An element A reacts with water to form a compound B which is used in white washing. On exposure to air compound B forms C. The compound C on heating forms an oxide D which on treatment with water gives back B. Identify A, B and C and D, write the balanced chemical equations for the reactions involved.
Answer:
A- Ca
B- Ca(OH)2
C-CaCO3
D- CaO
Explanation:
Element A is calcium. Calcium reacts with water to form calcium hydroxide (compound B) as follows; Ca(s) + 2H2O(l) ----> Ca(OH)2(s) + H2(g).
When exposed to air, calcium hydroxide (compound B) forms calcium trioxocarbonate IV (CaCO3) which is compound C as follows;
Ca(OH)2(s) + CO2(g) -----> CaCO3(s) + H2O(l)
On heating compound C, the oxide, CaO (D) is formed as follows;
CaCO3(s) ------> CaO(s) + CO2(g)
This oxide reacts with water to yield B again as follows;
CaO(s) + H2O(l) ----> Ca(OH)2(s)
The solubility product constant at 25°C for AgI(s) in water has the value 8.3 × 10–17. Calculate ∆Grxn at 25°C for the process AgI(s) <--> Ag+(aq) + I– (aq) where [Ag+] = 9.1 × 10–9 and [I–] = 9.1 × 10–9. –91.7 kJ/mol +91.7 kJ/mol 0.0 kJ/mol –4.4 kJ/mol +4.4 kJ/mol
Answer:
+91.7 KJmol-1
Explanation:
Recall that ∆G= -RTlnK
Since ∆G in this case is ∆Grxn and K is the Ksp
Note that the Ksp is the solubility product (as shown by the reaction equation)
∆Grxn is the change in free energy for the reaction, in this case the ionization of the silver iodide into silver and iodide ions.
R= 8.314JK-1 and T =25°C +273 = 298 K (the centigrade temperature must be appropriately converted to its corresponding absolute absolute before proceeding with the calculation)
Hence we can substitute values accordingly;
∆Grxn = -(8.314 × 298 × ln 8.3×10^-17)
∆Grxn = +91.7 KJmol-1
True or False a. Sodium chloride is the main salt found in sea water. ……………………………………………………………………. b. Potassium bromide salt is not found in sea water ……………………………………………………………………. c. Both evaporation and electric conduction techniques prove that sea water contain the dissolved salts. …………………………………………………………………….. d. The amount of fresh water is greater than 5% of the total Earth water. …………………………………………………………………….. e. In water treatment process, filter membrane is used to remove fine particles and other impurities from water. …………………………………………………………………………....
Answer:
A is true NaCl
B is false K2Br
C is true
D false its only 0.03 percent
E is true
how many different d orbits are within the 3d sublevel
Answer:
Its 5
Explanation:
2g of magnesium Oreo to excess dilute acid according to the equation Mg(s) + 2H (aq) --- Mg² (aq) + H2 (g) (Realitive atomic mass of Mg= 24, molar mass volume at room temperature and pressure = 24dm³) The volume of hydrogen, measured at room temperature I pressure, that is produced is A) 1000 cm³ B)1500 cm³ C) 2000 ³cm D) 24 000 cm³
Answer:
Option C. 2000 cm³.
Explanation:
We'll begin by calculating the number of mole in 2 g of Mg. This is illustrated below:
Molar mass of Mg = 24 g/mol
Mass of Mg = 2 g
Mole of Mg =?
Mole = mass /Molar mass
Mole of Mg = 2/24
Mole of Mg = 8.33×10¯² mole.
Next, we shall determine the number of mole of H2 produced from the reaction. This is illustrated below:
Mg(s) + 2H^+ (aq) —› Mg^2+(aq) + H2 (g)
From the balanced equation above,
1 mole of Mg reacted to produce 1 mole of H2.
Therefore, 8.33×10¯² mole of Mg will also produce 8.33×10¯² mole of H2.
Finally, we shall determine the volume of H2 produced. This is illustrated below:
1 mole of H2 occupy 24000 cm³ at room temperature and pressure.
Therefore, 8.33×10¯² mole of H2 will occupy = 8.33×10¯² x 24000 ≈ 2000 cm³ at room temperature and pressure.
