here is a generic thermochemical equation involving reactants a and b and products c and d: a 2b 2c d 78.3 kj what does the expression 78.3 kj signify?
Answers
The expression 78.3 kJ in the thermochemical equation represents the amount of heat energy released or absorbed during the reaction.
The expression 78.3 kJ in the thermochemical equation signifies the amount of heat energy released or absorbed during the reaction. In this case, the positive value of 78.3 kJ indicates that the reaction is exothermic, meaning that heat energy is released as a product of the reaction.
This means that the reaction releases 78.3 kJ of heat energy for every mole of product formed, and this energy can be measured experimentally using calorimetry techniques. The units of energy, in this case, are kilojoules (kJ), which is a standard unit of energy in the International System of Units (SI).
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--The complete question is, Here is a generic thermochemical equation involving reactants a and b and products c and d, a + 2b ----> 2c + d; 78.3 kJ. What does the expression 78.3 kJ signify?--
Related Questions
Multiple Choice
1. Think About the definition of remote sensing. Which of the following could be considered sensors?
2. When satellite images are analyzed a unit called the pixel is a key to calculating what?
3. One Pixel represents.
a temperature
a wind speed of 10 kilometers per hour
a land area of 30 by 30 meters
various colors depending on their size
Answers
Answer:
Remote sensing is the process of detecting and monitoring the physical characteristics of an area by measuring its reflected and emitted radiation at a distance (typically from satellite or aircraft). ... Cameras on satellites can be used to make images of temperature changes in the oceans.
2.The answer is Land Area. If you know the distance and scale at which the image was captured, than one pixel of the image is equal to an X amount of area. The land area is represented as one pixel in an image called Resolution.
3.A pixel is the smallest picture element addressable on a picture, it is a specific location, and at that location associated with that location, is color, intensity
a.mph (miles per hour), mph. knots, knots. m/s (meters per second), m/s. ft/s (feet per second), ft/s. km/h (kilometers per hour), km/h ...
Explanation:
7 kph 4.35 mph
8 kph 4.97 mph
9 kph 5.59 mph
10 kph
The apparatus or tools that could be considered as sensors are telecopes, probes and landsat satellites.
What is remote sensing?Remote sensing can be defined as a process that is used for the acquisition of information about a phenomenon or physical object on a planet without coming in close contact with it, especially through the use of a telecope, probe or landsat satellite.
When satellite images are analyzed by astronomers or scientists, a unit called the pixel is a key to calculating land area. Also, one pixel is a unit that represents a land area of 30 by 30 meters.
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3) Two plants are grown using the same light and pots. One plant is given water that has been
microwaved and the other plant is given regular tap water. Their height is measured after 2 weeks.
What are the independent and dependent variables?
Answers
Answer:
Independent variable- nature of irrigation water
Dependent variable- height of the plants
Explanation:
In every study, there must be an independent and a dependent variable. The dependent variable changes its value as the value of the independent variable changes.
When the nature of irrigation water is manipulated, the height of the plant changes accordingly. This implies that the nature of irrigation water (microwaved or tap water) is the independent variable while the height of the plant (the response) is the dependent variable.
In each of the following groups of substances, pick the one that has the given property. Justify your answer. a) highest boiling point: HBr, Kr, Cl2 b) highest freezing point: H2O, NaCl, Hf c) lowest vapor pressure at 25C: Cl2, Br2, I2 d) lowest freezing point: N2, CO, CO2 e) lowest boiling point: CH4, CH3CH3, CH3CH2CH3 f) highest boiling point: HF, HCl, HBr Could someone help me understand fully how to do this?
Answers
Answer:
A) HBr
b) NaCl
c) I2
d) N2
e) CH4
f) HF
Explanation:
a) HBr has the highest boiling point because its molecules are held by intermolecular hydrogen bonding unlike other compounds listed.
b) the freezing point of a substance is the same as its melting point. Ionic substances have the highest melting points. Hence NaCl has a melting (freezing) point of about 801°C
c) vapour pressure depends on molecular mass. The higher the molecular mass the lower the vapour pressure. I2 has the highest relative molecular mass and hence the lowest vapour pressure.
d) The molecule with the lowest molecular mass is expected to have the lowest intermolecular dispersion forces and hence the lowest freezing point.
e) Degree of dispersion forces and boiling point increases with increase in molecular mass. Since CH4 has the lowest molecular mass, it will also possess the lowest boiling point.
e) The magnitude of electro negativity decreases down the group. Hence, fluorine is the most electronegative element among the halogens. Hydrogen bonding results when hydrogen is covalently bonded to an electronegative element. The strength of the hydrogen bonding depends on the electro negativity of the electronegative element.
