Answer:Chemical reactions that release energy are called exothermic. In exothermic reactions, more energy is released when the bonds are formed in the products than is used to break the bonds in the reactants. Chemical reactions that absorb (or use) energy are called endothermic.
Explanation:
explain why multiple extractions are done on a compound (for example, in the caffeine lab you shook the water with caffeine in it with methylene chloride once, then removed the methylene chloride and added more methylene chloride to the water with caffeine).
To known the multiple extraction and methylene chloride reactions.
What is methylene chloride?
Dichloromethane, another name for methylene chloride, is an odorless, flammable liquid with a volatile nature similar to chloroform. Paint stripping, the production of pharmaceuticals, the production of paint removers, and the cleaning and degreasing of metal are just a few of the industries that use methylene chloride in various industrial processes.
What is multiple extraction?
In a multiple extraction procedure, a certain amount of solvent is used to successively extract one layer (often the aqueous layer). If the compound has a low partition coefficient in the organic solvent, the extraction may need to be repeated more than twice or three times.
Because it is denser than water, methylene chloride typically makes up the bottom layer of the two-part mixture. Caffeine can be drawn out of the organic layer by brewing tea and adding methylene chloride to it.
Therefore, Caffeine can be drawn out of the organic layer by brewing tea and adding methylene chloride to it.
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An electron in the n = 5 level of an h atom emits a photon of wavelength 94. 98 nm. To what energy level does the electron move?.
The electron will move to energy level
n =1 ..
We have, an electron in the n= 5 level of an Hydrogen atom emits a photon of wavelength 94.98nm...
Using the Rydberg formula ,
1/ λ = R ( 1/ n²ⱼ- 1/n²ᵢ)
where, lambda ----> wavelength of photon
nⱼ----> excited energy level
nᵢ---> initial energy level at which electron of hydrogen atom emits photon
R -----> Rydberg constant
photon are packet of energy.
we have give nᵢ = 5 , lambda = 94.98nm = 94.98×10⁻⁹m
R = constant = 1.097× 10⁷ m⁻¹
Substitute the values in formula we get ,
10⁹/ 94.98 = 1.097× 10⁷ ( 1/ n²ⱼ - 1/ 25) ⇒ 1/ n²ⱼ - 1/25 = 10^2/94.98×1.097 = 0.95975.68 ⇒ 1/n²ⱼ= 0.99975 ⇒ n²ⱼ= 1.00024 => nj = 1.00012
So, the electron moves from n= 5 energy level to to n= 1 energy level.
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Describe the properties of common alloys (carbon steel, bronze, brass, and sterling silver) and how their properties are different than their parts.
The properties of common alloys include the following:
High melting pointGood conductors of heat and electricity.Corrosive resistant.What is an Alloy?This is referred to as a substance which is composed of two or more elements in which one of them is usually a metal. Examples of alloys include bronze which is made up of copper and tin and brass which is made up of copper and zinc.
They are corrosive resistant and are good conductors of heat and electricity due to their high degree of hardness and toughness which makes them different from their parts and is therefore the correct choice.
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What does a molecule structurally have to have in order to be able to form condensation polymers vs only being able to form a single ester?.
The ester can polymerize if both the acid and the alcohol have different functional groups.
What is a molecule, for instance?A molecule is the smallest unit of any material that is composed of one or more elements and is capable of existing independently while maintaining all of the substance's physical and chemical properties. Further atom division occurs within molecules. For instance, the symbols for the oxygen atom and molecule are O and O2, respectively.
What is a molecule, exactly?The smallest component of a substance which possesses both its chemical and physical characteristics. One or even more atoms make up molecules.
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A sample of oxygen at a temperature of 20 °c occupies a volume of 335 ml. How many moles of gas are present if the pressure is 0. 998 atm?.
Us the PV=nRT formula!
How many protons, neutrons, and electrons for b+5
Explanation:
It has 5 protons,6 neutrons, 5 electrons.
give a brief explanation of the term ion selective electrode (ise). describe the ise used in this experiment.
Ion selective electrodes are those electrodes that converts concentration of a specific ion that is present in a solution into electrical potential.
These ion selective electrodes are basically electrochemical sensors that work based on the principle of galvanic cell. The set up of these electrodes generally consists of a reference electrode, ion-selective membrane and a voltmeter.
The transport of ions from a region of higher concentration to a region of lower concentration through the selective membrane creates a potential difference. This potential difference can be measured with respect to a standard reference electrode having a constant electrode potential.
They are used for chloride, potassium, calcium, carbon dioxide/carbonate, oxygen, and a variety of other ions. These methods are particularly well suited for field analysis and also online measurements.
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how many coefficients need to be changed to make this chemical equation balanced? Zn + HNO3 --> Zn (No3)2 + H2
Coefficient 2 should be placed in the equation before the nitric acid in the reactant so that the chemical reaction becomes balanced.
The given chemical reaction is,
Zn + HNO3 --------> Zn (No3)2 + H2
Here, the elements Hydrogen, Nitrogen, and Oxygen are unbalanced.
These elements are altogether found in HNO₃ on the reactant side and are found as nitrate and hydrogen gas on the product side.
To balance the equation, the coefficient 2 is to be added in the reactant side so that 2 moles of Hydrogen, Nitrogen, and Oxygen would be balanced with 2 moles of Nitrate and two moles of Nitrogen.
On adding 2 on reactant side, we get
Zn + 2HNO3 -----------> Zn(NO3)₂ + H₂
This gives us a balanced equation and thus the equation could be balanced this way.
Therefore, coefficient 2 is to be added to make the equation to be balanced.
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Imagine you are making s'mores. For each s'more you need 1 marshmallow, 2 graham crackers, and 1 piece of chocolate. You have 15 pieces of chocolate, 25 marshmallows, and 26 graham crackers. Which is the limiting reactant? Which reactants will you have in excess, and how many of each will be left? Explain your answer and include the definitions of a limiting reactant and an excess reactant.
Gram crackers are limiting reactants, and marshmallows and chocolate are excess reactants. 10 marshmallows and 2 chocolates are left.
What is a limiting reagent?A limiting reagent can be defined as the reactant in the reaction which is consumed first in the completion of a chemical reaction. The excess reactant is the one that is left unreacted after the completion of the chemical reaction.
The limiting reagent will decide the yield of the product when the amount of the reactants for a reaction is not taken in stoichiometry.
Given to make one s'more we need 1 marshmallow, 2 graham crackers, and 1 piece of chocolate.
1 marshmallow + 2 graham crackers + 1 piece of chocolate = 1 s'more
Given, the number of pieces of marshmallows = 25
The number of pieces of chocolate = 15
The number of pieces of graham crackers = 26
For 2 graham crackers, we need marshmallows = 1
For 26 graham crackers, we need marshmallows = 26/2 = 13
For 26 graham crackers, we need chocolate = 26/2 = 13
Therefore, graham crackers are a limiting reactant, and marshmallows and chocolate are excess reactants.
The number of marshmallow left = 25 - 15 = 10
The number of chlocales left = 15 -13 = 2
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Compare the behavior of the particles in hot tea with the behavior of the particles in ice
cream. How are they similar?
Answer: they are the same because they both convert and deal with thermal energy because it’s not created or destroyed
Explanation:
When gasoline is burned in a car engine, ________ energy is converted into _________ energy.
When gasoline is burned in a car engine, thermal energy is converted into mechanical energy.
What is energy conversion?
Energy conversion is the process by which energy is changed from forms supplied by nature to forms used by people.
For this goal, a huge variety of tools and systems have been created over the years. A few of these energy converters are really straightforward. Early windmills, for instance, used wind's kinetic energy to drive machinery that pumped water and ground grain.
Many of the forms that energy takes can be employed in natural processes. It also performs mechanical work to run the machines and offers various services to society, such as lighting, heating, and refrigeration. By applying pressure to the pistons and exerting work on them, the internal combustion engine of a car transforms the potential chemical energy in gasoline and oxygen into thermal energy, which is then translated into mechanical energy that drives the vehicle (raising its kinetic energy).
You can see that the vehicle engine converts the chemical energy that is contained in the fuel into the kinetic energy of expanding gas through combustion in the engine and the wheels. This is a practical energy transfer.
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select all the dibasic bases from the following list. multiple select question. sr(oh)2 ca(oh)2 nh2oh
Dibasic bases split into two OH- ions.
What is dibasic acid?
A dibasic acid is one that, when reacting with a base, can release two positively charged hydrogen ions, as well as protons. Diprotic acid is a more recent name for this kind of acid. Normally, an acid and a base will react to create salt and water. When the negative charges hydroxide ion from the base reacts with the positively charged hydrogen ion from of the acid, the result is water: H+ + OH- H2O. Two types of salt can be created from the two hydrogen atoms in a dibasic acid molecule, one of which is an acid salt with a hydrogen atom. One of the most well-known and frequently used acids is sulfuric acid, which is a good illustration of a dibasic acid.
Hence, the answer is Sr(OH)2 and Ca(OH)2.
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select the single best answer. halogens are not the only atoms or groups that can be replaced by nucleophilic aromatic substitution as the following reaction shows. h512p601 what is the leaving group in this reaction? (formal charges have been intentionally omitted.) h512p60c h512p60b h512p60a
NO2 is in the form of O=N+-O, As a nucleophilic leaving group it should be in form of O=N-O¯. So the correct option is first one.
What is nucleophilic aromatic substitution?
It is a classical reaction in which a nucleophile displaces a leaving group on an aromatic ring.The presence of electron-withdrawing group increases the rate of nucleophilic aromatic substitutionNucleophilic aromatic substitution does not follow SN2 reaction mechanism, as the substitution takes place at trigonal carbon atom having sp3 hybridisation.It does not follow the SN2 reaction mechanism because of the steric hindrance of the benzene ring.Nucleophilic aromatic substitution may follow SN1 reaction mechanism in presence of an excellent leaving group.SN1 reaction would involve elimination of leaving group and formation of aryl carbocation.Generally, Nucleophilic aromatic substitution follows elimination addition or addition elimination pathway.NO2 is in the form of O=N+-O, As a nucleophilic leaving group it should be in form of O=N-O¯. So the correct option is first one.
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note: complete question is attached
Question 1 (1 point)
Which of the following statements correctly describes the relationship between the
reactants and the products of a chemical reaction?
The total mass of the reactants must be less than the total mass of the products.
Products and reactants always have the same physical and chemical states.
Products always have a different physical and chemical state than reactants.
The total mass of the reactants must equal the total mass of the products.
Answer: A The total mass of the reactants must equal the total mass of the products.
Explanation:
In the introductory week 1 experiment, the developing solvents were 5% sodium chloride aqueous solution and 5% isopropanol aqueous solution. Draw separate molecular diagrams of how sodium chloride and isopropanol would interact in water. Identify the types of intermolecular attractions within each diagram. Based on the diagrams and intermolecular attractions identified in Question 2, predict and compare the nature of intermolecular interactions experienced by the FD&C Red No. 40, Blue No. 1, and Yellow No. 5 dyes with the two solvents. Chromatography paper, and paper in general, is highly hydrophilic. Paper is made from a natural polymer called cellulose, which is a long chain of glucose molecules. Glucose is a cyclic structure with a number of –OH groups around the ring. Predict and explain the types of intermolecular forces that would occur between paper and water. How do these interactions account for the hydrophilic nature of paper? Explain the types of intermolecular interactions that would occur between the FD&C Red No. 40, Blue No.1, and Yellow No. 5 food dyes and the paper.
2. When NaCl is dissolved in water it forms Nat and CL-ions which interact with water with ion-dipole forces of attraction. There exists a sphere of water molecules around respective ions.
