CHEMISTRY MIDDLE SCHOOL

A polar covalent bond is likely to form between two atoms that a. are similar in electronegativity

b. are of similar size

c. differ in electronegativity

Answers

Answer 1
Answer:

Answer:

c. differ in electronegativity

Explanation:

Covalent bond:

It is formed by the sharing of electron pair between bonded atoms.  

The atom with larger electronegativity attract the electron pair more towards it self and becomes partial negative while the other atom becomes partial positive.

For example:

In water the electronegativity of oxygen is 3.44 and hydrogen is 2.2. That's why electron pair attracted more towards oxygen, thus oxygen becomes partial negative and hydrogen becomes partial positive . The bond is polar.

When the elctronegativity difference is 0.4 or less than 0.4 the bond is non polar.

if the electronegativity difference is greater than 0.4 the bond is polar.


Related Questions

HIGH SCHOOL

Calculate the mass percent of copper in cus, copper(ii) sulfide. if you wish to obtain 10.0g of copper metal from copper(ii) sulfide, what mass of cus (in grams) must you use?

Answers

Using the relative atomic weights of both copper and sulfur ie copper = 63.55 and sulfur is 32.06 so 63.55+32.06=95.56 total mass and so of this, copper = 63.55/95.56=66.4%. So to get 10 grams of copper, use the formula 10g=66.4%xCuS so CuS=10/0.664=15.06 grams of CuS. 
COLLEGE

How does the boiling process at supercritical pressures differ from the boiling process at subcritical pressures?

Answers

Super critical, the fluid won't bubble. As you warm it, It will gradually change its properties to be an ever increasing number of gas like until the point when it winds up unclear from a gas. There is no stage change over the critical point. Though at subcritical pressures, there is dependably an distinct surface between the phases.
HIGH SCHOOL

Which of these is not true of Bohr's model of the atom ? A. It decribes electrons as particles
B. it predicts that electrons should spiral into the nucleus
C. the orbit of an electron cannot be described with certainty
D. electrons don't exist

Answers

B and D are not true of Bohr's model of the atom. Bohr's model assumed that electron of a hydrogen atom travels in discrete elliptical orbits (not circular, as you have probably been taught) whose size depended on the allowed energy levels of the electron.

Answer:

D. electrons don't exist

Explanation:

Bohr's model describes an atom as a planet and predict that electrons orbit the nucleus of the atom at a quantised energy level referred to as shells. If not quantised, then the electrons ought to spiral into the nucleus due to the attractive Coulombic forces between the them. The shells are not planar as imagined.

The model do not predicts that electrons don't exist.

MIDDLE SCHOOL

PLEASE HELP!!!!! The law of conservation of energy says you cannot ___ or ___ energy but it can be ___or ___ so when you consume energy it is not gone forever instead it is changed from one ___ to another.

Answers

Answer:The conservation of energy is an absolute law, and yet it seems to fly in the face of things we observe every day. Sparks create a fire, which generates heat—manifest energy that wasn’t there before. A battery produces power. A nuclear bomb creates an explosion. Each of these situations, however, is simply a case of energy changing form. Even the seemingly paradoxical dark energy causing the universe’s expansion to accelerate, we will see, obeys this rule.

The law of conservation of energy, also known as the first law of thermodynamics, states that the energy of a closed system must remain constant—it can neither increase nor decrease without interference from outside. The universe itself is a closed system, so the total amount of energy in existence has always been the same. The forms that energy takes, however, are constantly changing.

Potential and kinetic energy are two of the most basic forms, familiar from high school physics class: Gravitational potential is the stored energy of a boulder pushed up a hill, poised to roll down. Kinetic energy is the energy of its motion when it starts rolling. The sum of these is called mechanical energy. The heat in a hot object is the mechanical energy of its atoms and molecules in motion. In the 19th century physicists realized that the heat produced by a moving machine was the machine’s gross mechanical energy converted into the microscopic mechanical energy of atoms. Chemical energy is another form of potential energy stored in molecular chemical bonds. It is this energy, stockpiled in your bodily cells, that allows you to run and jump. Other forms of energy include electromagnetic energy, or light, and nuclear energy—the potential energy of the nuclear forces in atoms. There are many more. Even mass is a form of energy, as Albert Einstein’s famous E = mc2 showed.

