Answer:Because binary ionic compounds are confined mainly to group 1 and group 2 elements on the one hand and group VI and VII elements on the other, we find that they consist mainly of ions having an electronic structure which is the same as that of a noble gas. In calcium fluoride, for example, the calcium atom has lost two electrons in order to achieve the electronic structure of argon, and thus has a charge of +2:By contrast, a fluorine atom needs to acquire but one electron in order to achieve a neon structure. The resulting fluoride ion has a charge of –1:The outermost shell of each of these ions has the electron configuration ns2np6, where n is 3 for Ca2+ and 2 for F–. Such an ns2np6 noble-gas electron configuration is encountered quite often. It is called an octet because it contains eight electrons. In a crystal of calcium fluoride, the Ca2+ and F– ions are packed together in the lattice shown below. Careful study of the diagram shows that each F– ion is surrounded by four Ca2+ ions, while each Ca2+ ion has eight F– ions as nearest neighbors.
Thus there must be twice as many F– ions as Ca2+ ions in the entire crystal lattice. Only a small portion of the lattice is shown, but if it were extended indefinitely in all directions, you could verify the ratio of two F– for every Ca2+. This ratio makes sense if you consider that two F– ions (each with a –1 charge) are needed to balance the +2 charge of each Ca2+ ion, making the net charge on the crystal zero. The formula for calcium fluoride is thus CaF2.Figure 6.10.1
6.10.
1
: A portion of the ionic crystal lattice of fluorite, calcium fluoride. (a) Ca2+ ions (color) and F– ions (gray) are shown full size. “Exploded” view shows that each F– surrounded by four Ca2+ ions, while each Ca2+ ion is surrounded by eight F– ions. The ratio of Ca2+ ions to F– ions is thus 4:8 or 1:2, and the formula is CaF2. (Computer-generated). (Copyright © 1976 by W. G. Davies and J. W. Moore.)
Newcomers to chemistry often have difficulty in deciding what the formula of an ionic compound will be. A convenient method for doing this is to regard the compound as being formed from its atoms and to use Lewis diagrams. The octet rule can then be applied. Each atom must lose or gain electrons in order to achieve an octet. Furthermore, all electrons lost by one kind of atom must be gained by the other.
An exception to the octet rule occurs in the case of the three ions having the He 1s2 structure, that is, H–, Li+ and Be2+. In these cases two rather than eight electrons are needed in the outermost shell to comply with the rule.
Example 6.10.1
6.10.
1
: Ionic Formula
Find the formula of the ionic compound formed from O and Al.
Solution
We first write down Lewis diagrams for each atom involved:
alt
We now see that each O atom needs 2 electrons to make up an octet, while each Al atom has 3 electrons to donate. In order that the same number of electrons would be donated as accepted, we need 2 Al atoms (2 × 3e– donated) and 3 O atoms (3 × 2e– accepted). The whole process is then
alt
The resultant oxide consists of aluminum ions, Al3+, and oxide ions, O2–, in the ratio of 2:3. The formula is Al2O3.Figure 6.10.1
6.10.
1
: A portion of the ionic crystal lattice of fluorite, calcium fluoride. (a) Ca2+ ions (color) and F– ions (gray) are shown full size. “Exploded” view shows that each F– surrounded by four Ca2+ ions, while each Ca2+ ion is surrounded by eight F– ions. The ratio of Ca2+ ions to F– ions is thus 4:8 or 1:2, and the formula is CaF2. (Computer-generated). (Copyright © 1976 by W. G. Davies and J. W. Moore.)
Newcomers to chemistry often have difficulty in deciding what the formula of an ionic compound will be. A convenient method for doing this is to regard the compound as being formed from its atoms and to use Lewis diagrams. The octet rule can then be applied. Each atom must lose or gain electrons in order to achieve an octet. Furthermore, all electrons lost by one kind of atom must be gained by the other.
An exception to the octet rule occurs in the case of the three ions having the He 1s2 structure, that is, H–, Li+ and Be2+. In these cases two rather than eight electrons are needed in the outermost shell to comply with the rule.
Example 6.10.1
6.10.
1
: Ionic Formula
Find the formula of the ionic compound formed from O and Al.
Solution
We first write down Lewis diagrams for each atom involved:
alt
We now see that each O atom needs 2 electrons to make up an octet, while each Al atom has 3 electrons to donate. In order that the same number of electrons would be donated as accepted, we need 2 Al atoms (2 × 3e– donated) and 3 O atoms (3 × 2e– accepted). The whole process is then
alt
The resultant oxide consists of aluminum ions, Al3+, and oxide ions, O2–, in the ratio of 2:3. The formula is Al2O3.
