The percent yield of KOH is 78.7%.
Balanced chemical reaction:
4KO₂ + 2H₂O → 4KOH +3O₂
m(KO₂) = 22.4 g; mass of the oxide
m1(KOH) = 13.9 g; mass of the potassium hydroxide produced
n(KO₂) = 22.4 g ÷ 71.1 g/mol
n(KO₂) = 0.315 mol; amount of the oxide
From chemical reaction: n(KO₂) : n(KOH) = 1 : 1
n(KOH) = 0.315 mol; amount of the potassium hydroxide
m(KOH) = 0.315 mol x 56.1 g/mol
m(KOH) = 17.67 g; a theoretical yield of KOH
the percent yield = 13.9 g / 17.67 g x 100%
the percent yield = 78.7%
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A chemist measures the amount of fluorine gas produced during an experiment. He finds that 3.8 g of fluorine gas is produced. Calculate the number of moles of fluorine gas produced. Round your answer to 2 significant digits.
Answer:
0.10
Explanation:
Molar mass of F2 gas = 38 g/mol.
Moles of F2 gas = 3.8/38 g/mol
=0.1
Rounded to 2 significant digits is 0.10.
0.10 moles F2 has been produced.
An experiment requires 18.0 g of cyclohexane, which has a density of 0.7781 g/mL at 25°C. What volume of cyclohexane should be used?
Taking into account the definition of density, the volume of cyclohexane should be 23.13 mL.
Definition of densityDensity is defined as the property that matter, whether solid, liquid or gas, has to compress into a given space and allows us to measure the amount of mass in a certain volume of a substance.
The expression for the calculation of density is:
density= mass÷ volume
Volume of cyclohexaneIn this case, you know that:
Density= 0.7781 g/mLMass= 18 gReplacing in the definition of density:
0.7781 g/mL= 18 g÷ volume
Solving:
0.7781 g/mL ×volume= 18 g
volume= 18 g÷ 0.7781 g/mL
volume= 23.13 mL
In summary, the volume of cyclohexane should be 23.13 mL.
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H2po4-1 has a pka of 6.86. if the concentration of h2po4-1 is 0.622 mm and the concentration of h1po4-2 is 0.038 mm what is the ph of the solution?
H2po4-1 has a pka of 6.86. if the concentration of h2po4-1 is 0.622 mm and the concentration of h1po4-2 is 0.038 mm the ph value in the solution is 8.3
pH stand for potential hydrogen the pH of a solution also can be determined by finding the pOH. determine the concentration of the hydroxide ions by dividing the molecules of hydroxide by the volume of the solution and here to find pH value in the solution here the formula is
pH=pka log acid/base
ph=pka log h2po4-1/h1po4-2
ph=6.86×log0.622/ 0.038
ph=6.86×log16.36
ph=6.86×1.21
ph=8.3
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give an 3 examples for the following:
Solid to solid
Liquid to gas
*I'm in 6th grade and this subject is science, thanks!)
Explanation:
brass copper mixed with zinc
A dmixture of sugar and gari
A mixture of beans and rice
Calculate the number of atoms per cubic meter in aluminum. the density of al is 2.71 g/cm3, while its atomic weight is 26.98 g/mol.
The number of atoms per cubic meter in aluminum is 6.04 x 10²².
What is density?"Density is the mass per unit volume. Density is a scalar quantity. It is denoted by d and the symbol for density is given as rho, a Greek symbol. Density is calculated as mass divided by volume."
The density of Al is 2.71 g/cm3
The atomic weight of Aluminum is 26.98 g/mol.
The Avogadro's number is 6.023 x 10²³
To find the number of atoms per cubic meter
N = ρNa / A
N = 2.71 x 6.023 x 10²³ / 26.98 = 6.04 x 10²²
Thus, the number of atoms per cubic meter in aluminum is 6.04 x 10²².
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Help me pls Its not a exam its about Homogenous and heterogeneous pls help me and pls rigth its description
Answer: hope this helps :)
Explanation:
Heterogeneous:
soy sauce, pizza, fruit salad, halo halo, iced mango juice (assuming this is a mango milkshake), sago milk tea
Homogeneous:
vinegar, salt solution, sugar syrup
abno ka hahaha hatdog hamburger
Is it the power of material evidence that wins, not the authority of experts that
proves an answer in Science.
Yes, it is the power of material evidence that wins.
