Acetinilide is recrystallized using water as a solvent since it has a much higher solubility in hot water than in cold water. the purified solid will not recrystallize later in the experiment if high amount of hot solvent is added in the beginning. So we need to dissolve the sample in minimum amount of boiling water
What is recrystallizing ?
A purification method called recrystallization is used to get rid of contaminants from a sample. The impure sample is dissolved in an ethanol- or water-based solvent. The material dissolves in the liquid solvent after some brief heating. The solid precipitates out of the solution when the solvent cools down once more, leaving the impurities in the solvent that are still dissolved behind.
Then activated charcoal is added to remove the coloured impurities. After hot film pareshan insoluble impurities are removed. And then cold filtration separates the solid from solution.
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Which element is this?
How much of the concentrated solution would you use to prepare 450.0 mL of a 1.90 M solution?
The amount of concentrated solution required would be 0.855 moles.
As per the formula,
Molarity = [tex]\frac{moles of solute}{litres of solution}[/tex]
Given, Molarity = 1.90 M
The Volume of solution in litres = 450/1000 L
= 0.45 L
∴ 1.90 = [tex]\frac{moles of solute}{0.45}[/tex]
Moles of solute = 0.855 moles
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90% of Egypt is dessert that reveives very little rain.
TRUE OR FALSE
90% of Egypt is the desert that receives very little rain is False.
Moisture is generally carried by Mediterranean winds. Very little rain comes from the Red Sea. The mountains of Egypt are located in places where it doesn't get much rain. As a result, precipitation is significantly less than in parts of Israel Lebanon, and Iran. About 96% of Egypt's total area is desert.
Egypt is a very dry country with little rainfall throughout the year. Most of the rain falls along the coast, the highest rainfall ever recorded for the city of Alexandria. Annual precipitation is about 200 mm. The Red Land was a barren desert that protected Egypt on both sides. These deserts separated ancient Egypt from neighboring countries and invading armies.
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What is the total number of joules required to completely melt 65 g of water?
Specific heat capacity is the amount of heat required to raise the temperature by 1 degree Celsius. The total amount of heat absorbed by the water is 4079.4 J
What is Enthalpy?Enthalpy term is basically used in thermodynamics to show the overall energy that a matter have.
Mathematically,
Enthalpy=mass of ×specific heat capacity ×Change in temperature.
Initial temperature of water (T₁) = 25 °C
Final temperature (T₂) = 40 °C
Change in temperature ΔT= T₂ – T₁
=40 – 25
=15 °C
Mass of water (M) = 65 g
Change in temperature (ΔT) = 15 °C
Specific heat capacity of water (C) = 4.184 J/gºC
Heat absorbed (Q) = MCΔT
= 65 × 4.184 × 15
= 4079.4 J
Therefore, the amount of heat absorbed by the water to melt is 4079.4 J
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What three properties make radio waves ideal for communication?
The three properties that make radio waves ideal for communication include their long wavelengths, they can travel long distances and they can penetrate of many different types of materials.
What are radio waves?Radio waves can be defined as a class of radiation called electromagnetic waves which can be used in communication to transmit signals in space.
These types of waves (radio electromagnetic waves) are well known because they have long wavelengths, thereby they are able to travel long distances in a relatively short period of time and this type of radiation can also penetrate many different classes of materials, thereby being ideal in communication.
Therefore, with this data, we can see that the radio waves are ideal for communication due to many properties which include long wavelength, long distance for traveling, and also the ability to penetrate through different substances and materials.
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help please !! did i do it right?
Answer:
I think so? To calculate a mass percent, divide the total mass of the compound by the mass of the substance, then multiply by 100.
Explanation:
Which of the following is the best example of physical weathering?
Group of answer choices
A) Sediment piling up at the mouth of a river
B) Waves carrying sand away from a beach
C) Plant roots growing through concrete and splitting it
D) Small rocks being carried along a river bed
C) Plant roots growing through concrete and splitting it.
2. What is the mass of a piece of tin with a volume of 14.1 mL?
The number of units per volume, area, or length: as. a: a substance's mass per unit volume is 85.12 g.
What is density ?The number of units per volume, area, or length: as. a: a substance's mass per unit volume The distribution of a quantity (such as mass, electricity, or energy) per unit of space, typically.A liquid's density is a measure of how heavy it is for the amount measured. When equal amounts or volumes of two different liquids are weighed, the heavier liquid is more dense. If a liquid that is less dense than water is gently added to the water's surface, it will float.True density (p), defined as the quotient of mass over volume of a sample without taking pores into account (true volume). The terms particle density and particle volume are used in the context of granular materials.Therefore,
The density of tin in g ml = 6.037 g/ml.
so the mass of a piece of tin with a volume of 14.1 mL.
= 6.037 x 14.1 = 85.12 g.
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Which of the following are molecules? (select all that apply.)
MgCl2
K
Mg
H2
Mgcl2 is the molecule
What is molecule?
A molecule is two or more and atoms connected by the chemical bonds are
which form the smallest unit of a real substance that retains the composition and properties of that substance.
Molecules form the basis of chemistry.
Magnesium Chloride or the Magnesium Dichloride or Chloromagnesite is a chemical compound with the molecular formula is MgCl2. Magnesium is Chloride is an ionic salt that is highly soluble in water.
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The__ number equals the__ of ___electrons
ANYONE PLEASE ANSWER ASAP!!!!!!
Answer: the MAIN GROUP number equals the NUMBER of VALENCE electrons
approxiamtely how many human-made objects entered earth's orbit in 2020
I need help asap please. Thanks!
The type of reaction that is occurring, given the equation is single replacement reaction
What is a single displacement reaction?This is a reaction in which an element is replaced by another element which is higher in the electrochemical series. The following gives a better understanding of single replacement reaction.
CD + A -> AD + C
From the above, we can see that A has replaced C to produce AD
With the above idea, we can answer the question given as follow:
Co + 2AuNO₃ -> Co(NO₃)₂ + 2Au
We can see that Co replaces Au in the equation.
Thus, we can conclude that the reaction is single replacement reaction
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A and B are two imaginary substances. The molecules of substance A have weak electrical forces between them. The
molecules of substance B have very strong electrical forces linking them. Which boils at a lower temperature?
Substance A
It is impossible to know
Substance B
A and B are two imaginary substances. The molecules of substance A have weak electrical forces between them. The molecules of substance B have very strong electrical forces linking them. Substance A boils at a lower temperature.
Boiling is the process in which a liquid changes into a gas at its boiling point, which is the temperature at which its vapor pressure equals the atmospheric pressure. The boiling point of a substance is influenced by various factors, including the strength of the forces between its molecules.
In substance A, the molecules have weak electrical forces between them. These weak intermolecular forces imply that the molecules are not strongly attracted to each other. As a result, less energy is required to break these weak forces, and the substance can transition from a liquid to a gas more easily. Therefore, substance A will have a lower boiling point compared to substance B.
In substance B, the molecules have very strong electrical forces linking them. These strong intermolecular forces indicate that the molecules are strongly attracted to each other. Consequently, more energy is required to overcome these strong forces during the boiling process, making the substance have a higher boiling point.
Therefore, substance A, with weak intermolecular forces, would boil at a lower temperature, while substance B, with very strong intermolecular forces, would boil at a higher temperature.
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Which is the correctly balanced equation for the reaction of rust, Fe₂O3, and hydrochloric acid, HCI? O Fe₂O3 + HCI- FeCl₂ + H₂O O Fe₂O3 +3 HCI - 2 FeCl₂ + H₂O O Fe₂O3 +6 HCI - 2 FeCl3 + 3 H₂O O Fe₂O3 +3 HCI - 2 FeCl₂ + 3 H₂O
Answer:
Fe₂O3 +6 HCI - 2 FeCl3 + 3 H₂O
Explanation:
hope this helps.
The balanced equation obeys the law of conservation of mass. The balanced equation for the reaction of rust is Fe₂O₃ +6 HCI - 2 FeCl₃ + 3 H₂O. The correct option is C.
What is a balanced equation?A chemical equation in which the number of atoms of reactants and products on both sides of the equation are equal can be defined as the balanced chemical equation. The amount of products and reactants on both sides of the equation are equal.
The numbers which are added to balance a chemical equation are called the coefficients. They are added in front of the formulas.
The reaction of HCl with iron results in the formation of ferrous chloride (FeCl₂ or FeCl₃). When acid reacts with metal, it dissolves both the rust and the metal.
The balanced equation is:
Fe₂O₃ +6 HCI - 2 FeCl₃ + 3 H₂O
Thus the correct option is C.