Explanation:
what is the formula of the compounds in B
pls help
Answer:
PCl3
Explanation:
The molecular formular of a compound shows the exact number of atoms of elements present in the compound. In this illustration, there is one atom of P and 3 atoms of Cl.
The formular is given as; PCl3
Answer:
PCl³
Explanation:
because there are 1 phosphorus atom and 2 chlorine atom.
The valency of silver in silver sulphide (Ag₂S).
Answer:
Explanation:a
Living things respire to stay alive. In the mitochondria, sugar is combined with oxygen to produce energy, water and carbon dioxide. Write the equation of this chemical reaction
Answer:
C6H12O6 + 6O2 → 6CO2 + 6H2O
Explanation:
Cellular respiration occurs in the mitochondria of cells. It is a process in which sugar is combined with oxygen to produce energy, water and carbon dioxide. This is the major process by which energy is released in living organisms.
Aerobic respiration involves a series of chemical reactions. These reactions commence with sugar and oxygen then it produces carbon dioxide and water according to the reaction equation; C6H12O6 + 6O2 → 6CO2 + 6H2O.
Answer: The equation for this Chemical reaction is:
C6H12O6 (s) + 6 O2 (g) → 6 CO2 (g) + 6 H2O (l) + heat (energy)
Explanation:
Mitochondria is the site of chemical energy conversions for cell activities. In the mitochondria, sugar (chemical energy) is combined with oxygen to produce energy, water and carbon dioxide. The equation for this reaction is already given above.
All living cells need energy for the metabolic processes essential for life. They get this energy from the chemical energy stored in food (sugar).
In this process, oxygen is necessary for the chemical energy in sugar to be converted to carbondioxide, water and release of heat energy. It is therefore an oxidative reaction.
Furthermore, energy is not released in one big step as shown in the above reaction, but in a series of small steps which are catalysed by enzymes. The energy that is released, bit by bit, is stored in adenosine triphosphate (ATP) molecules. The oxidation of glucose to release energy in this manner is known as CELLULAR RESPIRATION. It occurs also in the mitochondria of all living cells.
Which of the following describes an orbital?
What rule/principle states that electrons in the same sublevel (p, d, or f) are placed in individual orbitals, before they are paired up, to increase atomic stability?
Aufbau principle
Hund’s rule
Pauli exclusion principle
Answer:
Hunds Rule
Explanation:
The principle states that electrons in the same sublevel (p, d, or f) are placed in individual orbitals, before they are paired up, to increase atomic stability is Aufbau principle, therefore option (a) is correct.
What is Aufbau principle ?
Aufbau principle states that electrons are filled into atomic orbitals in the increasing order of orbital energy level.
According to the Aufbau principle, the available atomic orbitals with the lowest energy levels are occupied before those with higher energy levels.
The rule/principle states that electrons in the same sublevel (p, d, or f) are placed in individual orbitals, before they are paired up, to increase atomic stability is Aufbau principle, therefore option (a) is correct.
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In order to make 1 batch of cookies it requires 2 cups flour, 3 eggs, and 1 cup sugar. What would be the coefficients for the flour, eggs, and sugar, assuming you wanted to make 10 batches of cookies? Write the coefficients below!
Does anyone know how kinetic energy and crater diameter are related??
Answer:
Crater size is related to the mass and velocity of the impacting body. Mass and velocity can be combined to find the kinetic energy of an impactor. ... This fundamental physical relationship allows an estimate of impactor mass to be made from crater diameter.
Explanation:
A scientists who studies how water moves around is called......
Answer:
A scientists who studies how water moves around is called "Hydrologist".
marking brainliest please help
A friend tells you that's after a candle burn there is less matter than before the flame was lit is your friend correct explain why or why not
Answer:
See explanation
Explanation:
The law of conservation of matter states that "matter cannot be created or destroyed. In a physical change, substances can change form, but the total mass remains the same."(Virginia)
Hence, the quantity of matter present before and after the candle burn must remain the same in accordance with this law stated above.
Hence, my friend was not correct.
i’m not even sure if this is the right subject or like if this is even a question lol anyways
List at least 3 physical or chemical properties of the element Cobalt
Which statement compares you tractive forces that hold particles together
Answer:
The answer is Ionic and covalent binding produces compounds, while hydrogen bonding and Van der Waals forces join separate molecules together.
chemical bonding explaining
Explanation:
A chemical bond is a lasting attraction between atoms, ions or molecules that enable the formation of chemical compounds. The bond may result frim the electrostatic force of attraction between oppositely charged ions as in ionic bonds or through the sharing of electrons as in covalent bonds.
what are the formulas for the following elements?
