Answer:
The high melting point is also consistent with its description as an ionic solid. In the crystal, each S2− ion is surrounded by an octahedron of six Ca2+ ions, and complementarity, each Ca2+ ion surrounded by six S2− ions.
Explanation:
You can use the periodic table to predict whether an atom will form an anion or a cation, and you can often predict the charge of the resulting ion. Atoms of many main-group metals lose enough electrons to leave them with the same number of electrons as an atom of the preceding noble gas. To illustrate, an atom of an alkali metal (group 1) loses one electron and forms a cation with a 1+ charge; an alkaline earth metal (group 2) loses two electrons and forms a cation with a 2+ charge, and so on. For example, a neutral calcium atom, with 20 protons and 20 electrons, readily loses two electrons. This results in a cation with 20 protons, 18 electrons, and a 2+ charge. It has the same number of electrons as atoms of the preceding noble gas, argon, and is symbolized Ca2+. The name of a metal ion is the same as the name of the metal atom from which it forms, so Ca2+ is called a calcium ion.
When atoms of nonmetal elements form ions, they generally gain enough electrons to give them the same number of electrons as an atom of the next noble gas in the periodic table. Atoms of group 17 gain one electron and form anions with a 1− charge; atoms of group 16 gain two electrons and form ions with a 2− charge, and so on. For example, the neutral bromine atom, with 35 protons and 35 electrons, can gain one electron to provide it with 36 electrons. This results in an anion with 35 protons, 36 electrons, and a 1− charge. It has the same number of electrons as atoms of the next noble gas, krypton, and is symbolized Br−. (A discussion of the theory supporting the favored status of noble gas electron numbers reflected in these predictive rules for ion formation is provided in a later chapter of this text.)
(b)
Analysis of a molecule of DNA showed that cytosine accounted for 42 per cent of the
content of the nitrogenous bases. Calculate the percentage of bases in the molecule
which would be thymine. Show your working.
8%
Explanation:
In a DNA molecule the no. of Adenine bases equal to that of Thymine bases
The no. of Cytosine bases equal to that of Guamine bases.
If we take no. of Thymine bases as x and no. of Cytosine bases as y,
Adenine + Thymine + Cytosine + Guamine = 100
x + x + y+y = 100
2( x+y) = 100
x+y = 50
y=42
therefore x= 50-42 = 8%
In which container are the particles of water moving fastest? In which container are the particles moving slowest
Answer:
Particles move faster the farther they are apart, so the container with the most spread out particles.
The half-life of Palladium-100 is 4 days. After 16 days a sample of Palladium-100 has been reduced to a mass of 6 mg. What was the initial mass (in mg) of the sample
Answer:
96mg
Explanation:
Since the half-life of Palladium-100 is 4 days and the sample has been reduced after 16 days, that means the sample has undergone four half-lives. To find the intial mass, just work backwards:
6 x 2= 1212 x 2= 2424 x 2= 48 48 x 2= 96As you see, I've worked backwards from the four half-lives. So the initial mass after 16 days is 96 mg.
Describe the two categories used to classify physical changes.
Answer:
Physical changes can be classified as reversible or irreversible. Melting is an example of a reversible physical change.
Explanation:
What do the carbon, oxygen, and nitrogen cycles all have in common? a. They all include an exchange of gases with the atmosphere. b. None of the cycles are biogeochemical cycles. c. They are all byproducts of photosynthesis. d. They all sustain life, but living organisms have no part in the cycle. Please select the best answer from the choices provided A B C D
how long does it take for chlorine to evaporate from water?
Answer:
1 to 5 days
Explanation:
Determina la molaridad de una solución de H2S, si se colocaron 37 ml del ácido en 890 ml de solución. La densidad del H2S es de 1.36 g/ml
Por definición de molaridad y densidad, la molaridad de la solución es 1.66 [tex]\frac{moles}{litros}[/tex].
La concentración molar o molaridad es una medida de la concentración de un soluto en una disolución que indica el número de moles de soluto que están disueltos en un determinado volumen.
