Calculate the standard enthalpy change for the reaction

2A+B⇌2C+2D 

Use the following data:

Substance ΔH∘f
( kJ/mol)
A -231
B -409
C 177
D -515
Express your answer to three significant figures and include the appropriate units.

0.025 M HCl solution has a pH of −log(0. 025)=1. 60.

The acid dissociation constant (Ka) must be used to determine [H+] even if the pH equation remains the same (pH = -log[H+]). The concentration of hydrogen ions can be calculated using one of two approaches. The quadratic equation is one. The other makes the assumption that the weak acid hardly separates from water and approximates the pH.

The pH of a 0.025 M HCl solution is 1.60 log (0. 025).

Acid dissociation percentage is calculated by multiplying [H+] [HA] by 100.

In most cases, the dissociation constant is computed by dividing the concentration of the solution by the concentration of each dissociated ion. For an all-purpose acid-base reaction, such as: HA + H 2 O H 3 O + + A

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To solve such this we must know the concept of synthesis reaction. Therefore, the correct option is option A that is It represents a synthesis reaction because two reactants form one product.

Chemical reaction is a process in which two or more than two molecules collide in right orientation and energy to form a new chemical compound. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, double displacement reaction.

It represents a synthesis reaction because two reactants form one product. This statements best explains the type of chemical reaction represented by Larry's picture. synthesis reaction is the one where two reactant combine to form one product.

Therefore, the correct option is option A.

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Answer: 0.27 M

Explanation:

c1V1=c2V2

c1=6.0 M;V1=45.0 mL

c2=?;V2=1.0 L=1000 mL

c2=(c1V1)/V2

c2=((6.0)(45.0))/1000

c2=0.27 M

The conjugate acid-base pairs are ( HF, F⁻) and ( H₂O, H₃O⁺ )

A conjugate acid-base pair, as defined by Bronsted-Lowry, consists of two compounds that are distinct only in that they contain a proton (H⁺). The addition of a proton to a base results in the formation of a conjugate acid, while the removal of a proton from an acid result in the formation of a conjugate base.

The reaction becomes:

HF + H₂O → H₃O⁺ + F⁻

The conjugate acid-base pairs are ( HF, F⁻) and ( H₂O, H₃O⁺ )

Here,

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Taking into account the definition of percent composition, the percent composition of O in this sample is 39.52%.

The percent composition is a measure of the amount of mass that an element occupies in a compound and indicates the percentage by mass of each element that is part of a compound.

The percent composition is calculated as the mass of the solute divided by the mass of the solution, the result of which is multiplied by 100 to give a percentage:

percent composition= (mass of solute÷ mass of solution)× 100%

In this case, you know that a 50 g sample contains 14.19 g of Na, 19.76 g of O, and 16.05 g of Cr.

Dividing the amount of mass of O present by the mass of the sample and multiplying it by 100, the percent composition of O can be obtained:

Percent composition of O= (19.76 g÷ 50 g)× 100%

Percent composition of O= 39.52%

Finally, the percent composition of O in the compound is 39.52%.

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To solve this type of question we must know the expression for rate law for first order kinetics. Therefore, the rate constant at 273 K is 8.11 x 10⁻⁷s⁻¹.

There are two kinds of rate law in chemical kinetics one is differential rate law and other is integrated rate law.

ln(k₁/k₂ )=-Ea /R(1/T₁-1/T₂)

Ea=102 kJ/mol

k₁=1.35 × 10⁻⁴ s⁻¹

T₁=306 K

k₂=?

T₂= 273 K

R=8.314J/kmol

substituting all the given values in the above equation, we get

ln(1.35 × 10⁻⁴ /k₂ )=-1.35 × 10⁻⁴ /8.314(1/306-1/273)

K[tex]_2[/tex]=8.11 x 10⁻⁷s⁻¹

Therefore, the rate constant at 273 K is 8.11 x 10⁻⁷s⁻¹.

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Answer:

minerals

Explanation:

its litteraly non of the others

Answer:

A. Converts sugars into acids, gases or alcohol.

The resistance of the light bulb is 266.7Ω

When an electric current flows through a bulb or any conductor, the conductor offers some obstruction to the current and this obstruction is known as electrical resistance and is denoted by R. Every material has an electrical resistance and this is the reason why conductors give out heat when current passes through it. The unit of electrical resistance is ohms.

