The standard enthalpy change for the reaction 2A + B ⇌ 2C + 2D is 195 kJ/mol.
What is the enthalpy of a reaction?The enthalpy of a reaction is a measure of the heat changes that occur when reactants form a product in a given reaction.
The enthalpy change of a reaction can be calculated using the formula given below:
Enthalpy of reaction = sum of enthalpies of the products - sum of enthalpies of the reactants
Considering the given reaction: 2A + B ⇌ 2C + 2D
Enthalpy of reaction = (2 * C + 2 * D) - (2 * A + B)
Enthalpy of reaction = {[2 * 177 + 2 * (-515)] - [2 * (-231) + (-409)]}
Enthalpy of reaction = 195 kJ/mol
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Write the acid-base reaction that occurs between HF and water . Identify the acid , base , conjugate acid, and conjugate base
The conjugate acid-base pairs are ( HF, F⁻) and ( H₂O, H₃O⁺ )
What is conjugate acid base pair?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,
F⁻ to HF is conjugate acid.H₃O⁺ to H₂O is conjugate base.HF to F⁻ is conjugate base.H₂O to H₃O⁺ is conjugate acid.To know more about conjugate acid-base refer to:
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How does Musculo-Skeletal System and Integumentary System work together in the human body
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.
What are the Musculo-Skeletal System and Integumentary System 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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What are some examples of non bases
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.
A 50.0 g sample of an unknown
compound contains 14.19 g Na,
19.76 g O, and 16.05 g Cr. What is
the percent composition of O in the
compound?
[?]% O
Round your answer to the hundredths place.
Taking into account the definition of percent composition, the percent composition of O in this sample is 39.52%.
Definition of percent compositionThe 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%
Percent composition of OIn 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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5. Practice: Turn off Show electron dot diagram. Use the Gizmo to create a neutral atom of
each of the following elements. Draw an electron dot diagram for each. When you are
finished, turn on Show electron dot diagram and check your answers.
H
He
Li
Be
B
C
N
O
F
Me
Na
Mg
Al
Si
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.
What is electron dot diagram?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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the scientist most likely answer by examining this fossil?
average monthly rainfall in the area?
=r was absorbed by the roots of the plant?
en was in the atmosphere surrounding the plant?
wironment like in the area when the plant was alive? ASAP IN 5-10 minutes
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.
What is a Fossil?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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6.
(04.01 MC)
Sulfuric acid, H2SO4, can be neutralized by sodium hydroxide, NaOH. The unbalanced equation is:
H2SO4(aq) + NaOH(aq) → Na2SO4(aq) + H2O(l)
A student who was asked to balance the reaction wrote the following:
H2SO4(aq) + Na2OH(aq) →Na2SO4(aq) + H3O(l)
Is this correct? Explain why or why not using what you know about the law of conservation of mass and chemical changes. If necessary, provide the correct balanced equation. (5 points)
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
Write a balanced chemical equation for the standard formation reaction of solid vanadium(V) oxide?
A balanced chemical equation for the standard formation reaction of solid vanadium ( V ) oxide is 4VO₂ + O₂ ⇒ 2V₂O₅.
What is vanadium oxide ?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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what is the pH of a 0.0250 M solution of an acid HY that is 0.038% dissociated?
0.025 M HCl solution has a pH of −log(0. 025)=1. 60.
How do you calculate pH from dissociation?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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Larry made this picture to represent a chemical reaction:
Which of the following statements best explains the type of chemical reaction represented by Larry's picture?
a
It represents a synthesis reaction because two reactants form one product.
b
It represents a synthesis reaction because the total mass of the product is less than the mass of the reactants.
c
It represents a decomposition reaction because one reactant breaks apart and forms two products.
d
It represents a decomposition reaction because the same atoms are present in the reactants and products.
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.
What is chemical reaction?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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The activation energy for a particular reaction is 102 kJ/mol. If the rate constant is 1.35 × 10⁻⁴ s⁻¹ at 306 K, what is the rate constant at 273 K?
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.
What is the expression for rate law for first order kinetics?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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Fermentation is the name of a chemical change that_________.
A. Converts sugars into acids, gases or alcohol.
B. Turns leaves various colors in the Autumn.
C. Converts yeast to a gas.
Answer:
A. Converts sugars into acids, gases or alcohol.
- Carver hoped that farmers would plant
Although Carver had many talents,
crops.
was his specialty.
Which of the following explains why saltwater is considered a mixture?
It is composed of two or more substances and has new chemical properties.
O It is composed of one element
O It is composed of two or more substances that retain their own chemical properties.
O
It is composed of one compound
Answer:
the answer is the option AEquilibrium 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:
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
How would you prepare 750 mL of a 10 fold dilution of a 17 M solution of acetic acid? How would you prepare 200 mL of a 20 fold dilution of a 17 M solution of acetic acid?
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.
What is the dilution factor?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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There is a current of 0.45 A through a lightbulb in a 120 V circuit. What is the resistance of this lightbulb?
The resistance of the light bulb is 266.7Ω
What is resistance?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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Joseph has hypothesized that sound travels in waves. If he were following the scientific method, what should he do next?
The following in the scientific method after the hypothesis is hypothesis testing which is carried out by experimental and or observation procedures.
What is the process of the scientific method?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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The percent error for the data set is 12%, which is greater than 5%. The range of the data is 0.1, which is considered very close together.
Which sets of terms describes the accuracy and precision of the data?
A. The data is both accurate and precise.
B. The data is not accurate but is precise.
C. The data is accurate but not precise.
D. The data is neither accurate nor precise.
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.
What is accuracy?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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What solid substances are found in rocks that make up the Earth's crust?
A. Concrete
B. Plastics
C. Minerals
D. Miners
Answer:
minerals
Explanation:
its litteraly non of the others
When 1600 joules of heat is added to a sample of solid copper (Cu), the temperature rises from 15.0 C to 30.0 C. the specific heat of solid copper is 0.385, how many grams of copper are in the sample.
Taking into account the definition of sensible heat, the mass of copper in the sample is 277.06 grams.
Definition of sensible heatWhen 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:
Q is the heat exchanged by a body of mass m.c is the specific heat substance.ΔT is the temperature variation.Mass of copper in the sampleIn this case, you know:
Q= 1600 Jc= 0.385 J/gCm= ?ΔT= Tfinal - Tinitial= 30 C - 15 C= 15 CReplacing 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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If 45.0 mL of a 6.0 M HCI solution are dilute with pure water to a volume of 1.0 L , what is the concentration of the resulting solution?
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
Which bond would you expect to be the most polar?
N-O
C-N
P-S
O-F
C-O
C-O
Explanation:
Thus, the largest difference of
electronegativity is between carbon and oxygen. Therefore, the C −O bond is most polar.
The solubility product for tin II hydroxide (Sn(OH)2) is Ksp = 5.5 x 10^27
For which of the following solutions will the molar solubility of Sn(OH)2 be the largest?
a) A pH = 4.00 buffer solution
b) A pH = 6.00 buffer solution
c) A pH = 7.00 buffer solution
d) A pH = 8.00 buffer solution
e) A pH = 10.00 buffer solution
Answer:
Answer: e) A pH = 10.00 buffer solution
A polyatomic ion is several ________ bonded together with ___________ ionic charge.
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.
Calculate the molecular mass of sulphur if 35.5 g of sulphur dissolves in 100.0 g of CS2 to produce a solution that has a boiling point of 49.48°C.
Which of the following would have the most momentum?
A. A tennis ball traveling a 10 meters/second
B. A tennis ball traveling at 5 meters/second.
C. A tennis ball traveling at 3 meters/ second
D. A tennis ball sitting on the ground.
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.
Nitrogen and hydrogen combine at a high temperature, in the presence of a catalyst, to produce ammonia.
N2(g)+3H2(g)⟶2NH3(g)
Assume 0.290 mol N2 and 0.954 mol H2 are present initially.
After complete reaction, how many moles of ammonia are produced?
Answer:
17 reactions
Explanation:
Carbon atoms always need four bonds to attain stability. Draw in the hydrogen atoms at the appropriate spots in the Lewis structure of the hydrocarbon chain to get a stable molecule.
As carbon always need four bound to stain stability which means it need eight electron in its valance cell.
Describe the Lewis Structure.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.
Describe stability.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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6. a. You perform a titration using phenolphthalein indicator to determine the concentration of an
unknown acid (HA)(aq). When titrating with 0.5 M NaOH, you find the endpoint of a 10 mL sample
of HA (aq) after 7.6 mL of NaOH is dispensed from the buret. What is the concentration of HA(aq)? (6
pt)
HA + OH A + H₂O
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