Fire is a conversion of chemical energy into thermal and electromagnetic energy via a chemical reaction that combines the molecules in fuel (wood, say) with oxygen from the air to create water and carbon dioxide. It releases energy in the form of heat and light. A battery converts chemical energy into electrical energy. A nuclear bomb converts nuclear energy into thermal, electromagnetic and kinetic energy.

As scientists have better understood the forms of energy, they have revealed new ways for energy to convert from one form to another. When physicists first formulated quantum theory they realized that an electron in an atom can jump from one energy level to another, giving off or absorbing light. In 1924 Niels Bohr, Hans Kramers, and John Slater proposed that these quantum jumps temporarily violated energy conservation. According to the physicists, each quantum jump would liberate or absorb energy, and only on average would energy be conserved.

Einstein objected fervently to the idea that quantum mechanics defied energy conservation. And it turns out he was right. After physicists refined quantum mechanics a few years later, scientists understood that although the energy of each electron might fluctuate in a probabilistic haze, the total energy of the electron and its radiation remained constant at every moment of the process. Energy was conserved.

Modern cosmology has offered up new riddles in energy conservation. We now know that the universe is expanding at a faster and faster rate—propelled by something scientists call dark energy. This is thought to be the intrinsic energy per cubic centimeter of empty space. But if the universe is a closed system with a finite amount of energy, how can it spawn more empty space, which must contain more intrinsic energy, without creating additional energy?

It turns out that in Einstein’s theory of general relativity, regions of space with positive energy actually push space outward. As space expands, it releases stored up gravitational potential energy, which converts into the intrinsic energy that fills the newly created volume. So even the expansion of the universe is controlled by the law of energy conservation.

Explanation:

Answer:

1) create 2) destroy  3) rearranged 4) replaced  5) place

Explanation:

the law of conservation of energy says you cannot create or destroy energy but it can be rearranged or replaced so when you consume energy it is not gone forever instead it is changed from one place to another.

HIGH SCHOOL

What is a the volume of a salt crystal measuring 3.22 x 10^-2 cm by 1.5 x 10^-4 cm by 4.30 x 10^-3 cm? A. 2.1 x 10^-8 cm3
B. 21 x 10^-9 cm3
C. 2.1 x 10^-24 cm3
D. 21 x 10^-6 cm3

Answers

Dimension of the salt crystal is:

Length = 3.22 x 10^-2 cm

Breadth = 1.5 x 10^-4 cm

Height = 4.30 x 10^-3 cm

So it is cuboidal in shape.

Volume = L × B × H


HIGH SCHOOL

Distinguish between a physical property and a chemical property, and give an example of each

Answers

In a physical property the chemical identity does not change like the chemical property does. Physical property can change for example the molecular weight and volume or the color. A chemical property possibly undergoes a chemical change for example the flammability or reactivity, etc.

physical property example: boiling water
chemical property example: rust

goodluck my friend! :-)
MIDDLE SCHOOL

The Cretaceous-Tertiary extinction, the most famous of all the Big Five, has been attributed to what major event that triggered the fall of the dinosaurs?

Answers

Answer:

meteorite or comet impact

Explanation:

The Cretaceous-Tertiary extinction is not the most devastating one that happened, but because of the organisms that got extinct are very well known and famous, it too became the most famous extinction. The reason for the extinction was an impact of a meteorite or comet where Yucatan is located in the present. The impact was so strong that the energy released from it wiped out everything in the surrounding area. But that was not all, as this impact also caused large scale wildfires, activated most of the volcanoes on the planet, triggered enormous tsunami, and a very hot air mass circled the whole planet and fried everything that was not sheltered. The dust, ashes, and other particles released into the atmosphere blocked the sun for a long period of time. the end result was the extinction of lot of animals and plants, most noticeably the dinosaurs.

COLLEGE

Trans-2-butene does not exhibit a signal in the double-bond region of the spectrum (1600–1850 cm−1); however, ir spectroscopy is still helpful in identifying the presence of the double bond. identify the other signal that would indicate the presence of a c=c bond.

Answers

However trans-2-Butene does not give a characteristic peak in 1620-1680 cm⁻¹ region but still the presence of carbon double bond carbon can be detected by detecting following peaks in IR Spectrum.

