The atomic mass of Hafnium is 357.1amu and atomic mass is the total mass of the subatomic particles in an atom and is measured in atomic mass units
Here given data is if in a sample, 10 have mass 176 amu, 38 have mass 177 amu, 54 have mass 178 amu, 28 have mass 179 amu, and 70 have mass 180 amu then
The atomic mass is a weighted average of all of the isotopes of that element, in which the mass of each isotope is multiplied by the abundance of that particular isotope
We have to find average atomic mass = ?
Average atomic mass = atomic weight of Hafnium/100
Now we can substitute the known values
Then, Average atomic mass = (176×10)+(177×38)+(178×54)+(179×28)+(180×70)/100
Average atomic mass = 357.1amu
357.1amu is the atomic mass of Hafnium
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What does this picture represent?
Answer:
Mixture because it isn't chemically combined
You determine that a sample of a compound contains 1. 4 mol c and 2. 1 mol h. What is the empirical formula for this compound?.
The empirical formula of the compound is C₄H₁.
An empirical formula represents the whole number ratio of various atoms present in a compound.
If the mass percent of various elements present in a compound is known, its empirical formula can be determined
We are given that a compound contains 4 mole C and 1 mole H.
Hence, the ratio of C: H is 4:1, which is already in the form of the simplest whole number.
Therefore, the empirical formula of the given compound is C₄H₁ and its molecular mass is 12 × 4 + 1 = 49u.
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1.Why exceptions to the ionization occur?
2. Name an exception to the ionization trend
DEFINE HEAT please help!
Answer:
A
Explanation:
heat is how hot something is
PLEASE SOMEONE ANSWER
an isotope of phosphorus contains 19 neutrons. construct the symbol for the isotope.
Isotope of phosphorus containing 19 neutrons can represented as ²⁴₁₅P.
Isotopes are those atoms of the same elements that have same number of protons or same atomic number but different mass number.
Atomic number = number of protons in the atom = number of electrons in the neutral atom
Mass number = number of protons + number of neutrons
Mass number is represented as Z
Atomic number is represented as A.
While writing the symbol of an atom the mass number is written on the left and side and as a superscript to the symbol of the atom and atomic number is written to the left and as a subscript to the symbol.
Howie wants to know how many apples he could pick from his grandpa's orchard. There are 9 rows of trees and he can pick 925 apples from each row. Approximately how many apples can he pick in total? Round the larger factor to the nearest hundred to estimate.
Answer:
8,300
Explanation:
925*9 is 8325.
After you round to the nearest hundred, its 8,300.
Answer:
Explanation:
eggggggggggg
Iodine is often seen as an example of a substance
that changes directly from a solid to a gas. However,
data books that give the standard physical
measurements for substances show values for the
melting point (114 °C) and boiling point (184 °C) of
iodine at atmospheric pressure.
a
Explain why iodine seems to miss out the
liquid stage if crystals are heated strongly in a
boiling tube.
b Suggest how you could demonstrate that iodine
can melt to form a liquid at atmospheric pressure.
The correct answer is :
a) The van der Waals forces are easily overcome and the molecule easily transitions into the gas phase when iodine crystals are heated. They dissolve into a dense cloud of purple colour.
London dispersion forces are another name for van der Waals forces.
Actually, the non-polar molecule is subject to these weak electrostatic forces. Or, to put it another way, since these are the only forces that interact with non-polar molecules, we can say that they are accountable for the neutral atom's existence.
The transitory or temporary dipoles produced in the non-polar elements are attracted to one another by these Van der Waals forces.
b) Iron nail (Ferrum) reacts with copper sulphate (CuSO 4) when it is dipped in it, changing the substance's colour from blue to pale green. This demonstrates that iron is more reactive than copper since it may take the place of copper in CuSO4.
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a certain ore is 28.4% nickel by mass. how many kilograms of this ore would you need to dig up to have 60.0 g of nickel?
A certain ore is 28.4% nickel by mass you need to dig up 473.33g for 60.0g of nickel.
In each kilogram of ore you would have 28.4×1kg=28.4 kilogram of nickel or 28.4×1000=28,400
So, for 60.0g 60/28400=473.33 kilogram
You need only to dig 473.33 kilogram of ore.
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Use the atomic mass of indium to calculate the relative abundance of indium-113.
The relative abundance of indium-113 is 4%.
The isotopes are species of the same element having the same atomic number but a different mass number.
The elements occurring in nature exist as multiple isotopes.
When we take into account the existence of these isotopes and their relative abundance (percent), the average atomic mass of that element can be computed, which is given by the following formula,
Average atomic Mass= (%age of isotope 1) x (Mass of isotope 1) + (%age of isotope 2) x (Mass of isotope 2)/100
Indium exists in the form of Indium-113 and Indium-115.
The mass of Indium-113 is 112.90 u.
The mass of Indium-115 is 114.90 u.
The average atomic mass of Indium is 114.82 u.
Let the %age of isotope 1(Indium-113) be X.
Then, the %age of isotope 2(Indium-115) would be 100-X.
Applying the values in the formula,
Average atomic mass = 112.90X+114.90(100-X)
114.82 = 112.90X+114.90(100-X)
On solving the above equation, the value of X comes out to be 4%.
Thus, the relative abundance/%age abundance of Indium-113 is 4%.
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(c) A sample of rust had the following composition:
51.85g of iron
22.22g of oxygen
16.67 g of water.
Calculate the following and then write the formula for this sample of rust.
number of moles of iron atoms, Fe =
number of moles of oxygen atoms, O =
number of moles of water molecules, H₂O =
simplest mole ratio Fe: O: H₂O is ........
formula for this sample of rust is
.......:
Rust is a flaky reddish brown layer that forms on metal. Rust is a Hydrated Iron (III) Oxide with the chemical formula Fe₂O₃ + H₂O.
Now, as per the question:
Mass of Iron = 51.85g
Mass of Oxygen = 22.22g
Mass of Water = 16.67g
Therefore,
Moles of Iron, Fe = [tex]\frac{ 51.85}{ 55.84}[/tex] mol
Moles of Oxygen, O = [tex]\frac{22.22}{15.99 }[/tex] mol
Moles of Water, H₂O = [tex]\frac{16.67}{18.01}[/tex] mol
Simplest mole ratio:
Fe: O: H₂O :: [tex]\frac{ 51.85}{ 55.84}[/tex] : [tex]\frac{22.22}{15.99 }[/tex] : [tex]\frac{16.67}{18.01}[/tex]
Fe: O: H₂O :: 0.92 : 1.38 : 0.92
Thus, the simplest mole ratio of Fe: O: H₂O is 0.92 : 1.38 : 0.92.
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How do I do this partial pressure problem? (AP CHEM)
The partial pressure of H(g) is 1.07 atm.
What is the partial pressure?We know that the total pressure of a mixture of gases is the sum of the individual pressure of the gases. Now we know from the Dalton law of partial pressure that the total pressure PT = PA + PB + PC + ........
Thus, the molecular hydrogen has a pressure of 2.14 atm and this molecular hydrogen is made to decompose. The partial pressure of each of the H(g) is 2.14/2 = 1.07 atm.
Hence, the partial pressure of H(g) is 1.07 atm.
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How many grams of alcohol with a density of 0. 900 g/cm3 will have the same volume as 20. 0 g of mercury with a density of 13. 6 g/cm3?
The mass of alcohol with a density of 0.900 g/cm^3 that will have the same volume as 20 g of mercury with a density of 13.6 g/cm^3 will be 1.32 grams.
The density of a substance is given by the following formula:
Density = Mass/Volume
As 20 grams of mercury is given, we can calculate its volume using the above formula
13.6 = 20/Volume
The volume of mercury comes out to be 1.47 ml.
As the volume of mercury and alcohol is given the same in the question, we can calculate the mass of alcohol by again using the same formula
0.900 = Mass/1.47
Mass = 1.32 g
Hence, the mass of alcohol with a density of 0.900 g/cm^3 that will have the same volume as 20 g of mercury with a density of 13.6 g/cm^3 will be 1.32 grams.
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A teacher adds a teaspoon of salt to his tea by mistake. He does not stir. Some students are discussing what will happen to the saltiness of the tea.
Answer:
ok so what is the question?
Why is little known about the interior of the earth?
Answer:
The Earth's interior is composed of four layers, three solid and one liquid—not magma but molten metal, nearly as hot as the surface of the sun.
The deepest layer is a solid iron ball, about 1,500 miles (2,400 kilometers) in diameter. Although this inner core is white hot, the pressure is so high the iron cannot melt.
The iron isn't pure—scientists believe it contains sulfur and nickel, plus smaller amounts of other elements. Estimates of its temperature vary, but it is probably somewhere between 9,000 and 13,000 degrees Fahrenheit (5,000 and 7,000 degrees Celsius).
Above the inner core is the outer core, a shell of liquid iron. This layer is cooler but still very hot, perhaps 7,200 to 9,000 degrees Fahrenheit (4,000 to 5,000 degrees Celsius). It too is composed mostly of iron, plus substantial amounts of sulfur and nickel. It creates the Earth's magnetic field and is about 1,400 miles (2,300 kilometers) thick.
You can get more info, in national geographic.
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1. A student averaged 45 miles per hour on a trip. What was his speed in kilometers per
second?
Answer: 0.0201 km per second
Explanation:
45 miles per hour = 0.0125 miles per second = 0.0201 km per second
when was the last year the theory of understanding the energetics and arrangement of atoms was developed
In 1897 the theory of understanding the energetics and arrangement of atoms was developed by Josheph Larmor.
