Disulfide bridges stabilize the tertiary level of protein structure.
Although many proteins are composed of many subunits, their organization into quaternary structures is not universal. Usually, disulfide bonds will link β-sheets, α-helices, and loops; this indicates that they predominantly maintain tertiary structure, as opposed to secondary structure, which refers to local conformations and is maintained mostly by hydrogen bonds, making proteins more stable and less likely to unfold. As the pH of a solution rises, acidic groups on proteins are deprotonated, resulting in a net positive charge on the protein. The spatial structure of a protein, however, is critical to its activity. It can only recognize and bind to the molecules it's designed to work with in its natural state.
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why do object fall toward. the. center. of the. earth
Answer:
because of the downward force called gravity
true/false. most chemicals can be cleaned up with a general spill kit, but a few chemicals require specialized spill procedures. for each substance listed, determine whether a general spill kit is sufficient or if a specialized spill kit is needed.
True, most chemicals can be cleaned up with a general spill kit, but a few chemicals require specialized spill procedures.
Weak chemicals can be cleaned up easily with general spill kits as they aren't corrosive enough to cause harm to living tissues and other non living materials such as marbles and construction units. Although, strong chemicals, like strong acids (such as hydrochloric acid, nitric acid) and strong bases are corrosive in nature, and need to be cleaned using specialised spill procedures for such chemicals. They can harm living tissues on contact and can degrade the quality of inanimate substances as well. Examples of some chemicals with what type of spill kit will be used for them:-
hydrofluoric acid = special
methanol = general
acetone = general
phosphoric acid = general
mercury = special
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describe osmosis as a special case of diffusion. distinguish between osmotic pressure and osmotic potential.
Osmosis can be thought of as a special type of diffusion in which only the solvent (water or another liquid) travels over a semipermeable membrane. Both diffusion and osmosis are examples of processes of passive transport that work to maintain the consistency of the concentration of a solution.
What is the difference between osmotic pressure and osmotic potential?Osmotic pressure is the name given to the hydrostatic pressure that maintains equilibrium and blocks the osmotic influx of water into a solution that is highly concentrated. As a consequence of the presence of dissolved solutes, a solution has the ability to draw additional water into itself via a membrane that is only partially permeable. This property is referred to as osmotic potential.
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Nitrogen dioxide, NO2, decomposes upon heating to form nitric oxide and oxygen according to the following equation: 2NO2(g) 2NO(g) + O2(g) At the beginning of an experiment, the concentration of nitrogen dioxide in a reaction vessel was 0.1103 mol/L. After 65.0 s, the concentration decreased to 0.1076 mol/L. What is the average rate of decomposition of NO2 during this time interval, in mol/(L s)?
The average rate of decomposition of NO₂ during this time interval, in mol/ L s is - 9 × 10⁻⁵ mol/ L.s.
The information given as :
The initial concentration = 0.113 mol / L
The concentration after 60 s = 0.1076 mol/L
The reaction is given as :
2NO₂ ----> 2NO + O₂
The average rate of decomposition :
r = - d [NO₂] / dt
r = - ( [NO₂] t2 - [NO₂] t1 ) / t2 - t1
r = - (0.113 mol/L - 0.1076 mol/L) / 60 s - 0 s
r = - ( 5.4 × 10⁻³ mol/L ) / 60 s
r = - 9 × 10⁻⁵ mol/ L.s
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if the flask is open to the atmosphere, the mercury levels are equal. for each of the following situations where a gas is contained in the flask, calculate the pressure in the flask in torr, atmospheres, and pascals.
The pressure in the flask in torr is 642 torr, the pressure in atmosphere is 0.845 atm and the pressure on pascals is 8.56 × 10⁴ pa.
Given that :
Atmospheric pressure = 760 mmHg
The difference in h = 118 mm
The pressure in the tank = 760 mmHg - 118 mmHg
The pressure in the tank = 642 mmHg
The pressure in torr = 642 mmHg ( 760 torr / 760 mmHg )
= 642 torr
The pressure in atmosphere = 642 mmHg ( 1 atm / 760 mmHg)
= 0.845 atm
The pressure in pascals = 642 mmHg ( 101325 pa / 760 mmHg )
The pressure in pascals = 8.56 × 10⁴ pa.
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Use the diagram below to answer the question: What element does this atom likely represent?
Lithium is the element because only lithium atom with 3 protons in this diagram.
What do you mean by an element ?An element is a pure substance that cannot be broken down into simpler substances through physical or chemical means.
