He atomic mass of an element is equal to ________. its mass number its atomic number one-twelfth of the mass of a carbon-12 atom the mass of an "average atom" the mass of the heaviest isotope
Gaseous methane ch4 will react with gaseous oxygen o2 to produce gaseous carbon dioxide co2 and gaseous water h2o . suppose 0.48 g of methane is mixed with 0.730 g of oxygen. calculate the maximum mass of water that could be produced by the chemical reaction. round your answer to 3 significant digits
What type(s) of intermolecular forces are expected between seh2 molecules?
Answer:
Induced and dipole forces.
Explanation:
Hello,
Due to its structure, [tex]SeH_2[/tex], one identifies the following two intermolecular forces:
- Induced: Ion-Induced Dipole Forces
At first, an ion-induced dipole attraction is present as a weak force which results when the approach of an ion induces a dipole in this nonpolar molecule by disturbing the arrangement of electrons.
- Dipole forces.
Now, dipole-dipole forces are present in such molecule as attractive forces between the positive end of one of the polar molecule and the negative end of another polar space in the molecule.
Best regards.
The types of intermolecular forces between SEH2 molecules are London dispersion forces and dipole-dipole forces.
The types of intermolecular forces that are expected between SEH2 molecules are London dispersion forces and dipole-dipole forces.
London dispersion forces occur between all molecules, and they result from the temporary fluctuations of electron distribution that create a temporary dipole.
Dipole-dipole forces occur when the positive end of one molecule attracts the negative end of another molecule due to the difference in electronegativity or polarity between the atoms of the molecule.
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Can somebody please help me with this question, I'm very confused! I thought i did it right because i found Kb and the conc. of OH- ions and then used pOH to find pH but the answer i get is very wrong!!!
What is the pH of a 0.51 mol L-1 CH3NH3+Cl- aqueous solution? pKb(CH3NH2) = 3.44 Answer to 2 decimal places.
(answer = 5.43)
Thank you!!!!
Which of the following is not a catalyst? A. Nickel B. Platinum C. Enzymes D. Phosphorus
Answer:
The correct answer is D. Phosphorus is not a catalyst.
Explanation:
A catalyst is a substance that accelerates a chemical reaction at a certain temperature, but does not itself wear off the reaction. It is involved in the chemical reaction but is not the starting or end product of the reaction.
Catalysts create an alternative reaction pathway for the reaction with a lower activation energy. Activation energy is the energy required for the reaction to take place. However, the catalyst cannot cause a reaction which does not take place without the catalyst.
Depending on the phases in which the catalyst and reactants are present, one speaks of homogeneous or heterogeneous catalysts. Biochemical processes are catalyzed by enzymes, while heterogeneous catalysts are metals, such as platinum and nickel.
If a neutral atom becomes negatively charged, it has undergone _________.
What is the molarity of a solution that contains 9.63 grams of HCl in 1.5 liters of solution? 1 H 1.01 Hydrogen 17 Cl 35.45 Chlorine
if a chemist has 2.3 moles of arsenic that has a molar mass of 74.92g/mol, which would be the best way to find out how many atoms of arsenic are in the sample?
Multiply 2.3 bu the molar mass of arsenic.
Divide 2.3 by the molar mass of arsenic.
Multiply 2.3 by Avogadro's number.
Divide 2.3 by Avogadro's number.
Multiply 2.3 by Avogadro's Number
Explanation:As we know that 1 mole of any substance contains exactly 6.022 × 10²³ particles which is also called as Avogadro's Number. So in order to calculate the number of particles (Atoms) contained by 2.3 moles of Arsenic (As), we will use following relation,
Moles = Number of Atoms ÷ 6.022 × 10²³ Atoms.mol⁻¹
Solving for Number of Molecules,
Number of Atoms = Moles × 6.022 × 10²³ Atoms.mol⁻¹ **
(**This is your answer)
Putting values,
Number of Atoms = 2.3 mol × 6.022 × 10²³ Atoms.mol⁻¹
Number of Atoms = 1.38 × 10²⁴ Atoms
Hence,
There are 1.38 × 10²⁴ Atoms present in 2.3 moles of Arsenic.
Explain why the column of a fractional distillation apparatus should be aligned as near to the vertical as possible
The column of a fractional distillation apparatus should be aligned as near to the vertical as possible for better separation, increased efficiency, and prevention of blockages.