According to Ohm’s law, there is a relation between the current flowing through a conductor and the potential difference across it. It is given by,

V ∝ I V = IR

Where,

V is the potential difference measured across the conductor (in volts)

I is the current through the conductor (in amperes)

R is the constant of proportionality called resistance (in ohms)

Therefore, R = V/I

To find the Resistance;

R = V/I

where V = 120V

I = 0.45A

R = 120/0.45

R = 266.7Ω

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The musculoskeletal and integumentary systems work together in the human body to ensure that the body is protected from injury and cold.

The musculoskeletal system and integumentary system also work together in the human body to ensure that the weight of the body is effectively supported and to ensure movement of the body.

The musculoskeletal system of the body refers to the systems of the organs and tissues that give shape and structure to the body as well as ensure the movement of body parts.

The musculoskeletal system includes all the bones and muscles of the body.

The Integumentary System of the body is the system of organs, tissues, and cells that provides a covering to the body acting as a physical barrier that protects the body from infection, injury, and sunlight.

The Integumentary System of the body includes the skin, nails, hair, and the glands and nerves on your skin.

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The percent error of the result is very high. Which means the accuracy of the data is very low. But the range of values are close to 0.1. Thus, the data is precise but not accurate.

Accuracy of a result is its closeness of the calculated or experimental value to the true value or accepted value. Thus, it tells that, how much the data can be taken to be true.

Precision is the closeness between the results of the same experiment. An experiment if  done in several trails, where the result of each time are closer then it is said to be precise.

The given results has 12% error thus, it is far from the true value indicates that the data is not accurate. But the data points comes in a close range of values. Thus. the data is precise.

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Answer:

17 reactions

Explanation:

Taking into account the definition of sensible heat, the mass of copper in the sample is 277.06 grams.

When heat added or removed from a substance causes a temperature change in it without affecting its molecular structure (physical state), it is called sensible heat.

The expression that allows to calculate heat exchanges is:

Q = c× m× ΔT

where:

In this case, you know:

Replacing in the definition of sensible heat:

1600 J = 0.385 J/gC× m× 15 C

Solving:

1600 J = 5.775 J/g× m

1600 J÷ 5.775 J/g= m

277.06 g= m

Finally, the mass of copper in this case is 277.06 grams.

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Answer:

baking soda

Explanation:

There are various uses of bases: 1: Bases are used to control the acidity which take place in your stomach. 2: Bases are used in homes, like baking soda. :)

Answer:the answer to your question is baking soda.

As carbon always need four bound to stain stability which means it need eight electron in its valance cell.

The valence shell electrons is defined as the electrons in which a molecule are depicted in an extremely easy manner by a Lewis Structure. It is used to signify how the electrons in a molecule are positioned near the particular atoms. Electrons are denoted as "dots" or, in the case of a bond, as a line connecting with the two atoms.

If an atom, molecule, or ion has the average amount of bonds for that species, it has a formal charge of zero. The more stable Lewis structure is the one that has the highest charges on the atoms closest to zero. The aforementioned SO Lewis structure is as follows.

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A balanced chemical equation for the standard formation reaction of solid vanadium ( V ) oxide is 4VO₂ + O₂ ⇒ 2V₂O₅.

The inorganic chemical with the formula V2O5 is called vanadium(V) oxide. Commonly referred to as vanadium pentoxide, it is a deep orange solid that is brown or yellow when freshly precipitated from aqueous solution. It is both an oxidizing agent and an amphoteric oxide due to its high oxidation state.

A lot of industrial chemical reactions use vanadium oxide as a catalyst. The following applications also employ it: in the production of laser crystals and other optical applications. in the use of nanowire and nanofiber.

Thus, A balanced chemical equation for the standard formation reaction of solid vanadium ( V ) oxide is 4VO₂ + O₂ ⇒ 2V₂O₅.

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Answer:

Answer: e) A pH = 10.00 buffer solution

The scientist most likely answer by examining this fossil is the environment like in the area when the plant was alive which is therefore denoted as option D.

This is referred to as the remains of plants and animals which have been preserved in the earth crust.

Fossils are very important as it gives an insight into how life and humans came from and also the various ways in which the Earth and our environment has changed over the years through the presence and absence of various structures which is therefore the reason why option D was chosen as the correct choice.

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Answer:

Moles of NaOH = 0.5 M x 0.0076 L = 0.0038 mol

Moles of HA = 0.0038 mol

Concentration of HA = 0.0038 mol/0.01 L = 0.38 M

Answer:

Answer:

It is not correct

Explanation:

there is no Na2OH because OH is -1 and Na is +1

there is no H30 because oxygen can only have 2 bonds with hydrogen

the balanced equation is:

H2SO4 + 2NaOH => Na2SO4 + 2H20

Answer:  You would put one dot for each valence electron the element has so Hydrogen would be 1 He:2 Li:1 Be:2  B:3 C:4 N:5 O:6 F:7 Ne:10

Na:1 Mg:2 Al:3 Si:4

Explanation:

This is also called the lewis structure you will draw the dots around the letter. 2 on each side and there are 4 sides per letter

Lewis diagram, or Lewis structure, is a diagram that employs dots to represent the valence electrons of such an atom. Hydrogen has 1 valence electron.

A Lewis electron dot diagram, also known as an electron dot diagram, Lewis diagram, or Lewis structure, is a diagram that employs dots to represent the valence electrons of such an atom. The amount of dots corresponds to the atom's valence electron count.

Chemical bonds are virtually often created by interactions between atoms' valence electrons. A straightforward technique to depict those valence electrons might be helpful to improve our comprehension of how they interact.

Element                         number of electron

   H                                    1

   He                                   2

  Li                                     1

  Be                                   2

Therefore, in above given way number of valence electron can be shown.              

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A) The volume of 75 ml of 17 M solutions of acetic acid is required.

B)  The volume of 10 ml of 17 M solution of acetic acid is required.

After dilution, the dilution factor indicates how much of the original stock solution remains in the whole solution. The dilution factor is usually expressed as a ratio, although it can also be represented as an exponent.

The stock solution to the part of the dilutant added or the part of the stock solution to the part of the total solution can be described by the dilution factor, which can be represented as a ratio or an exponent.

The mathematical formula can be used to calculate the volume of stock solution as:

[tex]{\displaystyle \frac{V_{diluted}}{V_{stock}} = Dilution \; \;factor[/tex]

Given the volume of the diluted solution = 750 ml

The dilution factor = 10

From the above formula: 750/V (stock) = 10

V (stock) = 750/10

V (stock) = 75 ml

Given the volume of the diluted solution = 200 ml

The dilution factor = 20

From the above formula: 200/V (stock) = 20

V (stock) = 200/20

V (stock) = 10 ml

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Answer:

A tennis ball traveling at 10 meters per second.

Explanation:

This is due to the fact that there is more speed- so more moentum.

The following in the scientific method after the hypothesis is hypothesis testing which is carried out by experimental and or observation procedures.

The process of the scientific method involves a series of well-detailed steps to collect scientific empirical evidence, which is characterized to have data that can be tested by experimentation or observation.

The process of scientific method starts with the observation of the natural world, which leads us to raise a question that must be answered by a plausible explanation called a hypothesis. Finally, we can prove those hypotheses by using experiments to collect info and results.

Therefore, with this data, we can see that the process of the scientific method involve the application of experimentation and or observational procedures to test hypothesis and this confirm or reject their assumptions.

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Answer:

A polyatomic ion, also known as a molecular ion, is a covalent bonded set of two or more atoms, or of a metal complex, that can be considered to behave as a single unit and that has a net charge that is not zero. They form a stable grouping which carries a charge (positive or negative). The group of atoms as a whole acts as a charged species in forming an ionic compound with an oppositely charged ion.

Answer:

Equilibrium is established for the reaction 2 X(s) + Y(g) ⇌ 2 Z(g) at 500K, the Kc value is 100.

Determine the concentration of Z in equilibrium with o.2 mol of X and 0.50 M of Y at 500K

answer

At equilibrium, the concentrations of X and Y will remain constant, so we can use the Kc expression to solve for the concentration of Z:

Kc = [Z]^2 / [X]^2

[Z]^2 = Kc * [X]^2

[Z]^2 = 100 * (0.2)^2

[Z] = √(100 * 0.04)

[Z] = 0.2 M

C-O

Explanation:

Thus, the largest difference of

electronegativity is between carbon and oxygen. Therefore, the C −O bond is most polar.