Which statement about exothermic reactions is accurate? a.As reactants form products, the potential energy decreases.
b.As reactants form products, the potential energy increases.
c.Thermal energy is transferred from the product to the reacting substances.
d.Thermal energy is transferred from the surroundings to the reacting substances.
Answers
Answer:
As reactants form products, the potential energy decreases.
Explanation:
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Answers
Answer : The properties of noble gases which usually occurs in Group 8 A periodic table are described below;
i) They have an outer electrons configuration as
ii) Some elements like Ne and Ar does not form a stable chemical compounds.
iii) They have a large ionization energy, He has the largest ionization energy amongst the group.
The properties of noble gases are listed as follows:
1. These have outer electronic configuration of , except Helium.
2. These are monoatomic under standard conditions.
3. These have high ionization energies.
4. These are the least reactive elements in the periodic table.
5. These have low melting and boiling points.
Further Explanation:
Periodic table:
A systematic arrangement of elements in various rows and columns is known as a periodic table. Here, elements are arranged in increasing order of their respective atomic numbers so that elements with the same chemical and physical properties lie in same group. Horizontal rows are called periods and vertical columns are called groups. There are 18 groups and 7 periods in a periodic table.
Elements are further classified as metals, non-metals and metalloids in the periodic table. The elements placed at the left side of the table are called metals and the elements placed at the right of the table are called non-metals. Metalloids are the elements kept between metals and non-metals.
Elements of group 8A of the periodic table are known as noble gases. These are also known as rare or inert gases. Noble gases are present at the rightmost corner of the periodic table. Helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn) are the noble gases present in group 8A.
The general outermost electronic configuration of noble gases is , except helium whose electronic configuration is
. These have completely filled valence shells in these elements and therefore they have a total of 8 valence electrons in their outermost shells, except for helium.
Due to the presence of filled valence shells, these have no tendency to react with other elements and thus called inert gases. These are the least reactive elements present in the periodic table
The noble gases have complete valence shells so these do not lose electrons and thereby possess very high ionization energies. Helium has the highest ionization energy among all the noble gases.
Because of their low reactivities, noble gases exist as monoatomic gases under standard conditions. These have weak interatomic forces and therefore have very low melting and boiling points.
Learn more:
1. Which ion was formed by providing the second ionization energy? brainly.com/question/1398705
2. Write a chemical equation representing the first ionization energy for lithium: brainly.com/question/5880605
Answer details:
Grade: High School
Subject: Chemistry
Chapter: Periodic classification of elements
Keywords: noble gases, ns2np6, He, Ne, Ar, Kr, Xe, Rn, helium, neon, argon, krypton, xenon, periodic table, elements, groups, periods, 8A, high ionization energy, least reactive, low melting and boiling points.
Answers
The ability to be drawn into thin sheet is called malleability. The ability to be drawn into thin wires is called ductility. Copper have a high melting point due to metallic bonding.
What is metallic bonding?
Metallic bonding is a type of chemical bonding that rises from the electrostatic attractive force between conduction electrons and positively charged metal ions. Metallic bonds are more more strong than covalent bond and ionic bond
Metallic bonds is between metals and metals, have the malleable and ductile property. Elements which have metallic bonding have high melting and boiling point. Since copper is a metal, it form strong metallic bond with itself. So, copper have a high melting point.
Therefore, copper have a high melting point due to metallic bonding.
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Answers
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Answers
Answer:
i) Highest osmotic pressure: CaCl2
ii) lower vapor pressure : CaCl2
iii) highest boiling point : CaCl2
Explanation:
The colligative properties depend upon the number of solute particles in a solution.
The following four are the colligative properties:
a) osmotic pressure : more the concentration of the solute, more the osmotic pressure
b) vapor pressure: more the concentration of the solute, lesser the vapor pressure.
c) elevation in boiling point: more the concentration of the solute, more the boiling point.
d) depression in freezing point: more the concentration of the solute, lesser the freezing point.
the number of particle produced by urea = 1
the number of particle produced by AgNO3 = 2
the number of particle produced by CaCl2 = 3
As concentrations are same, CaCl2 will have more number of solute particles and urea will have least
i) Highest osmotic pressure: CaCl2
ii) lower vapor pressure : CaCl2
iii) highest boiling point : CaCl2
Final answer:
The solution with the highest number of particles in solution (CaCl2 in this case), experiences the highest osmotic pressure, lowest vapor pressure and highest boiling point due to the principles of colligative properties.
Explanation:
The question pertains to the colligative properties of solutions, which would be governed by the number of particles in the solution. The solutions are 0.04 m urea [(NH2)2C=O)], 0.04 m AgNO3, and 0.04 m CaCl2. For (i) Highest osmotic pressure, the solution with the highest ion count would yield the highest osmotic pressure. CaCl2 dissociates into three ions (Ca²+, and 2 Cl¯), therefore, it would exhibit the highest osmotic pressure. For (ii) Lowest vapor pressure, this would coincide with the solution with the highest osmotic pressure, again making it CaCl2, due to the greatest decrease in vapor pressure. For (iii) the highest boiling point, this too would be CaCl2 for the reasons stated above. The presence of more particles in a solution interferes more with the evaporation process, requiring more energy (higher temperature) to achieve boiling.
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(2) emitted by the electron
(3) absorbed by the nucleus
(4) absorbed by the electron
Answers
An atom of oxygen is in an excited state. When an electron in this atom moves from the third shell to the second shell, energy is emitted by the electron. Hence, option B is correct.
What is an atom?
The smallest piece of stuff that still retains its characteristics is an atom. A gold atom, for instance, is the smallest piece of that element that will still retain all of gold's properties and behaviors. When an atom is disassembled into its component parts, the subatomic particles found inside each have special characteristics that are not at all similar to those of the element the atom represents. Protons, neutrons, and electrons are the three different subatomic particle kinds.
The electron that transitioned from a higher to a lower level felt the change in energy level. Since the nucleus is unaffected, its energy levels are unaffected as well. Since it requires more energy to keep an electron at a higher energy level than a lower one, the shift in energy levels indicates that the electron released some energy.
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In chemistry and phase equilibria, phase transition is a common phenomenon. There are many terms related to the phase transition. The process deposition is a physical process. This process is the opposite of sublimation.
Deposition is a phase transfer or phase transition process in which a substance in the gaseous state changes directly to the solid state. Freezing of air is an example of deposition in which the water vapour directly changes to ice.
Here the gaseous state converts into solid state without being in the liquid state.
An example is:
CO₂ (g) → CO₂ (s)
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