F bond angle of 100.6°. In solution at low concentrations this monomeric structure predominates, but at higher concentrations evidence suggests weak association between SeF4 molecules leading to a distorted octahedral coordination around the selenium atom. In the solid the selenium center also has a distorted octahedral environment.
Reactions
In HF, SeF4 behaves as a weak base, weaker than sulfur tetrafluoride, SF4 (Kb= 2 X 10−2):
SeF4 + HF → SeF3+ + HF2−; (Kb = 4 X 10−4)
Ionic adducts containing the SeF3+ cation are formed with SbF5, AsF5, NbF5, TaF5, and BF3.[3] With caesium fluoride, CsF, the SeF5− anion is formed, which has a square pyramidal structure similar to the isoelectronic chlorine pentafluoride, ClF5 and bromine pentafluoride, BrF5.[4] With 1,1,3,3,5,5-hexamethylpiperidinium fluoride or 1,2-dimethylpropyltrimethylammonium fluoride, the SeF62− anion is formed. This has a distorted octahedral shape which contrasts to the regular octahedral shape of the analogous SeCl62−. [5]
Explanation:
Label B-L in the diagram below
Answer:
B. Polar Easterlies
C. Sub polar low
D. Prevailing westerlies
E. Sub tropical high
F. Tropical easterlies
G. Inter tropical convergence zone
H. Tropical easterlies
I. Sub tropical high
J. Prevailing westerlies
K. Sub polar low
L. Polar easterlies
Explanation:
Atoms can gain, lose, or share
electrons during a chemical change. Why
doesn't this cause the atoms identities to
change?
Answer:
Atoms can gain, lose, or share electrons during a chemical change. Chemical changes do not affect the nucleus of an atom. For this reason, an atom has the ability to retain its properties or identity even if the number of electrons is different. Therefore, the atom's identity won't change.
Explanation:
What is the total number of electrons in As-3?
Answer:
Arsenic, As, has atomic number 33, which is the number of protons in the nuclei of its atoms. A neutral As atom would also have 33 electrons. The electron configuration of a neutral arsenic atom is [Ar]3d104s24p3
Explanation:
Which on, help me please, WILL BE MARKED AS BRAINLEST
Answer:
b and c
Explanation:
Because in a chemical change in order for a substance or matter to change shape it needs to either heat up or cool down
Shanika is an engineer at an amusement park who is experimenting with changes to the setup for a magnetic roller coaster ride. In one ride, there are two identical roller coaster cars (orange and green) that start on opposite sides of a large magnet located at the center of a station. Shanika wants to get the largest increase in potential energy she can by moving one car one space to the left or the right. Shanika can move the orange car to point A or point B, or she can move the green car to point C or point D. Which movement should she make? Why will that movement result in the largest increase in potential energy? Describe the magnetic force that will act on the roller coaster car she moves.
Answer:
Shanika should move the orange coaster car to point B. This movement will result in the largest increase in potential energy. This is because the carts are repelling, which means to increase the potential energy you have to go against the magnetic field. Because the carts are being repelled from the centre magnet to go against the magnetic field you would move the cart closer to the magnet. In this case, moving the orange cart to point b would increase the potential energy greater than any other move.
Explanation:
what i meant in the last sentence was that moving the orange cart to b (closer to centre magnet) would end in a greater potential energy change than moving the other, green, cart closer. This is because of the distances between the carts and the centre magnet. Potential energy does not increase linearly meaning that if a cart is one cart is an inch away from the magnet and another is a foot, if you moved both magnets a cm closer to the centre magnet the one an inch away would have a larger potential energy change.
Which of the following atoms has the largest radius
F
I
Cl
Br
Answer:
francium
Explanation:
Atomic radii bary in a predictable across the periodic table.
The atomic radius elements increases down a group. Hence in the halogen group the last element in the group that is I have the largest radius.
What is atomic radius?Atomic radius is the distance is the distance from the nucleus to the valence orbital. The atomic radius depends on the electronegativity and number of electrons in the atom.
In periodic table, atomic radius decreases from left to right because, the electronegativity that is the ability of atomic nucleus to attracts its electron increases and thereby the atoms shrinks.
Down a group the number of shells increases and thereby electrons are more screened from the nuclear attractive pulling. Therefore in the group from fluorine, chlorine, bromine and iodine, iodine has the less electronegativity and thus largest radius.
