Answer:
CaSO₃·2H₂O
Explanation:
Empirically => CaSO₃·nH₂O
%H₂O = n(H₂O)/f.wt. x 100%
23.1% = n(H₂O)100/Ca + S +3O + nH₂O
23.1 = n(18)·100/[40 + 32 + 3(16) + n(18)]
1800n = 23.1[40 + 32 + 3(16) + n(18)]
1800n = 924 + 739.2 + 1108.8 + 415.8n
1800n - 415.8n = 924 + 739.2 + 1108.8
1385n = 2772
n = 2772/1385 = 2
∴ numerical formula => CaSO₃·2H₂O
For doping silicon with boron, silicon specimen was kept in gaseous atmosphere containing B2O3 that maintained the B concentration at the surface of Si specimen at the level of 3*10^26 boron atoms/m^3. The process was carried out at 1100 degrees C. The diffusion coefficient of B in Si at 1100 degrees C is 4*10^-13 cm^2/s. Calculate the concentration of B at the depth of 10^-4 cm from the surface after 130 minutes of diffusion at 1100 degrees C
Solution :
From Fick's law:
[tex]$\frac{D_{AB}}{\Delta z } \times (C_{A1}-C_{A2})=N_a$[/tex]
Mass balance: Exits = Accumulation
[tex]-N_A A = \frac{dm}{dt}[/tex]
[tex]-N_A A = \frac{dVp}{dt}[/tex]
[tex]-N_A A = \frac{dV}{dt}p[/tex]
[tex]-N_A A = \frac{dhA}{dt}[/tex]
[tex]-N_A A = \frac{dh}{dt} \times Ap[/tex]
From the last step, area cancels out and thus leaves :
[tex]-N_A = \frac{dh}{dt} \times p[/tex]
So now we can substitute the [tex]$N_A$[/tex] by the Fick's law
[tex]$\frac{D_{AB}}{\Delta z } \times (C_{A1}-C_{A2})=\frac{dh}{dt} p$[/tex]
Substituting the values we get
[tex]$=\frac{-4 \times 10^{-13}}{0.0001} \times (3 \times 10^{26} - C_{A2}) = \frac{dh}{dt} \times 2.46$[/tex]
[tex]$=-4 \times 10^{-9} \times( 3 \times 10^{26} - C_{A2}) = 0.0001 \times 2.46$[/tex]
[tex]$= -7800 \times 4 \times 10^{-9} \times (3 \times 10^{26}-C_{A2})=0.000246$[/tex][tex]$=-(3 \times 10^{26}-C_{A2}) = 7.8846 \times 100 \times \frac{1}{69.62} \times 6.022 \times 10^{23}$[/tex]
[tex]$C_{A2} = 6.85 \times 10^{28} \ \text{ boron atoms} /m^3$[/tex]
H* ions increase in concentration at lower pH values.
Calculate how many more H" ions there are in a solution
at a pH =2 than in a solution at a pH =6. Find the
concentration of H* ions at a pH =2 and at a pH=6 in
Table B. Then divide the concentration of Ht ions at a
pH =2 by the of H* ions at a pH = 6. Record your answer
in Table C
the concentration of H* ions at a pH =2 = 10⁻²
the concentration of H* ions at a pH =6 = 10⁻⁶
a solution with a pH of 2 has 10⁴ times more hydrogen ions than a solution with a pH of 6
Further explanationThe concentration of H + ions in solution is measured in pH units. The greater the concentration of H + ions, the more acidic the solution will be, and vice versa if the concentration of H + ions is getting smaller, the more basic the solution and the greater the hydroxide concentration
The ph unit is on a scale between 0-14.
pH> 7, the solution is said to be alkaline
pH <7, the solution is said to be acidic
pH = 7, the solution is said to be neutral
Acidic solutions will have more hydrogen ions than hydroxide ions
A solution with a different value of n has a 10ⁿ difference in the concentration of H⁺ ions.
