Explanation:
BaF2(s) <------> Ba2+(aq) + 2F-(aq)
Ksp BaF2 = 1.0 x 10^-6.
Ksp BaF2 = [Ba2+(aq)]×[F-(aq)]^2 at equilibrium
When Qsp >Ksp, BaF2 will precipitate
Qsp = [Ba2+(aq)]×[F-(aq)]^2
[Ba2+(aq)]×[F-(aq)]^2 > 1.0 x 10^-6.
0.0122 moldm-3 × [F-(aq)]^2 > 1.0 x 10^-6
[F-(aq)]^2 > 1×10^-6 / 0.0122 mol2dm-6
[F-(aq)]^2 > 81.96 × 10^-6 mol2dm-6
[F- (aq)] > 9.05 × 10^-3 moldm-3
So F- concentration should be more than 9.05 × 10^-3 moldm-3
. Nhiệt độ ban đầu của 344 g một mẫu sắt là 18,2oC. Nếu mẫu sắt này hấp thụ 2,25 kJ nhiệt lượng thì nhiệt độ cuối của mẫu sắt này là bao nhiêu? (CFe = 0,449 J/g.K).
Answer:
i can't understand the question
TRUE or FALSE 1. Badminton began in India as a game called poona. 2. The shuttle was then called a bird because it was made from goose feather. 3. Ti jian zi played by throwing up in the air. 4. Racket is made of either metal or synthetic materials. 5. Head, throat, shaft, and handle are the parts of the rackets. 6. Shuttlecock is made up of 16 goose feathers. 7. Forehand, Backhand, and Sidestroke are the three basic skills of Badminton. 8. Backhand is use to depends on the type of shot to be executed. 9. Stroke means to propel with a controlled swinging blow. 10. The whole size of the badminton court has 39 meters.
Answer:
1.false
2.true
3.true
4.true
5.false
6.false
7.false
8.true
9.false
10.true
Explanation:
I took the test
When magnesium chloride is formed what question will the student need to ask prior to writing the formula?
A.
What are the oxidation numbers of each atom?
B.
What is the total number of electrons for each atom?
C.
What is the state of matter of each element in the formula?
D.
What period does magnesium belong to?
Prior to writing the chemical formula of magnesium chloride, a question which any student will need to ask is: A. What are the oxidation numbers of each atom?
A chemical formula can be defined as a scientific notation that is used to show (represent) the type and total number of atoms that constitute a particular chemical molecule or compound, by using the oxidation number, chemical symbols and subscripts.
Hence, a student would need to know the oxidation numbers of each atom when magnesium chloride is formed after a chemical reaction.
In Chemistry, an oxidation number represents the number of electrons gained or lost by an atom of a chemical element during a chemical reaction.
In conclusion, when magnesium chloride is formed, a question which the student will need to ask prior to writing the chemical formula is "what are the oxidation numbers of each atom?"
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________ are neutral particles found in the nucleus of an atom.
A radioactive sample has a half life of 1 hour. If you start with 1.000 gram of it at noon, how much of it remains at 4pm
The amount of the sample remaining at 4pm is 0.0625 g
We'll begin by calculating the number of half-lives that has elapsed
Half-life (t½) = 1 hour
Time (t) = 4 hour
Number of half-lives (n) =?n = t / t½
n = 4 / 1
n = 4Finally, we shall determine the amount the sample remaining at 4pmNumber of half-lives (n) = 4
Initial amount (N₀) = 1 g
Amount remaining (N) =?[tex]N = \frac{N_0}{ {2}^{n}} \\ \\ N = \frac{1}{ {2}^{4}} \\ \\ N = \frac{1}{16} \\ \\ N = 0.0625 \: g[/tex]
Thus, the amount remaining at 4pm is 0.0625 g
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describe radioisotope
Answer:
It is an unstable form of a chemical element that releases radiation as it breaks down and becomes more stable.
Explain why there might be a change in the density of a forged product as compared to that of the cast blank.
Answer:
Forged parts are often tougher than cast parts. This can be determined by performing tensile tests on various areas on the parts. Additionally, the microstructures of forged and cast parts can be used to determine if a part was forged or cast. The microstructure of a cast part will have a more uniform grain structure.
Explanation:
Which statement best describes a mechanical wave?
Answer:
A mechanical wave is a wave that is an oscillation of matter, and therefore transfers energy through a medium.
