Answer
A. -1305 kJ
Explanation
Given:
Equation: C2H4(g) + 302(g) ---- > 2C02(g) + 2H20(l).
Formation ΔH values:
for C2H4(g) = 52.30 kJ/mol,
for 02(g) = 0 kJ/mol,
for CO2(g) = -393.5 kJ/mol, and
for H20(1) = -285.8kJ/mol.
What to find:
The ΔHrxn from the ΔH of formation for the given reaction.
Step-by-step solution:
ΔHrxn = (Sum of ΔH formation for the product) - (Sum of ΔH formation for the reactants).
ΔHrxn = (ΔH for 2CO2(g) + ΔH for 2H2O(l)) + (ΔH for C2H4(g) + ΔH for 3O2(g))
ΔHrxn = [(2 x -393.5) + (2 x -285.8)] + [52.30 + (3 x 0)]
ΔHrxn =(-787.0 - 571.6) + (52.30 + 0)
ΔHrxn = -1358.6 + 52.30
ΔHrxn = -1306.3 kJ
so the closest answer is A. -1305 kJ
Predict the products for each of the following reactions. Write the molecular equation, the complete ionic equation, and the net ionic equation. Classify the reactions in as many ways as you can.
Aqueous sulfuric acid is added to aqueous potassium hydroxide.
The molecular equation of the reaction of sulfuric acid and aqueous potassium hydroxide:
H₂SO₄ (aq) + 2 KOH (aq) → K₂SO₄ (aq) + 2H₂O (l)
The net ionic equation is:
2H⁺ (aq) + 2OH⁻ (aq) [tex]\longrightarrow[/tex] 2H₂O (l)
What are the net ionic equations?The net ionic equation of a reaction can be described as an equation that expresses only those elements, compounds, or ions that directly contributed in that chemical reaction.
The balanced chemical equation reaction of sulfuric acid and aqueous potassium hydroxide:
H₂SO₄ (aq) + 2 KOH (aq) → K₂SO₄ (aq) + 2H₂O (l)
The complete ionic equation for the above reaction can be written as follows:
2H⁺ (aq) + SO²₄⁻ (aq) + 2K⁺(aq) + 2OH⁻ → 2K⁺ (aq) + SO₄²⁻ (aq) + 2H₂O (l)
In the ionic equation, the potassium and sulfate ions appear unchanged on both sides of the equation. When we mix the two solutions, the potassium and sulfate ions do not participate in the reaction. So potassium and sulfate ions can be eliminated from the ionic equation.
2H⁺ (aq) + 2OH⁻ (aq) [tex]\longrightarrow[/tex] 2H₂O (l)
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If 21.5 g of LiCl are dissolved 450.0 g of water at 20.0 °C in an insulated container, a temperature change is observed. The ∆H of solution of LiCl is -37.0 kJ/mol. Assuming that the specific heat of the solution is 4.184 J/(g°C), and that no heat is gained or lost by the container, what will be the final temperature of the solution?
The final temperature of the solution will be 29.5 °C.
What is the heat released when 21.5 g of LiCl is dissolved completely in water?The heat released when 21.5 g of LiCl is dissolved completely in water is determined from the enthalpy change, ∆H of the solution of LiCl as follows;
Moles of LiCl in 21.5 g = mass/ molar mass
molar mas of LiCl = 42.5 g/mol
Moles of LiCl in 21.5 g = 21.5/42.5
Moles of LiCl in 21.5 g = 0.506 moles
Heat released = 0.506 * -37.0 kJ/mol
Heat released = 18.722 kJ or 18722 J
Heat released = heat gained by solution
Temperature change of the solution = heat gained / mass * specific heat capacitymass of solution = 450 + 21.5
mass of solution = 471.5 g
Temperature change of the solution = 18722 / (471.5 * 4.184)
Temperature change of the solution = 9.5 °C
Final temperature of the solution = 20 °C + 9.5 °C
Final temperature of the solution =29.5 °C
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Patricia wants to examine the morphology of a hair sample. What is the BEST way for her to accomplish this task?
A.
Send the sample away to a lab for DNA testing.
