Which of the following is not true about chemical changes? a. They form a new substance. b. They can be reversed by physical changes. c. They can be detected by changes such as color. d. They have different properties from their starting materials.

All components in groups 4A or 14 finish in p2. This is how it works. There are several outliers for the metallic elements (groups 3–12). The basic norm is that the electron arrangement of an element terminates in d, regardless of its location.

because grouping 8 will be p6. we must count the two Groups I and Group II electrons from the "s" block. 

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The moles  of water  that are produced  from 13.35  mol of oxygen  is 26.70  moles (answer B)

calculation

2H2 +O2→ 2H2O

The moles of H2O is  calculated using mole ratio.

that is; from the balanced  equation above  the mole ratio of O2 :H2O  is 1:2

therefore  the moles of water=13.35 moles x 2/1 =26.70 moles

Isotopes are forms of an element with the same number of protons, but different numbers of neutrons. The difference between 88Sr and 84Sr is in the number of neutrons, with 88Sr having 50 neutrons and 84Sr having 46 neutrons. This affects their physical properties but not their chemical behavior.

The difference between an isotope of 88Sr and an isotope of 84Sr lies in the number of neutrons each isotope contains. Isotopes are different forms of an element that have the same number of protons but a different number of neutrons. In the case of strontium (Sr), the atomic number is 38 which means it has 38 protons. For 88Sr, subtracting the number of protons (38) from the mass number (88), we find that this isotope has 50 neutrons. For the isotope 84Sr, it has 46 neutrons (84-38). The difference in the number of neutrons results in different physical properties, but does not affect the chemical behavior of the isotopes.

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Final answer:

The factor in an experiment that changes due to manipulation of the independent variable is the dependent variable, which is observed and measured to see the effect of the independent variable.

Explanation:

A factor that changes in an experiment from manipulation of the independent variable is the dependent variable. In an experiment, the independent variable is the factor controlled or manipulated by the experimenter, and its effects are observed and measured in the dependent variable. All changes measured in the dependent variable are ideally due to manipulations made to the independent variable.

For example, in an experiment testing the effect of sunlight on plant growth, sunlight exposure is the independent variable, while the growth of the plant, which is measured in response to varying levels of sunlight, is the dependent variable. Controls and constants are also crucial in ensuring the experiment's validity by keeping all other variables unchanged to isolate the effect of the independent variable on the dependent variable.

The products of the oxidation of glucose with an excess of oxygen are carbon dioxide and water.

A combustion reaction can be defined as a reaction that produces heat and occurs at an elevated temperature. It is an exothermic reaction, a redox chemical reaction that occurs between a fuel (hydrocarbon) and oxygen in the atmosphere.

Oxygen is an essential component for combustion because combustion cannot take place in the absence of oxygen. Complete combustion occurs when hydrocarbon burns fully to form water, carbon dioxide, and heat.

The burning of wood is also combustion where the carbon present in wood reacts with oxygen gas in the air to liberate heat and form gaseous products.

During the combustion of glucose reacts with an excess of oxygen gas to give six molecules of carbon dioxide and six molecules of water.

[tex]C_6H_{12}O_6 + 6O_2 \longrightarrow \; 6CO_2 + 6H_2O[/tex]

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Moles of NAF are in 34.2 grams of a 45.5% by mass naf solution 15.6 g

One mole is the Avogadro number of particles (atoms, molecules, ions, or electrons) in a substance. One mole of atoms contains 6 x 1023 atoms. The 6.022 x 10 23 number is known as the number of Avogadro or the constant of Avogadro.

For the conversion of mass and number of particles, the definition of the mole can be used.

A mole is the quantity of anything that has the same number of particles found in 12.000 grams of carbon-12 percent  by mass = mass solute x 100 / mass solution percent mass = 45%mass of solution = 34.2 g

substituting the value,

45.5 % = mass solute NaF x 100 / 34.2 mass solute NaF              

              = 34.2 x 45.5 /100=15.6 g

Therefore, the total number of moles that are participating will be 15.6 g

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Answer : Option C) The polar bonds are oriented in opposite direction.