Therefore, 2000 cm³ of H2 were obtained from the reaction.
A stone bead and an iron bead are dropped into a cup of water. They both sink to the bottom of the cup. What can be said about these beads?Immersive Reader
Answer:
Both have densities greater than that of water
Explanation:
The ability of objects to either float or sink in a liquid depends on their relative densities.
If an object is denser than a liquid it will completely sink in it, but if the density of the object is less than that of the liquid, it will sink until the weight of liquid displaced is equal to the weight of the object, then it will finally float in that liquid.
In the case of the stone bead and iron beads dropped into a cup of water, hey both sank to the bottom because they are denser than water.
Which metal will react spontaneously with Cu2+ (aq) at 25°C?
Hg
Mg
Ag
Au
Answer:
Mg
Explanation:
The standard reduction potentials are
E°/V
Au³⁺(aq ) + 3e⁻ ⟶ Au(s); 1.42
Hg²⁺(aq) + 2e⁻ ⟶ Hg(l); 0.85
Ag⁺(aq) + e⁻ ⟶ Ag(s); 0.80
Cu²⁺(aq) + 2e⁻ ⟶ Cu(s); 0.34
Mg2+(aq) + 2e- ⟶ Mg(s); -2.38
The more negative the standard reduction potential, the stronger the metal is as a reducing agent.
Mg is the only metal with a standard reduction potential lower than that of Cu, so
Only Mg will react spontaneously with Cu²⁺.
Answer:
B. Mg
Explanation:
You are given a mixture of sand, sugar and sulphur. Give the method you will use to separate the three constituents. ___________
Answer:
1:put these in sneaker and add water since sulphur is insoluble and the sugar will dissolve and the sand will settle obtain the sulphur
2:filter the mixture of sand and sugar solution to obtain the sand as residue and solution as filtrate
3:using an evaporating dish evaporate sugar solution to saturation not dryness to get crystals.
what is heat energy in science
Answer:
Heat energy is the result of the movement of tiny particles called atoms, molecules or ions in solids, liquids and gases. Heat energy can be transferred from one object to another. the transfer or flow from one object to another is called heat.
hopefully this helped :3
Na-23 has 12 neutrons. What is it’s atomic number?
Answer:
11 Protons
Explanation:
Na-23 shows the mass of the element as 23. Therefore subtract 12 neutrons from the mass to get # of protons which is = to atomic #.
The atomic number of 23-Na is 11. It can be calculated from the number of protons present in the nucleus of an atom.
The atomic number is a fundamental property of an element and represents the number of protons found in the nucleus of an atom. It uniquely identifies each element on the periodic table. In a neutral atom, the atomic number also indicates the number of electrons present in the atom, as the number of protons and electrons in an atom are equal.
For example, hydrogen has an atomic number of 1, indicating that it has one proton in its nucleus. Oxygen has an atomic number of 8, indicating that it has eight protons in its nucleus.
The atomic number determines the element's position in the periodic table and provides important information about its properties and behavior.
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Hello, I am stuck on a chemistry question. Would you be able to help? You arrive at a crime scene and are told the body of the victim is at the bottom of a pool that is 10 m deep. You walk over to what you are told is a 12 m in diameter, cylindrical pool. From the outside of the pool, you can see that the body looks badly burnt. Your partner says, “It looks like our victim had been burned alive and tried to put out the fire by jumping in the pool. The victim likely drowned to death.”
Something does not sit right with you though. If there was a fire, where did it start? There are no signs of combustion anywhere. You aren’t so sure and ask the crime scene investigator to run a sample of the pool water before letting anybody try to pull the body out.
The CSI comes back to you and tells you that normal pool water pH is roughly around 7.2, but the pool pH is actually highly basic at a level of 13, with a concentration of hydroxide ions at 1.0 x 10-1 mol/L. It becomes obvious to you that the body wasn’t burned before going in to the pool, but AFTER, and there was no fire needed!