La molaridad de una solución se calcula dividiendo los moles del soluto por el volumen de la solución:
[tex]Molaridad=\frac{numero de moles de soluto}{volumen}[/tex]
La Molaridad se expresa en las unidades [tex]\frac{moles}{litros}[/tex].
Por otro lado, la densidad es una magnitud que permite medir la cantidad de masa que hay en determinado volumen de una sustancia.
Entonces, la expresión para el cálculo de la densidad es el cociente entre la masa de un cuerpo y el volumen que ocupa:
[tex]densidad=\frac{masa}{volumen}[/tex]
En este caso, siendo H₂S el soluto, se colocaron 37 ml del ácido, siendo su densidad 1.36 [tex]\frac{g}{mL}[/tex]. Reemplazando en la definición de densidad se obtiene:
[tex]1.36\frac{g}{mL}=\frac{masa}{37 mL}[/tex]
masa= 1.36 [tex]\frac{g}{mL}[/tex]× 37 mL
masa= 50.32 g
Siendo 34 g/mol la masa molar de H₂S, es decir la cantidad de masa que una sustancia contiene en un mol, la cantidad de moles de H₂S puede ser calculada como:
[tex]numero de moles de H_{2}S= 50.32 grams\frac{1 mole}{34 grams}[/tex]
número de moles de H₂S= 1.48 moles
Siendo 890 mL=0.890 L el volumen de la solución, entonces la molaridad puede ser calculada como:
[tex]Molaridad=\frac{1.48 moles}{0.890 L}[/tex]
Molaridad= 1.66 [tex]\frac{moles}{litros}[/tex]
Finalmente, la molaridad de la solución es 1.66 [tex]\frac{moles}{litros}[/tex].
Aprende más:
https://brainly.com/question/17647411?referrer=searchResultshttps://brainly.com/question/21276846?referrer=searchResultsWhat is an electrolysis
Answer:
Definition of Electrolysis :- Electrolysis, process by which electric current is passed through a substance to effect a chemical change. The process is carried out in an electrolytic cell, an apparatus consisting of positive and negative electrodes held apart and dipped into a solution containing positively and negatively charged ions.Explanation:
Hope this helps you dear ✌️Carry on learning !!about how many bacteria colines will grow in a agar plate with a swab of ginger oil
about 6 to 9 colines
if its from mouth if thats the case
Which factor most often affects wind and weather patterns on Earth?
Answer:
i think its solar radiation
A student has a sample of ocean water that they take to science class. what steps could be taken to determine to classify the ocean water as a suspension, solution, element, or compound?
A) Examine the pH of the sample. If the pH is exactly neutral, it is a pure substance that is a compound.
B) Evaporate the water. If salt is left behind, the sample is a mixture that can be defined as a solution.
C) Let the sample settle. If the salt settles to the bottom, it is a mixture that is classified as a solution.
D) Observe the diffraction of light as it moved through the sample. If light does not scatter, it is a pure substance that is elemental.
Answer:
A or D because B and C dont make sense
Which class of macromolecule was described as being most like the hydrocarbons?.
Answer:
Fats........................
Lipids is the class of macromolecule was described as being most like the hydrocarbons.
what are Macromolecules ?Macromolecules are bigger molecules of large size and made of smaller molecules called as monomers, Polymers are macromolecules.
All Macromolecules are not like the hydrocarbon because the macromolecules not only consists of C and H atoms but also N and O.
Macromolecules are classified into 4 types
Proteins , Carbohydrates , Lipids and Nucleic Acids
Lipids is the class of macromolecule was described as being most like the hydrocarbons.
Lipids are a broad category of chemicals that are mostly nonpolar in nature.
This is due to the fact that they are hydrocarbons with nonpolar carbon–carbon or carbon–hydrogen bonds.
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How are traits inherited?
