Answer:
A
Explanation:
just did the test
The electron cloud model is the modern model of the atom that contrasts the exact position of the electron. It is the currently accepted atomic model. Thus, option A is correct.
What is the electron-cloud model?The electron-cloud model is currently accepted and used model that states about the moving electron cloud around the nucleus in an atom. It contrasts with the previous models.
The electron cloud gives the probable position of the electron rather than a fixed position. It was given by Erwin Schrodinger that showed electrons no longer move in a fixed orbital around the atom.
The position of the electron is determined based on the cloud where they are most likely to be present. The field with high probability is represented as a dense area.
Therefore, option A. electron-cloud model is a modern atomic model.
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Compute the heat involved when 42.8 grams of calcium carbide, CaC2 cools from 74.2 c to 11.5 c
Name and describe the chemical models scientists use to make predictions.
How much HNO3 can be made from 25.0 g of NO2 according to the following reaction?
Answer:
1. Find the molar mass of NO2 (46.01)
2. Find the number of moles in 25 g of NO2 (by dividing 25 by the molar mass) 25/46.01 = .54
3. For every 3 moles of NO2 there are 2 moles of HNO3. multiply the number of moles of NO2 by 2/3
.54 x 2/3 = .36
4. Finally, multiply this number by the molar mass of HNO3 (63.018)
.36 x 63.018 = 22.68 g HNO3
Explanation:
The statement, that describes the mass of HNO₃ can be made from mass of NO₂ is "17.1 gram".
What is mass?A substance is something to do with mass that takes up space. The mass of a compound is the total amount of atoms present in grams that make up a molecule. The grams is the unit of mass. In order to determine the mass in grams, divide the given mass of the substance value by its molar mass to convert gram into mole.
What is gram?The mass about one cubic centimeter of distilled water at 4°C would be used to describe the gram as a unit.
Gram to mole conversion factor,
[tex]= grams\;*\;\frac{1\;mol}{grams}[/tex]
The balanced chemical equation comes out to be, 2NO₂ + H₂O → HNO₂ + HNO₃
Using the above equation, the moles of NO₂ can be determined from the given mass,
[tex]= \frac{given\;mass}{molar\;mass}\\= 25.0\;g\;*\;\frac{1\;mol}{46.005\;g} \\= 0.5434\;mol Now, HNO_{3} can be made from 25.0 g of NO2= 0.5434\;mol\;NO2\;*\;\frac{1\;mol\;HNO3}{2\;mol\;NO2}\;*\;\frac{63.01\;g\;HNO3}{1\;mol\;HNO3} \\= 17.119\;g\;HNO3\\=17.1\;g\;HNO3[/tex]
Hence the correct answer is 17.1 gram.
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5. A piece of copper metal is correctly placed on a triple
beam balance. The riders are all at the zero mark
except for the rider on 0-10 gram beam which is
located at the position shown.
5 6
What is the mass of the copper metal?
A) 0.455 g
B) 4. 56 g
C) 0.55 g
D) 5.50 g
In this reaction, how many moles of CO2 would be produced when methane (CHA) fully reacts with 6 moles of Oz? CH4 + 202 2H2O + CO2
O A. 12
O B. 6
O C. 3
O D. 2
WILL GIVE BRAINLEST!
In this reaction, 3 moles of CO2 would be produced when methane (CHA) fully reacts with 6 moles of Oz.
What is methane used for?Methane is an odorless, colorless, flammable gas. Its miles are used ordinarily as gasoline to make heat and light. it is also used to fabricate natural chemicals. Methane can be fashioned by way of the decay of natural substances and is common in landfills, marshes, septic structures, and sewers.
Is methane gas harmful to human beings?High tiers of methane can lessen the quantity of oxygen breathed from the air. this can result in temper changes, slurred speech, vision problems, memory loss, nausea, vomiting, facial flushing, and headache. In excessive cases, there can be changes in respiratory and coronary heart fee, balance problems, numbness, and unconsciousness.
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HELP PLZ MUCHO HELP I WILL GIVE BRAINLIEST IF CORRECT PLEASE NEED HELP
Lewis Dot Structure for Helium
(He)
Answer:
Hydrogen, symbol H, has 1 valence electron, Lewis structure is H. Helium, symbol He, has 2 valence electrons, Lewis structure is He: With helium, the first energy level (K shell) is full.
The Lewis dot structure for He has been shown in the image attached.
What is the Lewis dot structure?The general shape of a molecule and the number of bonds an atom can make can both be determined using Lewis structures. They provide a visual representation that aids in understanding chemical bonding and predicting the reactivity and other properties of molecules.
The three-dimensional form of molecules, molecular orbitals, or the presence of lone pairs of electrons are all ignored in Lewis structures, which are simplified models. Making this distinction is essential.
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which element has a stronger Zeff (effective nuclear change) Na or Rn and why?
Answer:
chlorine
Explanation:
Because chlorine is in the same period as phosphorus and sodium, but has the most protons in its shell (the most right within the same period) it has the greatest effective nuclear charge.
What's the actual size of an atom?
Why does the amount of protons change the atom but not the neutrons?
Are we able to "edit atoms" and create new elements
what happens when an atom becomes too positively charged or negatively charged
Answer:
1.An atom is the smallest constituent unit of ordinary matter that constitutes a chemical element. Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms. Atoms are extremely small; typical sizes are around 100 picometers ( 1 × 10−10 m, a ten-millionth of a millimeter, or 1/254,000,000 of an inch).
3.New elements aren't exactly discovered anymore. However, they can be made, using particle accelerators and nuclear reactions. A new element is made by adding a proton (or more than one) to a pre-existing element. This can be done by smashing protons into atoms or by colliding atoms with each other.
4.If an atom gains an electron, it becomes negatively charged.
If an atom loses an electron, it becomes positively charged.
The density of silver is 10.49 g/cm^3. Find the volume of a piece of silver with a mass of 31.5 grams.
Answer:
The answer is 3.00 cm³Explanation:
The volume of a substance when given the density and mass can be found by using the formula
[tex]volume = \frac{mass}{density} \\[/tex]
From the question
mass of metal = 31.5 g
density = 10.49 g/cm³
We have
[tex]density = \frac{31.5}{10.49} \\ = 3.002859866...[/tex]
We have the final answer as
3.00 cm³Hope this helps you
Find the mass of an object that has a volume of 6.0 cm ³ and density of 3.3 g / ml.
Answer:
The answer is 19.8 gExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volumeFrom the question
volume = 6 cm³
density = 3.3 g/cm³
We have
mass = 3.3 × 6
We have the final answer as
19.8 gHope this helps you
ASAP MULTIPLE CHOICE WILL MARK BRAINLIEST
What did J.J. Thomson's cathode-ray tube experiment show?
Atoms are small individual spheres.
Electrons are in a cloud surrounding positively charged particles.
Atoms consist of at least some negatively charged particles.
Matter can be neither created nor destroyed.
Answer:
Atoms consist of at least some negatively charged particles (Electron)
Explanation:
J.J. Thomson's experiments with cathode ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons.
Please correct me if I'm wrong.
Which would show an example of how physical changes are reversible?
A. cutting a gold bar in two pieces and then putting the pieces next to each other
B. burning a match and then relighting it
C. melting tin and then cooling it into a mold
D. combining sodium and chlorine to make the new material of table salt
Answer:
C) the tin one
Explanation:
because its the same substance, it was just heated and formed into a new shape.
Which name identifies the acid HBr?
A) hydrogen bromine acid
B) hydrousbromide acid
C) broom is acid
D) hydrobromic acid
Answer:
A
Explanation:
Please answer me ASAP
A technique that uses a porous barrier (separation with pores) to separate heterogeneous mixtures is _______.
a. distillation
b. chromatography
c. filtration
d. crystallization
Answer:
c.filtration is the answer
PLEASE HELP the density of aluminum foil is 0.789g/cm3. Calculate the mass of 10.0cm3 of aluminum foil.
Answer:
100.985
Explanation:
How many nonreactive elements are there in the periodic table??
Answer:
6
Explanation:
All noble gases are nonreactive, these include helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn).
Answer:
18 elements are nonreactive in the periodic table
A certain element exists as three different isotopes. 24.1% of all the isotopes have a mass of 75.23 amu, 48.7% have a mass of 74.61 amu, and 27.2% have a mass of 75.20 amu. What is the average atomic mass of this element?
Answer: A certain element exists as three different isotopes. 24.1% of all the isotopes have a mass of 75.23 amu, 48.7% have a mass of 74.61 amu, and 27.2% have a mass of 75.20 amu. What is the average atomic mass of this element?
Explanation: A certain element exists as three different isotopes. 24.1% of all the isotopes have a mass of 75.23 amu, 48.7% have a mass of 74.61 amu, and 27.2% have a mass of 75.20 amu. What is the average atomic mass of this element? 74.92 amu. Use your periodic table to determine which element this is. As. An element exists
The average atomic mass of the element is 74.93 amu
Let the 1st isotope be A
Let the 2nd isotope be B
Let the 3rd isotope be C
From the question given above, the following data were obtained:
For A (i.e 1st isotope)Abundance of A (A%) = 24.1%
Mass of A = 75.23 amu
For B (i.e 2nd isotope)Abundance of B (B%) = 48.7%
Mass of B = 74.61 amu
For C (i.e 3rd isotope)Abundance of C (C%) = 27.2%
Mass of C = 75.23 amu
Average atomic mass =?The average atomic mass of the element can be obtained as follow:
Atomic mass = [(mass of A × A%)/100] + [(mass of B × B%)/100] + [(mass of C × C%)/100]= [(75.23 × 24.1)/100] + [(74.61 × 48.7)/100] + [(75.23 × 27.2)/100]
= 18.13043 + 36.33507 + 20.46256
Average atomic mass = 74.93 amuThus, the average atomic mass of the element is 74.93 amu
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What is the formula for hydrosulfuric acld?