For hydrogen halides, HF has the highest boiling point since F is the most electronegative halogen and HF possess the greatest degree of hydrogen bonding among the hydrogen halides. Hydrogen bonding leads to increase in boiling point of substances.
The intermolecular forces in the compound have been responsible for the various properties of the compounds.
(a) Highest boiling point:
The hydrogen bonding has resulted from the electrostatic interaction of the H with the more electronegative atom. The strong interaction results in a higher boiling point.
HBr has consisted of the hydrogen bond, thus having the highest boiling point.
(b) Highest freezing point:
The higher hydrogen bonding in the structure results in a high freezing point. The ionic compounds with electrostatic interactions result in a high freezing point.
NaCl has been an ionic compound, thus has been consisted of the highest freezing point.
(c) Lowe vapor pressure:
Vapor pressure has been inversely proportional to the molecular mass. The higher the molecular weight, the lower has been the vapor pressure.
Iodine has the highest molecular weight, thereby has the lowest vapor pressure.
(d) Lowest freezing point:
Based on the molecular weight, the lower the molecular weight, the lower has been the freezing point of the molecule.
The \(\rm \bold{CH_4}\) has the lowest molecular weight, thus the lowest freezing point.
(e) Highest boiling point:
The more electronegative atom in the hydrogen bonding, the higher has been the stability and the higher the boiling point.
HF has the highest boiling point as it has H bonded with the most electronegative element.
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the term biodiversity means the variety of organism (true or false)
Answers
Answer:
true
Explanation:
Determine from the balanced chemical reaction if
the derived mole ratio is correct or incorrect.
2 FeBr3 + 3Na2S → Fe2S3 + 6NaBr
1 moles NaBr
1 moles Nas
Answers
Answer:
Explanation:
It's not 1:1 as the ratio implies
There's a 6 in front of the NaBr
There's a 3 in front of the Na2S
Arguement
The ratio is (6 NaBr // 3 Na2S}
Answer
The ratio is {2 NaBr:: 1 Na2S}
Find the change in the internal energy of one mole of a monatomic ideal gas in an isobaric expansion at 1 atm from a volume of 5 m 3
to a volume of 10 m 3
. (remember C p
=(5/2)R )
Answers
The change in the internal energy of one mole of a monatomic ideal gas in an isobaric expansion at 1 atm from a volume of 5 m³ to a volume of 10 m³ is -12.5 R J/mol.
Internal Energy, ΔU of an ideal gas in an isobaric expansion is given by the formula;
ΔU = nCpΔT
Where;n = number of moles of the gas
Cp = Specific heat capacity at constant pressureΔT = change in temperature. To identify the change in internal energy of one mole of a monatomic ideal gas in an isobaric expansion at 1 atm from a volume of 5m³ to a volume of 10m³, we are required to solve for the value of ΔU using the formula above. From the ideal gas equation;
PV = nRT,
we can also obtain the formula for isobaric expansion as;
ΔT = (PΔV/nR)
where;
P = pressure
V = volume
R = Gas constant
n = number of moles
Substituting into the formula for ΔU
ΔU = nCpΔT= (1 mole) × (5/2)R × (1 atm) × (5m³ - 10m³)/(1 mole × R)=-12.5 R J/ mole
ΔU = -12.5 R J/mol
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find the average speed of a person who swims 105 m in 70 s
Answers
Answer:
1.5 m/s
Explanation:
105 / 70 = 1.5
what do all atoms of any single element have in common
Answers
32.5 g to fluid ounces
Answers
Which type of behavior does an animal know how to do without have to learn it
Answers
Explanation: Instinct is the ability of an animal to perform a particular behavior in response to a given stimulus the first time the animal is exposed to the stimulus.
Picture for reference:
The part of the water cycle where water from the ocean is changed into vapor is
driven by energy from the ?
A) lunar tides
B) earth's gravity
C) magnitisim
D) sun's heat
Answers
Answer:
D) Sun's heat
Explanation:
The water cycle is driven primarily by the energy from the sun. This solar energy drives the cycle by evaporating water from the oceans, lakes and rivers.
