which of the following elements is chemically most similar to chlorine? A) helium b) sodium c) bromine d) hydrogen

It can be calculated using the equation: (1/2)ⁿ = x

x - decimal amount remaining, 

n - number of half-lives.

x = 12.5% = 12.5%/100% = 0.125

n = ?

(1/2)ⁿ = 0.125

log((1/2)ⁿ) = log(0.125)

n * log(1/2) = log(0.125)

n = log(0.125)/log(1/2) = log(0.125)/log(0.50) = -0.903 / -0.301 = 3

Number of half-lives is 3. 

Number of half-lives (n) is quotient of total time elapsed (t) and length of half-life (H).

n = t/H

t = n * H

n = 3

H = 47 years

t = 3 * 47 years = 141 years

Answer : The mass of oxygen is 160 grams.

Solution : Given,

Moles of [tex]O_2[/tex] = 5 moles

Molar mass of [tex]O_2[/tex] = 32 g/mole

Formula used :

[tex]\text{ Mass of }O_2=\text{ Moles of }O_2\times \text{ Molar mass of }O_2[/tex]

[tex]\text{ Mass of }O_2=(5moles)\times (32g/mole)[/tex]

[tex]\text{ Mass of }O_2=160g[/tex]

Therefore, 160 grams of [tex]O_2[/tex] are in 5.0 moles of the oxygen gas.

Burning fossil fuels releases carbon into the atmosphere, causing climate change and global warming. It also leads to environmental damage, such as water contamination and habitat destruction. The transition away from fossil fuels presents challenges due to our reliance on them for various aspects of our daily lives.

Burning fossil fuels, such as coal, oil, and natural gas, releases carbon into the atmosphere, contributing to climate change. Increased carbon dioxide in the atmosphere traps heat, leading to global warming and its associated impacts, such as rising sea levels and extreme weather events.

In addition to climate change, the extraction and use of fossil fuels have negative environmental consequences. Oil spills, coal mining, and fracking can contaminate water sources and harm wildlife habitats.

The dependence on fossil fuels also poses a challenge for transitioning to alternative energy sources in the future, as we currently rely on them for various aspects of our modern lifestyle, such as transportation.

Sodium sulfate (Na2SO4) is the ionic compound most likely to dissolve in water among the options provided.

The student is asking which of the listed ionic compounds is most likely to dissolve in water. Looking at the options, we have Calcium sulfate (CaSO4), Sodium sulfate (Na2SO4), Barium sulfate (BaSO4), and Strontium sulfate (SrSO4). According to solubility rules, most sulfate salts are soluble except for some exceptions, including BaSO4, SrSO4, and CaSO4. Given that sodium compounds are generally highly soluble, Na2SO4 is the compound that is most likely to dissolve in water. This is because there is less size mismatch between the Na+ and SO4(2-) ions compared to the other pairs of ions, which fits the trend that smaller size mismatches lead to greater solubility.

Answer:

Mg+2HF>2MgF+H2

Explanation:

An example of an element with an electron distribution ending in s2p1 is Boron (B) situated in Period 2 of the Periodic Table. However, there isn't an element with an electron distribution ending in s2d2 as 'd' orbitals start filling from the 3rd energy level and in a sequence after 'p' orbitals.

In the field of Chemistry, the electron distribution of an element refers to how the electrons are arranged in various energy levels around the nucleus of an atom. Electron distributions are typically written as series of numbers and letters, each of which indicate the energy level, type of orbital, and number of electrons in that orbital, respectively.

For an element with an electron distribution ending in s2p1, we look in the second period of the Periodic Table. An example of such element is Boron (B). It has the electron configuration of 1s2 2s2 2p1.

As for an element with an electron distribution ending in s2d2, we cannot find one because 'd' orbitals begin filling only from the 3rd energy level or Period 4 of the Periodic Table and after 's' orbital is fully occupied by 2 electrons, it's followed by 'p' orbital and then 'd'. So, there is no suitable element with an electron configuration ending in s2d2.

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Answer:

Element is a pure substance which cannot be splitted into smaller substances by simple chemical reactions. while Compound is a chemical combination of two or more substances at fixed ratio.