-Beryllium fluoride
-Barium fluoride
-Strontium sulfide
-Titanium(II) chloride
-Iron(II) sulfate
-Vanadium(III) cyanide
Answer:
Beryllium fluoride - BeF2
Barium fluoride - BaF2
Strontium sulfide - SrS
Titanium(II) chloride - TiCl2
Iron(II) sulfate - FeSO4
Vanadium(III) cyanide - V( CN )3
3. Why are amino acids important in living organisms?
Answer:
Explanation:
Their role is to compose proteins. Amino acids have many biologically important functions. They are also energy metabolites,many of them are essential nutrients. Amino acids can function as chemical messengers in communication between cells.
Answer:
well Aside from their role in composing proteins, amino acids have many biologically important functions. They are also energy metabolites, and many of them are essential nutrients. Amino acids can often function as chemical messengers in communication between cells.
Explanation:
this should be the answer
What does it mean when a cell is multicellular?
options:
A.) Multicellular organisms are simple. They contain cytoplasm, ribosomes, DNA and a cell membrane
B.) Multicellular organisms are made of many cells and have specialized shapes that allow them to perform specific functions
C.) Multicellular organisms are made of one cell and have simple shapes that allow them to perform multiple functions
D.) Multicellular cells do not come from pre-existing cells.
Answer:
B.) Multicellular organisms are made of many cells and have specialized shapes that allow them to perform specific functions
Explanation:
Multicellular means that there is more than one cell.
Hope this helps!
What is the frequency when the Energy is equal to 4.18 x 10-22 ?|
Answer:
6.31x10¹¹s⁻¹ = Frequency
Explanation:
To convert frequency to energy or vice versa we must use the equation:
e = h*f
Where e is energy in joules (4.18x10⁻²²J)
h is Planck's constant (6.626x10⁻³⁴Js)
Replacing:
4.18x10⁻²²J = 6.626x10⁻³⁴Js*f
6.31x10¹¹s⁻¹ = Frequency2.
Aluminium reacts with iron(III) oxide as shown.
iron(III) oxide + aluminium → iron + aluminium oxide
Which statement about this reaction is correct?
A
Aluminium is oxidised.
B
Aluminium oxide is reduced.
C Iron(III) oxide is oxidised.
D
Iron is oxidised.
Answer:
A is the answer..............
.............
If the temperature of a chemical reaction was reduced, how could the reaction rate most likely be increased?
Group of answer choices
decrease the pressure acting on the system
add a chemical inhibitor
decrease the surface area of the reactants
increase the concentration of the reactants
Answer:
Increase the concentration of the reactants.
Explanation:
This question seems vague, but to put it simply, the reaction rate decreases with a decrease in temperature, so we need to find a way to increase the reaction rate again. When you lower temperature, the molecules are slower and collide less. So therefore, in other words, we need to find a way to increase the rate of collisions between molecules. When the temperature drops, if we increase the concentration of the reactants, we are able to increase the rate of collisions between molecules. As a result, reaction rate is increased once again.
If the temperature of a chemical change was reduced,the reaction rate could most likely be increased by increasing the concentration of the reactants.
What is a chemical change?Chemical changes are defined as changes which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical change.
There are several characteristics of chemical changes like change in color, change in state , change in odor and change in composition . During chemical change there is also formation of precipitate an insoluble mass of substance or even evolution of gases.
There are three types of chemical changes:
1) inorganic changes
2)organic changes
3) biochemical changes
During chemical changes atoms are rearranged and changes are accompanied by an energy change as new substances are formed.
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A force of 792 mN is applied to a substance with a mass of 295,000 mg.
Determine the acceleration of the particle.
Answer:
Acceleration = 2.68 m/s² (Approx.)
Explanation:
Given:
Force = 792 mN = 0.792 N
Mass = 295,000 mg = 0.295 kg
Find:
Acceleration
Computation:
Acceleration = Force / mass
Acceleration = 0.792 / 0.295
Acceleration = 2.68 m/s² (Approx.)
A scientist is using robots to perform thousands of experiments on different
chemical compounds to see how they affect cancer cells. What is this
process called?
A. An intravenous solution
B. Evaluating test results
C. Screening
D. Engineering process
A scientist is using robots to perform thousands of experiments on different chemical compounds to see how they affect cancer cells.This process is called Screening.
What is screening?The method to test diseases and health condition of body used by scientist and doctor is called screening. The screening helps to find problem earlier and treat them.
What is an intravenous solution?The liquid given to replace water, sugar and salt needed if you are ill or having operation.There are three type of an intravenous solution, isotonic, hypotonic and hypertonic.This an intravenous solution used in an intravenous therapy.What is evaluating test?The process by which of system and component are compared against requirement and specification through testing. The result of the evaluating test is called Evaluating test resultsWhat is Engineering process?The process used by Engineer design and create functional products. This process is a series of steps.To learn more about chemical compounds here.