pH can be formulated:
[tex]\tt \boxed{\bold{pH=-log[H^+]}}[/tex]
the concentration of H* ions at a pH =2[tex]\tt 2=-log[H^+]\\\\(H^+]=10^{-2}[/tex]
the concentration of H* ions at a pH =6[tex]\tt 6=-log[H^+]\\\\(H^+]=10^{-6}[/tex]
pH 2 and pH 6
[tex]\tt \dfrac{10^{-2}}{10^{-6}}=10^4[/tex]
So a solution with a pH of 2 has 10⁴ times more hydrogen ions than a solution with a pH of 6
A reading before and after was taken from a burette, as shown.
What is the reading of the burette on the left, in mL? Do not type in units.
Im having a hard time reading the numbers on the left picture
Answer:
Reading on left looks like 1.4
Explanation:
Calculate the fraction of acetic acid that is in the dissociated form in his solution. Express your answer as a percentage. You will probably find some useful data in the ALEKS Data resource. acetic acid
Answer:
0.11%
Explanation:
Without mincing words, let us dive straight into the solution to the question/problem. The first step to solve this question is to write out the chemical reaction, that is the reaction showing the dissociation of acetic acid.
CH3COOH <=======================================> CH3COO⁻ + H⁺
Initially, the amount present in the acetic acid which is = 12M, the concentration for CH3COO⁻ and H⁺ is 0 respectively.
At equilibrium, the amount present in the acetic acid which is = 12 - x, the concentration for CH3COO⁻ = x and H⁺ = x respectively. Note that the ka for acetic acid = 1.8 × 10⁻⁵.
1.8 × 10⁻⁵ = x²/ 14 - x. Therefore, x = 0.0158 M.
The next thing to do is to calculate for the percentage of dissociation, this can be done as given below:
percentage of dissociation = x/14 × 100. Recall that the value that we got for x = 0.0158 M. Hence, the percentage of dissociation = 0.0158 M/ 14m × 100 = 0.11%
Which statement is FALSE?
A) Reproduction requires a lot of energy!
B) Some organisms choose not to reproduce because it uses too much energy.
C) Some organisms die after giving birth to their offspring. (Offspring means children).
D) Some organisms may fight to the death to mate with a female.
please helpp me i really need help
Answer:
second box is 2 C, third box is 3 C, and the last box is 3 C.
Explanation:
What happens at the cathode in an electrolytic cell?
(Answer is reduction)
Answer:
At the cathode in an electrolytic cell, ions in the surrounding solution are reduced into atoms, which precipitate or plate out on to the solid cathode. The anode is where oxidation takes place, and the cathode is where reduction takes place.
Explanation:
Since positive ions pick up electrons at the negatively charged cathode, reduction takes place there.
What is reduction?The process of obtaining electrons or a decrease in an element's oxidation state in such a chemical reaction would be known as reduction, which is the movement of electrons among species. An increase in the number of electrons connected to a single or a collection of atoms is the result of a reduction chemical process.
What is electrons?The electron would be a subatomic particle with a negative one elementary charge electric charge. Due to their lack of components or substructure, electrons, which are part of the lepton particle family's first generation, have been typically regarded to be elementary particles.
In an electrolytic cell, the cathode is where ions in the neighboring medium could be converted into atoms, which then plate out or precipitated onto the solid cathode. Both oxidation and reduction occur at the anode but also cathode, respectively.
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How many muscle types is the muscular system made up of
Answer:
3
Explanation:
there are three types of muscles:
Skeletal(striated)SmoothCardiacTo standardize a potassium permanganate solution, a 0.250 g sample of FAS (iron (II) ammonium sulfate hexahydrate; molar mass: 342 g) is dissolved in 25.00 mL distilled water, then acidified with sulfuric acid. The solution is then titrated with 35.00 mL potassium permanganate solution from a burette until a pale persistent purple color is attained. Calculate the molarity of the potassium permanganate solution.
