Select the three hypotheses that explain why being born in the United States leads to a higher chance of developing allergies


- The weather patterns in the United States bring more allergens compared to other countries

- cultural practices may play a part because some cultural foods have different anti-allergenic properties

- other factors which might influence why there are more children with allergies in the United States include climate, obesity, and the typical western diet with high amounts of processed foods.

- children in the United States are taught to believe in allergens, but really allergens don’t really exist.

- The hygiene hypothesis claims that children in the United States are not exposed to enough germs in their infancy and childhood to develop their immune system‘s properly.

Answer:

B.chlorine ,Cl2 is the one

Answer:

Chemical bonds

Explanation:

Chemical bonds are forces that hold atoms together to make compounds or molecules. Chemical bonds include covalent, polar covalent, and ionic bonds. Atoms with relatively similar electronegativities share electrons between them and are connected by covalent bonds.

Answer:

12ml per hour and

69% LOL

1) The rate of percolation would be 0.33 ml/s

Percolation rate = volume of water/time

                             =  600/1800s

                              = 0.33 ml/s

2) The percentage of water absorbed would be 40%

Percentage of water absorbed = amount absorbed/total water x 100

                 amount of water absorbed = 100 - 60

                                                      = 40 ml

                  total amount of water = 100 ml

   Percentage of water absorbed = 40/100 x 100

                                                       = 40%

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Answer:

Temporary hardness of water is caused when thermally unstable chemicals like magnesium hydrogen carbonate and calcium hydrogen carbonate are dissolved in water. Temporary hardness is treated by heating the hard water.

Hope that helps. x

Answer:

b

Explanation:

because its the atom of the same element, the no of protons doesn't change but the mass number changes so we can find the mass number by:

(mass number = atomic no/no of protons + no of neutrons)

here;

mass number given = 65

and we know, no of protons = 29

let no of neutrons = x

hence,

65 = 29 + x

x= 65 – 29

x= 36

hence your answer is b

Answer:

Any substance that cannot be decomposed into simpler substances by ordinary chemical processes.

Another definition:

An element is the simplest pure substance which can neither be split nor built up from other simpler substances by chemical reaction

Answer

153

Explanation:

51/120 = x/360

51(360) = 120x

18360 = 120x

18360/120x = 120x/120x

153 = x

Answer:

153

Explanation:

Answer:

Mass and relative abundance of each isotope of that element

The atomic mass of element has been dependent on  mass of each isotopes and their abundance in nature.

The atomic mass has been the mass of neutrons and protons of the element. There has been the presence of the isotopes of the elements, with varying abundance, and varying atomic masses.

The atomic mass of the element has been the relative average atomic mass of the element with respect to the mass of the isotopes and their percent abundance.

The average atomic mass (amu) has been given by:

[tex]amu=M_1A_1\;+\;M_2A_2[/tex]

Where, [tex]M_1A_1[/tex] has been the atomic mass and abundance of isotope 1.

[tex]M_2A_2[/tex] has been the atomic mass and abundance of isotope 2.

Thus, the average atomic mass has been dependent on mass of each isotopes and their abundance in nature.

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Answer:

12.5grams would remain after time has elapsed

Answer:

5 moles S x (36.02 g S/mole S) = 180.1 grams of S

Explanation:

The periodic table has mass units for every element that can be correlated with the number of atoms of that element.  The relationship is known as Avogadro's Number.  This number, 6.02x[tex]10^{23}[/tex] , is nicknamed the mole, which scientists found to be a lot more catchy, and easier to write than  6.02x[tex]10^{23}[/tex].  The mole is correlated to the atomic mass of that element.  The atomic mass of sulfur, S, is 36.02 AMU, atomic mass units.  But it can also be read as 36.02 grams/mole.

This means that 36.02 grams of S contains 1 mole (6.02x[tex]10^{23}[/tex]) of S atoms.

This relationship holds for all the elements.  Zinc, Zn, has an atomic mass of 65.38 AMU, so it has a "molar mass" of 65.38 grams/mole.  ^5.38 grams of Zn contains 1 mole of Zn atoms.  

And so on.

5.0 moles of Sulfur would therefore contain:

(5.0 moles S)*(36.02 grams/mole S) = 180.1 grams of S

Note how the units cancel to leaves just grams.  The units are extremely helpful in mole calculations to insure the correct mathematical operation is done.  To find the number of moles in 70 g of S, for example, we would write:

(70g S)/(36.02 grams S/mole S) = 1.94 moles of S.  [Note how the units cancel to leave just moles]

Answer:

You can't convert km to seconds because they are different units.

Answer:

38 pounds of gold in cubic mile of seawater.

Answer:

1 atmospheric pressure = 760.0 mm Hg

Thus 580 mm Hg = (580 mm Hg/(760 mm Hg/atm))

= 0.763 atm

[tex]\huge \bf༆ Answer ༄[/tex]

The trends showing increase in ionization energy on the periodic table ~

[ due to increase in effective nuclear charge ]

[ Due to decrease in number of shells ]

Ionization energy increases across a period from left to right in the periodic  table.

Ionization energy is the energy needed for the complete removal of valence electrons in its ground state from an isolated atom in its gaseous phase at a specified temperature to form an ion.

Ionization energy shows periodicity in that it shows a regular variation across a period and down a group in the periodic table.

Ionization energy increases across a period from left to right in the periodic  table.