B.
Observe the sample under a high-powered microscope.
C.
Add a solution to the hair to see if it reacts.
D.
Use a Hemastix strip to perform A-B-O testing.
The best way for her to accomplish the task of evaluating a hair strip is DNA testing. Hence, option A is correct.
What is DNA testing?The DNA testing in forensic laboratories include extract the DNA strands from the sample and strictly evaluate it some reagents and color indicators.
Hair analysis involves examining the DNA of cells linked to the hair's root as well as the hair's structure. It can be used to determine a person's family relationship. It is possible to use forensic hair analysis to identify a person who may have been at a crime scene. Hair samples are examined under a microscope and evaluated using particular chemicals.
Additionally, metal poisoning from lead or mercury can be detected through hair analysis. However, this form of testing often does not involve hair analysis alone.
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How many joules of heat are needed to raise the temperature of 100 g of iron from 23°C to 33°C, if the specific heat of iron is 0.45 J/g°C
Joules of heat are needed to raise the temperature of 100 g of iron from 23°C to 33°C, if the specific heat of iron is 0.45 J/g°C is 450 J.
Given that :
The specific heat capacity expression is given as :
Q = m cΔT
Q = heat energy
m = mass = 100 g
c = specific heat = 0.45 J/g °C
ΔT = change in temperature = 33 °C - 23 °C = 10 °C
substituting the values in the formula:
Q = m cΔT
Q = 100 g × 0.45 J/g °C × 10 °C
Q = 450 J
Thus, Joules of heat are needed to raise the temperature of 100 g of iron from 23°C to 33°C, if the specific heat of iron is 0.45 J/g°C is 450 J.
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There are 4 moles of methane burned to produce how many moles of water? CH4+2O2=CO2+2H2O
ANSWER
8 moles of water
EXPLANATION
The major products formed when an organic compound undergo combustion reaction are water and carbon dioxide
Below is the combustion formula
[tex]\text{ C}_xH_y\text{ + x + }\frac{y}{4}O_2\text{ }\rightarrow\text{ xCO}_2\text{ + }\frac{y}{2}H_2O[/tex]In the question above, 4 moles of methane reacts with oxygen
[tex]\begin{gathered} \text{ 4CH}_4\text{ + 4+}\frac{16}{4}O_2\text{ }\rightarrow\text{ 4CO}_2\text{ + }\frac{16}{2}H_2O \\ \\ \text{ 4CH}_{4(g)}\text{ + 8O}_{2(g)}\text{ }\rightarrow\text{ 4CO}_{2(g)}\text{ + 8H}_2O(l) \end{gathered}[/tex]Therefore, 4 moles of methane will give 8 moles of water
A solution is made by dissolving4.87 g of potassium nitrate in waterto a final volume of 86.4 mL solution.What is the weight/weight % orpercent by mass of the solute?Use 1.00 g/mL for the density of the solution.Enter text here
Answer
The weight/weight % of solute = 5.3%
Explanation
Given
Mass of solute (potassium nitrate) = 4.87 g
Volume of solvent (water) = 86.4 mL
Density of water = 1.00 g/mL
Required: Weight/weight% of the solute
Solution
Step 1: Covert the volume of water to mass
mass = density x volume
mass = 1.00 g/mL x 86.4 mL
mass = 86.4 g
Step 2: Calculate the weight/weight % of the solute
Mass % solute = [mass of solute/(mass of solute + mass of solvent)] x 100
Mass % solute = 4.87g/(4.87 + 86.4)
Mass % solute = 5.3%
What is the hydrogen ion and hydroxide ion concentration for a pH of 4.478? Is the solution acid or base?
Answer
The hydrogen ion concentration, [H⁺] is 3.327 x 10⁻⁵ M
The hydroxide ion concentration [OH⁻] is 3.01 x 10⁻¹⁰ M
The solution is acid.
Explanation
pH is a measure of how acidic or basic a solution is. The range goes from 0 - 14, with 7 being neutral. A pH of less than 7 indicates acidity, whereas a pH of greater than 7 indicates a base. pH is really a measure of the relative amount of free hydrogen and hydroxyl ions in the solution.