Answer:
D) sun's heat
Explanation:
The sun's heat provides enough energy to water molecules at the surface so they move fast enough to escape from the water. The water does not need to boil.
An na ion has a charge of 1 and an o ion has a charge of –2. how many na ions does one o ion need to balance charges?
Answers
A Na ion has the charge of the +1 and the an O ion has the charge of the -2. The number Na ion does O ion need to balance the charge is 2 ions.
The Na is the metal and the metal have tendency to donate the electrons form the ion called as the cation. The Oxygen is the non metal and it has tendency to accept the electrons to form the ion called as the anion. The oxygen has the charge of -2 and the Na has the charge of +1 , the number of Na ions need is two.
The compound formed has the chemical formula , Na₂O. The compound formed by the positive and the negative charge called as the ionic compound.
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describe what gas pressure is. explain how concentration and temperature both effect gas pressure in a sealed container.
Answers
Gas pressure can be described as the force exerted per unit area by gas molecules as they collide with the surface of a container. It is a measure of the average kinetic energy of the gas molecules.
The pressure of a gas depends on several factors including the temperature, the volume, and the number of gas molecules present in a container. Changes in temperature and concentration can have an effect on gas pressure within a sealed container.Concentration can affect gas pressure because increasing the number of gas molecules in a container will result in more collisions and a greater force being exerted on the container walls. The pressure of the gas will increase. If the concentration of gas molecules decreases, then there will be fewer collisions and the pressure of the gas will decrease.Temperature is another important factor that can affect gas pressure. According to Charles' Law, if the temperature of a gas increases, then the volume of the gas will also increase. This is because the gas molecules will be moving faster and will require more space to move around in. The pressure of the gas will increase. An increase in concentration or temperature will lead to an increase in gas pressure, while a decrease in concentration or temperature will lead to a decrease in gas pressure.For such more questions on Gas pressure
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ABC + DAB+CD
ΔΗ
rxn
= -80 kJ/mol and Ea(fwd) = 185 kJ/mol.
Assuming a one-step reaction, calculate Ea(rev).
kJ/mol
Answers
The Ea of the forward reaction is 297.5 kJ/mole. The E of the products is 33.6 kJ/mole LOWER than that of the reactants, hence the negative value. Thus, the Ea of the reverse reaction requires 33.6 kJ/mole to get back to the starting point and then an additional 297.5 kJ/mole to reach the threshold. Total = 331.1 kJ/mole.
What is chemical reaction ?Chemical reaction is the process by which one or more compounds, known as reactants, change into one or more new ones, known as products. Chemical components or compounds make up substances. The atoms that make up the reactants are rearranged in a chemical reaction to produce various products.
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an atom in its ground state absorbs a single photon of light and then relaxes back to the ground state by emitting an infrared photon (1,200 nm) followed by an orange photon (600 nm). what is the wavelength of the photon that was absorbed initially
Answers
Wavelength of the photon of light and then relaxes back to the ground state by emitting an infrared photon (1,200 nm) followed by an orange photon (600 nm) that was absorbed initially is 400nm
Wavelength of the photon that was absorbed initially can be calculated as follows:
Photon's energy is inversely related to its wavelength.
E ∝ 1/λA
Given that the energy of the absorbed photon () equals the total energy of the photons released (E₁ +E₂).
Eₐ=E₁ +E₂
the relationship between E and λ,
1 = 1 + 1
λₐ λ₁ λ₂
1 = 1 + 1
λₐ 600x 10⁻⁹ 1200x 10⁻⁹
λₐ = 400nm
Therefore, the wavelength of the absorbed photon is 400 nm.
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For each reaction indicated below, will a reaction move in the forward (right) or reverse (left) direction? (Of the reaction arrows presented in each reaction, select the arrow - via the multiple choice circle before it - that best indicates the acid-base equilibrium position.)
Answers
The reaction will advance in the direction indicated by the given statement.
What does a written reaction mean?A document is a piece of writing that expresses an individual's viewpoint on a certain piece of work. This essay should include a synopsis of the source material, but the main emphasis should be on your opinions and justifications regarding the topics included in the source text.
Is an answer a reaction?In the heat of the moment, decisions are made without much thought to the consequences of the possible consequences. Reaction: Making a comment in response to with an action or remark made by another person. Response is more thoughtful and logically based.