Explanation:
While waves can move over long distances, the movement of the medium of transmission—the material—is limited. Therefore, the oscillating material does not move far from its initial equilibrium position.
--------------
hope this helped!
✼-answers by brookeangelx
The wave transmits energy from one point to another in the form of signals. Some waves require a medium for propagation while some others does not require a medium for the propagation.
What is a mechanical wave?The mechanical wave is defined as the wave which involves the oscillation of matter and it is responsible for the transfer of energy through a medium. These types of waves does not need a medium for propagation.
The mechanical waves cannot travel through vacuum. Some of the examples of mechanical waves are sound waves, water waves, seismic waves, etc. These waves are not capable of transmitting its energy through a vacuum.
The sound wave is a mechanical wave and the medium which it propagates can be solid, liquid or gas. It can travel fastest in solids and slower in gases.
Thus mechanical wave is an oscillation of matter.
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solvent extraction explain ???
Answer:
this the partial removal of a substance from a solution or mixture by dissolving it in another immiscible solvent in which it is more soluble.
Which sentence best describes what happens during a change of state from
a solid to a liquid?
A. The temperature stays the same and the particle speed increases.
B. The temperature stays the same and the particle speed stays
constant
C. The temperature increases and the particle speed stays constant.
D. The temperature decreases and the particle speed decreases.
SUBMIT
Answer:
B
Explanation:
as temperature rises, the particles gain kinetic energy (they will move faster) so if temperatures stays constant, so will the movement or vibration of the particles
In chemical reactions, _______ always involves the release of energy during the reaction process.
a) the breaking of bonds
b) the formation of bonds
c) the addition of a catalyst
d) overcoming activation energy
Answer:
a. the breaking of bonds
Answer:
B
Explanation:
Hey, I am almost positive that the answer to this question is B. The breaking of bonds uses the energy but when they are created it releases energy. I hope this helps, Have a good day!
6) 0.5 moles of gas is kept at 2.0 L of volume and 0.75 atm of pressure. What is the temperature of the gas in K?
Answer:
310K
Explanation:
Rearrange PV=nRT to get T=PV/nR
T=(2.0L)(0.75atm)/(0.5mol)(0.08206)
=36.5 or 37
add 273 for K to get
310
how is atom and molecules related to our sense of smell?
Answer:
Atoms themselves do not have a smell. Molecules do.
Explanation:
What happens is that particular molecules bind to receptors in our nose, activating nerves, that then send signals to our brain, which we then interpret and perceive as “smells”. Different molecules bind to different receptors, which is why we can perceive a number of different smells
2. What pressure is required to compress 196.0 L of air at 1.00 atmosphere into a cylinder
whose volume is 26 0 L? (2 points)
Answer:
7.54 atmExplanation:
The required pressure can be found by using the formula for Boyle's law which is
[tex]P_2 = \frac{P_1V_1}{V_2} \\[/tex]
where
P1 is the initial pressure
P2 is the final pressure
V1 is the initial volume
V2 is the final volume
From the question we have
[tex]P_2 = \frac{1 \times 196}{26} = \frac{196}{26} \\ = 7.538461...[/tex]
We have the final answer as
7.54 atmHope this helps you
Is there more than one possible model that could be inferred from Rutherford’s data?
Rutherford proposed the nuclear model of atom. The only one model which can be inferred from this model is nucleus with protons and revolving electrons around.
What is Rutherford model?Rutherford proposed some aspects of atomic structure based on his gold foil experiment. He discovered that the alpha ray is scattering from foil by the repulsion it experienced from the metal.
This results lead to the discovery of positively charged particles in atom latter called as protons. Rutherford proposed that theses protons are located inside the nucleus and the electrons are revolving around the nucleus.
Latter Niels Bohr his student interpreted the nuclear model of Rutherford with quantum mechanics and theory of max planck and he proposed the equations for the determination of energy and momentum of electrons and the radius of atom.
Therefore, no other inferences except the presence of protons and revolving electrons can be obtained from Rutherford's model of atom.
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What happens to the particles of air inside a ball it warms in the sun?
Answer:
The particles start moving faster and expand making the ball expand.
Explanation:
The boiling point of a substance is tested. After 10 tests, the result is given as 37+/−3°C. Which conclusion can be drawn from this result? (1 point)
The scientists do not need to collect more data because they have narrowed down the range of the results.