Lithium is the symbol for the element. Because lithium has three protons, it has the atomic number 3. Because lithium atoms contain either 3 or 4 neutrons, it has an atomic mass of 6.94. On the periodic table, lithium is in group 1 and has one valence electron.
Thus, Lithium is the element because only lithium atom with 3 protons in this diagram.
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Which of the following processes is illustrated by the downward arrows from the atmosphere that show the conversion of nitrogen gas into usable forms available to producers?
A
Nitrogen assimilation
B
Nitrogen fixation
C
Photosynthesis
D
Weathering
Answer:
Explanation:
To be used by plants, the N2 must be transformed through a process called nitrogen fixation. Fixation converts nitrogen in the atmosphere into forms that plants can absorb through their root systems.
Which of these is an example of a chemical property?
A. A banana will oxidize quickly in a paper bag.
B. Sodium has a boiling point of 97.79⁰ Celsius.
C. Water has a melting point of 0° Celsius.
D. Titanium has the same density at 3g as it does at 5g.
Answer:
A. A banana will oxidize quickly in a paper bag.
Which of the following are correct statements regarding applications of the gas laws and kinetic-molecular theory to the Earth's atmosphere? Select all that apply.A. The gases in the atmosphere behave nearly ideally, so that volume percent equals mole percent.B. The pressure of the atmosphere increases as altitude decreases, and Avogadro's law states that gases are compressible as pressure increases.C. Charles's law helps explain air convection patterns in the lower atmosphere.D. Because of the low density of particles in the thermosphere, the transfer of kinetic energy is very slow and temperatures are very low.
The correct statements viewing applications of the gas laws and kinetic-molecular theory to the Earth's atmosphere are the gases in the atmosphere behave nearly ideally, so that volume percent equals mole percent and Charles's law aids explain air convection patterns in the lower atmosphere.
The gas laws are a bunch of laws that govern the behavior of gases by fitting out associations between the following: the volume inhabited by a gas, the pressure put forth by a gas on the partitions of its container, the absolute temperature of the gas, and the quantity of gaseous substance (or) the number of moles of gas. The five gas laws are Boyle's Law, Charles's Law, Gay-Lussac's Law, Avogadro's Law, and The Combined Gas Law (or the Ideal Gas Law). Under standard situations, all gases exhibit analogous behavior.
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predict whether the ph of pure neutral water will increase or decrease as temperature decreases and explain your reasoning using le chatelier's principle and the thermochemical equation of the autoionization of water.
The pH of pure neutral water will increase when temperature decreases.
The formation of hydrogen or hydronium ions and hydroxide ions from neutral water proceeds via an endothermic reaction. The equilibrium reaction is written as:
H₂O ⇄ H⁺ + OH⁻
In the forward reaction heat is absorbed.
According to Le Chatelier's principle, "if we increase the temperature of the water, the equilibrium will move to lower the temperature again. It will do that by absorbing the extra heat."
This means if a change is made to the conditions of a reaction in dynamic equilibrium, the position of equilibrium will move to counter the change that we have made.
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t question at position 9 which of the following is true concerning the motifs and domains of proteins?
The true statement concerning the motifs and domains of proteins is Separate proteins with similar domains are likely to have a similar function. The correct answe is C.
The biological activity of a protein can occasionally be anticipated by looking for existing proteins with comparable amino acid sequences since proteins with similar structures typically have similar activities.
Finding motifs and domains is a crucial part of biological sequence characterisation. Because freshly acquired protein sequences frequently lack significant similarity with database sequences of known functions over their entire length, making functional assignment challenging, it is crucial to identify unknown protein activities.
In this instance, the identification of brief consensus sequences linked to known functions can help researchers understand how the protein acts. The name "motifs" refers to these consensus sequence patterns.
Your question is incomplete but most probably your full question was
Which of the following is true concerning the motifs and domains of proteins?
Many domains make up a motif.
Every polypeptide chain is limited to one domain.
Separate proteins with similar domains are likely to have a similar function.
All domains of a protein have the same function.
None of the above are true
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please help me on my living environment homework
The great nutritional value of crickets, particularly in terms of protein, makes them an excellent dietary source.
Why should we consider adding crickets as part of your school lunches?In particular, lean protein, minerals, and vitamins are all abundant in crickets, which are a great source of these nutrients. Compared to chicken, they have a greater protein content of about 65%. In addition to having a high protein content, crickets also have chitin and other fibers that have an impact on gut health.
The primary benefit of using crickets as a food source is their high nutritional value, particularly in terms of protein.
In other words, crickets metabolize their food more effectively and need less food to produce the same amount of protein as cattle. This is known as a greater feed conversion rate. Less area will need to be set aside for the production of protein sources as a result.
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select the processes that need to occur in order to release all three carbon atoms from pyruvate (once it has been produced by glycolysis) in the form of carbon dioxide.
After glycolysis produces pyruvate, the following procedures must take place in order to release all three carbon atoms from pyruvate in the form of carbon dioxide.
What is pyruvate?A crucial stage in the metabolism of carbohydrates and lipids is the three-carbon molecule pyruvate. It is the result of the glycolysis process, which breaks down glucose to produce ATP, which is a kind of energy.
Pyruvate decarboxylation, which happens first, is the process by which pyruvate is transformed into acetyl-CoA. A sequence of processes take place in the citric acid cycle, commonly referred to as the Krebs cycle or the TCA cycle, where the acetyl-CoA is further degraded.
Enzymes work to convert acetyl-CoA to CO2 during the citric acid cycle, releasing high-energy electrons that are then used to create ATP.
The final step is oxidative phosphorylation, which takes place in the mitochondria's inner membrane. Here, electrons are transferred to the electron transport chain so that the ATP synthase enzyme can pump protons and produce ATP.
The CO2 that is released into the atmosphere is the end result.
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The color change of the copper (II) carbonate hydroxide hydrate as it was heated can help identify the product. Use the following list of copper compounds to identify the product. CuCO_3-light green powder Cu(OH)_2-blue green powder Cu_2O-reddish brown crystals CuO-black powder
The color change of the copper (II) carbonate hydroxide hydrate will be CuCO_3-light green powder.
Copper(II) carbonate or cupric carbonate is a chemical compound having chemical formula CuCO₃. At ambient temperatures, it is an ionic solid (a salt) which is consisting of copper(II) cations Cu²⁺ as well as carbonate anions CO₂⁻³. This compound is rarely encountered because it is very difficult to prepare[2] and readily reacts with water moisture from the air.
Copper carbonate will be green colored, when heated it gives out a black solid copper oxide. C u C O ₃ → C u O + C O ₂ [ g ] Zinc carbonate will be white colored, when heated it will gives a yellow solid - zinc oxide.
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Show how you might synthesize this compound from an alkyl bromide and a nucleophile in an SN2 reaction.
Use the wedge/hash bond tools to indicate stereochemistry.
Only draw the reactants.
If there is more than one possible combination of alkyl bromide and nucleophile, draw only one combination.
Do not include counter-ions, e.g. Na+, I-, in your answer.
To synthesize the given compound from an alkyl bromide and a nucleophile in an SN2 reaction, you need to draw the reactants using the wedge/hash bond tools to indicate stereochemistry.
If there is more than one possible combination of alkyl bromide and nucleophile , draw only one combination. Do not include counter-ions, e. g. Na+, I-, in your answer. For example, one possible combination could be:
R-Br + Nu: → R-Nu + Br-
An alkyl bromide is a type of organic compound that contains a carbon atom bonded to a bromine atom. Alkyl bromides are classified as alkyl halides, which are compounds that contain a carbon atom bonded to a halogen atom. Alkyl bromides are commonly used in a variety of organic reactions, such as in substitution reactions, in which the carbon-bromine bond is replaced by a different group. Alkyl bromides can also be used to make alkyl sulfonates, alkyl esters, and other compounds. Alkyl bromides are generally colorless liquids or solids, and have a low boiling point.
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on the website, the contributors all agreed that the average molecular kinetic energy is the same for both he and sf6. which of the following changes would best correct the distribution curve for sf6?
A change in the distribution curve for SF₆ will be observed and the curve will depict a much slower average speed and the shift on the curve will be to the left.
The Maxwell-Boltzmann equation tells about the kinetic theory of gases. It basically defines the distribution of the speeds for a gas at a particular temperature. From this distribution, we can derive the the average speed, most probable speed, and the root-mean-square speed.
The distribution depends mainly on two factors which are the mass and the temperature. Among He and SF₆, SF₆ has a higher mass and shows a shift on the curve. It shows a much slower average speed and the shift on the curve is observed to be towards the left.
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the nadh generated during glycolysis and the citric acid cycle feeds its high-energy electrons to which of the following?
The NADH generated during glycolysis and the citric acid cycle feeds its high-energy electrons to the electron transport chain (ETC) also known as the oxidative phosphorylation.
The ETC is a series of protein complexes and electron carriers that transfer electrons from NADH and FADH2 to oxygen, creating a flow of electrons through the chain. During glycolysis, the glucose molecule is broken down into two molecules of pyruvate, generating two molecules of NADH in the process. In the citric acid cycle, also known as the Krebs cycle, the pyruvate molecules are further metabolized, generating additional NADH and FADH2 molecules. The NADH and FADH2 molecules are high-energy electron carriers because they have a surplus of electrons. These high-energy electrons are then transferred to the electron transport chain.
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Convert 320 mmHg to kPa
Answer: 42 2/3 kPa
Explanation: To get the approximate answer, divide by 7.5
320/7.5 = 42.66666... = 42 6/9 = 42 2/3 kPa
the potential danger involved with ingesting certain compounds is associated with their solubility in the body's aqueous environment. which of the following would be most soluble in water?
A. It is advisable to base answers to questions on the physical characteristics of organic compounds on general chemistry concepts, particularly those pertaining to bonds polarity and molecular interactions.
It's vital to keep in mind that "likes dissolve likes" while discussing solubility. We are therefore seeking a molecule that most closely resembles the polar makeup of water. The greatest intermolecular force in which water molecules engage is hydrogen bonding; hence, the most soluble molecule should be comparable. Alcohols can also engage in hydrogen bonding, although this capacity declines as the alkyl component of the alcohol molecule grows larger because the hydrogen bonding network is disrupted by the more nonpolar alkyl group. Since ethanol (option (A)) has a smaller alkyl group than propanol (option (B)), it is more capable of forming hydrogen bonds and will thus be more soluble in water.The molecules in choices (C) and (D), a ketone and an ether, respectively, are less soluble in water because, although having polar carbon-oxygen bonds, they lack hydrogen atoms bound to electronegative (FON) atoms, which are necessary for hydrogen bonding. Answer option (A) is the right selection.
(B) Deformation The carbon chain of this molecule is one carbon longer than that of ethanol, despite the fact that the OH group may make hydrogen bonds. As a result, it is less soluble in water.
(C) Deformation Although ketones are capable of forming hydrogen bonds, they lack a dipole moment.
D) distortion Ethers are somewhat polar, but since they cannot form hydrogen bonds, they are not very water-soluble.
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The complete question is:
The potential danger involved with ingesting certain compounds is associated with their solubility in the body's aqueous environment. Which of the following would be most soluble in water?
A.CH3CH2OH
B. CH3CH2CH2OH
C. CH3OCH2CH3
What type of energy is chemical energy?
Answer: Potential Energy
Explanation:
Chemical energy is stored energy in between bonds. Any energy that is stored and therefore has to be released is potential energy.
A chemical property can be identified _____ changing the composition of a substance. with and without. without. with or without. only by
D) only by changing the composition of a substance, a chemical property can be identified.
What constitutes as a chemical property?An characteristic of a specific material that can be observed during a chemical reaction is called a chemical property. Main chemical properties include chemical stability, flammability, toxicity, heat of combustion, pH value, and rates of radioactive decay.
How can you determine what a substance is made of?The arrangement, ratio, and kind of atoms in chemical substance molecules are referred to as chemical composition. The molar mass of a mixture can be utilized to identify some of its chemical components. You can always just write down the chemical formulae and then multiply the atomic weight of each element by the amount of atoms that comprise each molecule. You can then verify the molar mass you get as a result with the sample's actual mass.
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A chemical property can be identified _____ changing the composition of a substance.
A)with and without.
B)without.
C)with or without.
D)only by
Give the IUPAC name for this compound pleaseee
The IUPAC name for the compound given in the diagram above is 2,4-dimethylhexane
How do I determine the IUPAC name for the compound?The IUPAC naming of organic compounds follows certain defined principles. These principles includes:
Locate the longest continuous carbon chain. This inturn gives the parent name of the compound.Identify the substituent groups attached to the compound.Give the substituents groups the lowest count by considering their location.Combine the above to generate the name of the compound.Now, let us determine the IUPAC name for the compound using the above principle.
The longest continuous carbon chain is 6. Thus, the parent name is hexaneThe substituent group attached is methylThere are two methyl groups. one is located at carbon 2, and the other at carbon 4Thus, the IUPAC name for the compound is:
2,4-dimethylhexane
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The pressure gauge on a compressed air tank reads 43.2 mmHg. What is the pressure in atm? atm
80 points
The pressure gauge on a compressed air tank reads 43.2 mmHg. 2.94 atmosphere is the pressure.
What is pressure ?The term pressure is defined as the amount of force exerted per area.
Pressure in compressed air tank reads 43.2 pounds per square inch (lb/in),
Then, convert pressure to atmosphere (atm)
Recall that 1 atm = 14.695964 lb/in
Thus, let Z = 43.2 lb/in
To get the value of Z, cross multiply
43.2 lb/in x 1 atm = 14.695964 lb/in x Z
43.2 lb/in atm = 14.695964 lb/in x Z
Z = 43.2 lb/in atm / 14.695964 lb/in
Z = 2.94 atm
Thus, the pressure of the compressed air tank reads 2.94 atmosphere.
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A force of 90n is applied to each cart below which one will accelerate the fastest
The cart with the fastest acceleration is 5 kg cart because its mass is the smallest.
What is mass?Mass can be experimentally defined as a measure of the body's inertia, meaning the resistance to acceleration when a net force is applied.
The parameters given include;
applied force, F_ = 90 N
mass of cart: 5kg, 6kg, 8 kg, 9 kg
According to Newton's second law of motion, the force applied to an object is directly proportional to the product of mass and acceleration of the object.
F_ = ma
The acceleration of the 5 kg cart is calculated as follows;
a = f_ /mass
a = 90/5
a= 18m/s²
The acceleration of the 6 kg cart is 15 m/s² (using Newton's second law)
The acceleration of the 8 kg cart is 11/25 m/s² (using Newton's second law)
The acceleration of the 9 kg cart is 10m/s² (using Newton's second law)
Therefore, the cart with the fastest acceleration is 5 kg cart because its mass is the smallest.
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Complete question:
A force of 90N is applied to each cart below, which one will accelerate the fastest?
Mass: 5 kg
Mass: 6 kg
mass: 8 kg
Mass: 9 kg
The molar mass of neon gas would be about 20.2 grams per mole. What is the molar volume of neon at STP?
The molar volume of neon gas at STP is 22.44cm³.
How to calculate molar volume?Molar volume is the volume occupied by one mole of a substance (especially of a gas).
At standard temperature and pressure (STP), the molar volume is the volume occupied by one mole of a chemical element or a chemical compound. It can be calculated by dividing the molar mass (M) by mass density (ρ).
Molar density of neon gas is 0.9g/cm³
Molar volume = 20.2g/mol ÷ 0.9g/cm³
Molar volume = 22.44cm³
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The decomposition of HI(g) at 298 K is represented by the equilibrium equation above. When 100. torr of HI(g) is added to a previously evacuated, rigid container and allowed to reach equilibrium, the partial pressure of I2(g) is approximately 3.7 torr. If the initial pressure of HI(g) is increased to 200. torr and the process is repeated at the same temperature, which of the following correctly predicts the equilibrium partial pressure of I2(g), and why?
answer choices
PI2 ≈ 14 torr, because it is directly proportional to the square of the initial pressure of HI.
PI2 ≈ 0.073 torr, because it is inversely proportional to the square of the initial pressure of HI.
PI2 ≈ 7.4 torr, because it is directly proportional to the initial pressure of HI.
PI2 ≈ 1.9 torr, because it is inversely proportional to the initial pressure of HI.
7.4 torr for PI2. Due to its direct proportionality to the initial pressure of HIHI, PI2 7.4 torrs.
The forward and reverse reactions happen simultaneously when the system is in equilibrium. Each reactant and product are present in equal amounts once equilibrium has been attained. The relationship between the concentrations of the reactants and the products is mathematically represented by the equilibrium constant equation.
The equilibrium state is the state of a system whose attributes are constant under constant external conditions. Even after equilibrium has been reached, reactants and products continue to change, making chemical equilibria dynamic in nature. However, the reaction time for moving forward and backward is the same. Balance examples include Placed on the table was a book. a vehicle that travels at a fixed speed. a chemical process where the rates of the forward and reverse reactions are equivalent.
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• Your patient receives Lanoxin 0.075 mg PO daily for cardiac arrhythmia. Available is Lanoxin elixir 50. mcg/mL. How many È mLs will you administer with each dose?
Your patient receives Lanoxin 0.075 mg PO daily for cardiac arrhythmia. Available is Lanoxin elixir 50. mcg/mL. 1.5mls administer with each dose.
What is cardiac arrhythmia ?An arrhythmia of the heart is an irregular heartbeat. When the electrical signals that coordinate the heart's beats fail to function properly, heart rhythm problems occur. Because of the faulty signaling, the heart beats too quickly,too slowly , or irregularly.
Patient receives lanoxin 0.075mg .
Available is 50mcg/ml.
0.075mg = 75mcg
Availanle = 50mcg/ml
50mcg = 1ml
1mcg = 1 ÷ 50ml
75 mcg = 1 ÷ 50 × 75ml
= 1.5ml
Patient receives 1.5mls with each dose.
Thus, Your patient receives Lanoxin 0.075 mg PO daily for cardiac arrhythmia. Available is Lanoxin elixir 50. mcg/mL. 1.5mls administer with each dose.
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How do ions form, and how does the octet rule determine if an atom becomes a cation or an anion?
When an atom gains or loses electrons from its outermost energy shell, ions form. When an electron or electrons are lost to achieve a full duplet or octet, elements form cations. An anion is formed when an element gains an electron or more than one electron.
What do you mean by octet rule ?The octet rule refers to atoms' preference for having eight electrons in their valence shell. Atoms with fewer than eight electrons are more likely to react and form more stable compounds.
Atoms can satisfy the octet rule in one of two ways. One method is for them to share their valence electrons with other atoms. The second method is to move valence electrons from one atom to another.
Thus, When an atom gains or loses electrons from its outermost energy shell, ions form.
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1. 50cm³ of 0.5 mol/dm³ NaOH solution and 50cm³ of 0.5mol/dm³ HNO3 were mixed at 20°c and stirred in a calorimeter with negligible heat capacity. The temperature of the mixture rose to 23.2°c.the density of each solution is 1.0g/cm³ and the specific heat capacity of each solution is 4.18J/K/g.calculate
i.the enthalpy for the neutralization
ii.calculate the change in enthalpy per mole of water formed
The enthalpy of neutralization is -53.6 kJ/mol
The change in enthalpy per mole of water formed is 53.6 kJ/mol.
What is the enthalpy of neutralization?We have to note that the enthalpy is the heat that have been evolved or absorbed in a reaction. We can see that in this case, the reaction involved the combination of sodium hydroxide and nitric acid.
Number of moles of the reactants = 50/1000 L * 0.5 mol/dm³
= 0.025 moles
Total mass of the reactants = 50 g + 50 g = 100 g (Since the density of the solution is 1.0g/cm³)
The heat evolved = mcdT
m = mass of the solution
dT = temperature change
c = Heat capacity of the solution
H = 100 * 4.18 * ( 23.2 - 20)
H = 1.34 kJ
The heat evolved = - ( 1.34 kJ/0.025 moles)
= -53.6 kJ/mol
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The following redox reaction occurs betwen the dichromate ion and ethanol:
3CH3CH2OH + 2CrO7^2- + 16H+ => 3CH3COOH + 4Cr^3+ + 11H2O
A chemist uses 26.25 mL of 0.500 M CrO7^2- to titrate a 10.0 mL sample of wine to the equivalence point.
a) What is the [CH3CH2OH] in the wine?
b) The concentration of ethanol in alcoholic beverages is expressed as percent by volume. If a wine is 10% alcohol, it means that there are 10 mL of ethanol for every 100mL of the beverage. The density of ethanol is 0.789 g/mL. Convert your answer in part (a) into percent by volume
Answer:
a) 1,69 M
b)11.55%
Explanation:
a) To determine the [CH3CH2OH] in the wine, we can use the stoichiometry of the balanced equation provided. Since the ratio of CrO7^2- to CH3CH2OH is 2:3, for every 2 moles of CrO7^2- that are consumed, 3 moles of CH3CH2OH are produced. Therefore, we can use the volume and molarity of the CrO7^2- solution to determine the number of moles of CH3CH2OH present in the wine sample.
The number of moles of CrO7^2- used in the titration is (26.25 mL)(0.500 M) = 13.125 moles. Therefore, the number of moles of CH3CH2OH present in the wine sample is (3/2)(13.125 moles) = 19.69 moles
Since the original volume of wine sample was 10.0 mL, the [CH3CH2OH] in the wine is (19.69 moles) / (0.01 L) = 1.969 M
b) To convert the answer in part (a) into percent by volume, we can use the density of ethanol and the conversion factor of 100mL/1L.
The density of ethanol is 0.789 g/mL, so the mass of ethanol in the sample is (19.69 moles) x (46.07 g/mol) = 910.1 g
The mass of ethanol in 100ml is (910.1g) x (100mL/1L) = 91.01 g/100mL
The volume of ethanol in the sample is (91.01 g/100mL) / (0.789 g/mL) =115.5 mL/L or 11.55% by volume.