Evidence used to support or refute a scientific theory or hypothesis is known as material evidence.Evidence is also used by scientists in various contexts, such as when they apply ideas to real-world issues.Whether a person accepts the data as proof depends on their presumptions or views regarding how observations relate to a theory.A creative hypothesis is developed by a scientist and may be refuted by testing it against evidence or established truths.Evidence can refute a hypothesis by demonstrating facts that are at odds with it. In contrast, the presence of evidence does not preclude the possibility of future, undiscovered evidence supporting the idea.Therefore, it is the power of material evidence that wins, not the authority of experts that
proves an answer in Science.
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A student wonders whether a piece of jewelry is made of pure silver. she determines that its mass is 3.17 g. then she drops it into a 10 ml graduated cylinder partially filled with water, and determines that its volume is 0.3 ml. could the jewelry be made of pure silver?
No, the jewelry, could not be made of pure silver.
State characteristics properties of silver.The characteristics of pure silver include being almost white, shiny, soft, ductile, malleable, and a superb conductor of both heat and electricity. Although it is not a chemically active metal, heated concentrated sulfuric acid and nitric acid both attack it and cause nitrate to form. Silver is one of the so-called precious metals, along with gold and the metals from the platinum group. Silver has been used for many years to make coins, ornaments, and jewelry due to its relative rarity, dazzling white color, malleability, ductility, and resistance to air oxidation. Silver is also a soft, malleable, highly ductile, and shiny metal. Despite having the highest electrical conductivity of any metal, its exorbitant cost prevents it from being widely used for electrical purposes. Silver is not a metal that reacts chemically.
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Phosgene (cl2co)(cl2co), a poison gas used in world war i, is formed by the reaction of cl2cl2 and coco. the proposed mechanism for the reaction is:________
Phosgene was used during the World War I as a poisonous gas. It can be prepared by the action of sunlight on a mixture of carbon monoxide and chlorine gases. Phosgene has the following elemental composition by weight: 12.14% C, 16.17% O and 71.69% chlorine. Its molecular weight is 98.9 g mol-1.
Phosgene is a foremost industrial chemical used to make plastics and pesticides. At room temperature (70°F), phosgene is a toxic gas. With cooling and pressure, phosgene fuel can be converted into a liquid so that it can be shipped and stored.
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When 10.286 g of a compound containing only carbon and hydrogen was burned completely in 38.265 g of oxygen, 33.264 g of carbon dioxide and some water were formed. calculate the mass of water.
Mass of water = 15.287 grams.
The equation here will look like this:
CxHy + O2 ------->CO2 + H2O
Hydrocarbon (contains c' and 'H' alone) and O2 are the reactants in this reaction.
Water and carbon dioxide are products.
Since mass cannot be created or destroyed in an isolated system, we now know this to be true. Although it is conserved, it can change forms.
Therefore, for chemical reaction
The mass of the reactants and the mass of the products must match. Here, just forms are altered to create the product.
Consequently, according to the Mass Law of Conversion:
Mass of Reactants = Mass of Products, we might say.
[(Mass of CO2) + (Mass H2O ] = [(Mass of Hydrocarbon) + (Mass of 02)]
[10.286 + 38.265] = [33.264 g + Mass of H20]
48.551 = 33.264 + Mass of H2O.
Mass of water equals 48.5519-33.261
The Mass of water will therefore be 15.287 grams.
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The mass of an atom doesn't include the mass of the electrons because?
a) of their negative charges
b) electrons are so small they don't really add any weight
c) they are outside the nucleus
I'm sure but a or c I'm sure
42.0 ml of 0.130 m naoh and 37.6 ml of 0.360 m naoh. assume that the volumes are additive.
Mixed molarity is 0.254 M
The volumes are additive is 1.22 M
Part A
mixed molarity = (M1 V1 + M2V2 )/ V1+V2
= (0.150 x 42 + 0.370 x 37.6 ) / (42+37.6)
= 0.254 M
NaOH = 0.254M
[Na+ ]= 0.254M
[OH-]= 0.254M
Part B
[Na+] = 2 x 44 x 0.1 / 44 + 25
= 0.1275 M
{SO4-2] = 44 x 0.1 / 44 + 25 = 0.063 M
[K+] =25 x 0.17 / 44 + 25 = 0.062 M
[Cl-] = 25 x 0.17 / 44 + 25 = 0.062 M
Part C
KCl moles = 3.70 / 74.55 = 0.0493
KCl molarity = 0.0493 / 0.075 = 0.66M
[K+] = 0.66 M
[Ca+2] = 0.280 M
[Cl-] = 0.66 + 2 x 0.280 = 1.22 M
Volume is a measurement of three-dimensional space that is occupied. Numerous imperial units or SI-derived units, such as the cubic meter and liter, are frequently used to quantify it numerically (such as the gallon, quart, and cubic inch). Volume and length (cubed) have a symbiotic relationship. The volume of a container is typically thought of as its capacity, not as the amount of space it takes up. In other words, the volume is the amount of fluid (liquid or gas) that the container may hold.
