During a chemical reaction, a fixed amount of Iron combines completely with a fixed amount of oxygen to form Iron oxide. Which statement best describes the mass of the iron odide that is
produced?
a)The mass is equal to the mass of the Iron minus the mass of the oxygen before reacting.
B)The mass is equal to the mass of the Iron plus the mass of the oxygen.
C)The mass is greater than the combined mass of both the Iron and the oxygen
D)The mass is less than the mass of the Iron but greater than the mass of the oxygen before reacting.

Answer:

In order to find the two statements, we must first define what the enthalpy of formation and the enthalpy of reaction mean.

Enthalpy of formation:

The change in enthalpy when one mole of substance is formed from its constituent elemetns at standard state.

Enthalpy of reaction:

The change in enthalpy when a reaction occurs and the reactants and products are in their standard states.

Now, we check the statements. The true ones are:

The Hrxn for C(s) + O₂(g) → CO₂(g) is the same as Hf for CO₂

This is true because the formation of carbon dioxide requires carbon and oxygen in their standard states.

The Hf for Br₂(l) is 0 kJ/mol by definition.

Because the bromine is present in its standard state, the enthalpy of formation is 0.

The Hrxn for the reaction 1.5H₂(g) + 0.5N₂(g) → NH₃(g) is the same as the Hf for NH₃(g)

The reactants and products are present in their standard state, and the reaction is the same as the one occurring during the formation of ammonia.

Answer:

the main use of coal in the United States is to generate electricity.

Coal is a combustible black or brownish-black sedimentary rock with a high amount of carbon and hydrocarbons

Coal is formed when dead plant matter decays into peat and is converted into coal by the heat and pressure of deep burial over millions of years.

A catalyst is a substance that speeds up a chemical reaction and is also consumed during the reaction.

A catalyst is a substance that increases the rate of a chemical reaction by providing an alternative reaction pathway with lower activation energy. It accomplishes this by facilitating the formation of intermediate species and reducing the energy barrier for the reaction to occur. The catalyst itself undergoes a reaction with the reactants, forming an intermediate complex, but it is regenerated and recovered in its original form at the end of the reaction.

The role of a catalyst can be explained through a simplified reaction mechanism. Consider a hypothetical reaction between reactants A and B to form product C. Without a catalyst, the reaction may proceed slowly due to a high activation energy. However, when a catalyst is introduced, it provides an alternative pathway with a lower activation energy.

The catalyst initially binds to the reactants, forming a catalyst-reactant complex. This complex undergoes rearrangements and reactions that lead to the formation of the product. At the end of the reaction, the catalyst is regenerated, allowing it to participate in subsequent reaction cycles.

The consumption of the catalyst occurs during the reaction, as it reacts with the reactants to form intermediates and ultimately the products. However, the catalyst is not permanently altered or consumed entirely. Instead, it is regenerated and can be reused in subsequent reactions.

In summary, a catalyst is a substance that accelerates a chemical reaction by providing an alternative reaction pathway with lower activation energy. It is consumed during the reaction as it reacts with the reactants to form intermediates and products. However, the catalyst is not permanently consumed and can be regenerated for reuse in subsequent reactions.

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To calculate the pH of the solution formed by adding 50.0 mL of 0.0200 M NaOH to 100.0 mL of 0.0100 M formic acid,

we first need to write the balanced equation for the reaction that occurs. The reaction between formic acid and NaOH is as follows: HCOOH + NaOH → NaCOOH + H2O,

From this equation, we can see that the acid and the base will react to form the salt NaCOOH and water. Now, we need to find the moles of formic acid and NaOH that are present in the solution.

Moles of formic acid = concentration x volume = 0.0100 M x 0.100 L = 0.00100 moles, Moles of NaOH = concentration x volume = 0.0200 M x 0.0500 L = 0.00100 moles, Since the moles of formic acid and NaOH are equal, they will react completely.

After the reaction occurs, the solution will contain the salt NaCOOH and water. Since NaCOOH is a salt of a weak acid, it will undergo hydrolysis in water, which means it will react with water to form an acidic solution. The hydrolysis reaction is as follows: NaCOOH + H2O → HCOOH + Na+ + OH-.

From this equation, we can see that the salt reacts with water to form formic acid, Na+ ions, and OH- ions. Now, we can write an expression for the equilibrium constant (Ka) for the hydrolysis reaction: Ka = [HCOOH][OH-] / [NaCOOH],

Since we know the value of Ka for formic acid (1.77 x 10^-4), we can use this equation to calculate the concentration of H+ ions in the solution,

which will give us the pH, [HCOOH] = [OH-] = x (since the solution is neutral, [H+] = [OH-]) , [NaCOOH] = 0.00100 moles / (0.100 L + 0.050 L) = 0.00667 M, Ka = [x][x] / 0.00667, 1.77 x 10^-4 = x^2 / 0.00667, x = 2.10 x 10^-4 M.

Therefore, the pH of the solution is calculated as follows: pH = -log[H+] = -log(2.10 x 10^-4) = 3.68, So the pH of the solution formed by adding 50.0 mL of 0.0200 M NaOH to 100.0 mL of 0.0100 M formic acid is 3.68.

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Answer:

Bison were saved through the combined efforts of conservationists, scientists, ranchers and ultimately the general public. As their comeback continues, I believe that they can teach us how to be better stewards of the land and provide a future for the Plains where ecosystems and human cultures thrive.

Explanation:

\(watch.some.anime\)

Answer:

Type of breath mint

Explanation:

The independent variable, in this case, would be the type of breath mint given to each study group.

An independent variable refers to a variable whose variation does not depend on another variable or factor. In research, the independent variable stands alone and the researcher can control or manipulate it in order to measure its effect on some other variables.

In the case of Mr. Krabs, the two types of breath mints administered to the two study groups represent the independent variable. Any differences in the experience of the two study groups can be attributed to the difference in the breath mint taken.

Answer:   17 (a) 360,000 ms         18 (a) 0.245 s

                     (b) 4.800 kg                   (b) 500 cm

                     (c) 560.0 dm                  (c) 68.00 m

                     (d) 72,000 mg                (d) 0.025 Mg

Explanation:

Use the following table.  Note the direction you are going to:

Right means move decimal to the right. Left means move decimal to the left.

               \(\boxed{\begin{array}{c|c|c|c|c|c|c|c|c|c}Mega&x&x&kilo&x&deka&unit&deci&centi&milli\\M\_\_&&&k\_\_&&dk\_\_&\_\_\_&d\_\_\)&c\_\_&m\_\_\end{array}}\)

**********************************************************************************************

17(a) 360 s to ms                                                        o       →         →        →o

                            \(\boxed{\begin{array}{c|c|c|c|c|c|c|c|c|c}Mega&x&x&kilo&x&deka&unit&deci&centi&milli\\M\_\_&&&k\_\_&&dk\_\_&\_\_\_&d\_\_\)&c\_\_&m\_\_\end{array}}\)

Move the decimal 3 places to the right   -->   360_ _ _.

Fill in the blanks with zeroes   --> 360,000

  (b) 4800 g to kg                            o←    ←     ←         o

                             \(\boxed{\begin{array}{c|c|c|c|c|c|c|c|c|c}Mega&x&x&kilo&x&deka&unit&deci&centi&milli\\M\_\_&&&k\_\_&&dk\_\_&\_\_\_&d\_\_\)&c\_\_&m\_\_\end{array}}\)

Move the decimal 3 places to the left   --> 4.8 0 0

 (c) 5600 dm to m                                                       o←     o

                             \(\boxed{\begin{array}{c|c|c|c|c|c|c|c|c|c}Mega&x&x&kilo&x&deka&unit&deci&centi&milli\\M\_\_&&&k\_\_&&dk\_\_&\_\_\_&d\_\_\)&c\_\_&m\_\_\end{array}}\)

Move the decimal 1 place to the left   --> 560. 0

 (d)  72 g to mg                                                         o         →        →        →o

                            \(\boxed{\begin{array}{c|c|c|c|c|c|c|c|c|c}Mega&x&x&kilo&x&deka&unit&deci&centi&milli\\M\_\_&&&k\_\_&&dk\_\_&\_\_\_&d\_\_\)&c\_\_&m\_\_\end{array}}\)

Move the decimal 3 places to the right   --> 72 _ _ _.

Fill in the blanks with zeroes   -->     72,000

***********************************************************************************************

18 (a) 245 ms to s                                                       o←       ←       ←        o

                             \(\boxed{\begin{array}{c|c|c|c|c|c|c|c|c|c}Mega&x&x&kilo&x&deka&unit&deci&centi&milli\\M\_\_&&&k\_\_&&dk\_\_&\_\_\_&d\_\_\)&c\_\_&m\_\_\end{array}}\)

Move the decimal 3 places to the left -->   . 2 4 5

     (b) 5 m to cm                                                        o        →        →o

                             \(\boxed{\begin{array}{c|c|c|c|c|c|c|c|c|c}Mega&x&x&kilo&x&deka&unit&deci&centi&milli\\M\_\_&&&k\_\_&&dk\_\_&\_\_\_&d\_\_\)&c\_\_&m\_\_\end{array}}\)

Move the decimal 2 places to the right   -->   5 _ _.

Fill in the blanks with zeroes   -->    500

      (c) 6800 cm to m                                                 o←      ←        o

                             \(\boxed{\begin{array}{c|c|c|c|c|c|c|c|c|c}Mega&x&x&kilo&x&deka&unit&deci&centi&milli\\M\_\_&&&k\_\_&&dk\_\_&\_\_\_&d\_\_\)&c\_\_&m\_\_\end{array}}\)

Move the decimal 2 places to the left   -->   68. 0 0

    (d)  25 kg to Mg    o←    ←    ←    o

                            \(\boxed{\begin{array}{c|c|c|c|c|c|c|c|c|c}Mega&x&x&kilo&x&deka&unit&deci&centi&milli\\M\_\_&&&k\_\_&&dk\_\_&\_\_\_&d\_\_\)&c\_\_&m\_\_\end{array}}\)

Move the decimal 3 places to the left -->   . _ 25

Fill in the blanks with zeroes  -->   .025

Acetylsalicylic acid, is the active ingredient in aspirin. 68 is the number of valence electrons are present in the lewis structure for this molecule.

A valence electron is an electron that is part of an atom's outer shell in chemistry and physics. If the outer shell is open, the valence electron can take part in the formation of a chemical bond. Each atom in the bond contributes one valence electron, forming a shared pair in a single covalent bond. The chemical properties of an element, such as its valence—whether it can connect with other elements and, if so, how quickly and with how many—may be affected by the existence of valence electrons.

C =4 valence electrons.

H = 1 valence electron.

O=6 valence electrons.

9 C x 4 valence electrons = 36 valence electrons

8 H x 1 valence electron = 8 valence electrons

4 O x 6 valence electrons = 24 valence electrons

Total valence electrons = 36 + 8 + 24 = 68

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A business can incorporate all of these options to align with green design principles.

Employees can produce fuel, heat, or power from renewable sources for use inside their workplace. Wind, biomass, geothermal, solar, ocean, hydropower, landfill gas, and municipal solid waste are a few examples of these sources.

The practise of taking into account and limiting environmental effect while producing goods is known as sustainable design or green design. Green design principles provide businesses a variety of opportunities to cut waste, repurpose resources, and recycle goods and materials.

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Answer:

Lithium, oxygen, and hydrogen.

What Is Chromium: Chemical Formula Of Sodium Bicarbonate

Uses Of Cotton: Acetone Formula

Solution Examples: Amino Acid Formula

Explanation:

HOPE ITS HELP;)

Answer:

False

Explanation:

Evaporation occurs when molecules in a liquid gain enough energy that they overcome attractions from other molecules and break away to become a gas. Adding energy increases the rate of evaporation.

Hope this helped!

Answer:

Five significant figures

Explanation:

You have to change the number to standard form

340500 = 3.405×10**5

** means raise to power

10**5

Where five represents the number of significant figures.

Answer:

4!

Explanation:

High quality charcoal that is lightweight and easily broken is made from hardwoods such as oak, maple, and hickory.

Charcoal is a porous, black, carbon-rich material that is produced by heating organic matter (such as wood or coconut shells) in the absence of air. The quality of charcoal can vary depending on the type of organic matter used, as well as the production method.

High quality charcoal that is lightweight and easily broken is typically made from hardwoods such as oak, maple, and hickory. These woods have a high density and a low moisture content, which makes them ideal for producing charcoal with a high carbon content and low ash content. In addition, the heating process used to produce this type of charcoal is typically done at high temperatures for a short period of time, which helps to remove impurities and create a more porous and lightweight material.

Overall, the type of organic matter used and the production method are important factors in determining the quality of charcoal, with hardwoods being a common choice for producing high quality charcoal that is lightweight and easily broken.

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Answer:

4.70 grams of NH4Cl is needed to prepare 350 mL of a 0.25 M ammonium chloride solution.

We need approximately 4.68 grams of NH4Cl to prepare a 0.25 M ammonium chloride solution with a volume of 350 mL.

To determine the mass of NH4Cl needed to prepare the solution, we us use the formula:

m=M x V x MM ... (i)

where,

m= mass in grams

M=molarity of solution

MM= molar mass of compound

V= volume in litres

The number of moles of NH4Cl needed can be calculated using:

  Moles = Molarity x Volume ...(ii)

  Moles = 0.25 mol/L x 0.350 L

  Moles = 0.0875 mol

Hence we can replace M x V with number of moles in equation i.

The molar mass of NH4Cl is :

  Molar mass of NH4Cl = (1 x 14.01 g/mol) + (4 x 1.01 g/mol) + (1 x 35.45 g/mol)

  Molar mass of NH4Cl = 53.49 g/mol

We have all the variables

Putting them in equation i.

Hence,

  Mass (g) = Moles x Molar mass

  Mass (g) = 0.0875 mol x 53.49 g/mol

  Mass (g) = 4.68 g

Therefore, you would need approximately 4.68 grams of NH4Cl to prepare a 0.25 M ammonium chloride solution with a volume of 350 mL.

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Answer:

Nucleus, chromosome, DNA, gene

Explanation:

A gene is a part of DNA.

chromosome is made out of DNA

Chromosomes are contained inside a nucleus

1) The dream of Mendeleev concerned the arrangement of the elements by mass

2) Periodicity is the changing properties of the elements

3)

Antoine Lavoisier - Arranged the elements by their properties

Johann Döbereiner - Arranged the elements into triads

John Newlands - Arranges the elements according to the order of increasing atomic mass

We define the periodic table as the arrangement of the elements in order of increasing atomic numbers. We know can see that several attempts have been made at the systematization of the elements and the approaches to the problem have taken different dimensions. In a dream, Mendeleev saw the elements line up in order of atomic masses and there was a visible pattern.

The term periodicity has to do with the regular repeating property of the elements and this can be seen when we follow the properties of the elements as they change down the group and across the period.

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First, we must know Avogadro's number:

1 mol of any substance = 6.02x10^23 formula units (ions, atoms, molecules, etc)

Also, we can say this:

1 mol of Li2O = its mass expressed in grams

(from Li2O molar mass = 30 g/mol approx.)

Now,

1 mol Li2O = 30 g = 6.02x10^23 molecules Li2O

30 g Li2O ----------- 6.02x10^23 molecules Li2O

x ----------- 2.8x10^24 molecules Li2O

x = 140 g approximately

Answer: 140 g

Eugenol can also be isolated from cloves using extraction with carbon dioxide:

Distillation: High purity, simplicity; challenges with temperature and separation efficiency.

Carbon dioxide extraction: Mild extraction, selectivity; higher equipment cost and complexity. Choice depends on purity and heat sensitivity.

1. High Purity: Distillation is a well-established technique for separating compounds based on their boiling points. It allows for the isolation of eugenol with high purity, as it vaporizes at a specific temperature and can be condensed back into a liquid.

2. Simple Process: Distillation is a relatively straightforward process that requires basic equipment and can be easily scaled up for industrial production. It is a commonly used method in the chemical industry, making it accessible and widely applicable.

1. Temperature Sensitivity: Distillation relies on heating the mixture to vaporize the desired compound. However, eugenol is sensitive to high temperatures and can be easily degraded or oxidized during the distillation process, leading to a loss of yield or degradation of the compound.

2. Separation Efficiency: Distillation is effective for separating compounds with significantly different boiling points. However, if there are other compounds present in the cloves extract with boiling points close to eugenol, achieving a complete separation becomes challenging. This can result in impurities in the final product.

1. Mild Extraction Conditions: Carbon dioxide extraction, also known as supercritical fluid extraction, can be performed at relatively low temperatures and pressures compared to distillation. This gentle extraction process helps preserve the integrity and quality of heat-sensitive compounds like eugenol.

2. Selectivity: Carbon dioxide extraction allows for selective extraction of specific compounds. By adjusting the temperature and pressure, it is possible to optimize the extraction of eugenol while minimizing the extraction of unwanted compounds from the cloves. This can result in a higher purity of eugenol in the extracted product.

1. Equipment and Cost: Carbon dioxide extraction requires specialized equipment capable of maintaining specific temperature and pressure conditions. This can make the setup more expensive compared to distillation. Additionally, the extraction process may take longer, resulting in increased production time and cost.

2. Complex Process: Carbon dioxide extraction is a more complex process compared to distillation. It involves handling high-pressure systems and requires a good understanding of the extraction parameters to achieve optimal results. This complexity may require more expertise and training to operate effectively.

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Answer:

solid: Relatively rigid, definite volume and shape. In a solid, the atoms and molecules are closely bonded that they vibrate in place but don't move around. liquids: Definite volume but able to change shape by flowing. In a liquid, the atoms and molecules are loosely bonded.

Explanation:

I hope this helps! :) if it does could you please mark me brainliest?

The reaction rate order for sn1 reaction rate will be CH3F < CH3Cl < CH3I. The reason for this is that the halide with the weaker nucleophile will have a higher sn1 reaction rate.

The nucleophile is a key factor in determining the rate of an Sn1 reaction. In general, the stronger the nucleophile, the faster the reaction will be. This is because the stronger nucleophile will be able to break the bond between the alkyl halide and the nucleophilic carbon more easily. For this reason, the order of increasing Sn1 reaction rate will be CH3F < CH3Cl < CH3I.

Complete Question:

List the following alkyl halides in order of increasing sn1 reaction rate. what will be the reaction rate order for sn1 reaction rate? provide your reasoning.

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Answer:

ФОТОГРОФИРУЙ

ИЛИ НАПИШИ

В КОМЕНТЫ

are there any answer choices?

Answer:

uno

Explanation:

uno uno unooo no no Bruno capaso

The following statements on HPLC modes are true is more polar compounds elute first in normal-phase HPLC (Option E).

The liquid chromatography (HPLC) is a technique in analytical chemistry employed for the separation, identification, and quantification of elements. It is considered a highly sensitive method, and it works by separating the components in a mixture with the assistance of a solvent under high pressure.

There are two modes of HPLC: Reversed-Phase HPLC (RP-HPLC) and Normal-Phase HPLC (NP-HPLC). In RP-HPLC, a nonpolar stationary phase, such as C18, is used, and polar solvents, such as water, are used as mobile phases. Polar stationary phases, such as silica gel, are used in NP-HPLC, while nonpolar solvents, such as hexane, are used as mobile phases.

More polar compounds have a greater affinity for the polar stationary phase than less polar compounds, which have a higher affinity for the nonpolar mobile phase in NP-HPLC. As a result, less polar compounds elute first in normal-phase HPLC.

Thus, the correct option is E.

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The answer is the phosphate concentration of \(8.40\times10^{-6}M\)

Calcium phosphate \($\left(\mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}\right)$\) is dissociate to form

calciumion \($\left(\mathrm{Ca}^{2+}\right)$\) and phosphate ion \($\left(\mathrm{PO}_{4}^{3-}\right)$\).

\($\mathrm{Ca}_{2}\left(\mathrm{PO}_{4}\right)_{2}(\mathrm{~s}) \longrightarrow 3 \mathrm{Ca}^{2+}(\mathrm{aq})+2 \mathrm{PO}_{4}^{3-}(\mathrm{aq})$\)

Soluability product expression of \($\mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}$\) is,

\($K_{s p}=\left[\mathrm{Ca}^{2+}\right]^{3} \times\left[\mathrm{PO}_{4}^{3-}\right]^{2} \longrightarrow (1)\)

given that, somability product \($\left(k_{s p}\right)=8.6 \times 10^{-19}$\)

concentration of \(\mathrm{ca}^{2+}$ ion $=0.0023 \mathrm{M}$\)

putting the value in equation (1) we get,

\($8.6 \times 10^{-19}=(0.0023)^{3} \times\left[\mathrm{PO}_{4}^{3-}\right]^{2}$\)

or, \($\left[\mathrm{PO}_{4}^{3-}\right]^{2}=\frac{8.6 \times 10^{-19}}{(0.0023)^{3}}=7.06 \times 10^{-11}$\)

or, \($\left[\mathrm{PO}_{4}^{3-}\right]=8.40 \times 10^{-6} \mathrm{M}$\)

So the phosphate concentration \($=8.40 \times 10^{-6} \mathrm{M}$\)

What is phosphate concentration ?

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The correct answer is e. The net reaction that occurs in the cell involves the oxidation of copper (Cu) to form copper ions (Cu+), and the reduction of cadmium ions (Cd2+) to form cadmium metal (Cd). This is represented by the equation: 2Cu+ Cd2+ > 2Cu* + Cd.

In this reaction, Cu+ is the oxidizing agent, as it gains electrons and becomes reduced, while Cd2+ is the reducing agent, as it loses electrons and becomes oxidized. This reaction can be used to generate electrical energy in a cell, such as a battery. Overall, the net reaction involves the transfer of electrons from one species to another, resulting in the formation of a metal and an ion.

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Answer:

b

Explanation:

the ocular lens or eyepiece lens ...so its b

Answer:

no of moles = (mass) ÷ molar mass

you get the molar mass from the periodic table

n = 20.0g ÷ ( 149.09 g/mol )

= 0.134 mol

number of formula units = number of moles × (6.022×10^23)

= 8.07×10^22 units

number of hydrogen atoms in (NH4)3 PO3 = 12 × number of formula units

= 9.68×10^23 hydrogen atoms