Which situation would result in a theory being replaced rather than revised?

Alkali metals are the most reactive, followed by alkaline earth metals. Noble gases are the least reactive. Thus, the correct sequence from most to least reactive is alkali metals, alkaline earth metals, noble gases. Option 1

In a periodic table, the reactivity of elements tends to decrease from the left to the right. Therefore, the correct sequence from most reactive to least reactive elements would be option 1: Alkali metals, alkaline earth metals, and then noble gases.

This is because alkali metals (group 1) are the most reactive elements, followed by alkaline earth metals (group 2). Noble gases (group 18) are very stable and hence the least reactive. On the other hand, transition metals are generally less reactive than alkali and alkaline earth metals, while halogens are more reactive than noble gases but less reactive than alkali and alkaline earth metals.

Option 1

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Answer:

The correct answer is class I explosives.

Explanation:

An explosive refers to a chemical, which leads to a sudden, almost immediate discharge of gas, pressure, and heat when exposed to sudden pressure, shock, or high temperature. These are unstable substances and are primarily of two kinds.  

The type one comprises of substances possessing the tendency of undergoing supersonic reactions, like TNT and nitroglycerin. The other kind comprises substances, which burn briskly, however, at a subsonic rate. The examples are rocket propellants, gunpowder, and fireworks.  

Final answer:

Thallium, being the heaviest member of Group 13, will have the largest number of electron shells, which makes its atomic radius the largest of the group.

Explanation:

The element in Group 3A (13) with the largest atomic size is thallium, which has the symbol Tl. Atomic size generally increases from top to bottom within a group on the periodic table due to the addition of electron shells.

Thallium, being the heaviest member of Group 13, will have the largest number of electron shells, which makes its atomic radius the largest of the group.

The element with the largest atomic size in Group 3A (13) is thallium (Tl), as atomic size increases down a group.

The molality of the table salt (NaCl) in the described mixture, where 2.00 lbs of NaCl is mixed with 12.00 lbs of ice (half of which melts), is approximately 5.71 mol/kg.

The question asks for the calculation of the molality of salt (NaCl) in a mixture which involves a 2.00 lb sample of NaCl and 12.00 lb sample of ice that eventually melts to half its quantity. The steps for finding molality in such a scenario involve the conversion of weight measurements to mole measurements and utilize the fact that molality is calculated as moles of solute (NaCl) per kilogram of solvent (water).

Step 1: Convert the amount of NaCl and water (melted ice) from lb to grams. 1 lb is approximately 453.592 grams. So, 2.00 lb of NaCl is 907.185 grams of NaCl and 6.00 lb of water is 2721.55 grams (since half of the 12 lb of ice melts). This needs to be converted to kilogram giving us 2.72155 kg.

Step 2: Convert grams of NaCl to moles. The molar mass of NaCl is approximately 58.44 grams per mole. Therefore, 907.185 grams of NaCl is approximately 15.54 moles.

Step 3: Determine the molality using the formula molality = moles of solute (NaCl) / kg of solvent (melted ice). This gives us a molality of approximately 5.71 mol/kg.

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Option A= 2

Atomic Number of Nickel (Ni) = 28

Electronic configuration is 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d8

By definition, the highest principle quantum number is the valence shell. In the case of Nickel, n = 4 is the highest QN and contains 2 electrons (max allowed) in the s-orbital.

ATP is a modified nucleotide used for cellular energy that contains the ribose sugar.

Further explanation

Ribose

It is a sort of sugar that is created by the body. It is utilized as a medicine. Ribose is utilized by mouth to diminish chest torment and improve heart work in individuals with coronary course illness.

ATP (Adenosine triphosphate)

It is an instant energy source. It is called as the energy currency of the cell.  It is used as a coenzyme in many processes. ATP is synthesized during Krebs cycle and glycolysis. Mitochondria and chloroplast are involved in the production of ATP. ATP is involved in the active transport of molecules, in the processes like muscle contraction, protein synthesis and Calvin cycle. We synthesize 60 Kg of ATP per day. ATP is a large molecule but its energy lies in the terminal phosphate bond. ATP provides energy to cell by breaking its phosphate bond. By breaking one phosphate group ATP is converted to ADP molecule but it can be regenerated. ATP is also consumed by plants in the process of photosynthesis. Animals use ATP in the breakdown of carbohydrate and lipids. In fact, it is the principal molecule used in biochemical reactions.

Structure of ATP

ATP is composed of adenine which is a purine base, a ribose sugar and three phosphoric acid molecules. It also has ester linkage and high energy phosphate bond.