Explanation:The column of a fractional distillation apparatus should be aligned as near to the vertical as possible for several reasons:
Aligning the column vertically allows for better separation of the different fractions. As the vapors rise through the column, the fractions with higher boiling points condense and collect at lower levels, while the fractions with lower boiling points remain in the vapor phase and rise towards the top.Alignment also ensures that the distillation process is more efficient. A vertical alignment allows for a greater surface area of contact between the vapor and the liquid fractions, facilitating the transfer of heat and increasing the rate of condensation.Lastly, a vertical alignment prevents any blockage or obstruction in the column. When the column is vertical, any liquid fractions that may condense and form droplets can easily fall back down towards the base of the column, avoiding any potential clogs or disturbances in the separation process.At 25 °C, what is the hydroxide ion concentration, [OH–], in an aqueous solution with a hydrogen ion concentration of [H ] = 4.2 × 10–9 M?
[OH-] = ____ M
Calculate the [OH–] if the hydrogen ion concentration is 3.64 x 10–8 M.
Using the ionic product of water, you can determine the hydroxide ion concentration [OH−] if you have the hydrogen ion concentration [H+]. In this case, [OH−] = 1.0 x 10^-14 / 3.64 x 10–8 M, results in [OH−] = 2.75 x 10^-7 M.
Explanation:To calculate the [OH−] if the hydrogen ion concentration is 3.64 x 10–8 M, first you need to understand the Ionic Product of water. It is the mathematical product of the concentrations of Hydrogen ions [H+] and Hydroxide ions [OH−], and its value is 1.0 x 10^-14 at 25 degrees Celsius. So, if you know the concentration of the hydrogen ions, you can calculate the concentration of the hydroxide ions using the equation [H+] x [OH−] = 1.0 x 10^-14.
Substituting the given value into the equation, we get:
3.64 x 10–8 M x [OH−] = 1.0 x 10^-14.
To solve for [OH-], divide both sides by 3.64 x 10-8M resulting to [OH−] = 1.0 x 10^-14 / 3.64 x 10–8 M = 2.75 x 10^-7 M
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You dissolve 4.5 mol of potassium hydroxide to make a 2 L solution. What is the molarity of the solution?
A 2.50-l volume of hydrogen measured at â196 °c is warmed to 100 °c. calculate the volume of the gas at the higher temperature, assuming no change in pressure
To solve this we assume that the hydrogen gas is an ideal gas. Then, we can use the ideal gas equation which is expressed as PV = nRT. At a constant pressure and number of moles of the gas the ratio T/V is equal to some constant. At another set of condition of temperature, the constant is still the same. Calculations are as follows:
T1 / V1 = T2 / V2
V2 = T2 x V1 / T1
V2 = (100 + 273.15) K x 2.50 L / (-196 + 273.15) K
V2 = 12.09 L
Therefore, the volume would increase to 12.09 L as the temperature is increased to 100 degrees Celsius.
The problem is about Charles's Law, which states the volume of a gas is directly proportional to its absolute temperature, while pressure is constant. With the data provided, using this concept in a formula, we calculate the volume of hydrogen to be roughly 12.16 Liters at 100°C.
Explanation:The question pertains to Charles's Law in Physics, specifically about gases. Charles's Law states that the volume of a given gas mass is directly proportional to its absolute temperature, provided that the pressure is kept constant.
For the problem given, the initial volume (V₁) of the hydrogen gas is 2.50 L, and its initial temperature is -196°C, which must be converted to Kelvin (K) by adding 273 (equating to 77K). The gas is warmed to 100°C, or 373K (T₂).
To calculate the volume of the gas at the higher temperature (V₂), we use the formula for Charles's Law: V₁/T₁ = V₂/T₂. Substituting in the provided values, we get (2.50 L / 77 K) = V₂ / 373K. Solving for V₂, we find that the volume of the hydrogen gas at 100°C is approximately 12.16 L.
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Determine the number of protons and neutrons in plutonium-239 and write its symbol in the form azx.
Explanation:
Atomic number of an atom means the sum of total number of protons present in an atom.
Mass number is the sum of total number of protons and neutrons present in an atom.
And, when we write the symbol of an atom then it is represented like this [tex]^{a}_{z}X[/tex], where "a" represents the mass number of the atom and "z" represents the number of protons.
Therefore, in plutonium-239 it is shown that mass number is 239 and atomic number of a plutonium atom is 94. Now, calculate its number of neutrons as follows.
Mass number = no. of protons + no. of neutrons
239 = 94 + no. of neutrons
no. of neutrons = 239 - 94
= 145
Thus, we can conclude that in plutonium-239 number of protons is 94, number of neutrons is 145 and its symbol is [tex]^{239}_{94}Pu[/tex].