Since pH of the solution is 4.478, then it means the solution is acid.
The hydrogen ion concentration, [H⁺] of the solution can be calculated using the pH formula.
[tex]pH=-log[H^+][/tex]Substituting pH as 4.478 into the formula, we have
[tex]\begin{gathered} 4.478=-log[H^+] \\ \\ Multiply\text{ }through\text{ }by\text{ }minus\text{ }(-) \\ \\ log[H^+]=-4.478 \\ \\ .[H^+]=10^{-4.478} \\ \\ .[H^+]=3.327\times10^{-5}\text{ }M \end{gathered}[/tex]The hydrogen ion concentration, [H⁺] is 3.327 x 10⁻⁵ M
The relation between the hydrogen ion concentration, [H⁺] and hydroxide ion concentration [OH⁻] is
[tex].[H^+]\times[OH^-]=10^{-14}[/tex]So, substituting [H⁺] as 3.327 x 10⁻⁵ M, we have:
[tex]\begin{gathered} 3.327\times10^{-5}\times[OH^-]=10^{-14} \\ \\ Divide\text{ }both\text{ }sides\text{ }by\text{ }3.327\times10^{-5} \\ \\ \frac{3.327\times10^{-5}\times\times[OH^-]}{3.327\times10^{-5}}=\frac{10^{-14}}{3.327\times10^{-5}} \\ \\ .[OH^-]=3.01\times10^{-10}\text{ }M \end{gathered}[/tex]Hence, the hydroxide ion concentration [OH⁻] is 3.01 x 10⁻¹⁰ M
If an element has a mass of 56 amu, and it has 26 protons, how many neutrons are present? How many electrons?
Answer:
1. 30 neutrons
2. 26 electrons
Explanation:
The number of neutron = mass - #protons = 56 - 26 = 30
The number of electrons = #protons = 26
Calculate the total energy 2.3 * 10^11 photons of gamma radiation having a wavelength of 3.9 * 10^-12 m
According to the Planck's equation,the total energy of 2.3×10¹¹ photons of gamma radiation is 11.7208×10[tex]^-3[/tex] J.
What is Planck's equation?Max Planck discovered the theory which stated that energy is transferred in the form of discrete packs which are called quanta and thus proposed an equation called the Planck's equation which relates energy and frequency of a photon and is given as, E=hcυ or in terms of wavelength it is ,E=hc/λ.
The equation makes use of a constant which is called the Planck's constant and it's value is 6.626×10[tex]^-34[/tex] Js.
In the given problem, the energy is calculated as, E=6.626×10[tex]^-34[/tex]×3×10⁸/3.9×10[tex]^-12[/tex]=5.096×10[tex]^-14[/tex] J.
Thus,for 2.3×10¹¹ photons it is 5.096×10[tex]^-14[/tex] ×2.3×10¹¹ =11.7208×10[tex]^-3[/tex] J.
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Name the following compoundCH3-CH-CH2-CH3 | Br
2 brome butane
it has 4 C atoms therefor we know it is a butan-- and the brome is placed in the second carbone so that gives the answer 2 brome butane
What wavelength (in nm) of light is emitted when an electron transitions from the n
= 8 to the n = 2 state?
The wavelength in nm of light emitted when an electron transitions from n = 8 to n = 2 state is 38900nm.
It is given that the electron transition took place from n = 8 to n = 2. To find the wavelength, the following formula is to be used:
1/λ = R(1/n²₁ - 1/n²₂)
Here, n₁ = 2 n₂ = 8 and R = 109677. Therefore,
1/λ = 109677(1/2² - 1/8²)
1/λ = 109677(1/4 - 1/64)
1/λ = 109677((16-1)/64)
1/λ = 109677((15)/64)
1/λ = 0.234375 x 109677
1/λ = 25,705.5469
λ = 1/25,705.5469
λ = 3.89 x 10⁻⁵cm
λ = 38900 x 10⁻⁹m
λ = 38900nm
Therefore, the wavelength in nm from n=8 to n=2 transition is 38900nm
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Virginia has 11 people in the House and 2 in the Senate. How many electoral votes does it have? ________________ Where is this addressed?
