Which best describes how magnesium (Mg) and oxygen (O) bond?

a
They form an ionic bond by exchanging two electrons.

b
They form an ionic bond by exchanging three electrons.

c
They form a covalent bond by sharing one electron.

d
They form a covalent bond by sharing four electrons.

Answer:

b. Gas particles are far apart so they are easy to compress together.

Explanation:

Answer:

180

Explanation:

just multiply and round to whole number

Answer:

Indicates the writer's stance on the main idea of a paragraph. The controlling idea appears in the paragraph's topic sentence. ... The final sentence of a paragraph that summarizes the topic sentence using different words. Words and phrases that show how the ideas in sentences and paragraphs are related.

Explanation:

HOPE THIS HELP

PICK ME AS THE BRAINLIEST

Answer:

he last paragraph relates to the main topic because the main topic is about cells and the last paragraph is saying how scientist are still discovering cells but the author says that the new cells are not listed in the article

Explanation:

i had a bad day i hope you have a good one -me    ;

The concentration in ppm = 125,000 ppm

The concentration of a substance can be expressed in several quantities such as moles, percent (%) weight / volume,), molarity, molality, parts per million (ppm) or mole fraction. The concentration shows the amount of solute in a unit of the amount of solvent.

ppm or parts per million (ppm) :

For water solvent = 1 ppm ⇒ 1 mg/L(1 kg=1 L,ρ water=1 kg/L)

In percent mass = 1 ppm ⇒ 1 mg/ 1 kg

Solution contains 0.25 kg of lead in 2 kg of water :

Solvent = water = 2 kg = 2 L

Solute= lead=0.25 kg=250000 mg

So the concentration in ppm :

[tex]\tt ppm=\dfrac{250,000~mg}{2~L}=\boxed{\bold{125,000~ppm}}[/tex]

Answer:

The concentration in ppm = 125,000 ppm

Explanation:

that is why chemistry is chemistry.

Answer:

The bond in a homonuclear diatomic molecule is non-polar due to the electronegativity difference of zero

Explanation:

The intermolecular forces or the strength of C is more than that of B.

What are intermolecular forces?

Here, we can see that C has dipole-dipole interaction while B has none.

Therefore, it states that the intermolecular forces present in C are much more than that in B.

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Glycogenolysis and Gluconeogenesis occur in the liver due to the action of Cortisol.

It is the process of storing excess glucose for body which can be used at later time. the glycogen stored by the liver is broken down to glucose and dispersed in the body.

Cortisol helps to decrease insulin and increase glucagon. glucagon is type of peptide hormone secreted by pancreatic cells to increase the process of gycogenolysis or gluconeogenis.   it is the primary stress harmone which increases glucose(sugar) in blood.

Gluconeogesis ia that process which tansform non carbohydrate substrate like amino acid ,gycerol into glucose.

Thus, Glycogenolysis and Gluconeogenesis occur in the liver due to the action of Cortisol.

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Answer:

44.80

Explanation:

Answer:

A. When a piece of copper is heated, it combines with oxygen to form copper oxide. The chemical reaction for the same is as follows:

              2 Cu (s) + O2(g) => 2CuO

B. The mass of the piece of copper will remain same and there will be no change in its mass. However, its volume will increase, so its density will decrease.

C. This is so because heating copper in its elemental form is a physical change and there is no change in mass during a physical change. Hence, the mass of copper remain same.

Answer

The Correct Answer Is D

The given question is incomplete. The complete question is:

Butane [tex](C_4H_{10}(g)[/tex], Hf = –125.6 kJ/mol) reacts with oxygen to produce carbon dioxide ([tex]CO_2[/tex] , Hf = –393.5 kJ/mol ) and water [tex](H_2O[/tex], Hf = –241.82 kJ/mol) according to the equation below. What is the enthalpy of combustion (per mole) of [tex]C_4H_{10} (g)[/tex]?

Answer: -2657.5 kJ

Explanation:

The balanced chemical reaction is,

[tex]C_4H_{10}(g)+\frac{13}{2}O_2(g)\rightarrow 4CO_2(g)+5H_2O(g)[/tex]

The expression for enthalpy change is,

[tex]\Delta H=\sum [n\times \Delta H_f(product)]-\sum [n\times \Delta H_f(reactant)][/tex]

[tex]\Delta H=[(n_{CO_2}\times \Delta H_{CO_2})+(n_{H_2O}\times \Delta H_{H_2O})]-[(n_{O_2}\times \Delta H_{O_2})+(n_{C_4H_{10}}\times \Delta H_{C_4H_{10})][/tex]

where,

n = number of moles

[tex]\Delta H_{O_2}=0[/tex] (as heat of formation of substances in their standard state is zero

Now put all the given values in this expression, we get

[tex]\Delta H=[(4\times -393.5)+(5\times -241.82)]-[(\frac{13}{2}\times 0)+(1\times -125.6)][/tex]

[tex]Delta H=-2657.5kJ[/tex]

Therefore, the enthalpy of combustion per mole of butane is -2657.5 kJ

The distance from object’s top to its bottom is Height

The distance from object’s side to side is Length

Answer:

Mass = 141.6 g

Explanation:

Given data:

Mass of Kr in gram =  ?

