An unknown or changeable quantity is called a(n)...

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

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.

To mix a 100 gallons of 25% solution from 10% and 45% solutions, create a system of equations representing total volume (x+y=100) and solute balance (0.10x+0.45y=25) to solve for x and y, which represent the volumes of 10% and 45% solutions needed.

The question is asking how to mix different concentrations of a solution to achieve a desired concentration in a specific total volume. To find out how much 10% solution and how much 45% solution are needed to make 100 gallons of a 25% solution, we can use a system of linear equations based on the concept of mass balance. The total amount of the solute in the final solution must be equal to the sum of the amounts in the individual components before mixing.

Let's denote x as the volume of the 10% solution and y as the volume of the 45% solution to be mixed. The mass of solute in the mixture must equal the mass of solute from both parts added together. Since we want 100 gallons of 25% solution, we can create the following equations:

Solving this system of equations will give the values of x and y, the volumes of 10% solution and 45% solution needed respectively. This involves substitution or elimination methods to find the solution to the system.

Final answer:

To solve for the amounts of 10% solution and 45% solution needed to make 100 gallons of a 25% solution, set up a system of linear equations using the total volume and concentration equations and solve for the two unknowns.

Explanation:

This problem is an example of a classic mixture problem in algebra, where we aim to find the proportions of two solutions of different concentrations to mix together to end up with a specific final concentration. We have two different solutions with concentrations of 10% and 45%, and we want to combine them to make 100 gallons of a 25% solution.

To solve this problem, let's let x represent the number of gallons of the 10% solution and y the number of gallons of the 45% solution. The total volume should be 100 gallons, so:

x + y = 100 gallons ... (1)

Now, we need to set up an equation based on the concentrations:

0.10x + 0.45y = 0.25(100)

0.10x + 0.45y = 25 ... (2)

Now we have a system of two equations:

x + y = 100

0.10x + 0.45y = 25

You can solve this system using either the substitution or elimination method. The solution will give you the amounts of 10% solution and 45% solution needed to obtain 100 gallons of 25% solution.

The method for calculation of the mass of CO2 emitted per Kj of heat produced in a combustion reaction has been explained below..

To answer this, let us use the combustion reaction of methanol which is;

CH3OH (l) + (3/2)O2 (g) = CO2 (g) + 2H2O (g)

We can find the enthalpy of combustion of this reaction from tables or it will be given to us. Let us use; ΔH = -638.54 KJ

This means for every 1 mole of CO2, the heat released is -638.54 KJ

Now, Molar mass of CO2 is 44 g/mol

Thus;

Mass of CO2 per Kj of heat produced is;

44 g/mol × 1 mol/-638.54 KJ

>> 6.89 × 10^(-2) g/kJ

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Answer:

Polar substances tend to mix with each other, while nonpolar substances tend to mix with nonpolar substances

Explanation:

The covalent bond is the chemical bond between atoms where electrons are shared, forming a molecule. Covalent bonds are established between non-metallic elements, such as hydrogen H, oxygen O and chlorine Cl. 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.

The covalent bond between two atoms can be polar or nonpolar. This depends on the type of atoms that make it up: if the atoms are equal, the bond will be nonpolar (since no atom attracts electrons more strongly). But, if the atoms are different, the bond will be polarized towards the most electronegative atom, because it will be the atom that attracts the electron pair with more force. Then it will be polar.

It can occur in a molecule that the bonds are polar and the molecule is nonpolar. This occurs because of the geometry of the molecule, which causes them to cancel the different equal polar bonds of the molecule (remember that not all polar bonds are equal, because they are due to the difference in electronegativity of the elements, which are not all same).

Solubility is a physical property that is directly related to the polarity of molecules.  With regard to solubility it is said that "the like is mixed with the like." That is, polar substances tend to mix with each other, while nonpolar substances tend to mix with nonpolar substances. For example, oil is a nonpolar substance, which when mixed with a polar substance such as water does not mix, generating two phases.

Final answer:

When comparing polar and nonpolar molecules of similar size, polar molecules will have stronger dipole-dipole interactions, while nonpolar molecules only experience London dispersion forces, affecting their solubility and interaction with solvents according to the principle 'like dissolves like'.

Explanation:

If the molecules of two different substances have a similar size but the molecules of one substance are polar while the molecules of the other substance are nonpolar, we can anticipate different behaviors with respect to their solubility and interaction with other substances.

Polar molecules often dissolve in polar solvents because the dipole-dipole interactions or hydrogen bonding are comparable in strength to the attractions in the pure substances, allowing them to mix easily.

Nonpolar molecules, on the other hand, are more likely to dissolve in nonpolar solvents, since the London dispersion forces present in these molecules are of similar strength to any solute-solvent interactions, thus adhering to the principle that "like dissolves like".