HOFBrINCl is a mnemonic to remember the seven diatomic molecules: hydrogen, oxygen, fluorine, bromine, iodine, nitrogen, and chlorine, used in Chemistry to balance equations and predict compound formulas.

HOFBrINCl is a mnemonic device used in Chemistry to remember the diatomic molecules, which are molecules consisting of two atoms. These seven diatomic molecules are hydrogen (H2), oxygen (O2), fluorine (F2), bromine (Br2), iodine (I2), nitrogen (N2), and chlorine (Cl2). You typically use this mnemonic when you are trying to recall which elements naturally form diatomic molecules, especially when balancing chemical equations or predicting formulas of compounds in Chemistry.

The answer is:

-Cellular respiration is a set of metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products.

-and Cellular respiration is the process of breaking down food such as glucose into carbon dioxide and oxygen. During the process, cellular respiration also releases energy in the form of ATP (adenosine triphosphate) for use by all energy consuming activities of the cell. It is found in the simultaneous process of Glycolysis and Kreb’s cycle. Glycolysis is the breakdown of glucose to two pyruvic acids. These two pyruvic acids will be used for the production of carbon dioxide and water in Krebs cycle.

The correct answer is 3. The molecular collisions are perfectly elastic.

Explanation- The rapidly moving particle of gas collides with the walls of the container. All these collision are perfectly elastic. The pressure exerted by the gas is due to this continuous collision and the force experienced per unit area of the walls of the container determines the pressure exerted by the gas.

Assumptions 2 and 3 of the Kinetic Molecular Theory explain gas pressure. High-speed molecular motion causes frequent, perfectly elastic collisions with container walls, generating pressure.

The pressure exerted by a gas can be explained by assumptions 2 and 3 of the Kinetic Molecular Theory.

1. **Assumption 2:** The molecules of a gas are in constant motion at high speeds. This motion creates collisions between the gas molecules and with the walls of the container.

2. **Assumption 3:** The molecular collisions are perfectly elastic. This means that when gas molecules collide with each other or with the walls of the container, there is no net loss of kinetic energy. The total kinetic energy of the system remains constant.

Now, let's delve into the step-by-step explanation of how these assumptions relate to the pressure exerted by the gas:

- When gas molecules collide with the walls of the container, they exert a force on the walls due to the change in momentum. This force per unit area is what we define as pressure.

- The faster the gas molecules are moving (assumption 2), the more forceful these collisions will be.

- Additionally, the more frequently these collisions occur, the greater the pressure will be.

- Since the collisions are perfectly elastic (assumption 3), the molecules rebound from the wall after collision without losing any kinetic energy. This means that each collision contributes equally to the pressure exerted by the gas.

- Therefore, both assumptions 2 and 3 are essential in explaining the pressure exerted by a gas.

So, the correct answer is: **2 and 3**.

Carbon's ability to attract electrons is determined by its electronegativity, which is a measure of an atom's tendency to attract electrons towards itself in a chemical bond.

The ability of carbon to attract electrons is determined by its electronegativity. Electronegativity is a measure of an atom's tendency to attract electrons towards itself in a chemical bond. The more strongly an atom attracts electrons, the higher its electronegativity.

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Answer:

(1) gains an electron and its radius increases

Explanation:

Hello,

Ionization involves the charge of a determined atom in order to form an ion, in this case, the chloride ion which is negative. In such a way, since chloride ion turns out negatively charged via ionization, it is evident that an electron is gained so its radius must increase as result of that gain, therefore, answer is:

(1) gains an electron and its radius increases

As long as a new particle is included into it.

Best regards.

Answer : The number of atoms of oxygen present in [tex]2Fe(NO_3)_2[/tex] are, 12.

Explanation :

As we know that, [tex]Fe(NO_3)_2[/tex] is made up of the combination of iron and nitrate molecule.

In [tex]2Fe(NO_3)_2[/tex] compound, there are three elements which are iron (Fe), nitrogen (N) and oxygen (O).