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Pick 3
Which of these are intensive properties?
1.a substance has a melting point of 40°C
2.a substance is very malleable (it can be hammered into a shape)
a substance has a mass of 1.25 g
3.a substance has a density of 4.13 g/cm³
4.a substance has a volume of 5.4 mL
Which equation obeys the law of conservation of
mass?
H₂(g) + O₂(g) →→ H₂O(g)
H₂(g) + O₂(g) →→ H₂O(g) +4He(g)
O2H₂(g) + O₂(g) → 2H₂O(g)
H₂(g) → H₂O(g)
H₂(g) + O₂(g) → 2H₂O(g)
The equation, 2H₂(g) + O₂(g) → H₂O(g) will obey law of conservation of mass.
What is law of conservation of mass?According to the law of conservation of mass, mass can only be changed from one type to another and cannot be produced or removed.
The law of conservation of mass would be like this. The identical mass that started from the reactants would arrive in the products of each chemical reaction. Mass is conserved in chemical reactions, as shown by balanced chemical equations.
→ In this reaction the count of hydrogen and oxygen atom will be equal on both side, hence, this will show the law of conservation of mass.
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A peptide has the following sequence: Glu-His-Trp-Ser-Gly-Leu-Arg-Pro-Gly.
What is the net charge of the molecule at pH 3, 8, and 11?
By analyzing the charges of all ionizable groups in this peptide (shown in the attached table), we can conclude that the net charge of the molecule at pH 3 will be +3, at pH 8 it will be +1, and at pH 11 it will be 0.
To answer this question, we must look at the pKa values of all the groups that can be ionized in this peptide.
Glu is glutamic acid, and because it is located on the N-terminus of this peptide, we need to consider its amino group (pKa = 9.67) and its side-chain carboxylic group (pKa = 4.25). For histidine (His) the only relevant group is the one in its side-chain (pKa = 6.00). Tryptophan (Trp), serine (Ser), one of the glycines (Gly), leucine (Leu), and proline (Pro) do not have side chains that can be ionized and their amino and carboxylic groups are engaged in the peptide bonds, so we do not have to consider them for this. However, we have to consider arginine's (Arg) side chain (pKa = 12.48) and C-terminus glycine's carboxylic group (pKa = 2.34).
Based on this, we can construct a table (attached below) that shows what charge (if any) the listed groups will bear at the given pH values, and sum them up to calculate the net charge.
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above a salt content of 24.7 g/kg, as the temperature decreases, the ______.
At all temperatures above the freezing point, seawater with a salinity greater than 24.7 becomes denser as the temperature drops. Pressure increases cause seawater's density to rise.
The pressure difference between the surface and the deep seafloor causes a 2% change in density. The density of water decreases as it gets warmer, taking up more space. The water sample with the higher temperature will have a larger volume when comparing two samples of water with the same salinity or mass. Salinity has less of an impact on water density than temperature does. Therefore, if the layer with higher salinity is significantly warmer than the layer with lower salinity, the higher salinity layer may actually float on top of the lower salinity layer.
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Ka is writing a paper about the nutritional benefits of omega-3 fats. One source says overconsumption of these fats can lead to cardiac problems, which the source’s author has personally experienced. Ka has already confirmed that the article appears in a trusted publication, and the author uses logical, moral, and emotional arguments based on evidence. What is the best thing Ka can do next to determine the objectivity of the source?
determine whether the evidence cited reflects more than one side
contact the author directly to learn more about his personal experience
conduct an internet search for “cardiac problems + omega-3 fats”
contrast the article with others written by the same author on different topics
The best thing Ka can do next to determine the objectivity of the source is conduct an internet search for cardiac problems + omega-3 fats. Thus option C is correct.
What are cardiac problems?Cardiac problems are defined as the problems that occurs in heart and blood vassals of heart.
The common cardiac problems are
Erratic anginaA heart attack.A heart attack.Arrhythmia (improper heartbeats)Disease of the valvesElevated blood pressure.Congenital cardiac problems.Heart problems that run in families.A significant family of polyunsaturated fats is the omega-3 family.
Thus, the best thing Ka can do next to determine the objectivity of the source is conduct an internet search for cardiac problems + omega-3 fats. Thus option C is correct.
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Answer:
it is A.
Explanation:
determine whether the evidence cited reflects more than one side
Simón Bolívar and José de San Martín are figures associated with what event?
A.
World Cup finals
B.
destruction of the rain forest
C.
conquering the Inca
D.
South American independence
The event is South American independence. Option D.
By 1820, royalist Peru was an isolated outpost of Spanish influence. San Martin liberated Chile and Argentina to the south while Simon Bolivar and Antonio Jose de Sucre liberated Ecuador Colombia, and Venezuela to the north leaving only Peru and present-day Bolivia under Spanish control.
Simon Bolivar wrote two of his political treatises. The Manifesto de Cartagena Declaration of Cartagena and Carta de Jamaica Letters from Jamaica told the people of South America that Spain urged them to rebel against their colonial rule. Simon Bolivar is a Creole who grew up in a wealthy family. Bolivar devoted his time and effort to fight for Venezuela's independence from Spain. Bolivar was inspired by the Enlightenment ideas of John Locke.
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Find the grams in 5.26 x 10^-4 mol of HC2H3O2.
The question requires us to calculate the mass, in grams, contained in 5.26 x 10^-4 mol of HC2H3O2.
To solve this question, first we need to calculate the molar mass of the compound, considering the number of atoms of each element, and then relate the value obtained with the number of moles given (5.26 x 10^-4 mol).
First, to calculate the molar mass of the compound, let's consider the following atomic masses:
atomic mass of C = 12.01 u
atomic mass of H = 1.007 u
atomic mass of O = 15.99 u
Next, we calculate the molar mass. To do that, we need to consider the number of atoms of each element: according to the chemical formula, there are 2 atoms of C, 4 atoms of H and 2 atoms of O:
molar mass (C2H4O2) = (2 * 12.01) + (4 * 1.007) + (2 * 15.99) = 60.03 g/mol
Now, we know that there are 60.03 g for each mol of the compound. With that information, we can estabilish the following relation to calculate the mass contained in 5.26 x 10^-4 mol of the compound:
1 mol --------------------- 60.03 g
5.26 x 10^-4 mol ----- x
Solving for x, we have:
[tex]x=\frac{(5.26\times10^{-4}\text{ mol)}\times(60.03\text{ g)}}{(1\text{ mol)}}=0.03158\text{ g}[/tex]Therefore, there are 0.03158 g of HC2H3O2 in 5.26 x 10^-4 mol of this compound.
A number that tells how many molecules there is of a certain compound is called a(n)_
*
20 points
subscript.
reaction.
coefficient.
formula.
A number that tells how many molecules there are of a certain compound is called a(n) coefficient.
A subscript is a small-sized variety on the bottom right of the image. It refers to the number of atoms of the detail. If the subscript seems on the lowest left of the image, it offers the detail's atomic range.
The chemical formulation which represents the actual range of atoms of every detail present in a molecule is called molecular formula.
The coefficients suggest the range of each substance worried inside the response and may be changed so that it will stabilize the equation. The coefficients deliver the number of molecules worried inside the response.
In the example reaction, molecules of hydrogen react with one molecule of oxygen and convey molecules of water. second: the coefficients deliver the range of moles of every substance concerned within the reaction.
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What are the limitations of a lewis dot structure of a ionic compound?
Answer:
Explanation:
Limitation of Lewis concept: -This fails to explain the cause of covalent bond formation and the nature of attractive force between the adjacent atoms in molecules likeH2,Cl2. -Fails to explain the geometry of a molecule. -It could not explain the release of energy during formation of covalent bonds.
what volume of 0.175 mna3po4 solution is necessary to completely react with 87.5 ml of 0.105 m cacl2 ?
0.073 L of volume of 0.175 M [tex]Na^{3}[/tex][tex]PO^{4}[/tex] solution is necessary to completely react with 95.4 ml of 0.102 m .
Each thing in three dimensions takes up some space. The volume of this area is what is being measured. The space occupied within an object's borders in three dimensions is referred to as its volume. It is sometimes referred to as the object's capacity.
The given reaction,
3CuCl2(aq)+2Na3PO4⇒ Cu3(PO4)2+6NaCl
3 molecules of copper chloride react with 2 sodium phosphate to form 1moles of copper phosphate.
Moles of Cu[tex]Cl^{2}[/tex]
n=MxV
where,
M = molarity = 0.102
V = volume =95.4 /1000 = 0.0954 L
put the value we get
n = 0.00973 moles
Moles of [tex]Na^{3}[/tex] [tex]PO^{4}[/tex]
n = 0.00973 x2/3
n = 0.00649 moles
Solve the molarity equation for volume, we get
V = 0.073 L
Hence, we can conclude that 0.073 L of 0.175 M [tex]Na^{3}[/tex][tex]PO^{4}[/tex] solution is necessary to completely react with 95.4 ml of 0.102 m CuCl2.
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please help. thank you!
Ca(OH)2+2CH3COOH → Ca(CH3COO)2+2H20. Option D.
Calcium acetate is obtained by reacting acetic acid and calcium hydroxide, and dry distillation of acetone and calcium carbonate. Acetic acid is the systematic name for acetic acid CH3COOH. The chemical formula for calcium hydroxide is CaOH2. Balanced word equation 2 moles of acetic acid react with 1 mole of calcium hydroxide to form 1 mole of calcium acetate and 2 moles of water.
When acetic acid reacts with calcium hydroxide calcium acetate and water are formed. Ammonium hydroxide reacts with sulfuric acid to produce ammonium sulfate and water. Acetic acid reacts with sodium bicarbonate to produce carbon dioxide. When carbon dioxide is passed through lime water, the lime water becomes cloudy. The milky appearance of limewater is due to the formation of solid calcium carbonate CaCO3.
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Suppose you scrape your knee falling off your bike. What may happen if mitosis doesn't start around the open wound? Explain.
If the cells do not multiply by mitosis then the wound will not heal.
What is mitosis?There are two kinds of cell division and these are mitosis and meiosis. We have to note that mitosis occurs at the body cells and the exact number of chromosomes in the parent cell is transferred to the daughter cells.
Meiosis occurs in the gamete cells and each of the parent cells would only contribute half of the maximum number of the chromosomes that they contain.
We know that when we have a cut, the cells around the area of the cut would begin to multiply by the process of mitosis helping the wound to heal.
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make gold-198 absorb a proton
This method tells us that the gold-198 atom undergoes decay to turn out to be an atom of mercury-198 by converting a neutron to a proton.
A proton is a strong subatomic particle, symbol p, H⁺, or ¹H⁺ with a fantastic electric rate of +1 e basic price. Its mass is slightly much less than that of a neutron and 1836 times the mass of an electron.
A proton is a subatomic particle located inside the nucleus of each atom. The particle has a fantastic electrical rate, equal and opposite to that of the electron. If isolated proton would have a mass of best 1.673 10-27 kilogram, just barely less than the mass of a neutron.
Proton, strong subatomic particle that has a wonderful price identical in importance to a unit of electron charge and a relaxation mass of 1.67262 × 10−27 kg, that is 1,836 instances the mass of an electron.
The nucleus of a hydrogen atom or the H+ ion is an example of a proton. regardless of the isotope, each atom of hydrogen has 1 proton; every helium atom consists of 2 protons; each lithium atom includes three protons and so forth.
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what is the noble gas notation of the metal that is a liquid at room temperature in group 15?
Only two elements on the periodic table are elements at room temperature. They are mercury (a metal) and bromine (a halogen).
Four other elements are liquids slightly warmer than room temperature. They are francium, cesium, gallium, and rubidium (all metals).
The reason these elements are liquids has to do with how tightly bound their electrons are to the atomic nucleus. Basically, the atoms don't share their electrons with nearby atoms, so it is easy to separate them from solids into liquids.
Help me with this science question
Answer: Last one( 4 pairs of valence electrons)
Explanation:
Question 7
Saved
What is the chemical formula for ammonia, according to this illustration?
Question 7 options:
A. N3H3
B.NH3
C.NH3
D.NH
E.N3H
F.NH3
G.N3H
The chemical formula for ammonia, according to this illustration is C) NH₃.
The balanced chemical equation for the formation of ammonia is given as follows:
N₂ + 3H₂ -----> 2NH₃
from the above reaction it is clear that :
1 mole of N₂ react with 3 mole of 3H₂ to produce 2 mole of ammonia.
according the question , :
blue represent = nitrogen
white represent = Hydrogen
there are 1 blue sphere, which is of Nitrogen and three white sphere which is of hydrogen . so, the compound form is NH₃.
Thus, The chemical formula for ammonia, according to this illustration is C) NH₃
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