Stars form in large, dense regions of gas and dust known as molecular clouds. These clouds are located primarily in the spiral arms of galaxies, where they are exposed to intense radiation from nearby stars. As the gas and dust in these clouds are subjected to this radiation, they begin to collapse under their own gravity. As the collapse continues, the cloud becomes denser and denser, and eventually a protostar forms at its center. Over time, this protostar continues to contract and heat up, eventually reaching the point where nuclear fusion can begin in its core. At this point, the protostar becomes a fully-fledged star, and the process of star formation is complete.
TL;DR: Within the clouds of dust and scattered throughout most galaxies.
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
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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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.
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:
The reaction between water and ammonium nitrate results in_____.
A. Light is emitted.
B. A precipitate (solid) is formed.
C. A temperature increase.
D. A temperature decrease.
The reaction between water and ammonium nitrate results in increase in a temperature.
Hence, Option C is the correct answer.
When ammonium nitrate is dipped in a beaker which contains the water, the beaker becomes cold because it is an endothermic reaction. The endothermic reaction is a reaction that it absorbs energy from the outside in the form of heat.
Thus we can say that hydrating ammonium nitrate is an endothermic reaction, because of that the beaker becomes cold.
We feels cold when ammonium nitrate is mixed in water that shows an endothermic reaction. In an endothermic reaction, the ammonium nitrate mixed in water, a chemical reaction occurs which absorbs heat rather than releases it.
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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.
What volume of 12 gas forms when 21 L Cl2 react at STP?
The volume of I₂ gas formed when 21 L of Cl₂ gas reacts at STP is 21 L
How do I determine the volume of I₂ gas formed?We'll begin by writing the balanced equation for the reaction. This is shown below:
2KI(aq) + Cl₂(g) -> 2KCl(aq) + I₂ (g)
From the balanced equation above,
1 L of Cl₂ reacted to produce 1 L of I₂
With the above information, we can obtain the volume of I₂ formed when 21 L of Cl₂ react at STP as follow: :
From the balanced equation above,
1 L of Cl₂ reacted to produce 1 L of I₂
Therefore
21 L of Cl₂ will also react to produce 21 L of I₂
Thus, the volume of I₂ formed is 21 L
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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:
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
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
The _______ atom in a water molecule points toward the sodium ion because its partial _______ charge is attracted to the sodium ion's ______ charge. This is called _______.
Answer:
Below
Explanation:
Oxygen negative positive hydration
The oxygen atom in a water molecule points toward the sodium ion because its partial negative charge is attracted to the sodium ion's positive charge. This is called hydration.
In a water molecule, the oxygen atom is more electronegative than the hydrogen atoms, causing it to pull the shared electrons in the covalent bonds closer to itself. As a result, the oxygen atom gains a partial negative charge (δ-) due to the presence of these electron-rich lone pairs.
On the other hand, when sodium chloride (NaCl) or any other ionic compound dissolves in water, it dissociates into its constituent ions (Na⁺ and Cl⁻). The positively charged sodium ion (Na⁺) attracts the partial negative charge on the oxygen atom of the neighboring water molecules.
This electrostatic attraction between the partial negative charge on the oxygen atom and the positive charge on the sodium ion is called an ion-dipole interaction. It is one of the primary forces that drive the dissolution of ionic compounds in polar solvents like water.
When many water molecules surround the sodium ion, with their oxygen atoms pointing toward it and forming ion-dipole interactions, the process is called solvation or hydration. The water molecules effectively surround the sodium ion, separating it from the rest of the sodium chloride crystal and keeping it in solution. This is a crucial process in dissolving ionic compounds in water and making them available for various chemical reactions and biological processes.
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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 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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Compare and contrast the terms primary standard and secondary standard
Reagents are primary standards that can be used in chemical processes. These substances are frequently employed to figure out the concentration of a solution that can interact chemically with the primary standard but whose concentration is unknown. The term "secondary standard solution" refers to a solution developed expressly for a given analysis.
What is Primary and secondary standard solution?A reagent with a high degree of purity is called a primary standard solution. It has a highly accurate concentration that mirrors the solute's molar concentration. Because of its purity, it may be used to accurately determine the mass to volume ratio.
The term "secondary standard solution" refers to a solution developed expressly for a given analysis. A secondary standard is a substance whose active agent content was discovered by comparison with a primary standard. This means that it is frequently bench marked against a major standard.
A primary standard solution is one that has a high purity and is less reactive. Secondary standards are not as pure as primary standards and are more chemically reactive.A primary standard solution is sterile. A secondary standard solution isn't very pure.A major standard solution, on the other hand, is not as reactive. A secondary standard solution is more reactive in comparison.A hygroscopic primary standard solution does not exist. A secondary standard solution is hygroscopic in various ways.A solution of primary standards used to standardize secondary standards and other reagents. For particular analytical chemistry studies, a secondary standard solution is utilized.To know more about concentration refer to:
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What causes a substance to undergo a phase change?
Answer: Substances can change phase — often because of a temperature change. At low temperatures, most substances are solid; as the temperature increases, they become liquid; at higher temperatures still, they become gaseous.
Explanation:
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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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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A sample of ideal gas at room temperature occupies a volume of 29.0 L at a pressure of 342 torr . If the pressure changes to 1710 torr , with no change in the temperature or moles of gas, what is the new volume, V2 ? Express your answer with the appropriate units.
Ideal gas law is valid only for ideal gas not for vanderwaal gas. To solve such, we need to know the relation between rate of effusion and molar mass of gases. Therefore, the new volume V₂ is 18L.
What is ideal gas equation?Ideal gas equation is the mathematical expression that relates pressure volume and temperature. an ideal gas on the walls of the container is inversely proportional to the volume occupied that gas.
Mathematically, Boyle's law can be written as
P₁V₁ = P₂V₂
P₁=initial pressure=342 torr
P₂=final pressure=1710 torr
V₁ = initial volume= 29.0 L
V₂=final pressure=?
Substituting all the given values in the above equation, we get
V₂ = P₁V₁/P₂
V₂ = (342 × 29.0)/1710
V₂ = 18L
Therefore, the new volume V₂ is 18L.
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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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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
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
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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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.
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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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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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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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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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
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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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 A