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how long did your addition of the acid mixture take? how much ethanol did you use for the recrystallization? what did your nitroacetanilide crystals look like? how long did you dry the final solid before taking the mass and melting point?
Answers
Recrystallization ; 25 mL of solvent are needed at 100 oC to dissolve 100 mg of the chemical. 75 mg of the chemical will precipitate at 0 oC while 25 mg will remain in solution.
what did your nitroacetanilide crystals look like? how long did you dry the final solid before taking the mass and melting point?The chemical compound para nitroacetanilide, commonly known as 4-nitroacetanilide, is a nitroacetanilide derivative made from acetanilide and a nitrating combination. A trace of ortho product also forms along with the para product.
Through nitration, the chemical molecule p-nitroacetanilide is created from acetanilide. P-nitroacetanilide is created when acetanilide is treated with a nitrating mixture, which is a combination of nitric acid and sulfuric acid. O-nitroacetanilide is also generated as a small byproduct along with p-nitroacetanilide. It is quite simple to separate p-nitroacetanilide through crystallization since o-nitroacetanilide is highly soluble in alcohol.
Because ethanol is endlessly cosoluble with water and has high dissolving properties for many organics, ethanol and water mixtures are frequently utilized. Many organic compounds' solubilities can be drastically and quickly decreased by the addition of water, which can cause crystallization.
The solution may become too diluted for crystals to form if you add too much solvent. The flask needs to be gently cooled, first at room temperature and then in cold water. Impurities will be captured by a hastily formed crystal's lattice. Smaller crystals will be produced as a result.
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2nd time posting someone please help
Answers
Answer:
Sb: Antimony
Si: 14 (atomic Number)
S: 32.06 u (atomic mass)
Explanation:
an aqueous solution of perchloric acid is standardized by titration with a 0.129 m solution of barium hydroxide. if 27.5 ml of base are required to neutralize 21.0 ml of the acid, what is the molarity of the perchloric acid solution?
Answers
The molarity of the perchloric acid aqueous solution standardized by titration with a 0.129 M solution of barium hydroxide is equals to the 0.169 M.
An acid-base titration involves the finding of the molarity of an unknown solution of acid or base from a solution of acid or base whose concertation is known.
Molarity of barium hydroxide = 0.129 M.
Volume of barium hydroxide = 27.5 mL.
Volume of perchloric acid = 21.0 mL.
We are asked to determine the molarity of the perchloric acid. This reaction undergo to form barium perchlorate and water. The reaction is Ba(OH)₂ + HClO₄ → Ba(ClO₄)₂ + H₂O
Because the reaction is not balanced, this is balanced by same number of H, O and other atoms, Ba(OH)₂ + 2HClO₄→ Ba(ClO₄)₂ + 2H₂O
The mole ratio of acid and base is 1: 2. This means that 1 mole of barium hydroxide results 2 moles of perchloric acid. Using the equation
Mb× Vb = 2×(Mₐ × Vₐ),
where, Mb = the molarity of barium hydroxide
Vb = volume of barium hydroxide
Mₐ = molarity of perchloric acid
Vₐ = volume of perchloric acid
Now, plugging all known values in above equation, 0.129 M × 27.5 mL = Mₐ ×21.0 mL
=> Mₐ = (0.129 M × 27.5 mL )/21.0 mL
=> Mₐ = 0.169
Thus the molarity of perchloric acid is 0.169 M.
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What is the sign of δg for the folding process? what about for the unfolding (denaturation) process? how do you know?
Answers
It is a thermodynamically spontaneous process that means Protein folding occurs. The value of ΔG must be negative in the case of folding but in the case of unfolding, the value of ΔG must be positive.
When the process is thermodynamically spontaneous process results in Protein folding otherwise the process is unfolding.
The value for ΔG must be negative in the case of the folding process and the value for ΔG must be positive in the case of the unfolding process. The value of a thermodynamic parameter for the reverse reaction has an opposite sign but the same value that's why the value for ΔG must be positive and known as unfolding (denaturation) process.
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Calculate the number of moles of NaCl contained in 5L of a 2.2M solution.