Calculate the radius of an aluminum atom in cm, given that al has an fcc crystal structure, a density of 2.70 g/cm3, and an atomic weight of 26.982 g/mol
A voltaic cell is constructed with two silver-silver chloride electrodes, where the half-reaction is
Which is a way that biotechnology has Not helped society? Bacteria is used to grow vaccines in large quantities. Drugs can be developed without the use of animal research. New, stronger bacteria have evolved that are resistant to antibiotics. Diabetics have a steady supply of inexpensive insulin.
A way that biotechnology has Not helped society stronger bacteria have evolved that are resistant to antibiotics. Antibiotic-resistant bacteria endangers everyone.
What is bacteria?Bacteria are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats.
The structure of bacteria is known for its simple body design. Bacteria are single-celled microorganisms with the absence of the nucleus and other cell organelles; hence, they are classified as prokaryotic organisms.
Ribosomes are the sites of protein synthesis. In addition to this DNA, they have an extra circular DNA called plasmid. These plasmids make some strains of bacteria resistant to antibiotics.
Therefore, A way that biotechnology has Not helped society stronger bacteria have evolved that are resistant to antibiotics. Antibiotic-resistant bacteria endangers everyone.
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When two electrons occupy the bonding molecular orbital above what type of bond results explain?
A covalent bond results when two electrons occupy a bonding molecular orbital, shared between two atoms due to the overlap of their atomic orbitals, creating a lower energy state.
Explanation:When two electrons occupy the bonding molecular orbital, a covalent bond results. This bond occurs when atomic orbitals from two atoms overlap in a way that their electron clouds are in phase, allowing the electrons to be shared between the atoms and creating a lower energy state than the original separate atomic orbitals. The type of covalent bond (single, double, triple) depends on the number of electron pairs shared and the orbitals involved, as described by the valence bond theory.
For instance, a single bond (σ bond) arises from end-to-end overlap and involves one electron pair, whereas double and triple bonds involve, respectively, one or more additional side-by-side π bonds created by the overlap of p orbitals. These concepts are also in line with the molecular orbital theory, where the filled bonding orbitals contribute to the bond strength of a molecule. The bond order, calculated from an energy level diagram showing the net number of bonding electrons, determines the strength and type of bond.
During dehydration synthesis, a ________ molecule is produced.
The observation that ethanol (C2H5OH) has a higher vapor pressure than water (H2O) at the same temperature is due to more
A. Hydrogen bonding in the water
B. Kinetic energy in the ethanol
C. London forces in the ethanol
D. Hydrogen bonding in the ethanol
E. London forces in the water
What is the correct order for the surface tension of the following substances?
A. Hg, C8H18, H2O
B. Hg, H2O, C8H18
C. C8H18, H2O, Hg
D. C8H18, Hg, H20
E. H2O, Hg, C8H18
Final answer:
1. OPTION A.
2. OPTION B.
Ethanol has a higher vapor pressure than water due to less extensive hydrogen bonding, and the surface tension order for the substances is mercury (Hg), water (H₂O), octane (C₈H₁₈), reflecting the strength of the intermolecular forces.
Explanation:
The observation that ethanol (C₂H₅OH) has a higher vapor pressure than water (H₂O) at the same temperature is primarily due to more hydrogen bonding in water. Water's ability to form stronger hydrogen bonds compared to ethanol results in fewer water molecules escaping the liquid and hence, a lower vapor pressure. Ethanol, though capable of hydrogen bonding, exhibits weaker intermolecular forces (IMFs) compared to water, allowing more ethanol molecules to escape into the vapor phase.
Regarding the surface tension question, the correct order for the surface tension of the substances listed would be Hg, H₂O, C₈H₁₈ based on the intermolecular forces present in each substance. Mercury (Hg) has a very high surface tension due to strong metallic bonding, water (H₂O) has high surface tension from hydrogen bonding, and octane (C₈H₁₈) has comparatively lower surface tension as it is primarily affected by weaker London dispersion forces.
Select the reason why two molecules of benzaldehyde cannot react via the aldol condensation.
The reason why two molecules of benzaldehyde cannot react via the aldol condensation is that in benzaldehyde, alpha hydrogen is not present to form enolate ion.
What is aldol condensation reaction?
Aldol condensation is a reaction in which beta-hydroxyaldehyde or ketone is formed by the reaction between an enolate ion and carbonyl compound.
Enolate ion which is formed in the aldol condensation is formed by the replacement of alpha hydrogen and then this ion will attack on the carbonyl group of another compound.
So, in the benzaldehyde alpha hydrogen is not present which in turn will not form enolate ion to attack that's why two molecules of benzaldehyde cannot react.
Hence due to lack of alpha hydrogen benzaldehyde will not reacts.