Volume in L = 9.59 L

Temperature = 46.0°C

Pressure = 4.62 atm

Solution:

The given problem will be solve by using general gas equation,

PV = nRT

P= Pressure

V = volume

n = number of moles

R = general gas constant = 0.0821 atm.L/ mol.K  

T = temperature in kelvin

Now we will convert the temperature.

46.0+273 = 319 K

4.62 atm × 9.59 L = n× 0.0821 atm.L/ mol.K  ×319 K

44.3 atm.L = n×26.19 atm.L/ mol

n = 44.3 atm.L / 26.19 atm.L/ mol

n = 1.69 mol

Mass in gram:

Mass = number of moles × molar mass

Mass = 1.69 mol × 83.79 g/mol

Mass = 141.6 g

Answer:

1.76 x 10²²molecucles

Explanation:

Given parameters:

Mass of the sugar  C₁₂H₂₂O₁₁  = 10g

Unknown:

Number of molecules  = ?

Solution:

The number of molecules can be determined if we find the number of moles first.

  Number of moles  = [tex]\frac{mass}{molar mass}[/tex]  

  Molar mass of C₁₂H₂₂O₁₁ = 12(12) + 22(1) + 11(16) = 342g/mol

 Number of moles  = [tex]\frac{10}{342}[/tex]   = 0.029mole

1 mole of C₁₂H₂₂O₁₁ will contain 6.02 x 10²³

  0.029 mole of C₁₂H₂₂O₁₁ will be made up of 0.029 x 6.02 x 10²³

                         = 1.76 x 10²²molecucles

Answer:

the answer should be A ! hope this helps :)

Explanation:

Answer:

All of the above

Explanation:

Answer:

a. BH₃

Explanation:

According to the octet rules, atoms reach stability when are surrounded by eight electrons in their valence shell when they combine to form a chemical compound.

From the options, the only compound in which the central atom does not meet the octet rules is BH₃. The central atom is boron (B), which has 3 electrons in its valence shell. When B is combined with hydrogen (H), 3 electrons from the 3 atoms of H are added. The total amount of electrons is 6, fewer than 8 electrons needed to meet the rule.

The compound which is showing exception to the octet rules is BH₃.

According to the octet rule in the outermost valence shell of any compound, eight electrons should present.

Among the given compounds only BH₃ will not satisfy the octet rule, as in the outermost shell of boron atom 3 electron are present following the electronic configuration 1s²,2s²2p¹ because its atomic number is 5. Now this boron atom will form bond with 3 hydrogen atoms and these hydrogen atoms will share 3 electrons to boron atom.

So, total electrons in the outer most shell of BH₃ compound is 3+3=6.

Hence, BH₃ is an exception of octet rule.

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Answer:

69.09 g

Explanation:

First we calculate the mass of the sample of concentrated H₂SO₄, using the given volume and density:

There are 70.288 grams of solution, of which 98.3% is H₂SO₄. Thus the H₂SO₄ mass is:

Taking into account the definition of density and percentage by mass, the mass of H₂SO₄ in a 38.2 cm³ sample of concentrated sulfuric acid is 69.09 grams.

But first you must know the definition of density. Density is defined as the property that matter, whether solid, liquid or gas, has to compress into a given space.

In other words, density is a quantity that allows us to measure the amount of mass in a certain volume of a substance. Then, the expression for the calculation of density is the quotient between the mass of a body and the volume it occupies:

[tex]density=\frac{mass}{volume}[/tex]

In this case, you know that:

Density= 1.84 [tex]\frac{g}{cm^{3} }[/tex]

Volume= 38.2 cm³

Replacing in the definition of density:

[tex]1.84 \frac{g}{cm^{3} }=\frac{mass}{38.2 cm^{3} }[/tex]

Solving:

mass= 1.84 [tex]\frac{g}{cm^{3} }[/tex]×38.2 cm³

mass= 70.288 g

So, the mass of the solution is 70.288 grams.

The percentage by mass expresses the concentration and indicates the amount of mass of solute present in 100 grams of solution.

In other words, the percentage by mass of a component of the solution is defined as the ratio of the mass of the solute to the mass of the solution, expressed as a percentage.

The percentage by mass is calculated as the mass of the solute divided by the mass of the solution, the result of which is multiplied by 100 to give a percentage. This is:

[tex]percentage by mass=\frac{mass of solute}{mass of solution}x100[/tex]

In this case, you know:

percentage by mass=98.3%

mass of solute= ?

mass of solution= 70.288 grams

Replacing in the definition of percentage by mass:

[tex]98.3=\frac{mass of solute}{70.288 grams}x100[/tex]

Solving:

[tex]\frac{98.3}{100} =\frac{mass of solute}{70.288 grams}[/tex]

[tex]0.983=\frac{mass of solute}{70.288 grams}[/tex]

0.983× 70.288 grams= mass of solute

69.09 grams= mass of solute

The mass of H₂SO₄ in a 38.2 cm³ sample of concentrated sulfuric acid is 69.09 grams.