You order the body to be removed from the pool, but the CSI interjects, “It would be too dangerous with a pH that high. I suggest you get some vinegar from the store and pour it in to the pool beforehand to drop the pH to 7. Draining the pool would take far too long and we need to examine the body as soon as possible.” She asks one of your constables to go to the store to purchase five 4L jugs of vinegar (pH = 2) to pour in the pool, as she states it is enough to bring the pH to a safe level of 7.
It sounds like it could be enough vinegar based on your knowledge of acids and bases, but you want to double-check her estimate before sending your constable to the store. Verify whether or not she is correct using calculations. A diagram may help you with your calculations.
Hint 1: 1m3 = 1000L
Hint 2: Vcylinder = πr2h
Answer:
The vinegar is not enough to neutralize the pool.
Explanation:
The [OH⁻] in the pool is 1.0x10⁻¹mol / L. To know how many moles of OH⁻ are in the solution, you must calculate volume of the pool thus:
V(pool) = πr²h
Where r, radius is d/2 = 12m/2 = 6m and h is deep of the pool = 10m
V(pool) = π(6m)²*10
V(pool) = 1131m³
As 1m³ = 1000L:
1131m³ × (1000L / 1m³) = 1131000L in the pool.
And moles of OH⁻ are:
1.0x10⁻¹mol / L ₓ 1131000L = 131100 moles of OH⁻ are in the pool
The neutralization of OH⁻ with H⁺ is:
OH⁻ + H⁺ → H₂O
That means to neutralize the pool you must add 131100 moles of H⁺.
The H⁺ concentration in a vinegar pH = 2 is:
pH = -log [H⁺]
2 = -log [H⁺]
1x10⁻²M = [H⁺]
4L are just 4x10⁻² moles of [H⁺]. As you need 131100 moles of H⁺:
The vinegar is not enough to neutralize the pool.pls help...
You are a forensic scientist working on a murder case. You have taken the blood sample from the crime scene and put it through Electrophoresis and Southern blotting. What step do you need to take next? A. Add ethanol B. Add restriction enzymes C. Add minisatellites D. Add radioactive probes
Add minisatellites. Hence, option C is correct.
What is Electrophoresis?Electrophoresis is a laboratory technique used to separate DNA, RNA or protein molecules based on their size and electrical charge.
You are a forensic scientist working on a murder case. You have taken the blood sample from the crime scene and put it through Electrophoresis and Southern blotting. you need to add minisatellites.
Hence, option C is correct.
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An electron in a hydrogen atom moves from level 1 to level 4. The electron then drops from level 4 to level 2. Which statement describes the most likely result?
A. The energy absorbed in the first move equals the energy released in the second move.
B. The energy absorbed in the first move is greater than the energy released in the second move.
C. The energy released in the first move equals the energy absorbed in the second move.
D. The energy released in the first move is greater than the energy absorbed in the second move.
Answer:
B. The energy absorbed in the first move is greater than the energy released in the second move.
Explanation:
It takes large amounts of energy for a electron to jump energy levels and the further it moves, the more it takes.
Answer:
B
Explanation:
The energy absorbed in the first move is greater than the energy released in the second move.
If the external vapor pressure is 2.0 atm , what is the vapor pressure of the water at its boiling point?
Answer:
22
Explanation:
22
Which of the following increases the average kinetic energy of colliding particles? A. adding a catalyst B. increasing the temperature C. increasing the reactant concentration D. increasing the surface area
The average kinetic energy of colliding particles can be increased by increasing temperature.
B.
Answer:
B
Explanation:
Increasing the Temperature
A proton travels at a speed of 2.0 × 106 meters/second. Its velocity is at right angles with a magnetic field of strength 5.5 × 10-3 tesla. What is the magnitude of the magnetic force on the proton?
So here we are given that the the velocity of the proton ( V ) is 2.0 × [tex]10^6[/tex] meters / second, with a magnetic field of strength 5.5 × [tex]10^{-3}[/tex] tesla. If they each form a right angle, they are hence perpendicular to one another, such that ....