The total number of electoral votes does Virginia have is 13. This addressed in congressional apportionment.
When people cast their vote, means they actually voting for the group of people called electors. Senator and representatives are equal to the number of voters in each state . According to the question , Virginia has 11 people in the house and 2 senate means 11 + 2 = 13 . the total number of electoral votes are 13. These votes are assigned by united states electoral college. In the constitution the congressional apportionment is addressed.
Thus, Virginia has 11 people in the House and 2 in the Senate. The total number of electoral votes does Virginia have is 13. This addressed in congressional apportionment.
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Based on the thermodynamic properties provided for water, determine the energy change when the temperature of 0.950 kg of water decreased from 103 °C to 60.5 °C.
Property Value Units
Melting point 0 °C
Boiling point 100.0 °C
ΔHfus 6.01 kJ/mol
ΔHvap 40.67 kJ/mol
cp (s) 37.1 J/mol · °C
cp (l) 75.3 J/mol · °C
cp (g) 33.6 J/mol · °C
The energy change when the temperature of 0.950 kg of water decreased from 103 °C to 60.5 °C is 2308.87 kJ.
What is the heat energy change when the temperature of 0.950 kg of water decreased from 103 °C to 60.5 °C?The heat energy change when the temperature of 0.950 kg of water decreased from 103 °C to 60.5 °C is determined from the formulas below:
Heat change 1 = Heat capacity as gas * moles * temperature change
Heat change 2 = Heat of vaporization, ΔHvap * moles
Heat change 3 = Heat capacity as liquid, Cp (l) * moles * temperature change
moles of water = 950 kg * 1000 g/kg * 1 mol/ 18g = 52.78 mole
Heat change 1 = 33.6 * 52.78 * (103 - 100) = 5320.224 J
Heat change 2 = 40.67 * 1000 * 52.78 = 2146562.6 J
Heat change 3 = 75.3 * 52.78 * (100 - 60.5) = 156986.193 J
Total heat change = 5320.224 J + 2146562.6 J + 156986.193 J
Total heat change = 2308869.017 J = 2308.87 kJ
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5
Select the correct answer from each drop-down menu.
Complete the following statements to describe solids, liquids, and gases. Select the correct answer from each drop-down
A solid
A liquid
Agas
a definite volume and
a definite volume and
V a definite volume and
a definite shape.
a definite shape.
a definite shape.
Reset
Next
A solid has an identifiable shape and volume. A liquid has a fixed volume and an ill-defined shape. A gas has an undefined shape and a fixed volume.
Which statement regarding solids, liquids, and gases is accurate?A solid is something that has a specific shape and volume. The definition of a liquid is something that has a fixed volume but no fixed shape. A gas is described as something that has neither a fixed shape nor a fixed volume.
What are the solid, liquid, and gas elements' four characteristics?A solid has a distinct volume and shape, a liquid has a distinct volume but no distinct shape, and a gas lacks both.
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How many atoms are in 275 grams of iron (III) hydroxide. Include units and name of atom/molecule.
To calculate the number of atoms of any compound it is necessary to use the Avogadro constant. This is a constant of proportion between the amount of matter and the number of entities that are linked to that amount. These entities can be atoms, molecules, ions, electrons, protons, neutrons. The value of the Avogrado constant is 6.022 x 10^23 mol^-1.
So to calculate the number of atoms in 275 grams of iron (III) hydroxide:
- First you need to transform grams into moles
- transform moles into atoms/molecule using Avogrado constant.
- To transform 275 grams of Fe(OH)₃ you need to use the molecular mass of Fe(OH)₃ and the following equation: mole = mass/molar mass
Molecular mass of Fe(OH)₃:
Fe - 55.85
O - 16
H - 1
(1x55.85) + (3x16) + (3x1) = 106.86 g/mol
Replace the value in the equation:
mole = 250/106.86
mole = 2.34 mole of Fe(OH)₃
- Now, let's solve the number of molecules of Fe(OH)₃ into 2.34 mole of Fe(OH)₃:
6.022 x 10^23 molecule --- 1 mol
x molecule ---- 2.34 mole
x = 1.41 x 10^24 molecules of Fe(OH)₃
Answer: There are 1.41 x 10^24 molecules of Fe(OH)₃
What kind of intermolecular forces act between a chloramine (NH₂CI) molecule and an oxide (0²-) anion?Note: If there is more than one type of intermolecular force that acts, be sure to list them all, with a comma between thename of each force.