Phosphate bond is highly reactive bond but when it reacts with nucleoside, adenosine it becomes less reactive.  

Answer details

Subject: Chemistry

Level: College

Keywords

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First let us get the molecular mass of the compound C2H5O.

C has molar mass of 12 amu, H is 1 amu, while O is 16 amu, therefore:

C2H5O = 12 amu * 2 + 1 amu * 5 + 16 amu = 45 amu

So to get 90 amu, simply double all the elements, therefore:

C4H10O2

Let us assume that the given formula of elements is empirical formula where elements have simplest whole number ratio

The empirical mass =  2 X atomic mass of carbon + 5 X atomic mass of hydrogen + at mass of O

The empirical mass = 2 X 12 + 5 + 16 = 45

The ratio of molecular mass and empirical mass = 90 / 45 = 2

Molecular formula is obtained by multiplying the empirical formula with this ratio / factor

molecular formula = 2 X (C2H5O) = C4H10O2

In a 0.370 mol sample of [tex](NH_4)_2SO_4[/tex], there are 0.740 mol of [tex]NH_4^+[/tex] ions and 0.370 mol of [tex]SO_4^{2-}[/tex] ions.

To determine the number of ammonium ([tex]NH_4^+[/tex]) and sulfate ([tex]SO_4^{2-}[/tex]) ions in a 0.370 mol sample of [tex](NH_4)_2SO_4[/tex], we use the stoichiometry of the compound. Each unit of ammonium sulfate contains two ammonium ions and one sulfate ion.

We calculate the number of ions as follows:

The sample therefore contains 0.740 mol of [tex]NH_4^+[/tex] ions and 0.370 mol of [tex]SO_4^2^-[/tex] ions.

Iki also known as Lugol's solution, is an indicator used to test for the presence of starch. Benedict's reagent is used to test for the presence of reducing sugars, such as glucose and fructose

Lugol's solution is a yellow-brown solution that turns blue-black in the presence of starch.

Benedict's reagent is a clear blue solution that changes color to green, yellow, orange, or red, depending on the amount of reducing sugar present. Benedict's test is commonly used in the laboratory to detect the presence of reducing sugars in various substances.

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Final answer:

Ions are created when neutral atoms either lose or gain electrons, forming cations and anions, respectively. The periodic table helps predict the charges of ions depending on their group, where alkali metals form +1 cations, alkaline earth metals form +2 cations, and halogens form -1 anions. The formation of ionic compounds involves the combination of these oppositely charged ions to achieve electrical neutrality.

Explanation:

Ions are formed when atoms gain or lose electrons. When a neutral atom loses one or more electrons from its valence shell, it becomes a cation (a positive ion). Conversely, when it gains one or more electrons in its valence shell, it becomes an anion (a negative ion).

Charges of Ions and Ionic Compounds:

The periodic table can be a tool for predicting the charges of many ions based on their group. For instance, alkali metals form +1 ions, while alkaline earth metals form +2 ions. Halogens typically form -1 ions. Ionic compounds consist of these positive and negative ions in a ratio that balances their total charges, resulting in an electrically neutral compound.

Electron Configurations and Ion Charges:

It's important to note that ions only form through the movement of electrons, not protons. For elements within the same group on the periodic table, the number of valence electrons determines the common ion charge. Elements will either reach a stable electron configuration by losing or gaining electrons to form ions.

Final answer:

To find the mass of methanol, divide the number of molecules by Avogadro's number to get moles, then multiply by molar mass. The mass of 9.79 × 10²⁴ molecules of methanol is 520.64 grams.

Explanation:

To calculate the mass of 9.79 × 10²⁴ molecules of methanol (CH₃OH), first, we need to determine how many moles of methanol there are. Since 1 mole of any substance contains 6.02 × 10²³ molecules (Avogadro's number), we can use this to find the number of moles:

Moles of methanol =
9.79 × 10²⁴ molecules / 6.02 × 10²³ molecules/mol

This calculation reveals that there are 16.27 moles of methanol. Next, we use the molar mass of methanol, which is 32.0 g/mol, to find the mass:

Mass of methanol = 16.27 moles × 32.0 g/mol = 520.64 grams. Therefore, 9.79 × 10²⁴ molecules of methanol have a mass of 520.64 grams.

Answer:

Explanation:

Acetaldehyde is a colorless, volatile liquid with a pungent and suffocating smell. It is produced as a result of the oxidation of ethyl alcohol to acid or acetic fermentation. Its formula is: CH3CHO formula.

Acetaldehyde occurs naturally in alcoholic beverages. In excess, however, it resembles the smell and taste of an immature green apple.

