Evaluate: (12)2 ×102 −6.3 ÷2.1


21.4 A


22 B


9.3 C


75 D HELP PLS

Answer:

20

Explanation:

You need 4 times the amount of B, compared to a (there is a 3A:12B which reduces to 1:4), so 4 times 5 is 20.

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The number of atoms of Hg in 4.5 mole sample has been given as [tex]\rm 2.7099\;\times\;10^2^4[/tex]. Thus, option A is correct.

The number of atoms in a mole of sample has been given by Avogadro number. Avogadro number has been a constant and has been given the value of [tex]\rm 6.023\;\times\;10^2^3[/tex].

The number of atoms in a mole of sample has been given as:

[tex]\rm 1\;mole=\;6.022\;\times\;10^2^3[/tex]

The given sample has been consisted of 4.5 moles of Hg. Thus, the number of atoms in the sample has been given by:

[tex]\rm 1\;mole\;Hg=\;6.022\;\times\;10^2^3\;atoms\\4.5\;mol\;Hg=4.5\;\times\;6.022\;\times\;10^2^3\;atoms\\4.5\;mol\;Hg=27.099\;\times\;10^2^3\;atoms[/tex]

The scientific notation has been the short hand used for writing the numbers. The short hand for atoms in 4.5 moles of Hg has been [tex]\rm 2.7099\;\times\;10^2^4[/tex].

Thus, the number of atoms of Hg in 4.5 mole sample has been given as [tex]\rm 2.7099\;\times\;10^2^4[/tex]. Thus, option A is correct.

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Explanation:

the equation is yes a the line of jointing line passing the ball to is

Answer:

the branch of science that deals with the identification of the substances of which matter is composed; the investigation of their properties and the ways in which they interact, combine, and change; and the use of these processes to form new substances.

Explanation:

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The downside of this is that the longer lasting material is more difficult to break down.

Both natural fibers and synthetic fibers are polymer materials. Polymer materials are materials that are made by the agglomeration of small molecules called monomers.

The natural fibers are less long lasting than the synthetic fibers. The downside of this is that the longer lasting material is more difficult to break down. As a result of these, synthetic fibers lead to environmental pollution problems.

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Answer:

the longer lasting material is more difficult to break down.

Explanation:

Answer:

There are several different types of tools you could encounter, including project management software, note-taking programs, journals, and day planners. Organization management tools help in sorting out one’s daily responsibilities and being more efficient with time: calendars, to-do lists, mind maps, document storage clouds.

Explanation:

what i know:) hope it helps

Answer:

4.58g

Explanation:

1.) What is the molar mass of CaCI2?

= 110.98 g/mol

2.) Find the mols

[tex]conc = \frac{mol}{volume(l)} [/tex]

conc × volume= mol

0.125 M x 0.33 L = 0.04125mol ( 330mL was converted to "L" by dividing 330 by 1000)

3.) The mass(g)

g= mol x atomic weight

g= 110.98g/mol × 0.04125

= 4.58 g

# NOTE M = mol/L

That is an ionic bond.

Explanation:

It has cations and anions

A. The abundance of the 2nd isotope is 48.119%

B. The mass of the 2nd isotope is 108.905 amu

Let the 1st isotope be A

Let the 2nd isotope be B

A. Determination of the abundance of the 2nd isotope

Abundance of isotope A = 51.881%.

Abundance of B = 100 – A

Abundance of B = 100 – 51.881

B. Determination of the mass of the 2nd isotope

Atomic mass of silver = 107.868 amu.

Mass of 1st isotope (A) = 106.906 amu

Abundance of isotope A (A%) = 51.881%.