Question 7
Anna is rolling a ball down a hill. As the ball rolls, the potential energy is changed to which type of energy?
A chemical energy
B
kinetic energy
С
light energy
D
stored energy
Define wavelength and identify TWO points that could be used in the diagram to measure it.
How does electroplating happen?
A. A thin layer of metal is removed from a cathode.
B. Metal ions form a solid layer on a metal cathode.
C. Metal on a cathode forms ions in solution.
D. Metal ions in solution form a precipitate.
(Answer is B.)
Answer:
B
Explanation:
An electroplating happen when metal ions form a solid layer on a metal cathode. Therefore, option B is correct.
What is an electroplating ?The term electroplating is defined as the process of aligning another metal on the metal. Electroplating is usually used to change the physical properties of an object.
An electroplating is accomplished by an electroplating apparatus that contain a brine solution, a battery, wires, and alligator clips that kept carbon rods attached to the metal to be electroplated and the metal to be layered.
This process is used to give objects increased wear resistance, corrosion protection or aesthetic appeal and greater thickness. While electroplating is like advanced technology. It is primarily used to change the physical properties of an object.
Thus, option B is correct.
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A 0.0795-g sample of magnesium metal reacts with hydrochloric acid to give 88.5 mL of hydrogen gas at 25 degree C and 766 mm Hg.
Required:
a. Calculate the moles of hydrogen gas produced.
b. Calculate the molar volume of hydrogen gas at STP.
c. What are major sources of experimental error?
Answer:
(a). 0.0037 mol.
(b). 22.42 L
(c). => When the measuring apparatus are not precise.
=> Error due to parallax.
=> Random errors.
Explanation:
Without mincing words let us dive straight into the solution to the question above. So, we are given the following parameters or information which are going to aid in solving this particular Question;
Mass of magnesium given= 0.0795 g, volume of Hydrogen = 88.5 mL = 0.0885 L, temperature = 25 degree C = 273 + 25 = 298K and pressure = 766 mm Hg = 766/760 = 1.00789 atm.
(a). In order to determine the number of moles of Hydrogen atoms,we will be making use of the formula below;
Number of moles = (pressure × Volume)/ gas constant,R × Temperature.
Thus,the number of moles of Hydrogen = 1.00789 × 0.0885 / [( 0.08206 × 298] = 0.0037 mol.
(b). The molar volume at stp can be calculated by using the same formula that was used in (a) above;
Molar Volume at stp = Gas constant,R × temperature/ Pressure = 0.08206 × 273 / 1 atm = 22.42 L.
(c). The major sources of errors are given below:
=> When the measuring apparatus are not precise.
=> Error due to parallax.
=> Random errors.
This process transforms_______ energy from the sun into chemical energy in the form of ______ which the plant can use to live and grow.
Answer:
uifhiuwrhuio fw
Explanation:
hfuiwehgu34iht3uht34[pht349348ut0tg
Which of the following produces identical nuclei in cells? A pollination B miltosis C osmosis D fertilization
Answer:
Mitosis.
Explanation:
During mitosis, two nuclei must form, so that one nucleus can be in each of the new cells after the cell divides. In order to create two identical nuclei, the DNA inside of the nucleus must be copied or replicated.
The permeability of packaging materials to CO2 is 6 times higher than the permeability to O2, which is 4 times higher than nitrogen. Despite its bigger molecular weight, carbon dioxide presents a much higher permeability, Why
Answer:
Due higher critical temperature, condensability and gas solubility.
Explanation:
The permeability of packaging materials to CO2 is 6 times higher than the permeability to O2 and nitrogen because carbondioxide gas has higher condensability and higher gas solubility in membranes. Due to its higher condensability and solubility, carbondioxide gas is more permeable that other gases such as oxygen and nitrogen gases. Carbondioxide gas also have higher critical temperature than other gases which make it more permeable than other gases.
How many hydrogen atoms are in 1.50 x 10(22) molecules of water. Show your work.