Please explain thoroughly
inherited traits are passed from parent to offspring according to the rules of Mendelian genetics. Most traits are not strictly determined by genes, but rather are influenced by both genes and environment
Vanadium crystallizes in a body-centered cubic lattice, and the length of the edge of a unit cell is 305 pm. What is the density of V
Answer:
5.96 g/cm^3
Explanation:
Corner atom = 1/8
Atoms in center = 1
Atoms in face of the cube= 1/2
Molar mass of V = 50.94 g/mol (from period table)
1 mole = 6.02x10^23
In BCC unit cell:
(8 x 1/8)+ 1=2 per 1 unit cell
Mass: 2(50.94g)/6.02x10^23 = 1.69x10^-22 g/unit cell
305pm=(305x10^-12m÷10^-2m) x (1mL÷1cm^3)
= 2.837 x 10^-23 mL
1pm=10^-12m
1cm=10^-2m
1mL=1cm^3
density=mass/volume
density of V = 1.69x10^-22g÷2.837x10^-23mL
=5.957g/mL
=5.96g/cm^3
Explain how magnesium is produced at the negative electrode from molten magnesium chloride
Answer:
being cation it migerates to cathode to be reduced to elemental magnesium
Explanation:
Mg+2. +2e -----------Mg
In a star, nuclear fusion occurs in the
A. core
B. radiative zone
C. photosphere
D. corona
Answer:
A. Core
Explanation:
The collisions which occur between the hydrogen atoms starts to heat the gas in the cloud. Once the temperature reaches 15,000,000 degrees Celsius, nuclear fusion takes place in the center, or core, of the cloud. The tremendous heat given off by the nuclear fusion process causes the gas to glow creating a protostar.
In a star, nuclear fusion which is a type of nuclear reaction occurs in the core.
What are nuclear reactions?There are two types of nuclear reactions which are nuclear fusion and nuclear fission .They involve the combination and disintegration of the element's nucleus respectively.
In nuclear fission, the nucleus of the atom is bombarded with electrons of low energy which splits the nucleus in to two parts .Large amount of energy is released in the process.It is used in nuclear power reactors as it produces large amount of energy.
In nuclear fusion,on the other hand, is a reaction which occurs when two or more atoms combine to form a heavy nucleus.Large amount of energy is released in the process which is greater than that of the energy which is released in nuclear fission process.
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Monica put four items on the desk that you need to measure the mass of. The items are listed below. Which of the following would need to be put in a container in order to measure the mass on a scale?
I. Flour
II. Sugar cubes
III. Milk
IV. An unbroken egg
A. I and III
B. I and IV
C. II and III
D. III and IV
Answer:
it D because it make more sense
When we lower the temperature of the solvent, the rate of dissolving of the solute will....?
Answer:
Decrease
Explanation:
An increase in temperature would increase the dissolution rate and a decrease in temperature would decrease the dissolution rate
Answer:
The rate of dissolving of the solute will increase I think
14 In which group are all the elements found
naturally only in compounds?
(1). 18
(3) 11
(2) 2
(4) 14
Distinguish between the first, second, and third ionization energies of an atom. b. How do the values of successive ionization energies compare
Answer:
The third ionization energy is the energy it takes to remove an electron from a 2+ ion. (That means that the atom has already lost two electrons, you are now removing the third.) And 2nd ionization energy is higher than 1st ionization energy, 3rd is higher than 2nd, and so forth.
hope it is helpful :)
what type of intermolecular force causes the dissolution of nacl in water?
Answer:
ion-dipole forces
Explanation:
positive sodium ion will be attracted to the slightly negative oxygen atoms in the water molecule, while the negative chloride ion is attracted to the slightly positive hydrogen atoms.
What are the word equations for the following? Please help
Calcium oxide + water
Magnesium + hydrochloric acid
Sodium hydrogen carbonate + citric acid
Iron + salt water
Calcium oxide + water = calcium hydroxide.
Magnesium + hydrochloric acid = magnesium chloride + hydrogen.
Sodium hydrogen carbonate + citric acid = Na3C6H5O7(aq)+3H2O(l)+3CO2(g)
Iron + salt water = 4Fe(OH)3 (rust)
Answer:
1. CaO + H2O _____ Ca(OH)2
Calcium oxide + Water _____ Calcium hydroxide
2. 2 HCI + MG _____ MgCl2 + H2
Magnesium + hydrochloric acid _____ Magnesium Chloride + hydrogen gas
what does a large positive standard cell potential imply about the spontenty of the redox reaction occuring in teh cell
Answer : E cell standard is the potential difference between the two electrodes under standard conditions. Overall tendency for the redox reaction to occur spontaneously. A large positive E cell means the reaction is more spontaneous, and a negative E cell indicates a non spontaneous reaction.
