Answer: is the same for all substances.
Explanation:
The number of molecules in one mole of a substance is the same for all substances because
A mole (which is the quantity of a substance that has the same number (Avogadro's number, is 6.022 * 10^23) of particles as are found in 12.000 grams of carbon-12 of the substance) for any substance has the same number of atoms, molecules, or ions contained in any other substance.
1 mole = 6.022 x 10^23 atoms, molecules, or ions
Use the graph to determine which is greater, the heat of fusion or the heat of vaporization. Explain how you used the graph to determine that.
(The substance is water)
Answer:
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What is the hydrogen ion concentration [H+] of a HCl solution if the pH is measured to be 2.0?
Answer:
.01
Explanation:
H30+=10^-pH
- Hope that helps! Please let me know if you need further explanation.
4. A burning candle is an example of a chemical reaction taking place. What i
can be inferred about this reaction? Choose the correct answer."
A.Mass is not conserved.
B. The reaction absorbs energy. C.The reaction releases energy
D.There are reactants but no products,
Answer:
C
Explanation:
heat is energy
What is the hydronium ion concentration of a 0.100 M acetic acid solution with Ka = 1.8 × 10-5? The equation for the dissociation of acetic acid is: CH3CO2H(aq) + H2O(l) ⇌ H3O+(aq) + CH3CO2-(aq) What is the hydronium ion concentration of a 0.100 M acetic acid solution with Ka = 1.8 × 10-5? The equation for the dissociation of acetic acid is: CH3CO2H(aq) + H2O(l) ⇌ H3O+(aq) + CH3CO2-(aq) 1.3 × 10-2 M 4.2 × 10-2 M 1.3 × 10-3 M 4.2 × 10-3 M
Answer:
1.3×10⁻³ M
Explanation:
Hello,
In this case, given the dissociation reaction of acetic acid:
[tex]CH_3CO_2H(aq) + H_2O(l) \rightleftharpoons H_3O^+(aq) + CH_3CO_2^-(aq)[/tex]
We can write the law of mass action for it:
[tex]Ka=\frac{[H_3O^+][CH_3CO_2^-]}{[CH_3CO_2H]}[/tex]
Of course, excluding the water as heterogeneous substances are not included. Then, in terms of the change [tex]x[/tex] due to the dissociation extent, we are able to rewrite it as shown below:
[tex]1.8x10^{-5}=\frac{x*x}{0.100-x}[/tex]
Thus, via the quadratic equation or solve, we obtain the following solutions:
[tex]x_1=-0.00135M\\x_2=0.00133M[/tex]
Obviously, the solution is 0.00133M which match with the hydronium concentration, thus, answer is: 1.3×10⁻³ M in scientific notation.
Regards.
Answer:
1.3×10^-3 M
Explanation:
Step 1:
Data obtained from the question:
Equilibrium constant (Ka) = 1.8×10^-5
Concentration of acetic acid, [CH3COOH] = 0.100 M
Concentration of hydronium ion, [H3O+] =..?
Step 2:
The balanced equation for the reaction.
CH3CO2H(aq) + H2O(l) ⇌ H3O+(aq) + CH3CO2-(aq)
Step 3:
Determination of concentration of hydronium ion, [H3O+].
This can be obtained as follow:
Ka = [H3O+] [CH3CO2-] / [CH3CO2H]
Initial concentration:
[CH3COOH] = 0.100 M
[H3O+] = 0
[CH3CO2-] = 0
During reaction
[CH3COOH] = – y
[H3O+] = +y
[CH3CO2-] = +y
Equilibrium:
[CH3COOH] = 0.1 – y
[H3O+] = y
[CH3CO2-] = y
Ka = [H3O+] [CH3CO2-] / [CH3CO2H]
1.8×10^-5 = y × y / 0.1
Cross multiply
y^2 = 1.8×10^-5 x 0.1
Take the square root of both side
y = √(1.8×10^-5 x 0.1)
y = 1.3×10^-3 M
[H3O+] = y = 1.3×10^-3 M
Therefore, the concentration of the hydronium ion, [H3O+] is 1.3×10^-3 M
When you add a controlled amount of substance known as an impurity to a pure semiconductor, its conductivity increases. This process is known as doping. The addition of an impurity can increase or decrease the number of available electrons. If the number of electrons is increased, the extra electrons conduct electricity. If the number of electrons is decreased, a vacant hole is created. The adjacent electron enters the vacant hole and conducts electricity. Thus, it seems like the holes act as charge carriers. They are considered to be positive charge carriers. Depending upon the charge carriers that conduct electricity, there are two types of semiconductors: p-type semiconductors and n-type semiconductors.Which of the following statements are correct with respect to semiconductors?
a) The addition of group 3A elements to group 4A semiconductors decreases the conductivity of the group 4A semiconductors.
b) The conductivity of semiconductors can be increased by the doping process.
c) As the temperature increases, the conductivity of semiconductors decreases.
d) The addition of group 5A elements to group 4A semiconductors increases the conductivity of the group 4A semiconductors.
e) Holes are charge carriers in p-type semiconductors.
f) Electrons are charge carriers in n-type semiconductors.
Answer:
See explaination
Explanation:
1. The addition of group 3A elements to group 4A semiconductors decreases the conductivity of the group 4A semiconductors: Wrong
The addition of 3A group elements inreases the conductivity and make them extrinsic semiconductors( p-type)
2. The conductivity of semiconductors can be increased by the doping process.: Correct
3.As the temperature increases, the conductivity of semiconductors decreases.. wrong
As the temperature increases, the conductivity of semiconductors increases.
4. The addition of group 5A elements to group 4A semiconductors increases the conductivity of the group 4A semiconductors: Correct : They will create n-type semicoductor.
5.Holes are charge carriers in p-type semiconductors: Correct
6. Electrons are charge carriers in n-type semiconductors: Correct
6.) (5 points) Assume you have a system with a fixed pH of 4.0. It is well buffered and therefore the pH will not change. What is the predominant state of a molecule with a dissociable proton with a pKa of 5.2 if it is introduced to that system (protonated or deprotonated)
Answer:
Dissociated state is the predominant one
Explanation:
When a molecule with pKa of 4.52 is in an aqueous solution at pH = 4.0, follows the H-H equation, thus:
pH = pKa + log₁₀ [A⁻] / [HA]
Where [A⁻] is the dissociated state and [HA] represents the protonated state
Replacing:
4.0 = 5.2 + log₁₀ [A⁻] / [HA]
-1.2 = log₁₀ [A⁻] / [HA]
0.063 = [A⁻] / [HA]
[HA] = 16 [A⁻]
That means you have 16 times more [HA] than [A⁻] and the dissociated state is the predominant one
Using Boyle's Law solve the following: An unknown gas has a volume of 200.0 mL and a pressure of 350.0 torr, pressure were increased to 700.0 torr, what is the resulting volume?
Answer:
400 mL
Explanation:
Boyle's Law: [tex]P_1*V_1 = P_2*V_2[/tex]
Let x = the resulting volume
350 (200) = 700 (x)
x = 400 mL
Which picture shows how the moon from earth when it’s in the position
Explanation:
This picture shows how the moon from earth when it is in position
What is the symbol for the entity that has 17 protons, 20 neutrons, and 18 electrons?
hEy!!!
Chlorine(CL) is the symbol for the entity that has 17 protons,20 neutrons and 18 electrons.
Hope it will be helpful to you...
Answer:chlorine
Explanation:
Porosities can have merits and demerits during manufacturing procedures of dental materials. Clarify this statement.
Answer:
The porosities in dental materials can be of merit and not merit since some dental materials need to be porous in order to reduce their weight and improve their properties and functions, whereas in those (which are the majority) porosities are not Merit, see the properties of the material, the function and can even influence dental rehabilitation.
An example of this is the use of vitreous ionomers, which is a dental material, where when it is spatulated it remains porous, it can give recurrence of infectious caries, since its permeability increases, the best cariogenic microorganisms are filtered and porosity works as a retentive site for these microorganisms that make up the dental biofilm.
In summary, the world of dental materials is very wide, some are resins, other cements, others have metallic claims, etc. To say that the presence of porosity is merit or demerit would be ideal because for some materials this is favorable and for others unfavorable since they are very versatile, with different qualities, different degrees of porosity, different molecules, different coefficients of thermal expansion, some do not set, others do not, some are light-cured, others do not, some withstand more mechanical forces and have more elastic modulus and less porosity, while others do not, and thus with many more variables.
Explanation:
In the manufacture of dental materials, much attention is always paid to what the manufacturer indicates in these indications that come on the reverse side of the material or on a paper inside the material container.
This is important to know, because the manufacturer is the one that indicates the mode of use and working time according to the trademark and the chemical composition of the dental material.
That a dental material in its manufacture is more or less porous, makes its density, weight and volume possibly be affected, there are materials that seek to increase porosity for a certain purpose, while others seek the opposite, depending on the function that is applied, will have more or less pores.
The example we gave above about the vitreous ionomer is an example that indicates that in the case of restorative dental materials where the function is to SEAL the porosity is almost nil, since otherwise it will not seal the cavity that was formed with caries and not the infectious problem would be solved.
On the other hand, in the surgical field of dentistry there are bone grafts or porous macroparticles that are for the purpose of bone replacement, which in order to be integrated need blood vessels that run over these pores, irrigating the area of bone neoformation well, in this case the merit of porosity if necessary and it is essential that they be very porous.
Dysphagia is the name of a disorder that disrupts
А
the swallowing reflex
B
the absorption of essential nutrients
acid levels in the stomach
C
D
the stomach lining
Answer:
A. The Swallowing reflex
Explanation:
Dysphagia Is a a condition that makes swallowing difficult.
What is the molarity of sodium hydroxide solution made by combining 2.0 L of 0.60
NaOH With 495 mL 3.0 M NaOH? Assume the volumes of the two solutions to be additive___M
Answer:
[tex]M=1.1M[/tex]
Explanation:
Hello,
In this case, since we are mixing two NaOH solutions, the first step is to compute the total moles once the mixing is done, by using the volumes and concentrations of each solutions and subsequently adding them:
[tex]n_T=2.0L*0.60\frac{mol}{L}+495mL*\frac{1L}{1000mL}*3.0\frac{mol}{L}= 2.7molNaOH[/tex]
Next, we compute the total volume by adding the volume of each solution:
[tex]V_T=2.0L+495mL*\frac{1L}{1000mL}= 2.495L[/tex]
Finally, we compute the molarity of the resulting solution by the division between the total moles and the total volume:
[tex]M=\frac{2.7mol}{2.495L}\\ \\M=1.1M[/tex]
Best regards.
If I add 50 mls of water to 300 mls of 0.6M KNO3 solution, what will be the molarity of the diluted solution?
Answer:
[tex]M_2=0.51M[/tex]
Explanation:
Hello,
In this case, for this dilution process, we understand that the moles of the solute (potassium nitrate) remain unchanged upon the addition of diluting water. However, the resulting or final volume includes the added water as shown below:
[tex]V_2=300mL+50mL=350mL[/tex]
In such a way, we are able to relate the solution before and after the dilution by:
[tex]V_1M_1=V_2M_2[/tex]
Hence, we solve for the final molarity as:
[tex]M_2=\frac{M_1V_1}{V_2}=\frac{0.6M*300mL}{350mL}[/tex]
Best regards.
[tex]M_2=0.51M[/tex]
2. What are the similarities between law of triads and law of octaves?
Answer:
The similarities are the groups, triads law is a law where they are in groups or three, the octaves law is the 'best' law, is the one who every atom wants, they do everything to be in groups of eight.
Explanation:
please do this guys i need a lot of help please!
Answer:
the European countries grew together.
Explanation:
Europe saw human inflows from east and southeast.
the Roman Empire came to dominate the entire Mediterranean basin.
European politics from 1947 to 1989 made the European countries grew together.
The roles of hydrochloric acid (HCl) in the digestive system?
Answer:
There are several roles of HCl in the digestive system. Some of them are as follows:
There is HCl present in the gastric juice of your stomach, otherwise known as stomach acid. The acidic nature of the HCl in the stomach acid make it useful for quickly breaking down food.HCl's acidic nature also allows it to kill bacteria and other pathogens that you may have ingested, keeping you safe from their dangerous effects.HCl can also contribute Hydrogen ions, which helps to activate pepsinogen, a substance secreted by the stomach wall. The activated pepsinogen is then converted into pepsin, which aids in the digestion of proteins. Because of this, HCl essentially keeps the systems of protein digestion in check. Too much or too little of it can be dangerous.HCl also makes sure that vitamins are properly absorbed and acts as a communicator to other organs in the digestive system.What is the concentration of a solution if 0.450 mol of NaCl dissolved in 750 mL of water?