A. 1.5 H atoms
B. 1.5 x 10(22) H atoms
C. 3 H atoms
D. 3 x 10(22) H atoms
Answer:
option B is a right answer
Explanation:
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Sodium hydrogen carbonate, on heating, produces sodium carbonate, water and carbon dioxide.
A recipe for chocolate chip cookies requires 1.5 dm' of carbon dioxide.
Calculate the mass of sodium hydrogen carbonate that should be used at R.T.P.
INa = 23; H = 1: C = 12; O = 16.]
[Note that 1 mole of gas occupies a volume of 24,000 cm at room temperature and pressure (RTP)]
The mass of sodium hydrogen carbonate : 10.5 g
Further explanationGiven
1.5 dm' of CO₂
1 mol gas= 24 L at RTP(25 °C, 1 atm)
Required
the mass of sodium hydrogen carbonate
Solution
Decomposition reaction of Sodium hydrogen carbonate :
2 NaHCO₃ (s) ⇒ Na₂ CO₃ (s) + H₂ O(g) + CO₂ (g)
mol CO₂ :
[tex]\tt mol=\dfrac{1.5}{24}=0.0625[/tex]
From the equation, mol ratio of NaHCO₃ : CO₂ (g) = 2 : 1, so mol NaHCO₃ :
[tex]\tt 2\times 0.0625=0.125[/tex]
Mass NaHCO₃(MW=23+1+12+3.16=84 g/mol) :
[tex]\tt mass=mol\times MW\\\\mass=0.125\times 84\\\\mass=10.5[/tex]
How many valence electrons does a lithium (Li) atom have? The Periodic Table O A. 1 O B. 7 O C. 2 O D. 3
Select the correct term to complete each sentence.
1. If you ___________ the wavelength, the electromagnetic radiation energy will double.
2. The energy of the electromagnetic radiation will_____________ if you halve the wavenumber.
3. When the frequency of the light is doubled, its energy will___________.
a. halve
b. double
Answer: 1. halve
2. halve
3. double
Explanation:
The relationship between wavelength and energy of the wave follows the equation:
[tex]E=\frac{hc}{\lambda}[/tex]
E= energy
[tex]\lambda [/tex] = wavelength of the wave
h = Planck's constant
c = speed of light
Thus as wavelength and energy have inverse realation, when wavelength will halve , energy will double.
2. The between wavenumber and energy of the wave follows the equation:
[tex]E=h\times c\times \bar{\nu}[/tex]
E= energy
[tex]\bar{\nu}[/tex][tex]\nubar[/tex] = wavenumber of the wave
h = Planck's constant
c = speed of light
Thus as wavenumber and energy have direct relation, when wavenumber will halve , energy will be halved.
3. The relationship between energy and frequency of the wave follows the equation:
[tex]E=h\times \nu[/tex]
where
E = energy
h = Planck's constant
[tex]\nu[/tex] = frequency of the wave
Thus as frequency and energy have direct realation, when frequency will double , energy will double.
This image shows the development of what climate phenomenon?
Answer:
Rain shadow
Explanation:
Climate is the average weather condition of a place over a long period of time.
The image shows a rain shadow effect around a mountainous region. The type of rainfall controlled this way is known as an orographic rainfall.
On the leeward side which is the opposite side of where the rain cloud forms, there is dryness and lack of rainfall. As moist air rises along the edge of the windward side, cloud forms. This windward side receives a significant amount of rainfall The windward side is hit with cold and dry wind and it is barren.Which of the following would increase as you move from the crust to the inner core? (There is only one right answer-- highlight it.) Temperature and pressure Water level and pressure Plant life and temperature Sunlight and temperature
Answer:
Temperature and pressure
Explanation:
As you go down within the earth from the crust to the core, the temperature and pressure levels increases significantly.
The deeper one goes within the earth, the hotter and more pressurized it becomes.