The scientists should not report these results until they have the exact number.
The actual boiling point is either 34°C or 40°C.
The actual boiling point is probably between 34°C and 40°C.
Answer:
Explanation:
The actual boiling point is probably between 34C and 40C.
Temperature measures the average kinetic energy of particles of the substances. Therefore, the correct option is option D that is the actual boiling point is probably between 34°C and 40°C.
What is temperature?Temperature is used to measure degree or intensity of heat of a particular substance. Temperature is measured by an instrument called thermometer.
Temperature can be measured in degree Celsius °c, Kelvin k or in Fahrenheit. Temperature is a physical quantity. Heat always flow from higher temperature source to lower temperature source.
We can convert these units of temperature into one another. The relationship between degree Celsius and Fahrenheit can be expressed as:
°C={5(°F-32)}÷9
The actual boiling point is probably between 34°C and 40°C.
Therefore, the correct option is option D.
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If 25 g of Al was added to 90 g of HCl, what mass of H2 will be produced?
Answer:
im pretty sure its 2.7 gms
Explanation:
im not for sure tho
study the graph above. In terms of bond energy, which statement is TRUE regarding the energy involved in breaking and making bonds.
a,b,c, or d?
The energy taken in to break the bond is greater than the energy released after the bond is made therefore the reaction is endothermic.
A plot of energy against time is called a reaction profile. The hump in the plot is known as the activation energy of the reaction. It stands as the energy barrier between reactants and products.
Looking at the reaction profile as shown, we can see that more energy is taken in to break the bonds than energy that is given out after making the bonds hence the reaction is endothermic.
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Answer:
the answer is c
Explanation:
usa test prep says so!
All of the following are properties of molecular compounds except
O A A crystal structure,
O B. low melting points.
C. bonds formed through shared electrons,
D. the inability to conduct electric current when melted or dissolved in water,
Answer: the answer is c.
Explanation:
i juss guessed and it was right?
Dissolution of KOH, ΔHsoln:
KOH(s) → KOH(aq) (10.1)
Neutralization of solid KOH, ΔHneut:
KOH(s) + HCl(aq) → H2O(l) + KCl(aq) (10.2)
1) Using Hess's law, show how to combine Reaction 10.1 and Reaction 10.2 to give
KOH(aq) + HCl(aq) → H2O(l) + KCl(aq) (10.3)
2)How should ΔHsoln and ΔHneut be combined (mathematically) to give the change in enthalpy for Reaction 10.3, ΔH?
Using Hess's law we found:
1) By adding reaction 10.2 with the reverse of reaction 10.1 we get reaction 10.3:
KOH(aq) + HCl(aq) → H₂O(l) + KCl(aq) ΔH (10.3)
2) The ΔHsoln must be subtracted from ΔHneut to get the total change in enthalpy (ΔH).
The reactions of dissolution (10.1) and neutralization (10.2) are:
KOH(s) → KOH(aq) ΔHsoln (10.1)
KOH(s) + HCl(aq) → H₂O(l) + KCl(aq) ΔHneut (10.2)
1) According to Hess's law, the total change in enthalpy of a reaction resulting from differents changes in various reactions can be calculated as the sum of all the enthalpies of all those reactions.
Hence, to get reaction 10.3:
KOH(aq) + HCl(aq) → H₂O(l) + KCl(aq) (10.3)
We need to add reaction 10.2 to the reverse of reaction 10.1
KOH(s) + HCl(aq) + KOH(aq) → H₂O(l) + KCl(aq) + KOH(s)
Canceling the KOH(s) from both sides, we get reaction 10.3:
KOH(aq) + HCl(aq) → H₂O(l) + KCl(aq) (10.3)
2) The change in enthalpy for reaction 10.3 can be calculated as the sum of the enthalpies ΔHsoln and ΔHneut:
[tex] \Delta H = \Delta H_{soln} + \Delta H_{neut} [/tex]
The enthalpy of reaction 10.1 (ΔHsoln) changed its sign when we reversed reaction 10.1, so:
[tex] \Delta H = \Delta H_{neut} - \Delta H_{soln} [/tex]
Therefore, the ΔHsoln must be subtracted from ΔHneut to get the total change in enthalpy ΔH.