Answer:
.6mol/L
Explanation:
molarity = number of moles / volume of solvent (in L)
750mL / 1000mL/L = .75L
M = .450mol / .75L
M = .6mol/L
Which statements describe inorganic compounds? Check all that apply
Inorganic compounds contain carbon
Inorganic compounds usually lack carbon
Inorganic compounds are not associated with or made from living things,
Inorganic compounds include fruits and vegetables,
Inorganic compounds include salt and water
Answer:
b, c, e
Explanation:
Inorganic compounds usually lack carbon.
Inorganic compounds are not associated with or made from living things.
Inorganic compounds include salt and water.
Answer:
yes the answer id bce
Explanation:
A crystal of table salt (NaCl) is dissolved in water. Which of the following statements explains why the dissolved salt does not recrystallize as long as the temperature and the amount of water stay constant?
A crystal of table salt (NaCl) is dissolved in water. Which of the following statements explains why the dissolved salt does not recrystallize as long as the temperature and the amount of water stay constant?
Na+ and Cl- ions lose their charges in the water.
Water molecules surround the Na+ and Cl- ions.
Na+ and Cl- ions leave the water through vaporization.
Water molecules chemically react with the Na+ and Cl- ions.
Your answer: -
Answer: B - Water molecules surround the Na+ and Cl- ions.
Lewisite (2-chloroethenyldichloroarsine) was once manufactured as a chemical weapon, acting as a lung irritant and a blistering agent. During World War II, British biochemists developed an antidote which came to be known as British anti-Lewisite (BAL) (2,3-disulfanylpropan-1-ol). Today, BAL is used medically to treat toxic metal poisoning. Complete the reaction between Lewisite and BAL by giving the structure of the organic product and indicating the coefficient for the number of moles of HCl produced in the reaction.
Answer:
2 HCl
Explanation:
Please kindly check attachment for the step by step solution of the given problem.
Which factor would slow down a chemical reaction? (Choose all that apply)
A)Adding an inhibitor
B)Decreasing temperature
C)Decreasing particle size
D)Increasing particle size
Answer:
(decreasing particle size) C
Explanation: That is one of the answers, if there are more I am sorry.
It takes 300 N to move a box 10 meters in 10 seconds. How much power is
required?
A. 30,000 W
B. 100 W
C. 3,000 J
D. 300 W
Plz help
Answer:
Power, P = 300 W
Explanation:
We have,
Force acting on the box to take it is 300 N
It is moved to a distance of 10 m in 10 seconds
It is required to find the power required to move the box. The rate at which work is done is called power required by an object. It can be given by the formula as follows :
[tex]P=\dfrac{W}{t}\\\\P=\dfrac{Fd}{t}\\\\P=\dfrac{300\times 10}{10}\\\\P=300\ W[/tex]
So, the power required is 300 W.
A chemist wants to increase the solubility of a solid in water. Which of the
following will NOT help? *
-increase the temperature
-decrease the particle size
-Increase stirring
-increase pressure
Answer:
- Increase pressure .
Explanation:
Hello,
In this case, during the dissolution process, the solute's molecules rearrange in order to get together with the solvent's molecules, in this case water.
Now, since we are talking about a solid whose particles are intimately held together, the only way to separate them is by increasing the temperature because the molecules start moving so they can join water's molecules, decreasing particle size since they will be more likely to separate to each other and increasing stirring since the applied energy will break the solid's intramolecular forces.
In such a way, since pressure significantly affects gases and slightly affects liquid, it is not able to modify a solid, just extreme pressures such as it needed to produce diamonds, is able to affect a solid. For that reason, increasing the pressure will not increase the solid's solubility.
Best regards.
If an insufficient amount of liquid unknown had been used, how would this have effected the value of the experimental molar mass
Answer:
Actual yield reduces the more.
Explanation:
An actual yield of the course of a chemical reaction is the mass of a product actually obtained from the reaction.
In practice you see it and It is usually less than the theoretical yield.
Various reasons may come up to explain this away but here is one:
• incomplete reactions, simply put here some of the reactants do not react to form the product.
The same applies in the question about the actual yield will reduce significantly in molar mass now that insufficient amount of reagent are used.
How to make isopropyl alcohol
Answer:
.It is easily synthesized from the reaction of propylene with sulfuric acid, followed by hydrolysis. Isopropyl alcohol (2-propanol) is made by indirect hydration of propylene (CH2CHCH3).… In some cases the hydration of propylene is carried out in one step, using water and a catalyst at high pressure.