It is also called solar system model of atom.
What is solar system model of atom?The “solar system” model indicates an atom as a whole massive positive body that is the nucleus similar to the sun in the solar system with negative entities that are the electrons as the planets in our solar system revolving around it.
Why this model not accepted?The thought about this model is that the electrons which revolves around the nucleus are the charged particles which have centripetal acceleration during the revolution. Even if they all are travelling at the same velocity in modulus, the trajectory of their velocity varies with respect to time which resulting in the centripetal acceleration. An accelerated charge particle will emit energy in the form of electromagnetic radiation. This results in the loss of energy which causes the charged particle to fall inside the nucleus. Therefore, this fails to happen.
Thus, we concluded that In 1897 the theory of understanding the energetics and arrangement of atoms was developed.
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A video shows the objects in the solar system orbiting the sun. Why do objects orbit the sun?
A:The sun is so massive that it creates gravity.
B:The sun is so bright that objects are forced away.
C:The sun is releasing heat and pushing objects away.
D:The sun is moving so quickly that other objects move around it
Objects orbit the sun because the sun is so massive that it creates gravity, hence, option A.
According to Sir Isaac Newton, all objects, big or small, are attracted to each other by a force. This force could be strong or weak, depending on the size of the objects and the distance between the two objects. This force is called gravity.
The force of gravity can be felt here on earth. It is the force that is constantly pulling everything towards the center of the earth. However, for an object as massive as the sun, the gravitational field it creates is so strong that it constantly pulls all the planets towards itself. Due to inertia, the planets don't just fall in a straight line towards the sun. Instead, they trace a circular path around the sun called an orbit.
The force of gravity gets weaker as the distance between two objects increase. Hence, planets far away from the sun tend to move slower than planets closer to the sun.
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What is the name of the building block/ monomer of your macromolecule?
Answer: monomers
Explanation: Most macromolecules are made from single subunits, or building blocks, called monomers. The monomers combine with each other using covalent bonds to form larger molecules known as polymers.
what occurs when the concentration of glucose in the water outside of a cell is higher than the concentration inside?
Answer:
Glucose will enter the cell through osmosis.
Explanation:
Diffusion causes molecules to move from high concentration to low concentration, so the glucose molecules outside the cell will move through the membrane to inside of the cell.
explain how absorbance and concentration date collected in light expiriments can be used to determine the concentration of an unknown solution
The calibration curve is used to determine the concentration of an unknown solution.
What is a spectrophotometer?A spectrophotometer is a device in which the absorbance of a substance could be measured. The absorbance refers to the amount of light that could be passed through a substance.
What we do is to first select the appropriate wavelength the would be used for the study. The absorbance of the solvent without the analyte is first measured. This is called the sample blank. Then several selected concentrations of the analyte is made to interact with light in the spectrophotometer and the absorbance is measured.
This is now used to create a line of best fit called calibration curve that could be used to determine the absorbance of any other concentration of the same solution.
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The solubility of o2 in water is 6. 5mg/l at an atmospheric pressure of 1. 0 atm and temperature of 40. 0 c. Calculate henrys law constant of o2 at 40c. The molar fraction of oxygen gas inair is 0. 209
The henry constant (Kh) is found to be 9.69 X 10⁻⁴moles/L atm .
The solubility of O₂ is 6.5 mg/l Or 0.0065 g/L
First we convert solubility into moles/L by dividing by molecular mass of O₂ (32 g/mole)
solubility = 0.0065/32 moles/L = 0.000203 moles/L
henry's law can be calculated by the formula, c = Kh X p , where x = mole fraction and p is partial pressure of gas, Kh is henrys constant and c is concentration.
On assuming, the percentage of oxygen in atmosphere is 20.95% and pressure is 1 atm
so partial pressure of O₂ = 20.95/100 X 1 = 0.2095 atm ( partial pressure = mole fraction X total pressure)
so now Kh = 0.000203/0.2095 = 0.000969 moles/L atm or 9.69 X 10⁻⁴ moles/L atm.
The quantity of dissolved gas in a liquid is inversely proportional to the partial pressure of the gas above the liquid, according to Henry’s law also called as Gas law. Henry constant mostly depend on the vapour pressue and solubility of the gas.
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a change will only occur one time. group of answer choices cyclic periodic unidirectional bidirectional
A change will only occur one time in unidirectional.
Because
Cyclic : Cyclic compounds are chemical compounds having a basic non-linear structure. In other words, these are ring structures. One or more series of atoms in the compound is connected to form a ring structure.
Periodic : The periodic table of chemical elements, often called the periodic table, organizes all discovered chemical elements in rows (called periods) and columns (called groups) according to increasing atomic number.