1)  3010-3100 cm⁻¹:
                               As in trans-2-Butene a hydrogen atoms ate attached to sp² hybridized carbon, therefore the stretching of =C-H (C-H) bond will give a peak of medium intensity in the range of 3010-3100 cm⁻¹.

2)  675-1000 cm⁻¹:
                             Another peak which is given by the bending of =C-H (C-H) bond with strong intensity will appear in the range of 675-1000 cm⁻¹.
MIDDLE SCHOOL

Help me please! Reflection Questions
1. Summarize the physical and chemical properties of Uranium.
2. In the lesson, many models were used to depict the atom. How does models help you understand atomic structure?
3. How do protons, neutrons, and electrons differ in terms of their electrical charges and locations within the atom?
4. Describe the four fundamental forces. Which of these forces are involved in chemical bonding?

Answers

Answer:

Explanation:

Q 1:

Summarize the physical and chemical properties of Uranium.

Physical properties:

Uranium is member of Actinide series.

Its atomic number is 92.

Its atomic mass is 238.0289 amu.

Its density is 18.95 g/cm³.

Its melting point is 1132 °C.

Its boiling point is 3818 °C.

Its vanderwaal radius is 0.121 nm.

It has eleven isotopes.

It is malleable and ductile.

Chemical properties:

It is used as primary material for the production of transuranium elements.

With oxygen it form oxides such as UO , U₂O₅, UO₃, UO₂, UO₄.2H₂ but most common form as U₃O₈ and UO₂.

It also form carbonates with oxidation state of VI.

It form halides with halogens. For example UO₂ react with HF and form UF₄.

UO₂ +  4HF  →  UF₄ + 2H₂O

It is used in bomb.

The first bomb made up of uranium was contained U-235. It start chain reaction and many uranium atom undergoes fission and produce large amount of energy.

The fertilizer such as phosphate contain large amount of uranium.

It is used in the production of steels and also in lamp.

Uranium-233 also used as nuclear fuel.

Q 2:

In the lesson, many models were used to depict the atom. How does models help you understand atomic structure?

Rutherford atomic model:

Atom consist of positive charges and most of the mass of an atom is concentrated in small region called nucleus but at that time Rutherford not aware of composition of this small region i.e, neutron and proton.

He stated that there are negatively charged particles revolve around the nucleus with a high speed.

Atom is neutral because it consist of negative charged electrons and positive nucleus equal in magnitude and there are strong electrostatic static forced between them.

The size of atom is greater than its nucleus.

Rutherford atomic model did not explain the stability of atom and also the arrangement of electrons in orbits.

Than in 1913 Bohr proposed that electrons are revolved in stable around the nucleus. He suggested that electron's angular momentum is quantized  and due to this quantization orbits have fixed energies and electron remain in its orbit can not jump into other orbit until it gain or lost the energy.

Q 3.

How do protons, neutrons, and electrons differ in terms of their electrical charges and locations within the atom?

The electron is subatomic particle that revolve around outside the nucleus and has negligible mass. It has a negative charge.

Symbol= e-

Mass= 9.10938356×10-31 Kg

It was discovered by j. j. Thomson in 1897 during the study of cathode ray properties.

While neutron and proton are present inside the nucleus. Proton has positive charge while neutron is electrically neutral. Proton is discovered by Rutherford while neutron is discovered by James Chadwick in 1932.

Symbol of proton= P+  

Symbol of neutron= n0  

Mass of proton=1.672623×10-27 Kg

Mass of neutron=1.674929×10-27 Kg

An atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.

All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. In other words we can say that negative and positive charges are equal in magnitude and cancel the each other. For example if neutral atom has 6 protons than it must have 6 electrons. The sum of neutrons and protons is the mass number of an atom while the number of protons are number of electrons is the atomic number of an atom.

Q 4:

Describe the four fundamental forces. Which of these forces are involved in chemical bonding?

Answer:

Electromagnetic force

Explanation:

There are four fundamental forces:

Gravity

Weak nuclear force

Strong nuclear force

Electromagnetic force

Gravitational force is too weak that's why can not take part in chemical reaction while strong and weak nuclear forces are just involve in nuclear reaction not chemical reaction.

The only fundamental force which is electromagnetic force is take part in chemical reaction. This force is of different types depending upon the type of bonding. For example:

In covalent bond this type of force is occur between the atoms of almost equal electronegativity.

In ionic bond this force is occur is between positive and negative ions.

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