To find more on atomic radius, refer here:
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A 200.0-mL sample of helium gas is in a cylinder with a movable piston at 110 kPa and 275 K. The piston is pushed in until the sample has a volume of 95.0 mL. The new temperature of the gas is 310. K. What is the new pressure of the sample? a)51.1 kPa b)261 kPa c)249 kPa d)274 kPa
Answer:
Option B. 261 KPa.
Explanation:
From the question given above, the following data were obtained:
Initial volume (V1) = 200 mL
Initial pressure (P1) = 110 kPa
Initial temperature (T1) = 275 K.
Final volume (V2) = 95 mL
Final temperature (T2) = 310 K
Final pressure (P2) =?
The new pressure (P2) can be obtained by using the following formula as illustrated below:
P1V1 /T1 = P2V2 /T2
110 × 200/275 = P2 × 95/310
22000 / 275 = P2 × 95/310
80 = P2 × 95/310
Cross multiply
80 × 310 = P2 × 95
24800 = P2 × 95
Divide both side by 95
P2 = 24800/95
P2 = 261 KPa.
Thus, the new pressure of the gas is 261 KPa.
This chemical equation represents a chemical reaction.
NaCN + HBr + NaBr + HCN
Which two chemicals are reactants in the chemical reaction?
A.NaCN
B.NaBr
C.HCN
D.HBr
Answer: NaCN and HBr
Explanation:
What is the chemical formula for the compound ammonium phosphate? Use the list of polyatomic ions and the periodic table to help you
answer.
OA. NH4H2PO4
OB. (NH4)2PO4
OC (NH)3PO4
OD. (NH4),PO4
Answer:
NH4)3PO4
this is a filler: jsjdkflflflsojsskksdnfkdod
UCI Chemistry researchers, Prof. F. Sherwood Rowland and Dr. Mario Molina werefirst to discovered in 1973 that chlorofluorocarbons (CFCs) were depleting the Earth’sozone layer when released into the atmosphere. Once they reach the stratosphere, Clis released from the CFCs molecules by interaction with UV light. Free Cl atoms areable to react with ozone in a catalytic cycle that converts O3into the more stable O2.It is estimated that a single Cl atom is able to react with∼100000 O3molecules.Although CFCs production was banned in 1996, there are still a substantial numberof motor vehicle air conditioners (MVACs) that use CFC-12 (CF2Cl2) as refrigerant.The average CFC-12 emission rate from operating MVACs has been estimated tobe 59.5 mg per hour per vehicle (Zhang et al.Environ. Sci. Technol. Lett.2017).How much chlorine, in kg, is added to the atmosphere in a year due to 100 millionMVACs using CFC-12 as refrigerant?
Answer:
15.27895 x 10⁶kg of chlorine radical is added to the atmosphere in a year due to 100 million MVACs
Explanation:
Chlorofluorocarbons (CF₂Cl₂) from refrigerants produce chlorine radicals according to the following equation
CF₂Cl₂ → CF2Cl + Cl ⁻ .........(1)
From equation 1, one mole of CF₂Cl₂ produces one mole of Chlorine radical
From the question,
The emission rate of CF₂Cl₂ is 59.5mg/hour/MVAC
In one day the emission rate would be 59.5 x 24hours
= 1428mg/day
In one year, the emission rate would be 1428mg/day x 365days
= 521220mg/year
= 521.220g/year/MVAC
Therefore the emission rate for 100 million MVAC using CF₂CL₂ in a year is
= 52122 x 10⁶g/year/MVAC
= 52122 x 10³kg/year/MVAC
The molar mass of CF₂CL₂ = 120.913g/mol
No of moles of CF₂CL₂ = mass/ molar mass
= 52122 x 10⁶g / 120.913g/mol
= 431 x 10⁶ moles of CF₂Cl₂
From equation 1, since one mole of CF₂Cl₂ produces one mole of Chlorine radical, it implies that
431 x 10⁶ moles of CF₂Cl₂ would produce 431 x 10⁶ moles of chlorine radical,
Therefore, to find the mass of chlorine radical produced, we use the formula
No of moles of chlorine radical = mass/ molar mass
431 x10⁶ moles = mass of chlorine radical /molar mass of chlorine radical
431 x 10⁶ moles = mass/ 35.45g/mol
mass of chlorine = 431 x 10⁶ moles x 35.45 g/mol
= 15278.95 x 10⁶ g
In Kg, the mass = 15,278.95 x 10³kg of cholrine radical
= 15.27895 x 10⁶ Kg of chlorine radical
which of the nonmetals is the least reactive?
a) Ne
b) O
c) Cl
d) F
Flourine
Explanation:
The element F has a high negative (ΔeqHө) but not so high IE1 . Therefore, it is the least reactive non-metal.
