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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an expression of Avogradros law
Answer:
The formula for Avagadro's law is V1/n1 = V2/n2, where V = volume and n = amount of gas (in moles).
Explanation:
an alloy composed of tin, lead, and cadmium is analyzed. the mole ratio of sn:pb is 2.73:1.00, and the mass ratio of pb:cd is 1.78:1.00. what is the mass percent composition of pb in the alloy
This problem is describe the mole-ratio composition of an allow composed by tin, lead and cadmium. Ratios are given as Sn:Pb 2.73:1.00 and Pb:Cd is 1.78:1.00, and we are asked to calculate the mass percent compositon of Pb in the allow.
In this case, according to the given information, it turns out possible realize that the following number of moles are present in the alloy, according to the aforementioned ratios:
[tex]2.73mol Sn\\\\1.00molPb\\\\\frac{1.00molPb*1.00molCd}{1.78molPb}= 0.562molCd[/tex]
Next, we calculate the masses by using each metal's atomic mass:
[tex]m_{Sn}=2.73mol*\frac{118.7g}{1mol}=324.05g\\\\ m_{Pb}=1.00mol*\frac{207.2g}{1mol}=207.2g\\\\m_{Cd}=0.562mol*\frac{112.4g}{1mol}=63.2g[/tex]
Thus, the mass percent composition of each metal is shown below:
[tex]\%Sn=\frac{324.05g}{324.05g+207.2g+63.2g} *100\%=54.5\%\\\\\%Pb=\frac{207.2g}{324.05g+207.2g+63.2g} *100\%=34.9\%\\\\\%Cd=\frac{63.2}{324.05g+207.2g+63.2g} *100\%=10.6\%[/tex]
So that of lead is 34.9 %.
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Hot air balloons are open at their lower and end. A basket is suspended from the balloon and can take several passengers as well as the pilot. A propane burner fixed to the basket is used to heat up the air in the balloon A hot balloon has a volume of 1500 m3 and its volume does not change when the enclosed air is heated.
1) Use the ideal gas equation, pV=nRT. to calculate how many molecules of the balloon contains at a temperature of 10 °C and a pressure 10.1 KP.
2) Calculate the mass of air it contains, assuming an average M of 29.
(a) The number of molecules contained by the balloon at the given condition is 6,438.97 moles.
(b) The mass of air in the balloon is 186.73 kg.
The given parameters;
volume of the balloon, V = 1500 m³temperature, T = 10⁰C = 273 + 10 = 283 Kpressure, = P = 10.1 kPa = 10,100 PaThe number of molecules contained by the balloon at the given condition is calculated as follows;
[tex]PV = nRT[/tex]
where;
R is ideal gas constant = 8.314 J/mol.Kn is the number of moles air in the balloon;[tex]n = \frac{PV}{RT} \\\\n = \frac{10,100 \times 1500}{8.314 \times 283} \\\\n = 6,438.97 \ moles[/tex]
The mass of air in the balloon is calculated as;
[tex]n = \frac{m}{M} \\\\m = nM\\\\m = 6,438.97\ moles \ \times \ 29 \ g/mol\\\\m = 186.73 \ kg[/tex]
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When two volumes of hydrogen gas react with one volume of oxygen gas, two
volumes of gaseous water are formed. Modify the diagram you made for #2 to
represent molecules of hydrogen, oxygen and water in this reaction
The box shows the chemical formula for bleach.
22. Which of the following molecules or ions contain polar bonds?
(a) O3
(b) S8
(c) 02 2-
(d) NO3
(e) CO2
(f) H2S
(g) BH4-
Answer:
D NO3 Nitrate is a nitrogen oxoanion formed by loss of a proton from nitric acid.
1 year = 365 days
1 day = 24 hours
How many years is 1,000,000 hours?
Has to be dimensional analysis
A mixture of methanol and water was distilled using both simple distillation and fractional distillation. Which statement is NOT true
With regard to distilling the mixture of methanol and water using simple
distillation and fractional distillation, a statement that can be made that is
not true is that; Methanol and water form an azeotrope.
Reasons:
Azeotrope are liquid mixtures that have the property of a constant boiling
point due to the contents of the vapor are the same as the mixture.
Water when mixed with methanol form network structures. However,
methanol does not form a binary azeotrope with water.
Therefore, a statement that is not true is that methanol and water form an
azeotrope a mixture that has a constant boiling temperature.
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40.0 g of ice cubes at 0.0°C are combined with 150. g of liquid water at 20.0°C in a coffee cup calorimeter. Calculate the final temperature reached, assuming no heat loss or gain from the surroundings. (Data: specific heat capacity of H2O(l), c = 4.18 J/g×°C; H2O(s) => H2O(l) DH = 6.02 kJ/mol)Calculate the final temperature reached, assuming no heat loss or gain from the surroundings. (Data: specific heat capacity of H2O(l), c = 4.18 J/g×°C; H2O(s) => H2O(l) DH = 6.02 kJ/mol)
The final temperature of the mixture in the coffee cup calorimeter is; 19.467 °C
According to the law of energy conservation:
As such; the heat transfer in the liquid water is equal to heat gained by the ice
Heat transfer by liquid water is therefore;
DH = m × c × DTDH = 6.02 kJ/mol) = 150 × 4.18 × (T1 - T2)6020 J/mol = 627 × (20 - T2)However, since 18g of water makes one mole
6020 J/mol = 6020/18 = 334.44 J/g.334.44 = 627 × (20 - T2)0.533 = (20 - T2)T2 = 20 - 0.533T2 = 19.467°C
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4. Use the atomic model to answer the following questions
A. How many protons?
B. How many neutrons?
C. What is the name of this atom?
Answer:
´protons: 16
neutrons: 16
name: sulfur
Explanation:
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
Hello, is there anyone here a pharmacy technician?