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Answer:

I think its a homogeneous mixture (pls correct me if im wrong)

Explanation:

It is a homogeneous mixture because its an alloy made of gold, silver, copper, and other metals that are melted together. A homogeneous mixture is composed of a uniform composition of particles.

There are two types of mixture, one is homogeneous mixture and other is heterogeneous mixture. Therefore, the term best describes 10-karat gold is homogeneous mixture.

When two or more compounds are combined but each ingredient retains its chemical identity, the result is referred to as a mixture. In other words, there is no chemical interaction between the parts of a combination. According to how consistent they are and how well the components' particle sizes match up, mixtures are categorized.

Because it is an alloy comprised of melted gold, silver, copper, and other metals, it is a homogenous combination. A homogeneous mixture has a consistent distribution of its constituent particles.

Therefore, the term best describes 10-karat gold is homogeneous mixture.

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Answer:

Table salt

Explanation:

Is most soluble in water

Answer:

Gold Iron Titanium Lithium

Explanation:

Answer:

please mark brainliest

Explanation:

The correct answer to this question is 0.2500 mol

Formula to calculate moles:

Moles = mass ÷ molar mass (n=m/M)

Mass = 50.15g

Atomic mass: 200.59 amu

Moles = 50.15g/200.59

= 0.2500 mol.

Explanation:

It has to be C, because Carbon can bond with four other atoms and is like a four-hole wheel.

(Sorry if my elplanation was kinds choppy Oof, helpfully it makes sense?)

Answer:

The answer is a,b, and c. This is for the USA tesprep videos

Explanation:

The characteristics that apply to the elements in the family are they are highly reactive, they are shiny, soft metals and the element form +1 ions when forming compounds. Thus option a, b and c is correct.  

Main group elements are defined as any of the element belonging to the s and p blocks of the periodic table.

They are most abundant element in universe and on earth.

This elements and their compound are one of the most important economical elements.

They are very good conductor of heat and electricity.

Thus, the characteristics that apply to the elements in the family are they are highly reactive, they are shiny, soft metals and the element form +1 ions when forming compounds. Thus option a, b and c is correct.  

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CH4 has more ideal gas behavior than CCl4 due to its higher intermolecular interaction.

We must note that ideal gases have minimal interaction with each other. Hence, in deciding which gas has ideal gas behavior, we have to consider the gas that has the least degree of intermolecular interaction.

However, the both gases contain nonpolar molecules but CCl4 has a greater molecular mass and has more intermolecular interaction than CH4 hence CH4 has greater ideal gas behavior than CCl4.

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Answer:

Giant Covalent Structures, Diamond and Graphite are giant covalent structures since they're allotropes of Carbon.

Answer:

Giant covalent structures contain very many atoms. , each joined to adjacent atoms by covalent bonds. The atoms are usually arranged into giant regular lattices - extremely strong structures because of the many bonds involved.

Taking into account the Brønsted-Lowry acid-base theory, a base/conjugate acid pair is H₂O/H₃O⁺.

The Brønsted-Lowry acid-base theory (or the Brønsted-Lowry theory) identifies acids and bases based on whether the species accepts or donates protons or H⁺.

According to this theory, acids are proton donors while bases are proton acceptors. That is, an acid is a species that donates an H⁺ proton while a base is a chemical species that accepts an H⁺ proton from the acid.

So, reactions between acids and bases are H⁺ proton transfer reactions, causing the acid to form its conjugate base and the base to form its conjugated acid by exchanging a proton.

In other words, a conjugate base is an ion or molecule resulting from the acid that loses the proton, while a conjugate acid is an ion or molecule resulting from the base that gains the proton:

acid + base ⇄ conjugate base + conjugate acid

In this case, you know:

H₂PO₄ + H₂O → H₃O⁺ + HPO₄⁻

H₂PO₄ behaves like acid because donates an H⁺ proton while H₂O behaves like base because accepts an H⁺ proton from the acid.

So, H₃O⁺ is the conjugate acid of the H₂O and HPO₄⁻ is conjugate base of H₂PO₄.

In summary,  a base/conjugate acid pair is H₂O/H₃O⁺.

Learn more about the Brønsted-Lowry acid-base theory:

Answer: The answer is 6  

1) Simplify  -3+6  to  3.

2×3

And then Simplify.

6

Sorry if im wrong

When the egg first forms it's only one cell, and is fertilized as it moves down the oviduct to be laid

__________________________________________________________

this point it's technically an embryo : though it doesn't look like a baby chick

___________________________________________________________

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Why scientists weren’t initially concerned that the ocean absorbs excess carbon dioxide was because they saw carbon dioxide as a pollutant

Generally, A pollutant is a material found in amounts that are harmful to organisms or exceed an environmental quality standard.

In conclusion,  scientists saw carbon dioxide as a major air pollutant, and the water was helping by absorbing it.

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Answer: A.6

Explanation:

The total number of molecules in the chemical formula is 6

Molecules  are the smallest particle of a substance that has all of the physical and chemical properties of that substance. Molecules are made up of one or more atoms.

The correct form of question will be:-6 molecule of methane CH₄

                       6CH4

⇒ Number of aton of carbon is 6

⇒Number of atom of hydrogen is 24

⇒Total number of atom is 30

An atom is a particle of matter that neither be created nor be destroyed. An atom consists of a central nucleus that is usually surrounded by one or more electrons. Each electron is negatively charged. The nucleus is positively charged, and contains one or more relatively heavy particles known as protons and neutrons.

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