Explanation : A molecule of carbon dioxide [tex] (CO_{2}) [/tex] contains two polar covalent bonds. This molecule is non-polar because the polar bonds are oriented in the opposite direction.

In order to be a polar molecule, carbon dioxide must have both a slightly negative side and a slightly positive side in its molecule. The orientation of the lone pairs of electrons present on each oxygen atom cancels each other, making the molecule non polar.

Answer: Option (c) is the correct answer.

Explanation:

Shape of a [tex]CO_{2}[/tex] molecule is linear, that is, carbon atom resides at the center and each oxygen atom lies on its left and right side.

Since, oxygen is more electronegative than carbon so, dipole moment will be towards oxygen atom. Hence, dipole moment cancel out as the bonds are in opposite directions.

Therefore, we can conclude that a molecule of carbon dioxide is non-polar because the polar bonds are oriented in opposite directions.

Answer:

Option (A), (C) and (D)

Explanation:

Shield volcanoes are generally characterized gentle slopes, and are dome shaped, resembling the shield that is used by the ancient warriors. This type of volcano produces magma that are basaltic in nature and have no silica content. So they can flow easily. The layers are often formed due to the gentle eruption of lava that solidifies. These volcanoes are not explosive but they can turn into a violent one if it comes in contact with water. They occur along the Pacific's ring of fire. The amount of pyroclastic materials is less than the total amount of lava it releases during a volcanic eruption.

Thus, the correct answers are options (A), (C) and (D).

Carbon (C) has the highest ionization energy in group 4A due to its position in the periodic table, with ionization energy increasing across a period and decreasing down a group.

The group 4A element with the highest ionization energy is carbon (C). Ionization energy tends to increase across a period (from left to right) and decreases down a group (from top to bottom) of the periodic table. Since carbon is above silicon, germanium, tin, and lead in group 4A, it possesses the highest ionization energy among these elements. This is due to its smaller atomic radius and the stronger attraction between the nucleus and the electrons in the outer shell, making it more difficult to remove an electron.

Additionally, the ionization energy follows the pattern where it increases for successive electrons being removed from valence orbitals, with a notably large increase when an electron is removed from a filled core level, which typically has the electron configuration of the preceding noble gas.

Answer: Sn + 2Ag⁺ → Sn²⁺ + 2 Ag

Explanation:

1) The half-reactions given are:

Sn → Sn²⁺

Ag⁺ → Ag

2) The first step that you should perform is to complete each half reaction with electrons to balance the charges. This is how:

Sn → Sn²⁺ + 2e⁻

Ag⁺ + 1e⁻ → Ag

3) The second step is to multiply the half-reactions by the appropiate coefficients to make the electrons on both reactions equal.

So, multiply the second reaction by 2:

Sn → Sn²⁺ + 2e⁻

2Ag⁺ + 2e⁻ → 2Ag

4) The third step is to add up the two equations:

Sn + 2Ag⁺ + 2e⁻ → Sn²⁺ + 2e⁻ + 2 Ag

5) Fourth step, cancell the electrons on both sides:

Sn + 2Ag⁺ → Sn²⁺ + 2 Ag

And that is the final answer.

The balanced overall equation for the two half reactions is:

We'll begin by balancing the various half reactions. This can be obtained as follow:

Sn → Sn²⁺ + 2e¯...... (1)

Ag⁺ + e¯ → Ag .......... (2)

Multiply equation (2) by 2 to balance the electron(s) on both equation

Sn → Sn²⁺ + 2e¯...... (1)

2Ag⁺ + 2e¯ → 2Ag .......... (2)

Combine equation 1 and 2 with the elimination of 2e¯ to obtain the overall reaction as shown below:

Sn + 2Ag⁺ + 2e¯ → Sn²⁺ + 2Ag + 2e¯

Sn + 2Ag⁺ → Sn²⁺ + 2Ag

Therefore, the balanced overall equation for the two half reactions is:

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The balanced chemical equation for the reaction between nitric oxide gas (NO) and hydrogen gas (H₂) to form ammonia gas (NH₃) and water vapor (H₂O) is:

[tex]\[ 3NO(g) + 2H_2(g) \rightarrow 2NH_3(g) + H_2O(g) \][/tex]

To balance this equation, we follow these steps:

1. Write down the unbalanced equation:

[tex]\[ NO(g) + H_2(g) \rightarrow NH_3(g) + H_2O(g) \][/tex]

2. Balance the nitrogen atoms first. There is one nitrogen atom on the reactant side in NO and three nitrogen atoms in the product NH₃. To balance the nitrogen atoms, we need to have three NO molecules on the reactant side:

[tex]\[ 3NO(g) + H_2(g) \rightarrow 2NH_3(g) + H_2O(g) \][/tex]

3. Next, balance the hydrogen atoms. There are six hydrogen atoms in the products (two NH₃ molecules have six hydrogen atoms in total, and one H₂O molecule has two hydrogen atoms). To balance the hydrogen atoms, we need to have two H₂ molecules on the reactant side:

[tex]\[ 3NO(g) + 2H_2(g) \rightarrow 2NH_3(g) + H_2O(g) \][/tex]

4. Finally, balance the oxygen atoms. There are three oxygen atoms on the reactant side (from three NO molecules) and one oxygen atom in the product Hâ‚‚O. The oxygen atoms are already balanced, so no changes are needed there.

5. Verify that the equation is balanced for all atoms:

- Nitrogen: 3 NO have 3 nitrogen atoms, and 2 NH₃ also have 3 nitrogen atoms.

- Hydrogen: 2 H₂ have 4 hydrogen atoms, 2 NH₃ have 6 hydrogen atoms, and 1 H₂O has 2 hydrogen atoms, making a total of 8 hydrogen atoms on both sides.

- Oxygen: 3 NO have 3 oxygen atoms, and 1 Hâ‚‚O has 1 oxygen atom.

The equation is now balanced with the same number of each type of atom on both sides of the equation.

Solid magnesium (Mg (s)) is classified as a metallic solid, which has a closely packed crystal structure and exhibits high electrical conductivity.

When classifying the solid magnesium (Mg (s)), it would be considered a metallic solid. Magnesium is a metal and in solid form, it exists as a metallic solid with closely packed magnesium atoms that form a metallic crystal structure. This structure allows for the free flow of electrons, which imparts metallic solids with characteristic properties such as high electrical conductivity and malleability.

Taking into account the definition of covalent and ionic bonds, the bonds of NaCl, CaCl₂ and KCl are ionic.

The covalent bond is the chemical bond between atoms where electrons are shared, forming a molecule. Covalent bonds are established between non-metallic elements. These elements have many electrons in their outermost level (valence electrons) and have a tendency to gain electrons to acquire the stability of the electronic structure of noble gas. The shared electron pair is common to the two atoms and holds them together.

On the other side, an ionic bond is produced between metallic and non-metallic atoms, where electrons are completely transferred from one atom to another. During this process, one atom loses electrons and another one gains them, forming ions. Usually, the metal gives up its electrons forming a cation to the nonmetal element, which forms an anion.

Considering the above, as Na, Ca and K are metals and Cl is a non-metal, the bonds of NaCl, CaCl₂ and KCl are ionic.

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According to the stoichiometry of the given chemical equation, 7.64 grams of NaCl is formed.

Chemical equation is a symbolic representation of a chemical reaction which is written in the form of symbols and chemical formulas.The reactants are present on the left hand side while the products are present on the right hand side.

A plus sign is present between reactants and products if they are more than one in any case and an arrow is present pointing towards the product side which indicates the direction of the reaction .There are coefficients present next to the chemical symbols and formulas .

As per the equation, 268.9 grams copper chloride gives 137 g so 15 g copper chloride will give 15×137/268.9=7.64 g.

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Final answer:

532.6 grams of [tex]Fe_{2}O_{3}[/tex] are produced.