F = q( V × B ),
F = q v B( sin ∅ ),
F = q v B( sin( 90 ) )
.... they form the following formula. Let's go through each of the variables in our formula here -
{ F = Magnetic Force ( which has to be calculated ), q = charge of proton (has charge of 1.602 × [tex]10^{19}[/tex] coulombs ), B = magnetic field }
All we have to do now is plug and chug,
F = ( 1.602 × [tex]10^{19}[/tex] )( 2.0 × [tex]10^6[/tex] )( 5.5 × [tex]10^{-3}[/tex] ) = ( About ) 1.8 × [tex]10^{-15}[/tex] Newtons
Answer: hey there, the answer to your question is (E)
Explanation:
Name the hydro carbon.... I really need your help guyz
Answer:
The given hydrocarbon is Butanol
The mass number of a chromium atom is 52 and it has 24 protons. How many neutrons does this atom have? 24 28 76 80
The number of protons and neutrons together makes the total atomic mass of the element. The atom of chromium has 28 neutrons. Thus, option b is correct.
What is an atomic mass?An atomic mass is the property of an element that defines the number of protons and neutrons of the atom placed in a periodic table. The atomic mass is represented at the lower half of the atomic symbol.
The atomic mass is the sum of the neutrons and the protons that are held together in the nucleus of the atom as a concentrated mass. The atomic number is given as,
Atomic number = number of protons + number of neutrons
Given,
The atomic mass of chromium = 52
Number of protons = 24
Substituting values above:
52 = 24 + number of neutrons
number of neutrons = 52-24
= 28
Therefore, the number of neutrons of a chromium atom is 28.
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Answer: option b, 28
Which of the following is not true of deciduous forests?
a.
characterized by four seasons
b.
trees lose their leaves in the fall.
c.
precipitation is concentrated in one season
d.
averages 30-60 inches of precipitation annually
The Option C is correct precipitation is concentrated in the season
Hope it help
Answer:
C) precipitation is concentrated in one season
Explanation:
edge 2020
hi :) , if the density of an object is the same as water , will the object float or sink?
Answer:
it will float if the object is 1g/cm^3(water 's density ) because it is less dense
Earth’s outermost layer is separated into a dozen or more large and small slabs, called _______. A. continental crust B. tectonic plates C. granite slabs D. Pangea
Answer:
Tectonic Plates
Explanation:
Answer:
Tectonic plates
Explanation:
anne added a sample of hydrochloric acid to water and determined the pH to be 1.79. what is the poH of the solution?
Answer: 12.21
Explanation:
It is well known that the sum of pH + pOH = 14.
To get the pOH of the solution, we subtract 1.79 from 14.
pH + pOH = 14
pOH = 14 - 1.79 = 12.21
pOH = 12.21
The instruction booklet for your pressure cooker indicates that its highest setting is 11.5 psi . You know that standard atmospheric pressure is 14.7 psi, so the booklet must mean 11.5 psi above atmospheric pressure. At what temperature in degrees Celsius will your food cook in this pressure cooker set on "high"
Answer:
16.83°
Explanation:
The computation of temperature in degrees is shown below:
For this we need to applied the combination of the Clasius Clapyeron equation which is
[tex]ln(\frac{P_2}{P_1}) = \frac{-\Delta Hvap}{R} \times (\frac{1}{T_2}- \frac{1}{T_1})[/tex]
Where
P_2 and P_1 represents the pressure of vapor at point 1 and 2
dH = Here we use J/mol
R = 8.314 J/mol K
T1 and T2 represent the temperature of Saturation temperature for point 1 and 2
Now
we have to change the negative signs
i.e
[tex]ln(\frac{P_2}{P_1}) = \frac{\Delta Hvap}{R} \times (\frac{1}{T_1}- \frac{1}{T_2})[/tex]
As we know that
dHvap for water = 40.67 kJ/mol
T1 = 373 K,
T2 = x
P1 = 14.7 psi;
P2 = 11.2 + 14.7 = 25.9 psi
Now put the values to the above formula
So,
[tex]ln (\frac{25.9}{14.7}) = \frac{40670}{8.314} \times (\frac{1}{373}- \frac{1}{T_2})\\\\T_2 = - (ln (\frac{25.9}{14.7})\times \frac{8.314}{40670} - \frac{1}{373})^{-1}[/tex]
After solving this
T_2 = 389.836K
T_2 = 389.836 - 273
T_2 = 116.836 °C
Therefore by 16.83°, it becomes higher
A mix of 0.5236 gr qe contains 42.30% calcium carbonate and 57.70% magnesium carbonate. This sample was treated with hydrochloric acid and the gas produced was collected.