Answers
The number of moles of NaCl contained in 5 L of a 2.2 M solution is 11 moles
How do i determine the number of moles?The molarity of a solution gives a relationship between volume and mole of substance. The mathematical relationship is given below:
Molarity = number of mole / Volume
With the above formula, we can determine the number of mole of NaCl in the solution. Details below:
Volume of solution = 5 LMolarity of solution = 2.2 MNumber of mole of NaCl =?Molarity = number of mole / Volume
Cross multiply
Number of mole = molarity × volume
Number of mole of NaCl = 2.2 × 5
Number of mole of NaCl = 11 moles
Thus, the number of moles of NaCl is 11 moles
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A science class was conducting an investigation about the transformation between potential energy and kinetic energy. The students dropped a
basketball from different heights above the floor. They videotaped the ball while it was falling and then calculated the ball's kinetic energy just before it
hit the floor.
When will the basketball have the highest kinetic energy and why?
Answers
When basket ball is dropped from a height, its potential energy decreases and its kinetic energy increases till it reaches the ground. The highest kinetic energy is at ground level.
What is kinetic energy ?The energy that an object has as a result of motion is known as kinetic energy. It is described as the effort required to move a mass-determined body from rest to the indicated velocity. The body holds onto the kinetic energy it acquired during its acceleration until its speed changes.
A ball drops from the top of a building and picks up speed as it descends. Its speed is increasing by 10 m/s every second. What we refer to as motion with constant acceleration is, for example, a ball falling due to gravity.
Thus, The highest kinetic energy is at ground level.
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The boiling point of chlorine (Cl2) is 171.6 K. Which of the
following best predicts the boiling point of iodine (12)?
Answers
Answer:
The boiling point of iodine is 363.7°F / 184.3°C
Explain how the atomic theory was modified from Dalton’s theory to Rutherford’s. Include an explanation of why the theory was modified
Answers
Answer:
Thomson's results showed that atoms contain smaller particles, so Dalton's theory had to be modified. Rutherford's results showed that most of an atom is empty space and that the mass is concentrated in the center of the atom.
Explanation:
( like and follow if it helps >W< )
what are salt properties of matter?
Answers
Answer: Salt is a chemical compound with a number of interesting properties: Crystals or white crystalline powder. Transparent and colourless in crystalline form – rather like ice. Crystallises in the isometric system, usually in the form of cubes.
Answer:
Salt is a chemical compound with a number of interesting properties: Crystals or white crystalline powder. Transparent and colourless in crystalline form – rather like ice. Crystallises in the isometric system, usually in the form of cubes.
Explanation:
give the first answer brainliest, im just fixing thier spelling
Magnesium fluoride can be formed by burning magnesium in fluorine gas. With reference to its bonding, explain why magnesium fluoride has a very high melting point.
Answers
Answer:
Magnesium Flouride is a ionic compound and thus has a giant lattice structure. Its ions are held together in this lattice by strong electrostatic forces of attraction. A large amount of energy is needed to overcome the strong electrostatic forces of attraction between the Mg2+ ions and the F- ions to separate the ions. Hence Magnesium fluoride has a very high melting point.
Nuclear fusion reactions release more energy than fission reactions while also generating less waste. However, nuclear fusion reactors are not currently used to generate electricity.
What is the main reason for this?
Answers
Nuclear fusion reactions release high energy and required tremendous temperature of nuclear reactors is the main reason for not used to generate electricity.
What are nuclear reactions?Nuclear reactions are those reactions which are taking place in the nucleus of any unstable atom and produces energy.
As in the question it is given that nuclear fusion reactions releases more energy and less wastage, but this energy are releases in the tremendous amount which can be proved harmful for the environment and the humans. To carry out this reaction we have to maintain the very high temperature of nuclear reactors of about 6 times greater than sun's temperature, which is not possible manually.
Hence, high temperature of nuclear reactors and high amount of energy released is the main reason.
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Please explain your reasoning and give explanation of why you chose that answer
Answers
Answer:
a. Cellular Respiration produces more ATP than Anaerobic Respiration.
Explanation:
Cellular Respiration creates a total of 36-38 ATP per round. Anaerobic processes only produce 2 ATP per cycle.
how many outer boundaries does a animal cell have
Answers
Answer:
The plasma membrane.
Explanation:
membrane, in biology, the thin layer that forms the outer boundary of a living cell or of an internal cell compartment. The outer boundary is the plasma membrane, and the compartments enclosed by internal membranes are called organelles.
The nucleus of a helium atom is identical to: A) a gamma particle B) an alpha particle C) a beta particle D) all of the above
Answers
Answer: D. All of the above
Answer:
B. Alpha Particles
Explanation:
P: Have a Nice Day!