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density:

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percentage by mass:

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Explanation:

There are ten d electrons in the outermost d subshell for Zn2+.

Answer:

6

Explanation:

The coordination number of a particular crystal structure arrangement is defined as the number of nearest neighbor atoms or ions surrounding an atom or ion.

We must note that in salts of the type MX, the coordination number of each ion must be equal. The structure of LiCl is built by placing each unit cell next to another such that ions residing in the corner, edge or face sites are shared between adjacent unit cells. The LiCl is in FCC arrangement.

Hence in LiCl, each Li+ ion is surrounded by 6 chloride ions.

Answer:

The answer is B. 11

Explanation:

I did the math and used what I know to find the answer. B is correct.

Answer:

The equation is balanced

Explanation:

There are 3Mg,2N,12H,6O and on the other side its the same amount on the other side

The molecular formula : C₄H₈O₂

Maybe a compound is 54.5% carbon, 9.1% hydrogen and 36.4% oxygen,so :

mol C :

[tex]\tt \dfrac{54.5}{12}=4.54[/tex]

mol H :

[tex]\tt \dfrac{9.1}{1}=9.1[/tex]

mol O :

[tex]\tt \dfrac{36.4}{16}=2.28[/tex]

Divide by 2.28(the smallest ratio) :

C H : O =

[tex]\tt \dfrac{4.54}{2.28}\div \dfrac{9.1}{2.28}\div \dfrac{2.28}{2.28}=2\div 4\div 1[/tex]

The empirical formula : C₂H₄O

(The empirical formula)n=molecular formula

(2.12+4.1+16)n=88

(44)n=88⇒n=2

The soil is still radioactively contaminated after the Chernobyl nuclear explosion. so NO,  Most of the people who left Chernobyl after the nuclear plant explosion have not  returned. NO, The accident at Chernobyl had not occurred during a safety test.. YES, Temperatures inside the reactor during the explosion were as hot as parts of the Sun's atmosphere. YES, The fuel in the reactor included U-238 from enriched uranium dioxide.

YES, A radioactive cloud blew across Northern Europe after the explosion. NO,Isotopes of the same element have not  the same number of neutrons. but Isotopes are atoms of the same element that have the same number of protons and electrons but different numbers of neutrons YES, When one mole of U-235 undergoes fission, the energy released can power about 400 average U.S. homes for a year.

YES, Nuclear reactors must have control rods to keep a chain reaction from occurring.

YES, Radioactive strontium can lead to bone cancer.

YES, The radioactive iodine released during the explosion still poses a health threat to people in Northern Europe.

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Answer:

See the answer below

Explanation:

If the root of a plant grows away from the pull of earth's gravity, it will not produce any effect on the plant provided that other conditions of growth are kept normal.

According to research, the force of the Earth's gravity has no effect on the growth features of plants. Plants that were grown away from the influence of gravity still grew normally in a research conducted in space by NASA in 2010.

This thus means that the upward growth of the stem and the downward growth of the root in a negative and positive response to gravity respectively  is dictated by the inherent attributes of plants themselves, and not by the force of the earth's gravity.

Answer:

are called Compounds

Answer:

Compouds

think of a group

an they are alll combined

also "compounds" com-bind = com-POUNDS

Make's sense now?

The question is incomplete, the complete question is; Describe the preparation of 2.00 L of 0.108 M BaCl2 from BaCl2.2H2O

Answer:

See explanation

Explanation:

First we must know the molar mass of the compound = 244.3 g/mol

Now we must calculate the number of moles of BaCl2.2H2O in the solution.

number of moles = concentration * volume = 0.108 M * 2.00 L = 0.216 moles

Now the mass of solid that we need to take can be obtained from;

number of moles = mass/molar mass

mass = number of moles * molar mass

mass = 0.216 moles * 244.3 g/mol

Mass = 52.8 g

Hence, we must weigh 52.8 g of BaCl2.2H2O accurately in a balance and dissolve it in 2 L of water to give 0.108 M solution of BaCl2.2H2O.

The answer is 1) Plant roots take in water through their roots.

Explanation:The biosphere is made up of all the lifeforms present on the Earth. The hydrosphere is constituted of all the water bodies and sources of water.

When a certain lifeforms from the biosphere reaches out to another sphere, preferably to fetch what if requires to survive, it is said that there is an interaction between two spheres of the larger environment.

These spheres are all interdependent on each other. (i did this before)

Answer:

Plant roots take in water through their roots.

Explanation:

EDGE 2021

Answer:

B) tetrahedral

Explanation:

From the information:

The given complex is [tex]\Big [Zn (NH_3)_2Cl_2 \Big ]^{2+}[/tex]. In this complex, the number of ligands attached to the central metal atom Zn is 4. This, in turn, affects the coordination number of the complex to be 4. For a coordination number with 4, the likely geometry can either be tetrahedral or square planar, and cis-trans isomerism only occurs in a square planar geometry.

But, from the question, we are informed that the complex does not exhibit cis-trans isomerism, therefore the complex must be tetrahedral.