Answer
Hydrogen bonding, dipole-dipole interaction, and dispersion forces.
Explanation
The chloramine (NH₂CI) molecule has N-H bonds, so there will be hydrogen bonding. Also, NH₂Cl is a polar molecule, so there will be dipole-dipole interaction. And as with molecules like O²⁻, there will be dispersion forces.
Therefore, the kind of intermolecular forces that act between a chloramine (NH₂CI) molecule and an oxide (O²⁻) anion are hydrogen bonding, dipole-dipole interaction, and dispersion forces.
What are two ways we can calculate volume described them in depth and why would you use one method over another explain
The volume can be measured by the displacement method and by the use of dimensions.
What is volume?The term volume has to do with the space that is occupied by a substance. Thus we know that a solid has a definite volume and a definite shape while a liquid has a definite volume but does not have a definite shape. On the other hand, the gases does not have a definite shape or a definite volume.
In this case, we are staying with the volume of a solid object because this is what have been implied by the question that we have before us here.
There are two ways that we can use to obtain the volume of an object and these two methods are;
1) By calculation: In this method, the dimensions of the object is measured and the volume of the object can be obtained from the dimensions of the object.
2) By displacement method: This involves a situation, in which a give volume of water is measured and then the object is added and the volume of the water that is displaced is measured and then taken as the volume of the object.
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What is one way an atom can become more stable?
Unstable atoms usually are very large atoms with a big nucleus, this configuration sometimes gives the atoms this unstable characteristic, which is why they decay so fast (some will decay in a matter of milliseconds), and radioactive decay is a way that atoms can find to become more stable, in this type of process, particles (alpha and beta decay) and energy (gamma decay), can be emitted from an atom in order to reach stability, therefore the best option is the 3rd option
An experiment begins
with 87.5g of
potassium and 13.2g of
chlorine. What is the
experiment mass of
the product?
The experiment mass of the product is 28.1g
What is mass ?
Mass is a physical body's total amount of matter. It also serves as a gauge for the body's inertia, or resistance to acceleration (change in velocity) in the presence of a net force. The strength of an object's gravitational pull to other bodies is also influenced by its mass.
The kilogramme is the primary mass unit in the SI (kg). Although weight is frequently measured using a spring scale rather than a balancing scale and compared directly with known masses, mass is not the same as weight in physics.
2K + Cl2 =====> 2KCl
70g Cl2 produces 2(39+35.5) = 149 g KCl
13.2g Cl2 produces 28.1g KCl
the experiment mass of the product is 28.1g
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A -13.68 gram of sample of iron is heated in the presence of excess fluorine. A metal Fluoride is formed with a mass of 27.64g. Determine the empirical formula of the metal fluoride.
Explanation:
A 13.68 g sample of iron is reacted in presence of excess fluorine and an iron fluoride with a mass of 27.64 g is formed.
We have to find the empirical formula of our compound. This compound has two elements: Fe and F. We can express it like:
metal fluoride = FeₐFₓ
Where a is the subscript of Fe and x is the subscript for F.
First we have to find the mass of F present in the compound. We know that our compound has a total mass of 27.64 g and the mass of Fe present is 13.68 g. Since it only has two elements we can find the mass of F.
mass of sample = mass of Fe + mass of F
mass of F = mass of sample - mass of Fe
mass of F = 27.64 g - 13.68 g
mass of F = 13.96 g
So we found that our sample has 13.96 g of F and 13.68 g of Fe. Now we can determine the number of moles of each element that are present in the sample by using their molar masses.
molar mass of Fe = 55.85 g/mol
molar mass of F = 19.00 g/mol
moles of Fe = 13.68 g * 1 mol/(55.85 g)
moles of Fe = 0.245 moles
moles of F = 13.96 g * 1 mol/(19 g/mol)
moles of F = 0.735 moles
By definition the empirical formula is "simplest whole number ratio of atoms present in a compound". So if we want to find the ratio between them we have to divide both of them by the smallest number.
a = subscript of Fe = 0.245/0.245 = 1
x = subscript of F = 0.735/0.245 = 3
So the empirical formula of our compound is:
empirical formula = FeₐFₓ
empirical formula = FeF₃
Answer: empirical formula = FeF₃
an avocado can be a simple model of the structure of a cell.
which cell structure is represented by the avocado's skin.
The body of avocado fruit can be compared with the cell structure. The skin of the avocado is relatable with the cell membrane. Thus option B is correct.
What is cell?Cell is the basic unit of life. Cells connect together to forms tissues and tissues forms organs and a group organs forms an organ system. These different organ systems buildup the whole body.
Cell contains the core called nucleus. Inside the nucleus genetic material DNA, ribosomes, Golgi apparatus, lysosomes etc are located. The function of cell membrane is to protect the cell from damages as the skin do for our body.
In plants unlike animals, their cell is protected by a cell wall apart from cell membrane and various other differences are there in the cell structure of plant cells.
The fluid filled portion of cell is called cytoplasm. The inner content of the avocado fruit is comparable with the cytoplasm and its seed can be considered as the model for nucleus.
Therefore, the avocado's skin represents the cell membrane. Hence, option B is correct.
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ectQuestion 13What is being reduced in the following reaction ?C2H4(g) + 302(g) → 2CO2(g) + 2H2O(g)C2H4H20No reduction or oxidation is occurringCO2
Step 1
The reaction is written and balanced as:
C2H4(g) + 302(g) → 2CO2(g) + 2H2O(g)
Step 2
Oxidation states are analyzed
For O2)
On the left, its oxidation state is 0 (O2)
On the right, it is -2 (H2O)
Step 3
The half-reaction is written as:
6 O + 12 e- => 6 O2-
Therefore, O2 is being reduced
Answer: O2
Why is reproducibility so important to scientistis
Answer: They serve as proof that an established and documented work can be verified, repeated, and reproduced.
Explanation: Reproducibility and research integrity are essential tenets of every scientific study and discovery. They serve as proof that an established and documented work can be verified, repeated, and reproduced. New knowledge in biomedical science is built on the shoulders of established and proven principles.
Answer:
Evidence of accuracy
Explanation:
it creates new opportunities for insights and facilitates innovation in terms of scientific knowledge.
what are the numbers in an equation under the letter called? and can they be changed or not. For example, the 2 under O2
- The numbers are called subscripts which is the total atoms of the elements present in a compound.
- The subsripts can change depending on the type of compound.
Explanations:The subcripts in a chemical compounds allow us to us know or determine the total atoms of such element that is present in the compound. For instance, in H2O (water), the subscript 2 in H2O shows that there 2 atoms of hydrogen in the compound (H2O).
They numbers differs depending on the type of compound. For instance O2 is oxygen while O3 is ozone
Triglycerides, waxes, and steroids are all _______ lipids because they contain only carbon, hydrogen, and oxygen.Question 20 options:A) long-chain compoundsB) methyl estersC) complexD) simple
Answer:
Explanation:
Here, we want to get the class of lipids that the given substances belong to
These substances are formed from glycerol and fatty acids
From their make up,we know that they are simple lipids
Thus, the answer here is simple
Some cracker tins include a glass vial of drying material in the lid to keep the crackers crisp. In many cases, the material is a mixture of magnesium sulfate and cobalt chloride indicators. As the magnesium sulfate absorbs moisture (MgSO4 ∙ H2O + 6H2O MgSO4 ∙ 7H2O), the indicator changes color from blue to pink (CoCl2 ∙ 4H2O + 2H2O CoCl2 ∙ 6H2O). When this drying mixture becomes totally pink, it can be restored if it is heated in an oven. What two changes are caused by the heating?