Explanation:
It can take up to two years to become a pharmacy technician, depending on the education program you choose. In fact, most pharmacy certification programs can be in a year, or less than eight months.
how many moles are there in 3.25x10^20 particles of lead oxide
Answer:
5.39 X 10-4
Explanation:
Try Checking It Out If It Right Or Not
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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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
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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if 2.4l of chlorine at 400 mm hg are compressed to 725 mm hg at a constant temperature. what is the new volume?
Answer: 1.324L
Explanation: use Boyles law, sorry so late!
Determine the molarity for each of the following Solution: 98.0 of phosphoric acids H3PO4 in 1.00L of Solution.
The molarity of the solution is 0.01.
Brainliest?
how is waste removed from the body
Waste is removed from the body in various ways. Kidneys filter out metabolic waste, excess fluid and eliminate it in the form of urine. Lungs exhale CO2 from the deoxygenated blood. The undigested solid waste is egested out from the large intestine. Excretion is the process of removing wastes and excess water from the body. It is one of the major ways the body maintains homeostasis. Organs of excretion make up the excretory system. They include the kidneys, large intestine, liver, skin, and lungs.
Atomic mass is an average of the elements_____.
Specific chemical element
Answer:
The atomic mass of an element is the average mass of the atoms of an element measured in atomic mass unit (amu, also known as daltons, D). The atomic mass is a weighted average of all of the isotopes of that element, in which the mass of each isotope is multiplied by the abundance of that particular isotope.
Explanation:
Write the balanced molecular chemical equation for the reaction in aqueous solution for ammonium sulfate and iron(II) chloride. If no reaction occurs, simply write only NR. ☐⁴⁻ ☐³⁻ ☐²⁻ ☐⁻ ☐⁺ ☐²⁺ ☐³⁺ ☐⁴⁺ 1 2 3 4 5 6 7 8 9 0 ☐₁ ☐₂ ☐₃ ☐₄ ☐₅ ☐₆ ☐₇ ☐₈ ☐₉ ☐₀ + ( ) → ⇌ (s) (l) (g) (aq) Ir N Fe O Am Cl NR S H Ch Reset
The balanced molecular chemical equation for the reaction is (NH4)2SO4(aq) + FeCl2(aq) -------> FeSO4(aq) + 2NH4Cl(aq).
The rule for writing a balanced chemical reaction equation is that the number of atom of each element on the right hand side must be the same as the number of atoms of the same element on the left hand side of the reaction equation. This is achieved by performing an atom count.
The balanced molecular chemical equation for the reaction in aqueous solution for ammonium sulfate and iron(II) chloride is;
(NH4)2SO4(aq) + FeCl2(aq) -------> FeSO4(aq) + 2NH4Cl(aq)
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Thin-layer chromatography explain ?????
Answer:
Explanation:
Thin-layer chromatography (TLC) is a chromatography technique used to separate non-volatile mixtures. ... After the sample has been applied on the plate, a solvent or solvent mixture (known as the mobile phase) is drawn up the plate via capillary action.
Electromagnetic waves travel fastest through
A -Solid
B -Liquid
C -Gas
D-Vacuum
Answer:
Gas
Explanation:
Mechanical waves- travel faster in solids & slowest in gases
Electromagnetic waves- travel fastest in empty space and slowest in solids.
Because they are so close, than can collide very quickly, i.e. it takes less time for a molecule of the solid to 'bump' into its neighborough. Solids are packed together tighter than liquids and gases, hence sound travels fastest in solids. The distances in liquids are shorter than in gases, but longer than in solids.
Answer C- Gas
Explanation:
Electromagnetic waves- travel fastest in empty space and slowest in solids.
Find the mass of 1.220 moles of PH5.
Answer:
43.93642
Explanation:
Phosphorus P 30.973762 1 86.0061
Hydrogen H 1.00794 5 13.9939
I don't know physics, but I hope this helps :)
(I'm a seventh grader so don't judge if this is wrong please)
6. What is the molarity of 175 mL of solution containing 2.18 grams of NazS04-10H2O?
Answer:
[tex]Molarity\,\,of\,\,the\,\,solution\,\,is\,\,S=0.039M[/tex]
Explanation:
[tex]W=2.18 g\\M=322g\\V=175mL=0.175L\\\\S=\frac{W}{MV} \\=>S=\frac{2.18}{322*0.175} \\So,S=0.039M[/tex]
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ask me if you have any confusion.....
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what is the common name of hydrated calcium sulphate?
Answer:
Gypsum
Explanation:
Calcium sulphate, is a naturally occurring calcium salt. It is commonly known in its dihydrate form, a white or colourless powder called gypsum.
The group of elements that make up the smallest percentage of the periodic table are the
Answer:
Explanation:wwwwwwwwwwwwwwwwwwww
why does a Costal area have less variation in temperature
Answer:
*The coastal areas experience less variation in temperature as compared to land. ... It means that water takes more time to get hot or cold then land. Therefore areas near sea or ocean have more moderate temperature in the day time and less cooler at night
Explanation:
How to find distance from motion graph velocity - time?
Answer:
by finding the slope of tangent (y2 - y1)/(x2 - x1)
HELP!! what are the usual products of combustion reactions?
Explanation:
Carbon dioxide and water
I hope it helps
Answer:
The usual products of combustion reactions are carbon dioxide and water.
Explanation:
Combustion reaction is when a substance reacts with oxygen gas, resulting in a release of energy in the form of light and heat. Combustion reactions must have oxygen (O2) as one of the reactants.