All molecules are subjected to London dispersion forces, but polar molecules also experience dipole-dipole interactions, which are generally much stronger for small polar molecules, making these interactions the predominant force.

As a result, a polar substance and a nonpolar substance, even if similar in size, will likely have different physical properties such as boiling point, melting point, and solubility.

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.

Chemistry is the study of matter, its properties, and transformations in various applications.

Chemistry is the branch of science that deals with the structure, composition, properties, and reactive characteristics of matter. It studies everything around us, from the liquids we use to the composition of materials like plastics and metals. Chemists play a crucial role in designing, predicting, and controlling chemical transformations for various applications.

1) The characteristics of nuclear fission reaction are [tex]\boxed{{\text{it involves splitting of an atom into two or more fragments}}}[/tex].

2) Both the nuclear fission and fusion reaction [tex]\boxed{{\text{release large amount of energy}}}[/tex].

3) The type of reaction shown in the diagram is [tex]\boxed{{\text{nuclear fission reaction}}}[/tex].

Further explanation:

Nuclear fission is defined as the splitting of heavy nucleus into two lighter ones. For example, a sample of uranium is bombarded with neutrons in an attempt to produce new elements with Z greater than 92. The lighter elements such as barium (Z = 56) were formed during the reaction and such products originate from the neutron-induced fission of uranium-235.

The reaction that shows nuclear fission is as follows:

 [tex]_{{\text{92}}}^{{\text{235}}}{\text{U}} + _{\text{0}}^{\text{1}}{\text{n}} \to _{{\text{56}}}^{{\text{141}}}{\text{Ba}} + _{{\text{36}}}^{{\text{92}}}{\text{Kr}} +{\text{3}}_{\text{0}}^{\text{1}}{\text{n}}[/tex]

The krypton-92 is the fission product. In this, the nucleus usually divides asymmetrically rather than symmetrically dividing into two equal parts, and the fission of a given nuclide does not give the same products.

In a nuclear fission reaction, more than one neutron is released by each nucleus on division. When these neutrons collide and induce fission in other nuclei, a series of nuclear fission reactions known as a nuclear chain reaction occurs.

In nuclear fusion, two light nuclei join to produce a heavier and more stable nucleus. Nuclear fusion is the opposite phenomenon of nuclear fission. The reaction that shows nuclear fusion is as follows:

[tex]{\text{2}}_{\text{1}}^{\text{2}}{\text{H}} \to _{\text{2}}^{\text{3}}{\text{He}} + _{\text{0}}^{\text{1}}{\text{n}}[/tex]

Nuclear fission and fusion reactions both produce large amount of energy.

1)

The characteristics of nuclear fission reaction are that it involves splitting of an atom into two or more fragments because it is a process in which a heavy nucleus splits into two lighter ones.

2)

Both the nuclear fission and fusion reaction involves splitting and collision of atoms that produce large amount of energy. Hence, both the reaction releases a large amount of energy.

3)

The type of reaction shown in the diagram is nuclear fission. In the diagram, a large atom split into two small atoms and again the atom forms split into two smaller atoms include a series of reactions called nuclear chain reaction. The nuclear chain reaction is a series of nuclear fission reactions in which neutrons collide and induce fission in other nuclei.

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1. Identify the precipitate of compounds https://brainly.com/question/2094744

2. How many covalent bonds does nitrogen forms https://brainly.com/question/2094744

Answer details

Grade: Senior School

Subject: Chemistry

Chapter: Nuclear binding energy

Keywords: Nuclear fission, nuclear fusion, splits, bombardment, uranium, krypton, heavy nucleus, nuclear chain reaction.

Inhibitory neurotransmitter

The four main components of air are nitrogen (N2), oxygen (O2), water vapor (H2O), and carbon dioxide (CO2). Nitrogen is the most abundant, followed by oxygen, while water vapor and carbon dioxide are in comparatively smaller amounts. Each component's molecular composition defines its physical and chemical properties.

The four main components of air in their molecular form are nitrogen (N₂), oxygen (O₂), water vapor (H₂O), and carbon dioxide (CO₂). Nitrogen contributes approximately 78.6 percent of the air's total composition, oxygen makes up about 20.9 percent, while water vapor and carbon dioxide represent smaller proportions, at around 0.5 percent and 0.04 percent, respectively.

Each of these gases exhibits different physical and chemical properties due to the combination of atoms within their molecules. In its molecular form, nitrogen is made up of two nitrogen atoms bonded together. Similarly, oxygen contains two bonded oxygen atoms. Water vapor is a molecule constituted of two hydrogen atoms and one oxygen atom, while carbon dioxide consists of one carbon atom and two oxygen atoms.

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The four main components of air in their molecular forms are Nitrogen (N₂), Oxygen (O₂), Water Vapor (H₂O), and Carbon Dioxide (CO₂). Nitrogen and oxygen constitute about 99% of the atmosphere. The rest is composed of argon, carbon dioxide, and trace gases.