What forces are present in this situation?
An elevator is rising at a constant speed; the elevator is the object in this situation.
A.gravity and tension
B.normal,gravity,and tension
C.normal and tension
D.gravity
Answer:
A. Gravity and Tension
Explanation:
Gravity and Tension would be the only things changing the rising speed of the elevator.
Normal makes no sense not sure why that is an answer.
Gravity effects how much Tension is pulling on the elevator to go down while the elevator is pushing up.
Let me know if you have any other questions.
In which of the following situations is a plant reproducing sexually?
Answer:
(ANSWER CHOICES ORDER MAY BE DIFFERENT FROM YOURS!!)
A.
The pollen from one flower is transported by an insect to the ovule of another flower.
B.
A potato plant produces a tuber, and the next year, a new plant grows from the tuber.
C.
Part of the stem segment of a cactus plant falls off and begins to form a new plant.
D.
A new shoot emerges from a strawberry plant and produces another plant.
Explanation:
It's "The pollen from one flower is transported by an insect to the ovule of another flower. " because i got it from study island
Which property can be used to tell gold and pyrite apart?
O A. Color
O B. Conductivity
C. Shininess
D. Malleability
Answer:
D. Malleability
Explanation:
Gold is made up of the element Au and it is a metal.
Pyrite is iron sulfide and it is a non-metal.
They have very similar appearance to such an extent that pyrite is widely called the fool's gold. To distinguish between the two, we simply explore their metallic properties. Gold is malleable. Pyrite is not. It will crumble under pressure.The outer shell of this element was determined as illustrated here.
It must be a _____.
If the molecules of a substanace spread out compltely to fill the entire shape of any container the substance is placed in , the substance is probly a
Answer:
Gas.
Explanation:
Matter can be found in nature in three states: solid, liquid, and gas. The main difference between these three states is the separation of its molecules.
A solid has a definite form, its molecules are closely packed together and there is little to no movement between each molecule. When put in a container, it retains its form.
A liquid does not have a definite form, its molecules can move past another and they are not as close as in a solid, but it is not as loose either. When put in a container, it takes the shape of the container but it has a defined surface.
A gas does not have a definite form, its molecules are totally free from one another and the distance that separates them is much larger than the size they have. When placed in a container, they spread out completely and fill the entire shape of the container.
n the Bohr model of an atom (shown), protons are represented in blue, the neutrons are red and the electrons are green. Use your periodic table and determine which of the following atoms is represented by the Bohr model.
Answer: B
Explanation: Valence electrons are the number of electrons out the outermost shell of the diagram. In this diagram, there is one valence electron. This means that it is highly reactive since the shell is not complete and needs other elements to be able to complete the outermost shell. If this model had a full outermost shell, then it would not be reactive (noble gases).
Answer: B
Explanation:This test it anoying.
Almost all of Earth's atmosphere is created through the process of photosynthesis.
True
False
Answer:
False
Explanation:
What will happen to the acquired energy of the ruler when you released its bent end?
Answer:
When the Ruler is bent the energy stored in it will be potential energy, When the ruler will be released this potential energy will be then converted into the Kinetic energy as a result the ruler will move Vibrations.
The energy conservation law can be applied here
K1 + U1 = K2 + U2
K1 - initial kinetic energy
U1 - Initial potential energy
K2 - final kinetic energy
U2 - final potential energy
Energy is known commonly as the ability to do work or move a matter. The type of energy that is stored is called potential energy.
So a bent ruler often has higher energy than a flat ruler. If the ruler moves, it is having an some form of kinetic energy and thus a flying bent ruler is having higher amount of energy than the one that is not bent.if the ruler is released at the bent end, the object or pebbles on it will fly. If you hold two positive charges near each other, they have potential energy because they will move if you release them.
If the object released is fired straight up into the air, it begins with a high kinetic energy. As it rises, it slows down due to the force of gravity pulling it toward the earth.
Due to the release, the object place on the ruler rises, its gravitational potential energy is therefore increasing and its kinetic energy is decreasing.