1) what is the gas collected
2) how many grams of gas were produced?
Answer:
1) CO₂
2) 0.2551 g
Explanation:
The balanced reactions are:
CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂
MgCO₃ + 2HCl → MgCl₂ + H₂O + CO₂
1) The gas produced is CO₂.
2) Calculate mass of CaCO₃:
(0.5236 g) (0.4230) = 0.2215 g CaCO₃
Convert to moles:
(0.2215 g CaCO₃) (1 mol / 100.1 g) = 0.002213 mol CaCO₃
Find moles of CaCO₃:
(0.002213 mol CaCO₃) (1 mol CO₂ / mol CaCO₃) = 0.002213 mol CO₂
Convert to mass:
(0.002213 mol CO₂) (44.01 g / mol) = 0.09738 g CO₂
Calculate mass of MgCO₃:
(0.5236 g) (0.5770) = 0.3021 g MgCO₃
Convert to moles:
(0.3021 g MgCO₃) (1 mol / 84.31 g) = 0.003583 mol MgCO₃
Find moles of MgCO₃:
(0.003583 mol MgCO₃) (1 mol CO₂ / mol MgCO₃) = 0.003583 mol CO₂
Convert to mass:
(0.003583 mol CO₂) (44.01 g / mol) = 0.1577 g CO₂
Total mass of CO₂:
0.09738 g CO₂ + 0.1577 g CO₂ = 0.2551 g CO₂
Label the chemical equation.
2 Mg(s) + O2(g) → 2 MgO(s)
Label the chemical equation.
2 Mg(s) + O2(g) → 2 MgO(s)
Answer:
Kindly check Explanation
Explanation:
Given the chemical equation:
2 Mg(s) + O2(g) → 2 MgO(s)
2 molecules of Magnesium + Oxygen gas (Reactant)
→ ( yield)
2 molecules of magnesium oxide (product)
2 in Mg and MgO (coefficients)
2 in Oxygen gas (subscript)
Solid (s) - physical state of Reactant Mg
Gas (g) - physical state of Reactant O2
Solid (s) - physical state of product 2MgO
someone help me please....
Answer:
i- In beaker A, sodium chloride will dissolve with water.
and in beaker B, there will be no reaction.
ii- sodium chloride is soluble in water, while sand is insoluble.
iii- The reaction can be increased by adding more sodium chloride to the beaker.
iv- The sodium chloride will no longer dissolve in the water.
What would 12.47 rounded to 2 sig figs be?
Answer:
12
Explanation:
To get to this answer you have to look at the number first. So the given number is 12.47 and you need 2 sig figs.
To help you understand this more start off by underlining the first 2 numbers because 2 sig figs are needed. 12.47
Now you want to look at the number after the underlined (I bolded that number). 12.47
If the number is above 5 then you would round the previous number up by one but in this case it is 4 so you do not increase the number. Hence, you getting 12 as your final answer.
Hope this helped! Let me know if you have any questions.
What are canal rays ?
Answer:
Channel rays or anode rays are a historical name for positive ion beams, due to their first embodiment. They were indeed observed experimentally for the first time by a German physicist, Eugen Goldstein, in 1886.
Explanation:
formula of sodium bicarbonate
please help me with this
Answer:
NaHCO₃
Explanation:
Sodium bicarbonate (baking soda) is a chemical compound with the formula NaHCO₃.
Which statement accurately describes a light-year
Answer:
B. distance light travels in a year
got it on edge :)
The statement which accurately and best describes a light-year is the total distance which light travels in a complete year
What is velocity of light?Velocity of light can simply be defined as that fundamental constant that represents the speed of electromagnetic radiation in a vacuum.
The velocity of light = 2.9979 × 10^10cm/s
So therefore, the statement which accurately and best describes a light-year is the distance which light travels in a complete year
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