Explanation: hope this answers your question
Determine the wavelength of the light absorbed when an electron in a hydrogen atom makes a transition from an orbital in which n=2n=2 to an orbital in which n=7n=7.
Answer:
The expression for the wavelength of radiation is,
λ
1
=R(
n
1
2
1
−
n
2
2
1
)
Substitute values in the above expression,
λ
1
=109677×(
2
2
1
−
4
2
1
)=109677×(
4
1
−
16
1
)=109677×(
64
12
)
λ=4.86×10
−5
cm=486×10
−9
m=486nm.
The line belongs to bluish green colour.
Can elements from group 1 and 2 show up as pure elements in nature? Except Hydrogen
Answer:
No. Although alkali metals and alkaline earth metals are found in nature, they are not found as pure elements. Group 1 and 2 are found in their chemical compounds, not pure form.
How could the student obtain zinc chloride solution from the reaction mixture when all the hydrochloric acid has reacted?
Answer:
zinc oxide is only sparingly soluble in water so best option is to add zinc oxide to diluted hydrocrolic acid
When all the hydrochloric acid (HCl) has reacted, the student can obtain zinc chloride (ZnCl) solution from the reaction mixture by adding ZnO to diluted HCl.
What is a mixture?
A mixture simply refers to a combination of two (2) or more substances or chemical compounds that are present in varied proportion, and they can be visibly seen with na-ked eyes.
In this scenario, the student can obtain zinc chloride (ZnCl) solution from the reaction mixture when all the hydrochloric acid (HCl) has reacted by adding zinc oxide (ZnO) to diluted hydrochloric acid (HCl) because it's sparingly soluble in water.
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which of these is a rough approximation of the cogito?
Given the Latin meaning of the cogito, we can confirm that it is roughly translated and summarized by the phrase "I think, therefore I am".
Cogito, ergo sum or "The Cogito" is an extremely popular, well-known philosophical phrase credited to Rene Descartes. This Latin phrase is roughly translated as "I think, therefore I am", which appeared originally in "The Principles of Philosophy", and was later translated to a variety of languages in an attempt to reach a wider public, most notably into Latin.
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List the 4 main components of air in their molecular form.
Answer:
Air is made up of 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and other gases in meager amounts.
What are the similarities and differences between living on Earth versus living in space?
find 5 points for each section
Answer:
Differences
• Space is everything in the universe beyond the top of Earth's atmosphere - The moon, Stars, Milky way, etc.
• In space, no one can hear you scream. This is because there is no air in space, i.e, it's vacuum.
• Earth is a planet on solar system. It is the only planet where life exists!!
• Earth is also called "blue sky" cause it has 75% water.
Similarities
•They need oxygen for survival: Man, animals in earth and space need oxygen for survival.
•Water is also need to stay alive.
•Food is very paramount to both man, animal s and organisms.
•Shelter, we all ned a place to lay our head in other to be safe.
•Air everywhere in the atmosphere.
•Water, air, food and shelter are available on earth but their availability differs in space.
•Astronaut need to bring everything one need in space with him or her from Earth. They often recycle the things they bring.
Hope it helps :)
The atmospheric conditions in earth and space is entirely different. Therefore the living in earth and space will be far different on many aspects such as adaptations, habits etc.
What are aliens?The living things that are believed to be exists in out of earth is called aliens. Some studies shows that there is a possibility to find exotic species living in space.
The study which deals with aliens is called exo-biology. The atmosphere thus, the presence gases, temperature, pressure, etc. will be different for space from that in the earth.
Hence, aliens may need not the presence of oxygen for living as well as the atmospheric conditions that maintains living in earth will not be there in space.
However, any living irrespective of earth or space need water and some kind of food to survive. Thus the presence of water in some planets opens the way to study the presence of livings there.
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Which body systems are responsible to transport materials around and out of the body?
Answer:
Circulatory System
Explanation: