Helium has the lowest boiling point of any substance, at 4.2 k. part a what is this temperature in âc?

The pressure of 0.840 atmospheres (atm) can be converted to millimeters of mercury (mm Hg) by using the conversion factor, 1 atm = 760 mm Hg. The result of this conversion is 638.4 mm Hg.

To convert the pressure from atmospheres (atm) to millimeters of mercury (mm Hg), we use the conversion factor of 1 atm = 760 mm Hg. This is a known standard in chemistry and physics. In this case, the conversion will be as follows:

0.840 atm x 760 mm Hg/1 atm = 638.4 mm Hg

Therefore, 0.840 atm is equivalent to 638.4 mm Hg.

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Answer: 2.01

Explanation:

[tex]C_6H_5COOH\rightleftharpoons C_6H_5COO^-+H^+[/tex]

initial : c         0             0

eqm: [tex]c(1-\alpha)[/tex]     [tex]c\alpha[/tex]      [tex]c\alpha[/tex]  

[tex]K_a=\frac{c\alpha\times c\alpha}{c(1-\alpha)}[/tex]

when [tex]\alpha[/tex] is very very small the, the expression will be,

[tex]k_a=\frac{c^2\alpha^2}{c}=c\alpha^2\\\\\alpha=\sqrt{\frac{k_a}{c}}[/tex]

And,

[tex][H^+]=c\alpha[/tex]

Thus the expression will be,

[tex][H^+]=\sqrt{k_a\times c}[/tex]

Now put all the given values in this expression, we get

[tex][H^+]=\sqrt{(6.4\times 10^{-5})\times 1.5}[/tex]

[tex][H^+]=9.7\times 10^{-3}M[/tex]

[tex]pH=-log[H^+][/tex]

[tex]pH=-log[9.7\times 10^{-3}]=2.01[/tex]

The total number of valence electrons in the Lewis structure of SEF2O is calculated by adding the valence electrons of each atom, giving us a total of 26 electrons.

The total number of valence electrons in the lewis structure of SEF2O can be calculated by adding up the valence electrons in each atom. Selenium (Se) has 6 valence electrons, each Fluorine (F) has 7 (so that's 14 for 2 Fluorines), and Oxygen (O) also has 6. So, the total number of valence electrons in SEF2O is 24+2 = 26.

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The total number of valence electrons in the Lewis structure of SeF2O is 26.

The Lewis structure of SeF2O consists of a central Se atom bonded to two F atoms and one O atom. To determine the total number of valence electrons, we need to add up the valence electrons of each particle. She has six valence electrons, each F atom has seven valence electrons, and O has six valence electrons. Therefore, the total number of valence electrons in the Lewis structure of SeF2O is 6 (Se) + 2(7) (F) + 6 (O) = 26.

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\Final answer:

A thermometer reading off by 1.5 °C would significantly impact the accuracy of experimental results by overestimating temperature values, potentially leading to incorrect conclusions in experiments that require precise temperature measurements.

Explanation:

If your thermometer is off by 1.5 °C, meaning it reads values that are 1.5 °C higher, this discrepancy would significantly affect the accuracy of your experimental results. This error would lead to consistently overestimated temperature readings, causing potential misinterpretations of the outcomes. For example, in experiments where precise temperature control and measurement are crucial, such as in testing product formulations or determining chemical reaction rates, an inaccurate thermometer could lead to incorrect assessments of these processes.

In laboratory settings, accurate temperature measurement is pivotal for ensuring the validity of experimental results. An error of 1.5 °C could not only impact the interpretation of a single experiment but also compound in experiments relying on precise temperature measurements to gauge reactions or behaviors, thereby misleading conclusions and potentially invalidating the experiment's purpose. Moreover, in cases like accelerated shelf life testing, a small temperature discrepancy could result in significant errors in the estimated product shelf life, underscoring the importance of using accurately calibrated equipment. Examples include estimating expiry dates based on the stability of products at increased temperatures where a minor measurement error could drastically skew the results. Hence, ensuring that laboratory equipment, especially thermometers, are correctly calibrated is essential for experimental integrity and accuracy.

In the Wittig reaction to synthesize 2-methyl-2-pentene, a phosphonium ylide and a carbonyl-containing molecule, such as an aldehyde or a ketone, are needed as reactants.

The reactants needed for the Wittig reaction to synthesize 2-methyl-2-pentene are a phosphonium ylide and a carbonyl-containing molecule. In this case, the carbonyl-containing molecule should be an aldehyde or a ketone. The phosphonium ylide is usually generated from a phosphine and an alkyl halide. For example, one possible combination of reactants could be triphenylphosphine and methyl iodide to form the phosphonium ylide, which can then react with an aldehyde or ketone to produce 2-methyl-2-pentene.

Answer: Option (a) is the correct answer.

Explanation:

Molar mass is defined as the mass in grams of one mole of a substance.

Mathematically,       Molar mass = [tex]\frac{mass in grams}{moles of substance}[/tex]

For example, molar mass of 1 mole of [tex]CH_{4}[/tex] molecule will be calculated as follows.

             Molar mass of [tex]CH_{4}[/tex] = [tex]mass of carbon atom + 4 \times mass of hydrogen atom[/tex]

                                 = [tex]12 + 4 \times 1[/tex]

                                 = 16 g

Therefore, 1 mole of [tex]CH_{4}[/tex] molecules has a molar mass of 16 g.

The concentration of the reactant PCl5 at equilibrium can be found using the given equilibrium concentrations of the products and the equilibrium constant by rearranging the equilibrium expression and substituting the known values.

To determine the concentration of the reactant PCl5 at equilibrium, we use the equilibrium constant Ke for the reaction, which is given as 0.0211. Let's set up the equilibrium expression for this decomposition reaction:

PCl5 → PCl3 + Cl2

The equilibrium constant expression is:

Ke = [PCl3][Cl2] / [PCl5]

We can rearrange this equation to solve for [PCl5]:

[PCl5] = [PCl3][Cl2] / Ke

We substitute the given concentrations [PCl3] = 0.180 M and [Cl2] = 0.250 M into the equation:

[PCl5] = (0.180 M)(0.250 M) / 0.0211

By calculating the above equation, we find the concentration of PCl5 at equilibrium.

Plants, the ocean, and soil serve as the primary natural carbon sinks. A portion of the carbon dioxide that plants absorb from the environment to use in photosynthesis is transferred to the soil as plants disintegrate and die.

Anything—natural or artificial—that gathers and stores a carbon-containing chemical compound over an extended period of time eliminates carbon dioxide from the atmosphere.

The ocean and vegetation are the two most significant carbon sinks on a global scale.

Typically, forests act as carbon sinks, absorbing more carbon than they emit. Through photosynthesis, they remove carbon from the atmosphere on a constant basis.

Another example of a carbon sink is the ocean, which takes in a lot of carbon dioxide from the atmosphere.

Therefore, the ocean, plants, and soil serve as the primary natural carbon sinks.

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Based on the Kf value and mass of the solvent naphthalene, the molar mass of the unknown compound is 154.58 g/mol.

The molar mass of a substance is the mass of one mole of that substance.

The molar mass of a substance can be calculated from the Kf value and mass of the solvent naphthalene as follows:

mass of naphthalene = 10 g or 0.01 kg.

mass of unknown compound = 1.00 g

ΔT of the solution = 4,47 °C.

Kf value of naphthalene = 6.91°C/m;

Molar mass of the unknown compound = 6.91°C/m · 1 g ÷ 0.01 kg × 4,47°C.

Molar mass of the unknown compound = 154.58 g/mol.

Therefore, the molar mass of the unknown compound is 154.58 g/mol.

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C. Lone elements and atoms in gases : 0

Elements in the free elemental have an oxidation number of zero

E. Elements in groups 1, 2, and 17 and polyatomic ions : Ionic charge

Group 1, 2, and 17 ions are formed by the alkali metals, alkaline metals and halogens respectively. Alkali metals, alkaline metals and halogens form +1, +2 and -1  ions respectively. Polyatiomic ions have -1, -2, -3 charges such as OH-, CO32-, PO43- respectively.

B. Hydrogen : +1, – 1 if bonded to a diatomic metal

H has an oxidation number of +1. H in metal hydrides such as NaH (sodium hydride) has an oxidation number of -1

A. Oxygen : Almost always –2  

O has an oxidation number of -2.

D. Elements with multiple oxidation states : Determined by other elements in the compound

V (vanadium) has different oxidation which depends on the compound in which V is found.

look at the thing attached

The energy due to the random motion of water molecules in a tank is thermal energy, which is related to the temperature of the water and can be transferred as heat.

The form of energy that water has due to the random motion of its molecules is called thermal energy. This energy arises from the kinetic energy that is present in the random microscopic motions of the water molecules. When these molecules move, collide, and bounce off each other, the average kinetic energy of these motions correlates with the temperature of the water. Furthermore, thermal energy can be transferred between objects or systems through processes like conduction, convection, and radiation, at which point it is commonly referred to as heat energy.

Answer : The mass of phosphoric acid produced is 6.89 grams.

Solution : Given,

Mass of [tex]P_4O_{10}[/tex] = 10.0 g

Molar mass of [tex]P_4O_{10}[/tex] = 284 g/mole

Molar mass of [tex]H_3PO_4[/tex] = 98.0 g/mole

First we have to calculate the moles of [tex]P_4O_{10}[/tex].

[tex]\text{ Moles of }P_4O_{10}=\frac{\text{ Mass of }P_4O_{10}}{\text{ Molar mass of }P_4O_{10}}=\frac{10.0g}{284g/mole}=0.0352moles[/tex]

Now we have to calculate the moles of [tex]MgO[/tex]

The balanced chemical reaction is,

[tex]P_4O_{10}+6H_2O\rightarrow 4H_3PO_4[/tex]

From the reaction, we conclude that

As, 1 mole of [tex]P_4O_{10}[/tex] react to give 2 mole of [tex]H_3PO_4[/tex]

So, 0.0352 moles of [tex]P_4O_{10}[/tex] react to give [tex]0.0352\times 2=0.0704[/tex] moles of [tex]H_3PO_4[/tex]

Now we have to calculate the mass of [tex]H_3PO_4[/tex]

[tex]\text{ Mass of }H_3PO_4=\text{ Moles of }H_3PO_4\times \text{ Molar mass of }H_3PO_4[/tex]

[tex]\text{ Mass of }H_3PO_4=(0.0704moles)\times (98.0g/mole)=6.89g[/tex]

Therefore, the mass of phosphoric acid produced is 6.89 grams.

Answer:

Displacement

Explanation:

To provide 0.252 moles of chloride ions, one would need 13.98428 grams of [tex]CaCl_2[/tex], using its molar mass of 110.98 g/mol and factoring in that each mole of [tex]CaCl_2[/tex] contains two moles of chloride ions.

To find out how many grams of calcium chloride ([tex]CaCl_2[/tex]) must be used to provide 0.252 moles of chloride ions, consider that each mole of [tex]CaCl_2[/tex] contains two moles of chloride ions. The molar mass of [tex]CaCl_2[/tex] is 110.98 g/mol.

To get the total number of moles of [tex]CaCl_2[/tex] needed, halve the number of chloride ions, which is [tex]\frac{0.252 moles}{2} = 0.126 moles[/tex] [tex]CaCl_2[/tex]. Then, use the molar mass to convert moles to grams:

0.126 moles [tex]CaCl_2[/tex] x 110.98 g/mol = 13.98428 grams of [tex]CaCl_2[/tex]

Therefore, you would need 13.98428 grams of [tex]CaCl_2[/tex] to provide 0.252 moles of chloride ions.

the answer is A and C

The balanced equation for the reverse reaction would be

[tex]2SO_3 (g) < ----- > 2SO_2 (g) + O_2 (g)[/tex]

They are reactions that proceed in opposing directions - that is, reactants to products and vice versa.

The equilibrium system between sulfur dioxide gas, oxygen gas, and sulfur trioxide gas can be represented as:

[tex]2SO_2 (g) + O_2 (g) < --- > 2SO_3 (g)[/tex]

Thus, the reverse reaction would be:

[tex]2SO_3 (g) < ----- > 2SO_2 (g) + O_2 (g)[/tex]

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The equilibrium system between sulfur dioxide gas, oxygen gas, and sulfur trioxide gas is given. Write the balanced chemical equation for the reverse reaction. Include physical states for all species.

Answer : The balanced chemical reaction will be,

[tex]2HNO_3(aq)+K_2SO_3(aq)\rightarrow K_2SO_4(aq)+H_2O(l)+2NO_2(g)[/tex]

Explanation :

Balanced chemical equation : It is defined as the number of atoms of individual elements present on reactant side must be equal to the product side.

When the nitric acid react with potassium sulfite to give potassium sulfate, water and nitrogen dioxide.

Thus, the balanced chemical reaction will be,

[tex]2HNO_3(aq)+K_2SO_3(aq)\rightarrow K_2SO_4(aq)+H_2O(l)+2NO_2(g)[/tex]

The balanced chemical equation is as follows:

[tex]\boxed{{\text{2HN}}{{\text{O}}_{\text{3}}}\left( {aq} \right) + {{\text{K}}_2}{\text{S}}{{\text{O}}_3}\left( {aq} \right) \to {{\text{K}}_2}{\text{S}}{{\text{O}}_4}\left( {aq} \right) + 2{\text{N}}{{\text{O}}_{\text{2}}}\left( g \right) + {{\text{H}}_{\text{2}}}{\text{O}}\left( l \right)}[/tex]

The phase of [tex]{{\mathbf{K}}_{\mathbf{2}}}{\mathbf{S}}{{\mathbf{O}}_{\mathbf{4}}}[/tex] is [tex]\boxed{{\mathbf{aqueous}}}[/tex], [tex]{\mathbf{N}}{{\mathbf{O}}_{\mathbf{2}}}[/tex] is [tex]\boxed{{\mathbf{gas}}}[/tex] and [tex]{{\mathbf{H}}_{\mathbf{2}}}{\mathbf{O}}[/tex] is [tex]\boxed{{\mathbf{liquid}}}[/tex].

Further Explanation:

The chemical reaction that contains equal number of atoms of the different elements in the reactant as well as in the product side is known as balanced chemical reaction. The chemical equation is required to be balanced to follow the Law of the conservation of mass.

The steps to balance a chemical reaction are as follows:  

Step 1: Complete the reaction and write the unbalanced symbol equation.

In the given reaction, [tex]{\text{HN}}{{\text{O}}_{\text{3}}}[/tex] reacts with [tex]{{\text{K}}_2}{\text{S}}{{\text{O}}_3}[/tex] to form [tex]{{\text{K}}_2}{\text{S}}{{\text{O}}_4}[/tex], [tex]{\text{N}}{{\text{O}}_{\text{2}}}[/tex] and [tex]{{\text{H}}_{\text{2}}}{\text{O}}[/tex]. The physical state of [tex]{{\text{K}}_2}{\text{S}}{{\text{O}}_4}[/tex] is aqueous, [tex]{\text{N}}{{\text{O}}_{\text{2}}}[/tex] is gas and [tex]{{\text{H}}_{\text{2}}}{\text{O}}[/tex] is liquid. The unbalanced chemical equation is as follows:

[tex]{\text{HN}}{{\text{O}}_{\text{3}}}\left( {aq} \right) + {{\text{K}}_2}{\text{S}}{{\text{O}}_3}\left( {aq} \right) \to {{\text{K}}_2}{\text{S}}{{\text{O}}_4}\left( {aq} \right) + {\text{N}}{{\text{O}}_{\text{2}}}\left( g \right) + {{\text{H}}_{\text{2}}}{\text{O}}\left( l \right)[/tex]

Step 2: Then we write the number of atoms of all the different elements that are present in a chemical reaction in the reactant side and product side separately.(Refer table in the attached image)

Number of hydrogen atoms is 1.

Number of nitrogen atoms is 1.

Number of oxygen atoms is 6.

Number of potassium atoms is 2.

Number of sulfur atoms is 1.

Number of hydrogen atoms is 1.

Number of nitrogen atoms is 1.

Number of oxygen atoms is 6.

Number of potassium atoms is 2.

Number of sulfur atoms is 1.

Step 3: Initially, we try to balance the number of other atoms of elements except for carbon, oxygen, and hydrogen by multiplying with some number on any side. The other elements except oxygen and hydrogen are balanced.

Step 4: After this we balance the number of atoms of oxygen followed by hydrogen atoms. To balance the number of atoms of oxygen and hydrogen, we have to multiply [tex]{\text{HN}}{{\text{O}}_{\text{3}}}[/tex] by 2, [tex]{\text{N}}{{\text{O}}_{\text{2}}}[/tex] by 2. The chemical equation is as follows:

[tex]{\text{2HN}}{{\text{O}}_{\text{3}}}\left( {aq} \right) + {{\text{K}}_2}{\text{S}}{{\text{O}}_3}\left( {aq} \right) \to {{\text{K}}_2}{\text{S}}{{\text{O}}_4}\left( {aq} \right) + 2{\text{N}}{{\text{O}}_{\text{2}}}\left( g \right) + {{\text{H}}_{\text{2}}}{\text{O}}\left( l \right)[/tex]

Step 5: Finally, we check the number of atoms of each element on both the sides. If the number is same then the chemical equation is balanced. The balanced chemical equation is as follows:

[tex]{\text{HN}}{{\text{O}}_{\text{3}}}\left( {aq} \right) + {{\text{K}}_2}{\text{S}}{{\text{O}}_3}\left( {aq} \right) \to {{\text{K}}_2}{\text{S}}{{\text{O}}_4}\left( {aq} \right) + {\text{N}}{{\text{O}}_{\text{2}}}\left( g \right) + {{\text{H}}_{\text{2}}}{\text{O}}\left( l \right)[/tex]

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Answer details:

Grade: High School

Subject: Chemistry

Chapter: Chemical reaction and equation

Keywords: Balancing, HNO3, K2SO4, K2SO3, NO2, H2O, phases, physical state, solid, liquid, gas, aqueous, law of conservation of mass.