Fermentation is a process that degrades molecules to transform them into other simpler molecules.

The most frequent causes for which the impurity of acetaldehyde can be generated in fermentation:

The solubility of carbon dioxide in water at 25 °C increases from 0.0351 m at 785 torr to approximately 0.0675 m at 1510 torr.

The solubility of a gas in a liquid is described by Henry's Law, which states that at a constant temperature, the solubility of a gas in a liquid is directly proportional to the pressure of the gas above the liquid.

Using this law, we can calculate the solubility of carbon dioxide (CO₂) in water at a different pressure while keeping the temperature constant at 25 °C.

At 785 torr, the solubility of CO₂ is 0.0351 m. According to Henry's Law, the solubility (S) can be calculated using the formula S₁/P₁ = S₂/P₂, where S₁ and S₂ are the solubilities at pressures P₁ and P₂, respectively.

If the pressure is increased to 1510 torr, we can find the new solubility (S₂) as follows:

S₂ = S₁ x (P₂/P₁)
= 0.0351 m x (1510 torr / 785 torr)
= 0.0351 m x (1510/785)
= 0.0351 m x 1.9235671
= 0.067533 m (approx)

The solubility of CO₂ at 25 °C and 1510 torr is approximately 0.0675 m.

Answer: The correct answer is Option D.

Explanation: Organic compounds are defined as the compounds which have hydrogen and carbon atoms in it. They are also known as hydrocarbons.

From the given options:

Option 1: [tex]Ca_3(PO_4)_2\text{ and }CO_2[/tex] are not organic compounds because these two compounds do not contain hydrogen element in it.

Option 2: [tex]CaCl_2\text{ and }CaCN_2[/tex] are not organic compounds because these two compounds do not contain hydrogen and carbon elements in it.

Option 3: [tex]CaSO_4[/tex] is not an organic compound because this compound do not contain hydrogen and carbon elements in it.

Option 4: All the compounds contain hydrogen and carbon elements in it and hence, all the compounds are organic compounds.

Therefore, the correct option is Option D.

Ans: 7.50% of P

Given:

Mass of NPK sample = 100 g

Mass of P in sample = 7.5 g

To determine:

The % P in the given sample

Explanation:

The percent of a particular substance (say,X) in a given total amount (M) is generally expressed as:

% X = [Mass of X/Total mass]*100

In this case:

%P = [mass of P/mass of NPK sample]*100

    = [7.5/100]*100 = 7.5%

Answer:

Chlorine and Flourine

Explanation:

It is important to identify the groups in which the elements being to. The elements in each group have the same number of electrons in the outer orbital. Those outer electrons are also called valence electrons.

Since elements in a group have the same number of valence electrons, they behave similarly in chemistry.

Nitrogen - Group 5

Chlorine - Group 7

Barium - Group 2

Flourine - Group 7

Sulphur - Group 6

This means the most similar elements would be flourine and Chlorine because they are both group 7 elements.

The pKa of a weak acid can be determined using the equation: pKa = -log10(Ka). In this case, we are given that 99.4% of the weak acid remains intact, which means that only 0.6% has dissociated. Therefore, we can calculate the equilibrium concentration of HA by multiplying the initial concentration of HA by 0.006.

The pKa of a weak acid can be determined using the equation: pKa = -log10(Ka), where Ka is the acid dissociation constant. In this case, we are given that 99.4% of the weak acid remains intact, which means that only 0.6% has dissociated. Therefore, we can calculate the equilibrium concentration of HA by multiplying the initial concentration of HA by 0.006.

Since the [HA] is equal to the [HA]₀ * 0.006, we can use this calculated equilibrium concentration along with the given Ka value to find the pKa.

For example, let's assume the initial concentration of HA is 0.2 M. The equilibrium concentration of HA would be 0.2 M * 0.006 = 0.0012 M. Using the equation pKa = -log10(Ka), we can find the pKa value.

Final answer:

The respiratory and renal systems are crucial in maintaining the acid-base balance of blood, by managing the levels of CO2 and bicarbonate, respectively.

Explanation:

The two body systems that contribute to the acid-base balance of blood are the respiratory system and the renal or excretory system. The primary blood buffer system is carbonic acid/hydrogen carbonate, which aids in maintaining the blood pH within a narrow range. The respiratory system regulates blood pH by exhaling carbon dioxide (CO2), while the renal system adjusts blood pH through the excretion of hydrogen ions (H+) and the conservation of bicarbonate (HCO3-). These two systems play a vital role in the acid-base homeostasis by removing excess acids or bases from the body.