The reason for this is because of the increase in the overburden on the earth surface. As we move from a zone powered by the external heat engine, we launch into a phase dominated by internal processes. The internal processes are driven by the internal heat engine. The space here is confined and heat is not readily lost. Also, the overburden rock above increases the pressure as you go deeper.During photosynthesis, water and carbon dioxide react to form oxygen and glucose.
True
False
Answer:
it's answer is true
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Someone who knows how to do this please help me!!!!!
3
Solve and derive the unit for Power
Answer:
Unit of power is watt
Explanation:
Power = rate of doing work
or
Power, P = W/t
Where
W is work done and t is time
The unit of work done is Joules and that of time is seconds.
Power, P = J/s
We know that, J/s = watts
Hence, the unit of power is watts.
Use the graph to answer these questions. The total energy of the reactants is –3,811.92 kJ. –1,273.02 kJ. –2,538.90 kJ.
Answer:
its -3,811.92 aka.) A
Explanation:
The overall enthalpy of the reaction is represented in the graph by the letter A. The activation energy is represented by the letter B and the activated complex is represented by C.
What is an energy diagram of a reaction ?The energy diagram of a reaction represents the energy change with respect to the rate of the reaction. It clearly depicts the energy profile of reactants and products, transition state of the reaction, activation energy and the overall enthalpy of the reaction.
The given diagram represents the energy profile for the photosynthetic reaction. The state with the highest activation energy is called transition state of the reaction. The minimum energy that must be acquired by the reactants to overcome the barrier potential is called activation energy.
For the given graph, the activation energy is represented by the letter B. The overall enthalpy of the reaction is represented in the graph by the letter A and the activated complex is represented by C.
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Your question is incomplete. But your complete question probably was:
Letter__shows the overall enthalpy of reaction.
Letter___shows the activation energy for the reaction
The activated complex is represented by
NOT A TEST AND I WILL GIVE BRAINLEIST DON'T ANSWER IF YOU DON'T KNOW
Which particles are in the nucleus of an atom? What are their charges?
Which particles orbit the outside of the atom? What is their charge?
Answer:
In the nucleus of an atom ,there are protons & neutrons. Protons have charge of 1.6× 10^-19 C, while neutrons have 0C charges. Electrons orbit outside the atom. Their charge is - 1.6 ×10^-19C
Explanation:
Daniella found an iron metal cube. The volume of the cube is 20 cm3 as shown below.
non
20.0 cm
If the density of iron is 7.9 g/cm3, what is the mass in grams of this iron cube?
A) 0.395 g
B) 2.53 g
C) 27.99
D) 158 g
Answer:b) 2.53
Explanation:
Which of the following forces always exists between any two objects having mass?
Elastic force
Contact force
Gravitational force
Magnetic force
Answer:
C . Gravitational force
Explanation:
Answer:
Gravitational force
Explanation:
Gravitational force is commonly known as gravity or gravitation, which is a force that exists between all the objects present in this universe. For any two objects or particles having non-zero mass, a force of gravity exists between the which tends to attract them towards each other.
Fill in the coefficients that will balance the following reaction: (Note: Use 1 as coefficient where appropriate.) NaCl + CaS → Na2S + CaCl2
Answer:
2NaCl + 1CaS → 1Na2S + 1CaCl2
Explanation:
The reaction in the question is a double-replacement reaction. The general formula is:
BX + CY → CX + BY
Where the cations of two salts exchange anions to produce 2 news products.
To balance the reaction:
NaCl + CaS → Na2S + CaCl2
We can balance as first the Na:
In reactants there is just 1 Na in NaCl but in products there are 2.
To balance Na:
2NaCl + CaS → Na2S + CaCl2
Now, there are 2 Na in reactants and products
There are 2 Cl in reactants and products
There is 1 Ca in both sides
And 1 S in both sides.
The balanced reaction is:
2NaCl + 1CaS → 1Na2S + 1CaCl2
Answer:
the answer is
2,1,1,1
Explanation:
Hope this helped!