The number of atoms of iron = 2

The number of atoms of nitrogen = 4

The number of atoms of oxygen = 12

Hence, the number of atoms of oxygen present in [tex]2Fe(NO_3)_2[/tex] are, 12.

The solubility of substances in water can be predicted using solubility rules: NaNO3 is soluble, AgBr and Ag2CO3 are insoluble, NH4OH and NH4Br are soluble, BaSO4, Pb(OH)2, and PbCO3 are insoluble.

To predict the solubility of the following substances in water we need to consider general solubility rules:

Final answer:

Solubility in water can be predicted using solubility rules. NaNO3 and NH4OH (or NH3 in water) are soluble, while AgBr, Ag2CO3, BaSO4, Pb(OH)2, and PbCO3 are generally insoluble.

Explanation:

To predict the solubility of substances in water, we refer to solubility rules and know that:

Compounds containing the nitrate ion (NO3-) such as NaNO3 are generally soluble.

Halides, except those of silver, mercury, and lead, are typically soluble, which means AgBr would be insoluble.

Compounds with the ammonium ion (NH4+) like NH4OH (ammonium hydroxide, which is actually NH3 in water) are soluble.

Most compounds containing the carbonate ion (CO3 2-) are insoluble, so Ag2CO3 is likely insoluble.

As with NH4OH, NH4Br contains the ammonium ion, hence it is soluble.

Sulfates are generally soluble but there are exceptions like barium sulfate, thus BaSO4 is insoluble.

Hydroxides are usually insoluble except for those of alkali metals and a few others, indicating that Pb(OH)2 will be insoluble in water.

Lead carbonate, PbCO3, would follow the solubility trend of carbonates and be considered insoluble.

Among the given options, MgF2 is an ionic compound.

An ionic compound is formed between a metal and a nonmetal. Among the options given, H2O and C2H4 are covalent compounds because they contain only nonmetal elements. NH3 is also a covalent compound because it contains only nonmetals. On the other hand, BrCl is a covalent compound because it contains two nonmetals. Lastly, MgF2 is the correct answer because it contains the metal magnesium (Mg) and the nonmetal fluorine (F). Therefore, MgF2 is an ionic compound.

The 80 ml solution has (.04)(80) ml of the medicine, or 3.3 ml of medicine.The pharmacist adds V ml of 7% solution, or .07V ml of medicine. The total amoune of medicine is (.07V + 3.2) mg. The total volume of solution is (V + 80) ml, so (.07V + 3.2) / (V + 80) = .05.

Solve for V.

V = 40 ml.

First write and balance the equation, being: CaCO3 - CaO + CO2 Then, using the periodic table, find the molecular masses of CaCO3 and of CaO, finding their ratio. That will be 100g:56g or 0.1kg:0.056kg. Since you have 4.7kg of CaCO3, it corresponds to Xkg of CaO. Making x the subject, it should be X= 4.7*0.056/100=0,002632

Answer : The mass of calcium oxide produced is, 2632 g

Solution : Given,

Mass of calcium carbonate = 4.7 Kg = 4700 g      (1 Kg = 1000 g)

Molar mass of calcium carbonate = 100 g/mole

Molar mass of calcium oxide = 56 g/mole

First we have to calculate the moles of calcium carbonate.

[tex]\text{Moles of }CaCO_3=\frac{\text{Mass of }CaCO_3}{\text{Molar mass of }CaCO_3}=\frac{4700g}{100g/mole}=47moles[/tex]

Now we have to calculate the moles of calcium oxide.

The balanced decomposition reaction will be,

[tex]CaCO_3\rightarrow CaO+CO_2[/tex]

From the balanced reaction we conclude that,

As, 1 mole of calcium carbonate decompose to give 1 mole of calcium oxide

So, 47 moles of calcium carbonate decompose to give 47 moles of calcium oxide

Now we have to calculate the mass of calcium oxide.

[tex]\text{Mass of }CaO=\text{Moles of }CaO\times \text{Molar mass of }CaO[/tex]

[tex]\text{Mass of }CaO=(47moles)\times (56g/mole)=2632g[/tex]

Therefore, the mass of calcium oxide produced is, 2632 g