Unidirectional : compound is operating or moving in one direction only and it does not move in other direction.
Bidirectional : Capable of reacting or functioning in two, usually opposite, directions.
Thus, A change will only occur one time in unidirectional.
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What defines our current ‘standard’ for one meter?
In the bicarbonate buffering system, carbon dioxide and water join to form ___________, which dissociates into hydrogen and ________________.
In the bicarbonate buffering system, carbon dioxide and water join to form carbonic acid, which dissociates into hydrogen and bicarbonate.
What is a buffering system?A buffering system can be defined as a complex solution that serves to buffer sudden changes in the pH of a given solution, which is fundamental to maintaining homeostasis.
In conclusion, in the bicarbonate buffering system, carbon dioxide and water join to form carbonic acid, which dissociates into hydrogen and bicarbonate.
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the main function of a(n) is to help an interaction between two chemicals to occur, changing both chemicals.
The main function of a vitamin is to help interaction between two chemicals to occur, changing both chemicals.
What are vitamins?Vitamins can be defined as a special class of micronutrients that must be obtained from the diet in order to maintain body homeostasis, which can be liposoluble or hydrosoluble.
In conclusion, the main function of a vitamin is to help interaction between two chemicals to occur, changing both chemicals.
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according to the following reaction, how many moles of silver chloride will be formed upon the complete reaction of 25.5 grams of silver nitrate with excess copper(ii) chloride?
Upon the complete reaction of 25.5 grams of silver nitrate with excess copper(ii) chloride, 0.075 moles of silver chloride will be formed.
When silver nitrate reacts with copper(II) chloride, silver chloride and copper(II) nitrate are produced. The balanced equation for this reaction is:
[tex]2AgNO_{3(aq)} +CuCl_{2(s)}[/tex] ⇒ [tex]2AgCl_{(s)} +Cu(NO_{3})x_{2(aq)}[/tex]
Using the formula to find the molar mass M = m / n, get the number of moles of silver nitrate when its mass is 25.5 grams.
M = m / n
where M = molar mass
m = mass of a substance
n = number of moles of the substance
M = m / n
169.87 g/mol = 25.5 grams / n mol
n = 0.1501147937 mol
From the balanced equation of the reaction, 2 moles of silver nitrate reacted with 1 mole of copper(ii) chloride will produce 2 moles of silver chloride and 1 mole copper(II) nitrate.
If 25.5 grams of silver nitrate is equal to 0.1501147937 mol, and for every 2 moles of it will produce 1 mole of silver chloride, then the reaction will produce 0.075 mol silver chloride.
n = 0.1501147937 mol / 2
n = 0.07505739683 mol
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difference between carbonic acid and Sulphuric acid
Answer:
Because HSO4- has sulfur, which has a greater electronegativity than carbon, the anion is more stable (Due to electron delocalization) and thus its acid is stronger.
Explanation:
Sulfuric acid is very reactive and dissolves most metals, it is a concentrated acid that oxidizes, dehydrates, or sulfonates most organic compounds, often causes charring.
Sulphuric acid is produced from sulphur. Sulphur dioxide is first obtained by the burning of the molten sulphur in presence of air.
Calculate the maximum wavelength of light capable of dissociating the i–i bond in one molecule of iodine if the bond energy, or bond dissociation energy, is 153 kj/mol.
The iodine molecule's i-i bond can be broken by light at a maximum wavelength of =782.39 nm.
The wavelength, what is it?A waveform signal's wavelength is defined as the separation between two identical points (adjacent crests) in adjacent cycles as the signal travels through space or along a wire. This length in wireless systems is typically expressed in meters (m), centimeters (cm), or millimeters (mm) (mm).
Light with a specific wavelength has the following energy:
E = hc/λ
E = energy of light
h = planck's constant = 6.626*10⁻³⁴J-s
c = speed of light = 3*10⁸ m/s
We are given bond energy of one mole i–i , but we are required to dissociate one molecule of bromine monochloride bond.
Bond energy of one mole i–i = 153kJ/mol ( 1 mol = 6.022*10²³ )
Bond energy of one molecule of i–i = 153/6.022*10²³ kJ/molecule (1kJ = 1000J)
E = (153)*(1000)/(6.022*10²³ )J/molecule (Multiplied 1000 to change kJ to J)
E = hc/λ
153*(1000)/6.022*10²³ = 6.626*10⁻³⁴*3*10⁸×λ
λ = 782.39nm
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Scientific explanations are based on objective and systematic observations carried out under carefully controlled conditions
Answer:
Yes, its carried out under carefully controlled conditions because it might some times have a negative impacts towards humans.
Thomson concluded that ____ have ____ mass than the atom.
a
electrons; more
b
protons; less
c
electrons; less
d
neutrons; less
Answer: Either b or c or d. More information is needed to answer the question.