Abundance of isotope B (B%) = 48.119%

[tex]atomic \: mass = \frac{mass \: of \:A \times \:A\%}{100} + \frac{mass \: of \:B \times \:B\%}{100} \\ \\ 107.868 = \frac{106.906\times \ \: 51.881}{100} + \frac{mass \: of \:B \times \:48.119}{100} \\ \\ 107.868 = \: 55.464 + 0.48119 \times mass \: of \:B \\ \\ collect \: like \: terms \\ \\ 0.48119 \times mass \: of \:B = 107.868 - 55.464 \\ \\ divide \: both \: side \: by \: 0.48119 \\ \\ mass \: of \:B = \frac{107.868 - 55.464 }{0.48119} \\ \\ mass \: of \:B =108.905 \: amu \\ \\ [/tex]

Therefore, the mass of the 2nd isotope is 108.905 amu

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Answer:

Power Plant = Mitochondria (Mitochondria is the powerhouse of the cell)

City Limits = Cell Membrane (Outer layer of a cell)

City Hall = Nucleus (The nucleus is the control center in a cell)

City Food Processing Plant (Chloroplast process the cells food)

City Plans = Chromosomes (They contain the genetic information about the cell)

Community = Cytoplasm (Mainly process of elimination)

Explanation:

Explanations are in parenthesis

Answer:

a) sodium oxide

b) potassium peroxide

c) Hydrogen chloride

d) form ammonia

e) Calcium nitride

Hydrogen  bonding interaction occurs between  the oxygen atom of water and  the hydrogen atom of allyl alcohol that is covalently bonded to the oxygen atom.

We must recall that allyl alcohol is a molecular substance. Molecular substances do not dissociate into ions in water. As such particles of allyl alcohol remain intact when dissolved in water.

Hydrogen bonding occurs when hydrogen is bonded to an electronegative atom such as oxygen. In allyl alcohol, hydrogen  bonding interaction occurs between  the hydrogen atom of water and the oxygen atom of allyl alcohol.

Also,  hydrogen  bonding interaction occurs between  the oxygen atom of water and  the hydrogen atom of allyl alcohol that is covalently bonded to the oxygen atom.

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Answer:

Extensive or inextinsive and either physical or chemical

What factors can influence the properties of glass, which include its ability to transmit, reflect, or absorb light, or to be transparent?

Answer · 47 votes

The properties can be influenced by many factors. The most common are the shape of the object, the lighting where the object is located, the environment (colors, shapes, density of other objects, etc.), and the viewing angle of the observer.

Plants and animals use glucose as a soluble, easily distributed form of chemical energy which can be 'burnt' in the cytoplasm and mitochondria to release carbon dioxide, water and energy. Pure monosaccharides, such as glucose, attract water.

An animal's body breaks down carbohydrates and converts them into simple sugar such as glucose. Glucose in the form of energy is carried through the blood and delivered to every cell of the body.

Carbohydrates are an important compound of all life on this planet. Both plants and animals utilize carbohydrates as a source of energy to keep their body functioning at the most basic level.

Carbohydrates fulfill needs by helping in the synthesizing of other chemicals and giving structure to cells within the body. Carbohydrates are carrying out normal functions such as growth, movement, and metabolism.

Carbohydrates store energy in the form of starch and provide either simple or complex sugars. Polysaccharides, give a steady supply of energy while sugars, monosaccharides, and disaccharides, supply quick energy on dissolving.

Carbohydrates have the side effect of helping with the processing of other body's chemicals. As carbohydrates break down, they release energy.

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#SPJ2

Answer:

I think it's is because during osmosis because when the cell duplicates in osmosis it divides into two smaller daughter cells; in diffusion there is a higher concentration near where it is but its getting smaller particles from where the source is

Answer:

I think it is A

Explanation:

if I am wrong I am so so so sorry

but i'm pretty sure I am right.

please let me know if I am right :)

The heat of combustion of the sample is calculated to be  -1300 kJmol-1.

We know that energy is neither created nor destroyed but is converted from one form to another. The heat lost by the ethanol when it is burnt is equal to the heat gained by the calorimeter.