HSO 2
H252
H 2 SO 2
H2S
What is the molar mass of silver (Ag)?
Answer:
should be 107.8682u
Explanation:
Answer:
C. 107.87 g/mol
Explanation:
I got it right
what is the density of an object has a mass of 10 G volume of five CM^3
Answer:
The answer is 2.0 g/cm³Explanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\[/tex]
From the question
mass = 10 g
volume = 2 cm³
We have
[tex]density = \frac{10}{5} \\ [/tex]
We have the final answer as
2.0 g/cm³Hope this helps you
can you hellp me plez
Answer:
srry, I don't understand, I would need more info
Which of the following is an accurate definition of power?
Answer:
the ability to do something or act in a particular way, especially as a faculty or quality.
Explanation:power, authority, jurisdiction, control, command, sway, dominion mean the right to govern or rule or determine. power implies possession of ability to wield force, authority, or influence. the power to mold public opinion authority implies power for a specific purpose within specified limits.
The mass of a solid is 6.75 g and its volume is
3.5 cm. What is the density of the solid?
Answer:
1.93 (rounded to nearest .00)
Explanation:
[tex]\frac{M}{V}[/tex] (mass divided by volume)
What word is not associated with Exothermic? A)absorbs energy B )burning firewood C )freezing water D) releases energy
Answer:
C
Explanation:
Answer:
D
Explanation:
Not a because the term exo means outward, so exothermic means releasing energy so D.
Not B or C because they have nothing to do with exothermic (exo- outward thermic- energy)
How did Albert Einstein explain the photoelectric effect?
A) light is made of atoms
B) light is made of photons
C) light is made of electricity
D) light is made of electrons
Answer:
C
Explanation:
Because you can't open your lamps when there's no electricity or if it's brownout,,,,
An atom has 6 protons, 6 neutrons, and 6 electrons. What is the charge of the atom's
nucleus?
Explanation:
Carbon-12 (12C) is the more abundant of the two stable isotopes of carbon (carbon-13 being the other), amounting to 98.93% of the element carbon;[1] its abundance is due to the triple-alpha process by which it is created in stars. Carbon-12 is of particular importance in its use as the standard from which atomic masses of all nuclides are measured, thus, its atomic mass is exactly 12 daltons by definition. Carbon-12 is composed of 6 protons, 6 neutrons, and 6 electrons.
Which term describes the materials magma is made of?
cooled
molten
extrusive
intrusive
Answer:
The correct answer is Molten
Explanation: The proof is in the attachment below, the answer is correct on the quiz I took
The term molten describes the materials magma is made up. Thus, option B is correct.
What is element?
Silver is a shiny metal that conducts electricity very well . It can be molded into thin sheets it means it can spread into a like a sheet and these type of properties is known as malleability.
Potassium is dull and brittle it means that it can't be change into sheet when you try to change in sheet it will break and these properties are called as brittlness and when it is has been dissolved into water, which it does quite easily. Physical properties of matter include color, hardness, malleability, solubility, electrical conductivity, density, melting points and boiling points.
Carbon is an element which is a chemical by nature and it is represented by C and the atomic number of carbon is 6. The atomic mass of carbon is 12.011 u and the carbon contain 2, 4 electrons per shell with the electronegativity of 2.55 .
Therefore,the term molten describes the materials magma is made up. Thus, option B is correct.
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The isotopes of Madeupium (Ma) and their abundance in nature are shown below. Which is the most likely estimate of what the atomic mass is close to?
Ma-74 (74.333 - 85%)
Ma-75 (74.999 - 10%)
Ma-76 (75.700 - 5%)
A. 74 g
B. 75 g
C. 76 g
Answer:
A = 74 g
Explanation:
Given data:
Ma-74 (74.333 - 85%)
Ma-75 (74.999 - 10%)
Ma-76 (75.700 - 5%)
Atomic mass close to = ?
Solution:
1st of all we will calculate the average atomic mass.
Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) + (abundance of 3rd isotope × its atomic mass) / 100
Average atomic mass = (85×74.333)+(10×74.999)+(5×75.700) /100
Average atomic mass = 6318.305 +749.99+ 378.5 / 100
Average atomic mass= 7446.795/ 100
Average atomic mass = 74.467 amu
The average atomic mass is closer to the 74 g.
During an endothermic reaction, heat is
Answer:
Absorbed during the above reaction.
Explanation:
It is lowering the temperature of the reaction mixture, and thus the reaction flask feels cold.
Answer:
Endothermic reaction: absorbs heat from its surroundings.
Explanation:
"Endo" means inside. "Thermic" refers to heat.