Hope it'll help!
stay safe:)
Claims • Evidence • Reasoning Make
a claim about ways people can stay safe
during storms with high wind and heavy
rains. Summarize evidence to support the
claim and explain your reasoning.
Answer:
the claim is that when people avoid storms they hide in any secret place in there house
Explanation:
when people do that they don't even have to worry about a single thing that will happen to them
the diagram above represents a reflex arc in a human. This pathway responds when someone touches something that causes pain, such as a hot stove. Which of the following shows the correct order of the body systems involved in this response?
A) Integumentary, respiratory, digestive
B) Circulatory, respiratory, nervous
C) Integumentary, nervous, muscular
D) Circulatory, digestive, nervous
Answer:
C) Integumentary, nervous, muscular
Explanation:
When a human body touches a hot stove , our sense organ which is integumen first of all receives the impulse of heat . The impulse is transformed into electrical signal which is transmitted to brain which is a part of nervous system . Then brain processes it and command signal is sent to muscle of hand to move it away from that place . Hence the order is
Integumentary, nervous, muscular .
Considering the limiting reactant, what is the mass of zinc sulfide produced from 0.250 g of zinc and 0.750 g of sulfur? Zn(s)+S(S) ZnS(s)
Answer:
The mass of zinc sulfide produced is [tex]M_{ZnS} = 0.76 \ g[/tex]
Explanation:
From the question we are told that
The mass of zinc is [tex]m_z = 0.750 \ g[/tex]
The mass of sulfur is [tex]m_s = 0.250 \ g[/tex]
The molar mass of [tex]Zn_{(s)}[/tex] is a constant with value 65.39 g /mol
The molar mass of [tex]S_{(s)}[/tex] is a constant with value 32.01 g/mol
The molar mass of [tex]ZnS_{(s)}[/tex] is a constant with value 97.46 g/mol
The reaction is
[tex]Zn_{(s)} + S_{(s)} ------> ZnS_{(s)}[/tex]
So from the reaction
1 mole of [tex]Zn_{(s)}[/tex] react with 1 mole of [tex]S_{(s)}[/tex] to produce 1 mole of [tex]ZnS_{(s)}[/tex]
This implies that
65.39 g /mol of [tex]Zn_{(s)}[/tex] react with 32.01 g/mol of [tex]S_{(s)}[/tex] to produce 97.46 g/mol of [tex]ZnS_{(s)}[/tex]
From the values given we can deduce that the limiting reactant is sulfur cause of the smaller mass
So
0.250 g of [tex]Zn_{(s)}[/tex] react with 0.250 of [tex]S_{(s)}[/tex] to produce [tex]x \ g[/tex] of [tex]ZnS_{(s)}[/tex]
So
[tex]x = \frac{97.46 * 0.250}{32.01}[/tex]
[tex]x = 0.76 \ g[/tex]
Thus the mass of the mass of zinc sulfide produced is
[tex]M_{ZnS} = 0.76 \ g[/tex]
Describe an autopsy table
After the body is cleaned, the body is weighed and measured before being placed on the autopsy table for reexamination. The autopsy table is typically a slanted, aluminum table with raised edges that has several faucets and drains used to wash away collecting blood during the internal investigation.
Answer:
A table used to scientifically determine the cause of death of a human or animal
Explanation:
Describe the catenation property of carbon by illustrating the formation of a straight chain and branched chain compounds
Answer:
Catenation refers to the ability of an atom to link to other atoms of the same kind to form a chain.
Explanation:
Catenation is the binding of an element to itself through covalent bonds to form chain or ring .Catenation can also be defined as the self-linking of atoms of an element to form chains and rings. This definition can be extended to include the formation of layers like two-dimensional catenation and space lattices like three-dimensional catenation. Thus, we can boldly say that, Catenation occurs when atoms of the same element covalently bond to one another to create a chain or ring.
Catenation occurs most readily in carbon, forming covalent bonds to and longer chains and structures with other carbon atoms. This is why the vast number of organic compounds are found in nature. Carbon is best known for its catenation properties, with the analysis of catenated carbon structures in organic chemistry.
Carbon is by no means the only element capable of forming such catenae, however, and several other main group elements are capable of forming a wide range of catenae, including silicon, sulfur, and boron. In group 14, the high bond energy of carbon makes it able to self-link almost indefinitely when compared with other members of the group which form only a few bonds to other atoms of the same element.