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write the symbolic notation of an isotope of an element having 8 protons 8 electrons and 11 neutrons click on the Templates button
The isotope with 8 protons (atomic number), 8 electrons, and 11 neutrons is Oxygen. The symbolic notation of this isotope would be represented as 19\8O, where 'O' is the symbol for Oxygen, '19' is the mass number (protons + neutrons), and '8' is the atomic number (protons).
Explanation:The element with 8 protons and 8 electrons is Oxygen. Therefore, the element you're asking about is an isotope of Oxygen. Isotopes are distinguished by the number of neutrons. In this specific case, we have 11 neutrons.
The symbolic notation of an isotope is represented as follows: The symbol for the isotope is the element's symbol (X), the mass number (A) is written as a superscript, and the atomic number (Z) is written as a subscript. In your case:
Z = 8 (number of protons)
X = O (symbol for Oxygen)
A = Z + N = 8 + 11 = 19 (Sum of protons plus neutrons)
Therefore, the symbolic notation of the isotope would be 19\8O.
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Determine whether each of the examples or phrases describes an essential amino acid, a nonessential amino acid, or both essential and nonessential amino acids. a table of amino acids can be found here. note: if you answer any part of this question incorrectly, a single red x will appear indicating that one or more of the phrases are sorted incorrectly.
Methione phrases describes an essential amino acid, whereas a glycolytic intermediate phrases describes an non-essential amino acid
Further explanationAmino acids are the basic building blocks of proteins. Nonessential amino acids can be made by the body, while essential amino acids cannot be made by the body so wemust get them from our diet.
Determine whether each of the examples or phrases describes an essential amino acid, a nonessential amino acid, or both essential and nonessential amino acids. a table of amino acids can be found here.
Note: if you answer any part of this question incorrectly, a single red x will appear indicating that one or more of the phrases are sorted incorrectly.
Categories: Essential Amino Acids, Nonessential amino acids, or Both
Essential Amino Acids
made from aspartate and pyruvate in an eleven-step pathway branched-chain amino acids obtained from food only the amino acid that is a thioetherNonessential amino acids
synthesized by humans an amino acid synthesized from pyruvate in humansBoth
-methionine : Methionine is an essential amino acid in humans. So methione phrases describes an essential amino acid
derived from 3-phosphoglycerate, a glycolytic intermediate: Serine amino acids is derived from the glycolysis intermediate 3-phosphoglycerate. Serine is non-essential amino acid supplied from food or synthesized by the body from a number of metabolites, including glycine. So a glycolytic intermediate phrases describes an non-essential amino acid
The correct answers are:
Essential amino acids:
Made from Aspartate and Pyruvate in an eleven-step pathwayBranched-chain amino acidsObtained from food onlyMethionineNonessential amino acids:
Synthesized by humansAn amino acid synthesized from pyruvate in humansBoth
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Subject: chemistry
Chapter: amino acid
Keywords: an essential amino acid, nonessential amino acid, amino acid, both essential and nonessential amino acids, phrases
An analytical chemist has determined by measurements that there are 96.5 moles of carbon in a sample of acetic acid. how many moles of oxygen are in the sample
In a sample of acetic acid, the number of moles of oxygen can be calculated by understanding the molecular formula of acetic acid (CH3COOH) and using it to establish the ratio of carbon to oxygen. Given 96.5 moles of carbon in the sample, there would be 193 moles of oxygen.
Explanation:To find the amount of moles of oxygen in a sample of acetic acid, we must first understand the molecular formula of acetic acid which is CH3COOH. This reveals that for each molecule of acetic acid, there are 2 atoms of carbon and 4 atoms of oxygen. Hence, in mole terms, for each mole of acetic acid, there are 2 moles of carbon and 4 moles of oxygen. If the analytical chemist has determined that there are 96.5 moles of carbon, this implies that there are 48.25 moles of acetic acid in the sample (since 2 moles of carbon correspond to each mole of acetic acid). Given the ratio of carbon to oxygen is 2:4 according to the molecular formula, we can multiply the number of moles of acetic acid by 4 to get the number of moles of oxygen, thus: 48.25 moles * 4 = 193 moles of Oxygen. Therefore, you can expect 193 moles of oxygen in the acetic acid sample.
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96.5 moles of carbon in the sample of acetic acid contains 96.5 moles of oxygen.
First, we need to understand the molecular formula of acetic acid, which is CH₃COOH. This means each molecule of acetic acid contains 2 carbon atoms, 4 hydrogen atoms, and 2 oxygen atoms.
Given that the chemist has determined there are 96.5 moles of carbon in the sample, we can determine the moles of acetic acid molecules by dividing the moles of carbon by 2 (since each molecule of acetic acid has 2 carbon atoms):
96.5 moles of C / 2 = 48.25 moles of acetic acid
Since each acetic acid molecule contains 2 oxygen atoms, we can find the total moles of oxygen by multiplying the moles of acetic acid by 2:
48.25 moles of acetic acid x 2 = 96.5 moles of oxygen
Thus, there are 96.5 moles of oxygen in the sample.
Which statement explains why the bonds between non metals tend to be covalent
Answer: C. They have small difference in electronegativity.
Explanation:
got it correct on text !
Solid solution alloying is the principal strengthening mechanism in high strength low alloy (hsla) steels?
Yes the above statement is true.
Solid solution alloying is the principal strengthening mechanism in high strength low alloy (hsla) steels.
Alloying is a process in which two or more than two metals are combined or mixed together and solid solution alloying is a solid form mixture of substances. For example a solid solution of iron and carbon which is used in construction as steel.
Your license can be suspended for three months if you accumulate 18 points within a(n) ____________ period.
Answer:
18 months
Explanation:
The point system gives points for the traffic violations in which you might incur. If you accumulate a certain number of points in a period of time, your license can be suspended. As a consequence of this system, if you accumulate 18 points within an 18 months period, your license can be suspended for three months.
A crystallographer measures the horizontal spacing between molecules in a crystal. The spacing is 10.59 nm . What is the total width of a crystal in millimeters 105 molecules across?
Please select the best answer and click "submit."
Constants for water
Hvap 40.65 kJ/mol
Hf -285.83 kJ/mol
Hfusion 6.03 kJ/mol
specific heat 4.186 J/gC
molar mass 18.02 g
How much energy is generated from freezing 2.5 g water?
A. 2.5 g 1 mol/18.02 g (285.83) kJ/mol
B. 2.5 g 1 mol/18.02 g 4.186 kJ/mol
C. 2.5 g 1 mol/18.02 g 40.65 kJ/mol
D. 2.5 g 1 mol/18.02 g (-285.83) kJ/mol
The energy released from freezing 2.5 g of water can be calculated by converting the grams to moles and then multiplying by the negative enthalpy of fusion, which is -6.01 kJ/mol, indicating an exothermic process.
Explanation:Calculating Energy Released During Freezing of Water
To determine the energy generated from freezing 2.5 g of water, we need to use the enthalpy of fusion, which is the energy change when 1 mole of water freezes. Since the process of water freezing is exothermic, the enthalpy of fusion will be negative, reflecting the release of energy.
Step-by-step calculation:
Convert grams of water to moles: (2.5 g)2.5 g
1 mol/18.02 g
(-6.01 kJ/mol)
The correct answer is influenced by the fact that the energy change is negative in an exothermic process, which in this case is the freezing of water.
Therefore, the correct answer to the question is:
D. 2.5 g
1 mol/18.02 g
(-6.01 kJ/mol)
Calculate the vapor pressure (in torr) at 298 k in a solution prepared by dissolving 15.3 g of the non-volatile non-electrolye urea {co(nh2)2} in 107 g of water. the vapor pressure of water at 298 k is 23.76 torr. enter your answer to 2 decimal places
The vapor pressure of the solution at 298 K is 22.80 torr. This is calculated by determining the mole fraction of water in the solution using the given masses of urea and water, and applying Raoult's law with the vapor pressure of pure water.
Explanation:To calculate the vapor pressure of the solution at 298 K, we must apply Raoult's law, which states that the vapor pressure of a solution is directly proportional to the mole fraction of the solvent. In this case, we are given the mass of urea (15.3 g) and the mass of water (107 g), along with the vapor pressure of pure water at 298 K, which is 23.76 torr.
First, we need to convert the masses to moles. The molar mass of water (H2O) is about 18.015 g/mol, and the molar mass of urea (CO(NH2)2) is approximately 60.06 g/mol. Therefore:
Number of moles of water: 107 g / 18.015 g/mol = 5.942 molesNumber of moles of urea: 15.3 g / 60.06 g/mol = 0.255 molesThe total number of moles in the solution is the sum of moles of water and urea, which is 5.942 + 0.255 = 6.197 moles. Now we determine the mole fraction of water:
Mole fraction of water (XH2O) = Moles of water / Total moles = 5.942 / 6.197 ≈ 0.959
Using Raoult's law, the vapor pressure of the solution (Psolution) is the product of the mole fraction of water and the vapor pressure of pure water:
Psolution = XH2O * Vapor pressure of pure water = 0.959 * 23.76 torr ≈ 22.80 torr
Therefore, the vapor pressure of the solution at 298 K is 22.80 torr.