When the object reaches the top of its arc, it kinetic energy is zero and its potential energy is maximum.
Then gravity still to pull the object down the earth and the object will fall toward the earth and just as it falls down, its speed increases and its height decreases.
So, its kinetic energy will thus increases as it falls and its potential energy decreases.
When the object has returns to its original height, its kinetic energy will be the same as when it started upward.
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Suppose you want to make 2000g of a solution of glucose in water that has
2.8% (m/m) concentration. How much glucose should you use?
Answer:
56 g of glucose
Explanation:
We can find the mass of glucose used as follows:
[tex] \%_{m/m} = \frac{m_{s}}{m_{sol}}\times 100 [/tex] (1)
Where:
[tex]m_{s}[/tex] is the solute's mass =?
[tex]m_{sol}[/tex] is the solution's mass = 2000 g
% (m/m)= 2.8 %
By solving equation (1) for [tex]m_{s}[/tex] we have:
[tex] m_{s} = \frac{\%_{m/m}*m_{sol}}{100} = \frac{2.8*2000 g}{100} = 56 g [/tex]
Therefore, you used 56 g of glucose to make 2000 g of a solution of glucose in water.
I hope it helps you!
A dachshund walked 20 meters in 30 minutes. Calculate the speed. Provide your
answer in meters per hour.
when temperature increase gas decrease or increase support u r answer with daily life example
Answer:
increase
Explanation:
dont known reason burr answer is correct
Answer:
When temperature increases ,gas increases ,because of the rise in temperature evaporation will take place.
Explanation:
When you boil water to make coffee/tea the kettle/boiler releases the evaporation caused by the rise in temperature.
YALL can you please answer this
Write a balanced chemical equation for the reaction that occurs when calcium metal undergoes a combination reaction with O2(g).
Answer:
CaO[tex]_{s}[/tex]
Explanation:
The chemical reactants are;
Calcium metal = Ca[tex]_{s}[/tex]
Oxygen gas = O₂[tex]_{g}[/tex]
Now let us write the reaction:
2Ca[tex]_{s}[/tex] + O₂[tex]_{g}[/tex] → 2CaO[tex]_{s}[/tex]
The product is CaO in solid form.
This reaction is a combination or synthesis reaction in which two substances combine to give a single product.
What causes uneven heating on Earth? *
Temperature Differences
Earth's Rotation
Earth's Revolution
Global Wind System
if u get it right i will give brainliest
Answer:
temperature differences
Explanation:
Solar heating of the Earth's surface is uneven because land heats faster than water, and this causes air to warm, expand and rise over land while it cools and sinks over the cooler water surfaces. ... Wind is the result of pressure changes in the atmosphere.
Which scientist is known for developing the planetary model of the atom
Answer:
Ernest Rutherford
Explanation:
The Rutherford model, proposed originally in 1911, dipicts a planetary model of the atom in which there is a nucleus and electrons circling it.
Answer:
Niels Bohr
Explanation:
Can you think of other solutions that might be
acidic?
Answer:
i think the answer is yess
Answer:
Limes, Lemons, Vinegar, Stomach acid, Batteries, Sour Candy, etc.
Nitric Acid, Chloric Acid, Carbonic Acid, Citric Acid, Perchloric Acid, Flouric Acid, etc.
Hope this helps!
Explanation:
Need help fast please I am timed and giving 47 points.
Four groups of students plan scientific investigations to answer four questions for the science fair.
Questions for Science Fair:
1-What kinds of plant life grow naturally in the town parks?
2-Which types of treats do different breeds of dogs like best?
3-Do different types of grass affect how far a ball rolls?
4-How are the chemicals in different vegetables similar?
Which question would most likely be answered with an experimental investigation?
A-1
B-2
C-2
D-4
Answer:
C
Explanation:
Answer:
C - 3
Explanation:
This can be actually tested
5. A family is traveling using three different modes of transportation. Seven of them travel in a large recreational vehicle, two in a car, and one on a motorbike. They start from the same place, travel at the same speed, and reach the final destination at the same time. *
Answer:
All three vehicles have the same kinetic energy because they have equal speed.
I just need to know which ones are insulators and the others conductors
Answer:
below
Explanation:
Insulators: wood, tire, glass cup, wool hat
Conductors: frying pan, penny, wire
A. O CN
B. O NH4+
C. O s2-
D. O Cro 2-
Which of the following is an oxyanion?