Heat gained by calorimeter =  2.×10^3 g ×  2. 45 Jg-1°C-1 × 1. 33°C

= 6.5 kJ

Number of moles of ethanol =  0. 2301 g/46 g/mol = 0.005 moles

Heat of combustion of the sample = -( 6.5/0.005 moles) = -1300 kJmol-1

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The compound that contains both sigma and pi bonds has been [tex]\rm \bold{H_2CO}[/tex]. Thus, option B is correct.

The compounds have been resulted by the sharing of the valence electrons between atoms, for the completion of octet of each elements.

The bonds can be saturated with the presence of only sigma bond. The unsaturated bonds has presence of pi bonds as well. The bond with one pi and one sigma has been a double bond, while 1 sigma and 2 pi has been a triple bond.

The bonds present in the following structures has been:

[tex]\rm HCCl_3=4\;\sigma\;bonds\\H_2CO=2\;\sigma,\;1\;\pi\;bond\\H_2S=2\;\sigma\;bonds\\HBr\;=1\;\sigma\;bond[/tex]

The compound with the presence of both sigma and pi bonds has been [tex]\rm \bold{H_2CO}[/tex]. Thus, option B is correct.

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The designation "4" before Na2SO3 simply means that there are four molecules of sodium sulfite.

A molecule is formed when two or more atoms of the same or different elements come together. The formula of the molecule must reflect the number of atoms from which it is formed. The designation "4" before Na2SO3 simply means that there are four molecules of sodium sulfite.

The "The World on Turtle's Back" is a legend creation story. According to this story, the world was created on a giant turtle back. The folktale is common among the  Iroquois Native Americans.

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Answer:

It's because it has 2 electrons on its outer ring

Explanation:

It has a -2 ion due to it having 2 more electrons than protons making it an overall negative. It's well known in chemistry that the first ring can only hold 2 electrons while the second and furthermore can hold up to 8. But what happens when you have 9? a new ring starts and it would only contain 1 electron.. In our case here it has 2 more electrons than protons and those 2 electrons are located on the outer ring

The hybridization state of the central sulfur atom is sp3d.

The valence shell electron pair repulsion theory describes the shape of molecules in terms of the number of electron pairs that surround the valence shell of the central atom in the molecule.

There are certain molecular shapes that are associated with certain hybridization states of the central atom. Since the central sulfur atom is trigonal bipyramidal, the hybridization state is sp3d.

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Answer:

58.64

Explanation:  You want to use the combined gas law equation (P1*V1)/(n1*T1)=(P2*V2)/(n2*T2). So first cross out what remains constant, so pressure and I assume moles (since it was not mentioned as a change). You want to change the temperature to Kelvin (always) to do work, then you can solve algebraically for the answer! Once you have your answer change it to Celsius since that's what you were asked for.

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Answer:

1) actual yield - 2.675 g

Theoretical yield - 4.0539 g

2)a) 41.257 g

b) 0.6857moles

c) 23 g

Explanation:

1)

Theoretical yield is the mass of the product that can obtain from the equation, it is not practical.

Theoretical yield:

Mr of SiO2 - 60

Moles of SiO2 - 2.339/60 = 0.03898 moles

Mr of SiF4 - 104

Mass of SiF4 - 0.03898 * 104 = 4.05392 g

2)

a)

mr of B2H6 - 28

Moles of B2H6 - 36.1/28 = 1.2893 moles

Mr of O2 - 32

Mass of O2 - 32 * 1.2893 = 41.257 g

b)

Moles of B2H6 - 19.2/28 = 0.6857 moles

Stoichiometry 1:1 ratio between B2H6 and H2O

So moles of H2O is 0.6857

c) moles of O2 - 2/24(r.t.p) = 0.083 moles

Mass of B2H6 - 0.083 * 28 = 2.3 g

Answer:

the 4 properties of waves are frequency, amplitude, wavelength, and speed.

Explanation:

Answer:

Sulfur hexafluoride

Explanation:

It is heavier than air that we breathe so it has an opposite effect.

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As we know, Number of protons = Atomic Number

So,

And, Atomic mass = Number of protons + Number of Neutrons (N)

therefore ~

Number of Neutrons = 19