Volume was initially measured using naturally occurring vessels of a comparable shape and then with standardized containers. Arithmetic formulas can be used to quickly calculate the volume of several straightforward three-dimensional shapes.
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A sample of monochloro pentaborane (9), b5h8cl, has a mass of 20.1 g. what amount, in moles, does this mass represent?
The number of moles in monochloro pentaborane (9) [tex]B_5H_8Cl[/tex] is 0.37056.
We know that ,
Number of moles = Given mass/ Molar mass
Given mass of monochloro pentaborane (9) is 20.1 g
The molar mass of monochloro pentaborane (9) is
= [tex]5*B + 8*H + Cl[/tex]
= [tex]5* 10.811 + 8 * 1 + 35.453[/tex]
= 54.241
Thus number of moles = 20.1/54.241
= 0.37056
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Around 1750 Benjamin Franklin knew of two opposite types of electric charge, produced by rubbing a glass rod or amber rod with fir. He decided that the charge developed on the glass rod should be "positive" charge, and from there on charges were defined. What would have changed if Franklin had decided the amber rod was the positive charge?
If Benjamin Franklin had decided to call the charge on the amber rod positive, nothing would have changed only that we would have a different convention for identifying charges.
What would have changed?We know that electricity has to do with the flow of current, there are fundamentally two kinds of charge, a positive and a negative charge. We know that the kind of charge that a material carries is arbitrary.
As we can see here, it was Benjamin Franklin in 1750 that defined the charge on the glass rod and the charge on the amber rod as negative. If Benjamin Franklin had decided to call the charge on the amber rod positive, nothing would have changed only that we would have a different convention for identifying charges.
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All of the following are clues that a chemical reaction has taken place except:_______
a. a color change occurs.
b. a flame occurs.
c. the reactant is smaller.
d. bubbles form.
e. a solid forms.
Explanation:
a color change occurs cause when it Colides it mixes in with the other color and changes it completely
The correct answer is option C . Clue that a chemical reaction has taken place is not that the reactant is smaller.
Let's break down each of the options to understand why option c is incorrect:
a. A color change occurs: When a chemical reaction occurs, there may be a change in color. For example, when iron rusts, it changes from a metallic silver color to a reddish-brown color.
b. A flame occurs: Some chemical reactions produce heat, and if the reaction is exothermic enough, it can produce a flame. For instance, when wood burns, a flame is produced as a result of a chemical reaction between the wood and oxygen.
c. The reactant is smaller: This statement is incorrect. A chemical reaction does not necessarily mean that the reactant becomes smaller. Reactants can combine to form a larger product or they can rearrange to form different molecules without changing their size.
d. Bubbles form: When a gas is produced during a chemical reaction, bubbles may form. For example, when vinegar (acetic acid) reacts with baking soda (sodium bicarbonate), carbon dioxide gas is released, causing bubbles to form.
e. A solid forms: Some chemical reactions involve the formation of a solid. For instance, when a metal reacts with a non-metal, such as sodium reacting with chlorine to form sodium chloride, a solid salt is formed.
Thus, clues that a chemical reaction has taken place include a color change (option a), a flame (option b), bubbles forming (option d), and a solid forming (option e). The incorrect option is c, which states that the reactant becomes smaller.
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Why is there more variety in kingdom than there is in a species? give an example.
Please I’m begging you I really need to get this thing on this test thing I’m begging you whoever will do it please
An element with the electron configuration 1s22s22p63s23p6 has how many electrons?
An element with the electronic configuration [tex]1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6}[/tex] has Eighteen electrons.
The electronic configuration [tex]1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6}[/tex] is of a Argon. The Atomic number of argon is eighteen. It is represented by the symbol Ar. It belongs to Group 18 and period number 3 of the periodic table. Argon belongs to the family of noble gases. It is a p-block element. The atomic mass of Argon is 39.948 u.
The number of electrons in an element is equal to the atomic number of the element. As the given electronic configuration is of atomic number eighteen , so the total number of electrons in it is also Eighteen.
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1. Eight atoms of carbon react with 18 atoms of hydrogen, forming only one molecule of CsHis. Is the
forming of only one molecule considered a violation of the law of conservation of mass? Explain.