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Answer: screening
Explanation:
Thread-like structures that are found in the nucleus of a cell that contains all DNA.
A.) DNA
B.) Genes
C.) Chromosomes
D.) Nucleus
Describe the effect of cooling a gas in a container?
Answer:
By cooling the gas in the container the partial pressure of the gas will cause the gas to condense. Imagine water vapor in a bottle if you cool it down it will condense into droplets as the molecules of gas start to slow down to to lower temp
Explanation:
What is the final temperature of a sample of magnesium (c = 0.24 cal/g°C), if 1835 cal is
added to 612 g of magnesium at an initial temperature of 19.3°C?
Answer:31.8 °C
Explanation:
Delta T=?
C= .24 cal/g°C
M=612g
Q=1835
Delta T= 1835 cal/(.24cal/g°C)(612g)=12.50°C
Intial temp= 19.3°C
Add intial temp to new temp
12.50+19.3=31.8°C
Light-colored moths blend with light-colored tree bark in their environment. A moth with a dark- colored variation blends with dark-colored tree bark but stands out against light-colored bark. What environmental change would give the dark-colored moth in the picture an adaptive advanage and enhance its survival?
A. The dark-colored moth will have an advantage if it begins to feed at night.
B. If the climate warms, dark-colored moths will absorb more heat.
C. Light-colored moths will be killed more readily if the climate cools.
D. If a change in the environment causes most of the trees to darken, the dark-colored moth will have an advantage.
When most liquids freeze, explain what happens to the motion and the space between the atoms.
Answer:
atoms relative motion slow down and begin to vibrate in place
314.5g HBr (MMHBr = 80.91g/mol), is mixed into 4.50L solution. Find Molarity (M) of the
solution.
Answer:
[tex]\boxed {\boxed {\sf M \approx0.864 \ M \ HBr}}[/tex]
Explanation:
The molarity of a solution is the moles per liter. It is found using this formula:
[tex]M=\frac { moles \ of \ solute}{liters \ of \ solution}[/tex]
First we must calculate moles, since we are given grams. To convert from grams to moles, the molar mass is used. This is also given to us, it is 80.91 grams per mole. We can use it as a ratio.
[tex]\frac {80.91 \ g \ HBr}{1 \ mol \ HBr}[/tex]
Multiply by the given number of grams.
[tex]314.5 \ g \ HBr *\frac {80.91 \ g \ HBr}{1 \ mol \ HBr}[/tex]
Flip the fraction so the grams of HBr cancel.
[tex]314.5 \ g \ HBr *\frac {1 \ mol \ HBr}{80.91 \ g \ HBr}[/tex]
[tex]\frac {314.5 \ mol \ HBr}{80.91 }=3.88703497714 \ mol \ HBr[/tex]
Now we know the moles, and can calculate the molarity.
There are 3.88703497714 moles of solute and 4.50 Liters of solution.
[tex]M= \frac {3.88703497714 \ mol }{ 4.50 \ L}[/tex]
[tex]M= 0.863785550476 \ mol/ L[/tex]
The original measurements have 4 and 3 significant figures, so we use the lowest number of 3 for our answer. For the number we calculated, that is the thousandth place.
The 7 in the ten thousandth place tells us to round the 3 to a 4.
[tex]M \approx 0.864 \ mol/ L[/tex]
[tex]M \approx 0.864 \ M \ HBr[/tex]
The molarity of the solution is about 0.864 M HBr.
2 C2H6 + 7 026 H2O + 4 CO2
If 5.25 moles of ethane (C2H6) and 15.0 moles of oxygen are reacted,
which is the limiting reactant?
Answer:
Oxygen is limiting reactant
Explanation:
Based on the chemical reaction:
2C2H6 + 7O2 → 6H2O + 4CO2
2 mole of ethane reacts with 7 moles of oxygen
For a complete reaction of 5.25 moles of ethane are required:
5.25 moles Ethane * (7mol Oxygen / 2mol Ethane) = 18.38 moles of oxygen
As there are just 15.0 moles of oxygen
Oxygen is limiting reactantBombardier beetles release a burst of hot chemical spray with a popping sound. The chemical is sprayed from a structure present under the belly of the beetles.
Which is the likely advantage of such a behavior?
It allows the beetles to attract mates.
It allows the beetles to move obstacles out of their paths.
It allows the beetles to escape from predators.
It allows the beetles to stay warm in cold conditions.
It allows the beetles to escape from predators