Whereas in isopropyl alcohol there exists H- Bonds as well as Ion-dipole forces in these dyes in comparison to those there will
3.) There will exist H bonding in all these dyes along with ion-dipole forces of attraction as well as repulsive forces as well because of nonpolar groups in dyes and polar water molecules but attractiveness will be more than that of repulsive ones.
4. Chromatography papers are generally made up of cellulose which is again a polymer of glucose. Now there exist H bonds between hydroxyl groups of paper that are hydrophilic which means water-loving. polymer and water molecules. Because of this H binds chromatography.
B. There will exist again hydrogen bonds among dye and chromatogram more will be the attractions between dye and paper lesser will be retention factor it will adsorb more or lesser will go with solvent.
In chromatography, there are also intermolecular forces such as hydrogen bonding and dipole-dipole interactions that help keep the analytes on the stationary phase of the column. The stronger the intermolecular forces, the stronger and longer the compound will be retained on the column. It is a type of planar chromatography that uses cellulose filter paper to act as the stationary phase for the separation of compounds.
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What are values for standard temperature? Check all that apply.
0°C
20°C
25°C
-273.15°C
273.15 K
i really think the answer is
Answer:
What are values for standard temperature?
Check all that apply.
A) 0
E) 273.15
Explanation:
edge 2023
Students in class argue about whether salt (nacl) or water (h2o) has stronger intramolecular forces. Which argument is best?.
Since, intermolecular forces is stronger in a solid than a liquid, then NaCl has stronger intermolecular forces than H2O.
Intermolecular forces exists between molecules of the same or different kinds. Water has a dipole moment hence it can interact effectively with the ions in NaCl. This leads to an ion dipole interaction that results in the dissolution of NaCl in H2O.
NaCl is a solid and water is a liquid. Since intermolecular forces is stronger in a solid than a liquid, then NaCl has stronger intermolecular forces than H2O.
Hence, the best argument that compares the intermolecular interactions in water and NaCl is; salt is a solid and water is a liquid, so water has stronger intramolecular forces.
What does intramolecular forces mean ?
An intramolecular power (or essential powers) is any power that ties together the particles making up an atom or compound, totally unrelated to intermolecular powers, which are the powers present between atoms. The unpretentious distinction in the name comes from the Latin underlying foundations of English with entomb importance between or among and intra meaning inside.Chemical bonds are viewed as intramolecular powers which are frequently more grounded than intermolecular powers present between non-holding particles or atoms.
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classify the substances according to the type of bonds (nonpolar covalent, polar covalent, or largely ionic) that occurs between the atoms based on electronegativity differences. drag the appropriate substances to their respective bins.
When two atoms have an electronegativity difference of 0.4 or less they form a nonpolar covalent bond.
A covalent bond in which the electron density is unevenly distributed between the two bonded atoms due to differences in electronegativity or inductive effects. If there are two non-metals involved in some bonding activity, it could be a covalent bond. A general rule of thumb is when you have metals and non-metals.
This is probably an ionic bond. These are general rules of thumb. Ionic compounds are formed when metals react with non-metals or polyatomic ions. A covalent bond is formed when two non-metals react with each other. Since hydrogen is a non-metal, binary compound containing hydrogen are usually also covalent compounds.
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Disclaimer:- your question is incomplete,please see below for the complete question.
classify the substances according to the type of bonds (nonpolar covalent, polar covalent, or largely ionic) that occurs between the atoms based on electronegativity differences. drag the appropriate substances to their respective bins.
A.Nacl
B. CCl4
C.H2O
If you have 50mg of a radioactive isotope, how much will remain after 1 Half Life? How much after 2 half lives?
Answer:The quantity of radioactive nuclei at any given time will decrease to half as much in one half-life. For example, if there were 100 g of Cf -251 in a sample at some time, after 800 years, there would be 50 g of Cf -251 remaining. After another 800 years (1600 years total), there would only be 25 g remaining.
Explanation:
molality is defined as the number of moles of solute per kilogram of solvent. in dilute aqueous solutions of electrolytes, the greater the number of particles produced by the electrolyte per kilogram of water, the lower the freezing point of the solution. the freezing points of dilute aqueous solutions of equal molality of the two electrolytes in which of the following pairs would be most different from each other?
The freezing points of dilute aqueous solutions of equal molality of the two electrolytes then pairs would be most different from each other are LiBr and Al₂(SO₄)₃
Molality is defined as the number of moles of solute per kilogram of solvent freezing point is the temprature at which liquid become a solid called as freezing point and the freezing point of solution are all lower than that of the pure solvent and is directly proportional to the molality of the solute then the pairs would be most different from each other are LiBr and Al₂(SO₄)₃
The given question is incomplete so the complete question is
Molality is defined as the number of moles of solute per kilogram of solvent. In dilute aqueous solutions of electrolytes, the greater the number of particles produced by the electrolyte per kilogram of water, the lower the freezing point of the solution. The freezing points of dilute aqueous solutions of equal molality of the two electrolytes in which of the following pairs would be most different from each other?
A. K2SO4 and CoI2
B. AgClO4 and Ni(NO3)2
C. LiBr and Al2(SO4)3
D. MgCl2 and ZnSO4
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Convert 6.7 x 10^24 atoms of sulfur into moles of sulfur
Answer:
1.1142614300909401e-23
Explanation:
1.1142614300909401e-23
What is the difference between allergens and smog?
Answer:
It can make you allergic to pollution. With the increase in urbanization and industrialization, air pollution has been on a rise. Correlatively, cases of air pollution allergy have also shot up. In fact, air pollution alone causes allergic rhinitis in 40% of the world population.
Explanation:
1. what would be the order of elution of your crude product mixture (a mixture of 1-bromobutane and 1-butanol) if you injected your distillate into the injector port of the gas chromatography equipped with a polar column (such as carbowax polyethylene glycol)?
Bromobutane and 1-butanol would come in first and second, respectively.
What does chromatography serve as a tool for?Chromatography's goal is to separate different components of a mixture. Applications can be anything from a straightforward analysis of a compound's purity to a precise breakdown of its constituent parts.
What is the best chromatography?High-performance column chromatography is a distant contender to gas chromatography as the most widely used chromatography technique. This technique is used in many labs because to its effectiveness in moving samples through the apparatus with a high-pressure pump employing a liquid (or solvent) mobile phase.
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which of the following groups of elements is arranged correctly in order of increasing first ionization energy?
The following groups of elements are arranged correctly in order of increasing the first ionization energy Al<B<O<F.
That atom will easily lose electrons which will achieve a stable configuration on its loss and its ionization energy will be less. So, Al and B will have a fully filled configuration after the loss of an electron. Fully filled configuration is exceptionally stable. Effective nuclear charge is inversely proportional to ionization energy.
First ionization energies vary in predictable ways across the periodic table. The ionization energy decreases in groups from top to bottom and increases over time from left to right. Therefore, helium has the highest initial ionization energy and francium has the lowest one. The initial ionization energy increases as one progresses through the rows of the periodic table from left to right.
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Disclaer:- your question is incomplete,please see below for the complete question.
which of the following groups of elements is arranged correctly in order of increasing first ionization energy.
A. Al<F<O<B
B. Al<B<O<F
C. B<O<F<Al
D. B< O < Al < F
What is the mass of a billiard ball that has a volume of 100 cm³ and a density of 2. 5 g/cm³?.
the mass of a billiard ball that has a volume of 100 cm³ and a density of 2. 5 g/cm³ is 250 g
mass can be determined by the density of an object and volume.
The mass of a substance can be calculate by using the formula
From the question
mass = density * volume
mass = 2. 5 g/cm³ * 100 cm³
mass = 250 g
therefore,the mass of a billiard ball that has a volume of 100 cm³ and a density of 2. 5 g/cm³ is 250 g
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a stock solution of potassium chloride has a concentration of 200.0gl. what volume of the stock solution is required to prepare a 2.00l solution with a concentration of 50.0gl?