The air we breathe is a mixture of gases. Among these, the four main components of air in their molecular forms are:

These gases make up the majority of the Earth's atmosphere, with nitrogen and oxygen accounting for about 99% of the air. The remaining 1% consists of argon, carbon dioxide, and other trace gases. Each gas exerts a partial pressure that contributes to the overall atmospheric pressure.

Final answer:

The most important lab safety rule is to follow all safety instructions and guidelines given by your teacher and lab instructions.

Explanation:

The most important lab safety rule is to follow all safety instructions and guidelines given by your teacher and lab instructions.

By following safety rules, you ensure your own safety as well as the safety of others in the laboratory.

For example, one important safety rule is to never eat or drink in the laboratory and to avoid using laboratory glassware for eating or drinking. This is because table tops and counters could have dangerous substances on them and leftover substances in glassware could interact with future experiments.

only a few should pass

The result of Rutherford's experiment demonstrates that most of the positively charged particles should bounce back at a range of angles as they collide with the atoms in the foil; only a few should pass straight through the foil. Thus, the correct option is A.

Ernest Rutherford was a British physicist who remarkably discovered the atomic nucleus first and proposed a nuclear model of the atom. He also performs an experiment on the Gold foil.

The nuclear model experiment of Rutherford showed that the atom is mostly empty space with a small, dense, positive charge. In the Gold foil experiment, most of the alpha particles did pass straight through the foil, while others bounce back at a range of angles.

Therefore, the correct option for this question is A.

To learn more about Ernest Rutherford, refer to the link:

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The bond length of H-Br in the HBr molecule, estimated using the dipole moment and the percent ionic character, is approximately 159 picometers.

The dipole moment (μ) of a molecule is given by the product of the charge (q) and the distance between the charges (d). In this case, you have been provided with the dipole moment, the physical constants, and the percent ionic character. Let's use these details to estimate the bond length. According to the given data, the dipole moment (μ) is 0.797 D, which is equivalent to 0.797 * 3.34*10^-30 C.m (as 1 D = 3.34*10^-30 C.m).

Since HBr has 11.8% ionic character, the effective charge (q_eff) is 11.8% of the charge of one electron, which is 1.6*10^-19 C. Therefore, q_eff = 0.118 * 1.6*10^-19 C. Thus, using the definition μ = q_eff . d (d = bond length), we can solve for d = μ / q_eff. Substituting the given and calculated values, we get d is approximately equal to 159 picometers.

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The estimated bond length of the [tex]\( \text{H-Br} \)[/tex] bond in picometers is approximately [tex]21 Pm[/tex].

To estimate the bond length of [tex]\( \text{HBr} \),[/tex] we will use the given dipole moment and percent ionic character.

Given.

- Dipole moment [tex](\( \mu \))[/tex] of [tex]\( \text{HBr} \)[/tex] = 0.797 d [tex](debye)[/tex]

- Percent ionic character = 11.8%

First, convert the dipole moment from debye to SI units coulomb meters.

[tex]\[ \mu = 0.797 \text{ d} \][/tex]

Since [tex]\( 1 \text{ d} = 3.34 \times 10^{-30} \text{ C} \cdot \text{m} \),[/tex]

[tex]\[ \mu = 0.797 \times 3.34 \times 10^{-30} \text{ C} \cdot \text{m} \][/tex].

[tex]\[ \mu = 2.66198 \times 10^{-30} \text{ C} \cdot \text{m} \][/tex].

Calculate the bond moment in a purely ionic bond [tex](\( \mu_{\text{ionic}} \)):[/tex]

For a bond with 100% ionic character, the dipole moment is given by.

[tex]\[ \mu_{\text{ionic}} = \sqrt{q \cdot r^2} \][/tex]

where [tex]\( q \)[/tex] is the charge in coulombs and [tex]\( r \)[/tex] is the bond length in meters.

Given [tex]\( q = 1.6 \times 10^{-19} \) C (charge for 100% ionic character),\[ \mu_{\text{ionic}} = \sqrt{1.6 \times 10^{-19} \cdot r^2} \][/tex]

Solve for [tex]\( r \):[/tex]

[tex]\[ \mu_{\text{ionic}} = 2.66198 \times 10^{-30} \text{ C} \cdot \text{m} \][/tex]

[tex]\[ \sqrt{1.6 \times 10^{-19} \cdot r^2} = 2.66198 \times 10^{-30} \][/tex]

[tex]\[ 1.6 \times 10^{-19} \cdot r^2 = (2.66198 \times 10^{-30})^2 \][/tex]

[tex]\[ 1.6 \times 10^{-19} \cdot r^2 = 7.0865 \times 10^{-60} \][/tex]

Divide both sides by [tex]\( 1.6 \times 10^{-19} \)[/tex].

[tex]\[ r^2 = \frac{7.0865 \times 10^{-60}}{1.6 \times 10^{-19}} \][/tex]

[tex]\[ r^2 = 4.42906 \times 10^{-41} \][/tex]

Take the square root to find [tex]\( r \)[/tex]

[tex]\[ r = \sqrt{4.42906 \times 10^{-41}} \][/tex]

[tex]\[ r \approx 2.105 \times 10^{-21} \text{ m} \][/tex]

Convert meters to picometers  

[tex]\[ r \approx 2.105 \times 10^{-21} \text{ m} \times 10^{12} \text{ pm/m} \][/tex]    

[tex]\[ r \approx 21.05 \text{ pm} \][/tex]

Answer: Option (B) is the correct answer.

Explanation:

When we move from top to bottom in a group then size of elements keep of increasing due to the addition of more number of electrons into new shells.

But when we move across a period then there occurs a decrease in size of the elements due to the addition of electrons into the same shell.

So, if we move from bottom to top then it means there is decrease in size of atoms as number of electrons decreases then.

Thus, we can conclude that atomic size decreases as one moves from bottom to top in a group.

Answer:

The theoretical zero volume temperature of a gas.

Explanation:

The experimental data for effect of temperature on Volume of a gas is plotted in the graph. The graph is a straight line. It has been extrapolated where dash line meets the temperature axis. This point shows the temperature that the gas would have if it had zero volume. Experimentally, this data is not obtained but theoretically measured by extrapolating the volume versus temperature curve.

Thus, the point where blue line meets is the theoretical zero volume temperature of  a gas.

Final answer:

A magnesium atom becomes a magnesium ion by losing two electrons, forming a Mg²⁺ ion with a 2+ charge. This process results in the magnesium atom achieving the stable electron configuration of the noble gas, neon. The formation of a magnesium ion is an oxidation reaction and is vital in forming ionic compounds like magnesium oxide.

Explanation:

When a magnesium atom becomes a magnesium ion, it undergoes a process in which it loses two electrons. This occurs because magnesium is located in group 2 of the periodic table, indicating that it is a metal with two valence electrons. Metals tend to form positive ions, or cations, by losing electrons. As magnesium loses two electrons, it achieves the electronic configuration of neon, the preceding noble gas, resulting in a more stable electron arrangement. Consequently, the magnesium ion has a 2+ charge and is symbolized by Mg²⁺.

The formation of a magnesium ion involves oxidation, where the Mg atoms lose electrons and the electrons are accepted by another atom, such as oxygen, to form ionic compounds like magnesium oxide (MgO). In the case of magnesium and chlorine, when they form an ionic compound, magnesium provides two electrons, one to each chlorine atom, resulting in a Mg²⁺ ion and two Cl⁻ ions, making the ionic compound MgCl₂.

Answer:

It's slightly soluble in an aqueous solution of [tex]NaHCO_{3}[/tex], and almost insoluble in an aqueous solution of NaOH.

Explanation:

Sodium benzoate comes from benzoic acid, which is a weak acid. It means that in an aqueous solution benzoic acid does not ionize easily to form the ions [tex]H_{3}O^{+}[/tex] and [tex]C_{7}H_{5}O_{2} ^{-}[/tex]

It also implies, according to the Le Châtelier's principle, that the ion [tex]C_{7}H_{5}O_{2}^{-}[/tex] tends to form the acid [tex]C_{7}H_{6} O_{2}[/tex] more easily. It can be seen in the following equation:

[tex]C_{7}H_{6} O_{2}[/tex]  ⇔ [tex]C_{7}H_{5}O_{2}^{-}[/tex]  + [tex]H_{3}O^{+}[/tex]

In an aqueous solution, the equilibrium shifts to the left, thus letting water dissolve sodium benzoate.  But why? Because water in that case would produce enough [tex]H_{3}O^{+}[/tex] ions to facilitate the disolution of sodium benzoate. It's shown by its solubility in water at 15°C (62.78g/100mL, according to Wikipedia).

In contrast, the presence of NaOH or [tex]NaHCO_{3}[/tex], both chemical species producing the [tex]OH^{-}[/tex] ions in aqueous solution, would make the equilibrium shift to the right because it would be a higher need of [tex]H_{3}O^{+}[/tex] ions to offset the presence of [tex]OH^{-}[/tex].

However, the effect of NaOH is not the same due to [tex]NaHCO_{3}[/tex], because the first is a strong base and the other is a weak one. Thereby it is reasonable to think that solubility of sodium benzoate is greater in water than in [tex]NaHCO_{3}[/tex] and NaOH.

Solubility in water > solubility in  [tex]NaHCO_{3}[/tex]> solubility in NaOH.

Answer:

NF3

Explanation:

Test review said this was right

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.