Eight atoms of carbon react with 18 atoms of hydrogen , forming only one molecule of [tex]C_{8} H_{18[/tex] is considered as violation of the law of conservation of mass .
According to the law of mass conservation , neither chemical processes nor physical changes can create or destroy mass in an isolated system . The mass of the products and reactants of a chemical reaction must be equal, in accordance with the law of conservation of mass .
The reaction occur when eight atoms of carbon react with 18 atoms of hydrogen , forming only one molecule of [tex]C_{8} H_{18[/tex] is given as .
8C +18[tex]H_{2}[/tex] → [tex]C_{8} H_{18[/tex]
Mass of reactants = 8 × 12 + 18 × 2 = 132 g
Mass of reactants = 8 × 12 + 18 = 114 g
So , mass of reactant is not equal to the mass of product .
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An element that has the electron configuration 1s22s22p 4 has how many electrons?
Electrons ruminate around the nucleus in particular circular path known as orbit called shell.
Electronic configuration is the dispense of electrons.
Electronic configuration is also known as electronic structure.
Also termed as spatial methodize.
More than one orbital in the electron shell is known as subshell, they have similar energy level.
In Electronic configuration there are four shell present namely k,l,m,n and there are 4 sub-shell namely s,p,d,f.
As we know that every subshell fills gradually s max 2 electrons p - 6 , d - 10 and f - 14.
So,
According to questions,
Thge element has configuration 1s2 2s2 2p4 hence 8 electrons.
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The oxygen anion in carbon monoxide has an atomic number of 8, an atomic mass of 16, and an electrical charge of -2. how many electrons does the oxygen anion have?
Explanation:
Oxygen has atomic number eight. This means that the nuclei of all oxygen atoms have eight protons. A neutral oxygen atom will also have eight electrons.
In an oxygen ion with a
2
−
charge, the number of protons is still 8, but the number of electrons is 10.
This results in the oxygen ion having an octet (8) of valence electrons.
What would be the number of na , k and atp molecules inside the cell after 100 cycles of the pump and what would be the net charge differential across?
The number of sodium, potassium and ATP would be: 700 Na+ ions, 200 K+ ions and 900 ATP molecule.
The net charge differential would be -200.
Potassium is important for keeping the body hydrated and with sodium support cellular function (sodium-potassium ( Na⁺/K⁺) pump).
The sodium-potassium pump releases three Na+ ions, while in the same time two K+ ions exit the cell. For this process one molecule of ATP is consumed.
Inside the cell, there are 1000 sodium ions, 1000 molecules of ATP.
While outside the cell, there are 1000 potassium ions.
After 100 cycles, 300 sodium ions will exit the cell and 200 potassium ions will enter the cell, using 100 ATP molecules.
1000 - 300 = 700; number of sodium ions (Na+) left in the cell
1000 - 100 = 900; ATP molecules left in the cell
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A new element was discovered on the planet zeb ii. it was named zebnium, and given the symbol zb. if the formula for the zebnate ion is zbo43-, what would be the formula for the zebnite ion?
A new element was discovered on the planet zeb ii. The name of the element zebnium, and the symbol of the element, is zb. The formula for the zebnite ion is ZbO³⁻₃.
What is an element?Chemical elements are a substance that is present in the free form or mixed form in the earth's crust. They are represented in the periodic table.
The ion is the charged form of the element. So it will contain a negative or positive sign in with the charge in the compound.
Thus, if the formula for the zebnate ion is zbo43-, The formula for the zebnite ion is ZbO³⁻₃.
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Evaluate 4x+13 when x=-3
4x + 13
4 * -3 + 13
-12 + 13
1
Identify the difference between sterile water (sw) and bacteriostatic water, if any.
Use only sterile water, as was previously indicated. Water is made bacteriostatic by adding benzyl alcohol. You can immediately decide which is suitable based on allergies.
If you are allergic to benzyl alcohol, avoid using or drinking bacteriostatic water altogether and opt for sterile water.
Another distinction is with indications. The FDA regulates the purposes for which drugs are used or what is disclosed on their labels. While sterile water is designated for both irrigation and injection, bacteriostatic water is only intended for injections.
The difference of several uses, as has previously been established, is crucial. Due to the absence of a bacteriostat, sterile water can only be utilized once.
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among the three named compounds, predict which one has the highest viscosity at 25°c. ethane pentane decane
Decane has the highest viscosity at 25°C.
The viscosity of a fluid is a measure of its resistance to gradual deformation by shear stress or tensile stress.
Viscosity depends on intermolecular interactions and molar mass of the substance.
Ethane, pentane and decane are acyclic saturated hydrocarbons (alkanes).
At 25°C, ethane (C₂H₆) is in gaseous state of matter. Its molecular mass is the smallest of these three molecules, so it has lowest viscosity.
Decane (C₁₀H₂₂) and pentane (C₅H₁₂) are liquids at 25°C, but decane has greater molecular mass, therefore the highest viscosity.
M(C₂H₆) = 30 g/mol; molar mass of an ethene
M(C₁₀H₂₂) = 72 g/mol; molar mass of pentane
M(C₅H₁₂) = 144 g/mol; molar mass of decane
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Enter the molecular equation representing aqueous acetic acid neutralized by aqueous barium hydroxide. express your answer as a balanced molecular equation. identify all of the phases in your answer.
The molecular equation representing aqueous acetic acid neutralized by aqueous barium hydroxide:
2CH₃COOH(aq) + Ba(OH)₂(aq) → (CH₃COO)₂Ba(aq) + 2H₂O(l).
CH₃COOH is acetic acid
Ba(OH)₂ is barium hydroxide
(CH₃COO)₂Ba is barium acetate
H₂O is water
Acetic acid is an acid and barium hydroxide is a base. They form salt and water and neutralization reaction takes place.
Neutralization is is reaction in which an acid (in this example acetic acid CH₃COOH) and a base (in this example barium hydroxide) react quantitatively with each other.
Reactants and products are present in undissociated form in molecular equations.
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paulo is experimenting with H2O in its different states. He would like to present all the information he collected in one place. He thinks he should use a phase change diagram, but he isn’t sure. What information could you give Paulo to encourage him to use a phase change diagram?
The phase diagram makes it possible to predict the stability of any of the phases of water based on the diagram..
What is a phase diagram?Water is able to exist in three phases; solid, liquid and gas. The reason behind the phases of water is the fact that there are different degrees of intermolecular interactions that exists in the various phases of water.
Thus, on the phase diagram, of is easy to trace the the regions of temperature and pressure that corresponds to the solid, gaseous and liquid states of a given substance that could be used to make deduction about the substance.
The phase diagram shows the interaction between the various phases of water on the same diagram. This makes it possible to predict the stability of any of the phases of water based on the diagram.
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What is the relationship between events and patterns?
O A. Patterns cause events to occur.
B. Events that happen over and over form a pattern.
C. Events explain how patterns work.
D. Patterns explain what causes events to happen.
The correct answer is Events that happen over and over form a pattern.
An Event is a collection of an experiment's results. Say, for instance, that you throw a coin as part of an experiment. This experiment's result is whether the coin lands "heads" or "tails." These can be regarded as the events related to the experiment. Data repetitions in predictable ways are referred to as patternsPattern helps to understand the trend of occuring event. The general format that an event follows is called the pattern. Pattern cannot exist without a number of events. Events, however, sometimes happen randomly.Pattern doesn't explain the cause of the event.Therefore the correct answer is B. Events that happen over and over form a pattern.
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What multiplicities are observed for the signals in the off-resonance decoupled 13c nmr spectrum of (2e)-3-chloroacrylaldehyde?
A singlet, a triplet, and a quartet multiplicities are observed for the signals in the off-resonance decoupled 13c NMR spectrum of (2e)-3-chloroacrylaldehyde
A spectrum is defined as the characteristic wavelengths of electromagnetic radiation (or parts thereof) emitted or absorbed by an object or substance, atoms or molecules. Multiple: Spectrum. A spectral line is an otherwise smooth and continuous spectral dark or bright line resulting from the emission or absorption of light in a narrow frequency range compared to adjacent frequencies.
These applications include Voice of America broadcasting, weather services, radar and voice communication systems for controlling commercial and civil air and sea traffic, weather satellite systems, flood warning and water control systems, and time signals.
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Metallic bonds are responsible for many properties of metals such as conductivity true or false?.
It is true that metallic bonds are responsible for many properties of metals such as conductivity.
Metallic bond is a type of chemical bond.
Metallic bond is formed between electrons and positively charged metal ions.
Substances with metallic bond conduct an electric current in liquid and solid state, because they have mobile electrons.
Most metals (for example sodium, calcium, iron, silver) have strong metallic bond, because strong electrostatic attractive force between valence electrons (metals usually have low ionization energy and lose electrons easy) and positively charged metal ions.
Metallic bond increace electrical and thermal conductivity.
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