The equation M1V1 = M2V2 is used to solve problems related to dilution in chemistry
Given data in the question
intial concentration = 200 g/l
final concentration = 50 g/l
volume = 2.00 l
Now we know that
M1V1 = M2V2
where
M1 = initial concentration
M2 = concentration after mixing or diluting
V1 = initial volume,
V2 = total final volume
The equation M1V1 = M2V2 is used to solve problems related to dilution in chemistry
What is dilution?
It is process of decreasing the concentration of a solute in a solution, usually simply by mixing with more solvent like adding more water to solution.”
200 g/l × V = 50 g/l × 2
V = ( 50 × 2 ) / 200
= 0.5 L
Volume of stock required is 0.5L
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what is the molality of a solution in which 0.145 mol co2 (molar mass = 44.01 g/mol) is dissolved in 591 g water?
The molality of the solution is 0.010mole/kg.
Molality of a solution is the amount of the substance dissolved in the solvent. It is defined as the molar mass of the solute per 1kilogram of a solvent. Molar mass of the solvent is the amount of the compound divided by the amount of the substance .It is measured in moles.
We can calculate molality by dividing the amount of the solute by the mass of the solvent. Here amount of the solute calculated in moles and the mass of the solvent in grams.
Molality= amount of the solute/mass of the solvent
here, amount of the Co2 is 0.145 mole , molar mass is 44.01g/mole and mass of the water is 591 g(0.59kg).
so, substituting all value in the expression of molality, we get,
Molality=0.145* 0.044 /0.59kg
=0.010mole/kg
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Determine whether each of the preceding is exothermic or endothermic Drag the items into the appropriate bins. Reset Help exothermic endothermio Part B Indicate the sign of Δ H Drag the items into the appropriate bins. a. natural gas burning on a stove b. isopropyl alcohol evaporating from skin c. water condensing from steam
The correct options are
a. natural gas burning on a stove - exothermic reaction
b. isopropyl alcohol evaporating from skin - endothermic reaction and
c. water condensing from steam - exothermic reaction.
The gas burning is the reaction between natural gas and oxygen that releases products and heat energy. Thus it is exothermic process. Isopropyl alcohol is liquid which on evaporation converts into steam. This requires energy and hence is endothermic process. The water condensation from steam requires loss of energy, thus this process is exothermic.
Exothermic process release energy and is represented by negative ∆H. The opposite is true of endothermic reactions that absorbs energy and is represented by positive ∆H.
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Calculate the mass of 1.3mol of Hydrogen Sulfide
Answer:
mass = 44.2 g
Explanation:
We are asked to calculate the mass of 1.3 mol of hydrogen sulfide, H₂S.
To do this, we can use the following formula:
[tex]\boxed{\mathrm{mass = No. \ of \ moles \times M_r}}[/tex].
The [tex]\mathrm{M_r}[/tex] (relative molecular mass) of H₂S is:
[tex]\mathrm{M_r}[/tex] = (2 × 1) + 32
= 2 + 32
= 34
Therefore, using the formula above and substituting the data, we get:
mass = 1.3 × 34
= 44.2 g
select all that apply: why do you want to continue to collect at least 4 or 5 measurements after hitting the experimental end point?
Titration is repeated at least 4 to 5 times in order to provide a statically valid answer.
What is Titration-
Titration is a typical laboratory technique for quantitative chemical analysis used to calculate the concentration of an identified analyte (also known as titrimetric and volumetric analysis) (a substance to be analyzed). A standard solution with a known concentration and volume is prepared as the reagent, also known as the titrant or titrator.
Its a form of volumetric analysis to uncover the concentration of a substance, and the readings should all be within a very small number of units of one another.
The closeness of two or more measurements to each other is known as the precision of a substance. Precision is independent of accuracy.
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