The two indicators given are there to absorb water or moisture. So when the indicator is totally pink it means it has been used to its total potential.
By heating the indicator, this can evaporate the water from the indicator, thus restoring it. This means that the indicator will go back to its blue color and it can be re-used.
So the two changes caused by heating:
1. Indicator changes color back to blue.
2. Water is evaporated from the indicator.
explain absolute entropies and it's determination in terms of heat capacity
The total entropy that a pure material would accumulate upon warming from absolute zero (where S=0) to the specific temperature is the absolute entropy of that substance at that temperature.
What is entropy?
One of the key ideas that students studying physics and chemistry need to grasp with clarity is entropy. More importantly, entropy has multiple definitions and can be used in a variety of contexts, including the thermodynamic stage, cosmology, and even economics. Entropy is a notion that mostly discusses the spontaneous changes that take place in commonplace phenomena or the universe's propensity for chaos.
Determination in terms of heat capacity
The third rule of thermodynamics has two significant ramifications: it establishes a constant reference point that enables us to measure the absolute entropy of any substance at any temperature, and it specifies the sign of the entropy of any substance at temperatures above absolute zero as positive. We look at two different approaches to calculating S for a reaction or a physical change in this section.
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Explain how you would calculate the total change in bond energy for the reaction H₂ + Cl₂ → 2HCI. How would you know if the reaction was endothermic or exothermic? State your answer in 3-5
Answer:
The total change in energy is -183 kJ/mol, and the reaction is exothermic.
Explanation:
1st) To calculate the total change in bond energy, it is necessary to calculate the energy of the broken bonds (in the reactants side) and the energy of the formed bonds (in the products side):
• Energy of broken bonds:
H-H: 1 x 432 = 432 kJ/mol
Cl-Cl: 1 x 239 = 239 kJ/mol
Total energy of broken bonds = 432 kJ/mol + 239 kJ/mol
Total energy of broken bonds = 671 kJ/mol
• Energy of formed bonds:
H-Cl: 2 x 427 = 854 kJ/mol
Total energy of formed bonds = 854 kJ/mol
2nd) Now to calculate the total change in bond energy, we have to subtract the Total energy of broken bonds minus the total energy of the formed bonds:
Total change in energy = Total energy of broken bonds - Total energy of formed bonds
Total change in energy = 671 kJ/mol - 854 kJ/mol
Total change in energy = -183 kJ/mol
Finally, the total change in energy is -183 kJ/mol, and the negative sign means that the reaction is exothermic, because
Answer: The total change of the energy is -183 kJ/mol
Explanation:
The way I would calculate the total change in the bond energy in the following steps:
- To calculate the whole change in the bond energy. By calculating the energies of the broken bonds and then the energy of the formed bonds.
-132 kJ/mol + 239 kJ/mol = a total of 671 kJ/mol broken bonds.
-H-CI: 2 x 427 = 854 kJ/mol
-Second to calculate the change in the bond energy we now need to subtract the total energy of the broken bond from the total energy of the formed bonds.
-Change in energy = 671 kJ/mol - 854 kJ.mol
-The total change of the energy is -183 kJ/
- Having the negative, therefore, means the reaction is exothermic.
what is the pH of a neutral solution? a.10 b. 7c. 14 d. 0
According to the pH scale, the pH can range from 0 to 14, and the lower the pH, the more acidic the solution is, the same goes if the pH is higher, the solution will be basic. These two informations are based on the neutral value of pH, which is 7. Letter B is the answer
7. The average human can hold 4.0 L of oxygen (O₂) in their lungs. At body temperature (37 °C) and 110 kPa, how manymoles of gas is that?
Answer
number of moles = 0.171 mol
Explanation
Given
Volume of oxygen = 4.0 L
Temperature = 37 °C = 310 K
Pressure = 110 kPa = 1.08562 atm
we know R = 0.082 L.atm.k/mol
Required: number of moles
Solution
To solve this problem, use the ideal gas law
PV = nRT
n = PV/RT
n = (1.08562 x 4.0 L)/(0.082 L.atm.k/mol x 310 K)
n = 0.171 mol