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A 14.0 L container at 323 K holds a mixture of two gases with a total pressure of 8.00 atm. If there are 1.50 mol of Gas A in the mixture, how many moles of Gas B are present
The number of moles of gas B present in the gas mixture is 2.72 moles.
The given parameters;
Volume of the gases, V = 14 LTemperature of the gases, T = 323 KTotal pressure of the gases, P = 8 atmNumber of moles of gas A = 1.5 molesThe total number of moles of the gases is calculated by applying ideal gas law;
PV = nRT
where;
R is ideal gas constant = 0.0821 L.atm./mol.K
n is the total mole of the gases
[tex]n =\frac{PV}{RT} \\\\n = \frac{8 \times 14}{0.0821 \times 323} \\\\n = 4.22 \ moles[/tex]
The number of moles of gas B is calculated as follows;
[tex]n_B = 4.22 - n_A\\\\n_B = 4.22 - 1.5\\\\n_B = 2.72 \ moles[/tex]
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Oxidation Unit Test
Use the galvanic cell reaction to answer the question.
2Cr(s) + 3Cu2+(aq) → 2Cr3+ (aq) + 3Cu(s)
Which half reaction occurs at the cathode?
(1 point)
The reduction half equation of the galvanic cell is is; 3Cu2+(aq) + 3e ------> 3Cu(s).
A galvanic cell is a cell that produces chemical energy by a spontaneous chemical reaction. The equation of the reaction is; 2Cr(s) + 3Cu2+(aq) → 2Cr3+ (aq) + 3Cu(s). We can see that chromium was oxidized and copper was reduced.
Since reduction occurs at the cathode, it follows that the reduction half equation is; 3Cu2+(aq) + 3e ------> 3Cu(s).
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what is the mass number of an atom with 3 protons,4 nuetrons, and 3 electrons
Answer:
Neon 10, mass: 20.18
Explanation:
A metal (FW 341.1 g/mol) crystallizes into a body-centered cubic unit cell and has a radius of 1.74 Angstrom. What is the density of this metal in g/cm3
This problem provides the molar mass and radius of a metal that has an BCC unit cell and the density is required.
Firstly, we consider the formula that relates molar mass and also includes the Avogadro's number and the volume of the unit cell:
[tex]\rho =\frac{Z*M}{V*N_A}[/tex]
Whereas Z stands for the number of atoms in the unit cell, M the molar mass, V the volume and NA the Avogadro's number. Next, since BCC is able to hold 2 atoms and M and NA are given, we calculate the volume of the atom in the unit cell given the radius in meters:
[tex]V=a^3=(\frac{4R}{\sqrt{3} } )^3=(\frac{4*1.74x10^{-10}m}{\sqrt{3} } )^3=6.49x10^{-29}m^3[/tex]
And finally the required density in g/cm³:
[tex]\rho =\frac{2*341.1g/mol}{6.49x10^{-29}m^3\frac{m^3}{atom} *6.022x10^{23}\frac{atom}{mol} } =17455257.8g/m^3\\\\\rho=17.5g/cm^3[/tex]
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Doing Labs at home
I’m a junior and I’m staying home for this semester and I have to take chemistry and a lot of my work is Labs but I don’t know how to do them since I don’t have the materials at home to do the labs. Someone please help!!!
Answer:
go get the stuff.
Explanation:
Which of the following is a way to increase pressure on a gas?
Answer:
increase the number of gas particles
Explanation:
a 13.5 g sample of zinc(zn) heated from 24.2 degrees celsius to 83.6 degrees celsius that absorbs 312j of heat? use specific heat
Explanation:
83.6-24.2= 59.4 which is the change in heat
A particular reaction has a DH o value of -164 kJ and DS o of -185 J/K at 298 K. Calculate DG o at 617 K in kJ (with 3 significant digits), assuming that DH o and DS o hardly change with temperature
Answer:
e
Explanation:
When the following equation is balanced, the coefficients are ________.
NH3 (g) + O2 (g) ---> NO2 (g) + H2O (g)
a. 1,1,1,1
b. 4,7,4,6
c. 2,3,2,3
d. 1,3,1,2
e. 4,3,4,3
Answer:
B
Explanation:
Option B is the correct answer. When you add 7 in front of the O2 in the left side, and then you add 4 and 6 in front of NO2 and H2O respectively, the number of oxygen atoms is the same in both sides.