Explanation:

To calculate the grams of [tex]Fe_{2}O_{3}[/tex] produced, we need to follow a stoichiometry calculation using the balanced chemical equation given. The molar ratio between [tex]FeS_{2}[/tex] and [tex]Fe_{2}O_{3}[/tex] is 1:1, so the amount of [tex]Fe_{2}O_{3}[/tex] produced will be equal to the amount of [tex]FeS_{2}[/tex] used.

First, we convert the grams of [tex]FeS_{2}[/tex] to moles using its molar mass. Then, we use the molar ratio to determine the moles of [tex]Fe_{2}O_{3}[/tex] produced. Finally, we convert the moles of [tex]Fe_{2}O_{3}[/tex] to grams using its molar mass.

Let's calculate:

Convert grams of [tex]FeS_{2}[/tex] to moles using its molar mass: 294 g [tex]FeS_{2}[/tex] × (1 mol [tex]FeS_{2}[/tex] ÷ 87.9 g [tex]FeS_{2}[/tex]) = 3.343 mol [tex]FeS_{2}[/tex]

Use the molar ratio from the balanced equation to find moles of [tex]Fe_{2}O_{3}[/tex] produced: 3.343 mol of [tex]FeS_{2}[/tex] × (1 mol [tex]Fe_{2}O_{3}[/tex] ÷ 1 mol [tex]FeS_{2}[/tex]) = 3.343 mol [tex]Fe_{2}O_{3}[/tex]

Convert moles of [tex]Fe_{2}O_{3}[/tex] to grams using its molar mass: 3.343 mol [tex]Fe_{2}O_{3}[/tex] × (159.7 g [tex]Fe_{2}O_{3}[/tex] ÷ 1 mol [tex]Fe_{2}O_{3}[/tex]) = 532.6 g.

To find the grams of Fe₂O₃ produced when reacting 294 grams of FeS₂ with 176 grams of O₂, first identify O₂ as the limiting reagent and then calculate the resultant Fe₂O₃ mass to be 159.69 grams.

To determine the grams of Fe₂O₃ produced when 294 grams of FeS₂ react with 176 grams of O₂ according to the equation FeS₂ + O₂ → Fe₂O₃ + SO₂, follow these steps:

Thus, 159.69 grams of Fe₂O₃ are produced in this reaction.

Answer:

There are 5 orbitals in the "d" sublevel.

Explanation:

In the d sublevel, there are 5 orbitals. The d sublevel consists of 5 atomic orbitals: dxy, dxz, dyz, dx2-y2, and dz2. Each orbital can hold a maximum of 2 electrons.

In the d sublevel, there are 5 orbitals.

The d sublevel consists of 5 atomic orbitals:

Each orbital can hold a maximum of 2 electrons, resulting in a total of 10 electrons in the d sublevel.

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The three correct rules or principles are the Aufbau Principle, Hund’s Rule, and the Pauli Exclusion Principle. Aufbau’s Principle states that each electron orbits the lowest energy orbital. It also states that all orbitals related to an energy level are of equal energy. Hund’s Rule states that single electrons with the same spin must occupy each equal-energy orbital before additional electrons with opposite spins can occupy the same orbitals. And finally, the Pauli Exclusion Principle states that a maximum of two electrons may occupy a single orbital, but only if the electrons have opposite spins. Hope this helps.

The three rules that define that how the electrons are arranged in atoms are the Aufbau Principle, Hund's rule, and the Pauli Exclusion Principle.  

• According to the Aufbau Principle, each electron holds the lowest energy orbital, and all the orbitals associated with an energy level are of the same energy.  

• According to Hund's rule, the single electrons with a similar spin must attain the equal energy orbital before the other electrons with the contrasting spins can attain similar orbitals.  

• According to the Pauli Exclusion principle, only a maximum of up to two electrons can occur in a single orbital, and only if the electrons exhibit opposite spins.  

Thus, the three rules, which illustrate that how the electrons are aligned in atoms are the Aufbau Principle, Hund's Rule, and the Pauli Exclusion Principle.

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Answer:

PCI5

Explanation: