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
it takes 26.23 mL of a 1.008 M NaOh solution to neutralize a solution of an unknown monoprotic acid in 150.2 mL of solution. What is the molarity of the unknown?
Answer:
.176 M
Explanation:
set the number of moles of the base equal to the number of moles of acid.
(1.008 mol/L)(26.23 x 10^-3 L)=(150.2x10^-3 L)(x)
x = .176030892 mol/L
If a mineral isn't scratched by a fingernail, what can you conclude about the minerals
hardness?
It is at least a hardness of 4.0
A mineral can't be tested by a fingernail.
The hardness is more than 2.5.
The hardness is less than 2.5.
Answer:
The hardness is more than 2.5. Hope this helps.
Answer:
The hardness is more than 2.5.
Explanation:
Which chemical is responsible for opening the hair cuticle?
A
Peroxide
B
Ammonia
С
Powder persulphate
D
None of the above
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.How much heat will be absorbed by 122 g of water when its temperature is raised by 17oC? The specific heat for water is 4.18 J/g oC. Use significant figures.
Answer:
Heat energy = 8669.32J
Explanation:
Mass = 122g
Change in temperature ∇T = 17°C
Specific heat capacity (c) = 4.18J/g°C
Heat energy (Q) = ?
Heat energy (Q) = mc∇T
Q = heat energy
M = mass of the substance
C = specific heat capacity of the substance
∇T = change in temperature of the substance
Q = mc∇T
Q = 122 × 4.18 × 17
Q = 8669.32J
The heat energy required to raise 122g of water by 17°C is 8669.32J
Answer:
[tex]Q=8669.3J=8.67kJ[/tex]
Explanation:
Hello,
In this case, we can compute the absorbed heat of water needed to raise its temperature by 17 °C by using the following formula:
[tex]Q=mCp\Delta T[/tex]
In this case, the mass is 122 g, the specific heat 4.18 J/(g°C) and the temperature change 17 °C, hence the heat turns out:
[tex]Q=122g*4.18\frac{J}{g\°C}*17\°C\\ \\Q=8669.3J=8.67kJ[/tex]
Best regards.
What is the specific heat values for all the metals.
Answer:
Substance c in J/gm K
Copper 0.386
Aluminum 0.900
Lead 0.128
Iron 0.450
Explanation:
A 99.8 mL sample of a solution that is 12.0% KI by mass (d: 1.093 g/mL) is added to 96.7 mL of another solution that is 14.0% Pb(NO3)2 by mass (d: 1.134 g/mL). How many grams of PbI2 should form?
Pb(NO3)2(aq) + 2 KI(aq) PbI2(s) + 2 KNO3(aq)
Answer:
[tex]m_{PbI_2}=18.2gPbI_2[/tex]
Explanation:
Hello,
In this case, we write the reaction again:
[tex]Pb(NO_3)_2(aq) + 2 KI(aq)\rightarrow PbI_2(s) + 2 KNO_3(aq)[/tex]
In such a way, the first thing we do is to compute the reacting moles of lead (II) nitrate and potassium iodide, by using the concentration, volumes, densities and molar masses, 331.2 g/mol and 166.0 g/mol respectively:
[tex]n_{Pb(NO_3)_2}=\frac{0.14gPb(NO_3)_2}{1g\ sln}*\frac{1molPb(NO_3)_2}{331.2gPb(NO_3)_2} *\frac{1.134g\ sln}{1mL\ sln} *96.7mL\ sln\\\\n_{Pb(NO_3)_2}=0.04635molPb(NO_3)_2\\\\n_{KI}=\frac{0.12gKI}{1g\ sln}*\frac{1molKI}{166.0gKI} *\frac{1.093g\ sln}{1mL\ sln} *99.8mL\ sln\\\\n_{KI}=0.07885molKI[/tex]
Next, as lead (II) nitrate and potassium iodide are in a 1:2 molar ratio, 0.04635 mol of lead (II) nitrate will completely react with the following moles of potassium nitrate:
[tex]0.04635molPb(NO_3)_2*\frac{2molKI}{1molPb(NO_3)_2} =0.0927molKI[/tex]
But we only have 0.07885 moles, for that reason KI is the limiting reactant, so we compute the yielded grams of lead (II) iodide, whose molar mass is 461.01 g/mol, by using their 2:1 molar ratio:
[tex]m_{PbI_2}=0.07885molKI*\frac{1molPbI_2}{2molKI} *\frac{461.01gPbI_2}{1molPbI_2} \\\\m_{PbI_2}=18.2gPbI_2[/tex]
Best regards.
Answer:
Mass PbI2 = 18.19 grams
Explanation:
Step 1: Data given
Volume solution = 99.8 mL = 0.0998 L
mass % KI = 12.0 %
Density = 1.093 g/mL
Volume of the other solution = 96.7 mL = 0.967 L
mass % of Pb(NO3)2 = 14.0 %
Density = 1.134 g/mL
Step 2: The balanced equation
Pb(NO3)2(aq) + 2 KI(aq) ⇆ PbI2(s) + 2 KNO3(aq)
Step 3: Calculate mass
Mass = density * volume
Mass KI solution = 1.093 g/mL * 99.8 mL
Mass KI solution = 109.08 grams
Mass KI solution = 109.08 grams *0.12 = 13.09 grams
Mass of Pb(NO3)2 solution = 1.134 g/mL * 96.7 mL
Mass of Pb(NO3)2 solution = 109.66 grams
Mass of Pb(NO3)2 solution = 109.66 grams * 0.14 = 15.35 grams
Step 4: Calculate moles
Moles = mass / molar mass
Moles KI = 13.09 grams / 166.0 g/mol
Moles KI = 0.0789 moles
Moles Pb(NO3)2 = 15.35 grams / 331.2 g/mol
Moles Pb(NO3)2 = 0.0463 moles
Step 5: Calculate the limiting reactant
For 1 mol Pb(NO3)2 we need 2 moles KI to produce 1 mol PbI2 and 2 moles KNO3
Ki is the limiting reactant. It will completely be consumed ( 0.0789 moles). Pb(NO3)2 is in excess. There will react 0.0789/2 = 0.03945 moles. There will remain 0.0463 - 0.03945 = 0.00685 moles
Step 6: Calculate moles PbI2
For 1 mol Pb(NO3)2 we need 2 moles KI to produce 1 mol PbI2 and 2 moles KNO3
For 0.0789 moles KI we'll have 0.0789/2 = 0.03945 moles PbI2
Step 7: Calculate mass of PbI2
Mass PbI2 = moles PbI2 * molar mass PbI2
Mass PbI2 = 0.03945 moles * 461.01 g/mol
Mass PbI2 = 18.19 grams
which is a type of heat transfer that causes the air at the top floor of a building to be hotter than the bottom floor of a building
Answer: I believe it's convection
Good luck and I hope this helps!!
Answer: Convection
Explanation: Edge
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 .
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.
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:
Which species acts exclusively as spectator ions in this reaction
Answer:
K^+ and NO3^-
Explanation:
In a balanced ionic equation, we usually see the species that react to yield the main product in the reaction.
Consider the reaction;
Pb(NO3)2(aq) +2 KI(aq) -------> PbI2(s) + 2KNO3(aq)
The main product in this reaction is PbI2. Hence the balanced ionic equation is;
Pb^2+(aq) + 2I^-(aq) ------> PbI2(s)
Notice that K^+ and NO3^- did not participate in this reaction. All ions that are part of the molecular equation but do not participate in the ionic reaction equation are called spectator ions. Hence K^+ and NO3^- are spectator ions in this reaction as can be seen clearly above.
PbCl2+ AgNO3------>Pb(NO3)2+ AgCl
Decomposition
Synthesis
Double displacement
Exothermic
Answer:
Option C
Explanation:
A double displacement reaction is the one in which two chemical compounds having a cation and anion in each exchange their positive and negative ions thereby forming new compounds or products.
Here,
The first compound [tex]PbCl_2[/tex] has a positive ion [tex]Pb[/tex] and negative ion [tex]Cl^-[/tex]
Like wise the second compound [tex]Ag(NO_3)[/tex] has a positive ion [tex]Ag[/tex] and negative ion [tex]NO_3[/tex]
The new compounds will be formed when cation of one compound attaches with the anion of other compound. Hence the new compounds are
[tex]Pb(NO_3)_2[/tex]
[tex]AgCl[/tex]
This is example of double displacement reaction.
Option C is correct
Argon-40 undergoes positron emission as shown:
48 Ar X+ IB
Enter the appropriate values for A and Z and the chemical
symbol for X
Answer:
[tex]\frac{40}{18}Ar => \frac{40}{17}Cl + \frac{0}{1}e\\[/tex]
Explanation:
The process of positron emission is better understood by the following reaction:
[tex]\frac{40}{18} Ar[/tex] → + [tex]\frac{40}{17} Cl + \frac{0}{1} e[/tex]. What is Positron emission?Positron emission may be defined as a subordinate type of radioactive decay called which is effectively known as beta decay. Due to this emission, a proton that is present inside a radionuclide nucleus significantly transformed into a neutron while liberating a positron and an electron neutrino.
According to the context of this question, Argon-40 undergoes the process of beta decay. Through which X element is formed which is known as chlorine. The atomic number (Z) of chlorine is 17, while the atomic mass (A) is 40 which is as identical to argon.
Therefore, the appropriate values for A and Z and the chemical symbol for X are 40 and 17 respectively.
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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.
Help me 6th grade science !:))
Answer:
I believe it is C.Shelter.
Answer:
C
Explanation:
The butterflies use the trees for shelter, because the trees protect them from the weather and the cold air.
What are the variables in Gay-Lussac’s law
Answer:
The variables in Gay-Lussac's law are the initial temperature (T1), the initial pressure (P1), the final temperature (T2) and the final pressure (P2)....
Explanation:
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
I'll give you the brainiest please help.
Answer:
c
Explanation:
38 mL of a gas was collected at 581 mm Hg and 25 degrees Celsius. What would the volume be at standard pressure (560 mm Hg) if the temperature remained constant?
At what temperature will a gas be, if you allow it to expand from its original volume of 756 mL at 65.0 °C to 1.40 L? (hint volume needs to be the same)
Answer:
120.4 gradius Celcius
Explanation:
Please see the step-by-step solution in the picture attached below.
Hope this answer can help you. Have a nice day!
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 reaction?
Answer:
A chemical reaction is a process in which one or more substances, also called reactants, are converted to one or more different substances, known as products. ... A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products.
Explanation:
Hopefully this is what you needed
What type of ions do metals produce?
Answer:
Ionic bonds
Explanation:
It rymes. haha i dont even know how to spell it! ;)
10. When the pressure on a gas inetcases three times, by how much will the volume incrcase or decrease?
Answer:The answer to this question comes from experiments done by the scientist Robert Boyle in an effort to improve air pumps. In the 1600's, Boyle measured the volumes of gases at different pressures. Boyle found that when the pressure of gas at a constant temperature is increased, the volume of the gas decreases. when the pressure of gas is decreased, the volume increases. this relationship between pressure and volume is called Boyle's law.
Explanation: So, at constant temperature, the answer to your answer is: the volume decreases in the same ratio as the ratio of pressure increases.
BUT, in general, there is not a single answer to your question. It depend by the context.
For example, if you put the gas in a rigid steel tank (volume is constant), you can heat the gas, so provoking a pressure increase. But you won't get any change in volume.
Or, if you heat the gas in a partially elastic vessel (as a tire or a soccer ball) you will get both an increase of volume AND an increase of pressure.
FINALLY if you inflate a bubblegum ball, the volume will be increased without any change in pressure and temperature, because you have increased the NUMBER of molecules in the balloon.
There are many other ways to change volume and pressure of a gas that are different from the Boyle experiment.
An aqueous solution of HNO2 is poured onto a solid pile of SrCO3. Identify the net ionic equation for this reaction.
A) SrCO3(s) + 2 HNO2(aq) → Sr(NO2)2(aq) + HCO3(aq)
B) no reaction occurs
C) Sr2+ + CO32- + 2 H+ → Sr2+ + H2O + CO2(g)
D) SrCO3(s) + 2 HNO2(aq) → Sr(NO2)2 + H2O + CO2(g)
E) SrCO3(s) + 2 H+ → Sr2+ + H2O + CO2(g)
Answer:
D) SrCO3(s) + 2 HNO2(aq) → Sr(NO2)2 + H2O + CO2(g)
Explanation:
When an acid react with carbonate, it produces nitrate, carbon-dioxide gas and water molecule. When nitrous acid react with Strontium carbonate, three products are formed i. e. Strontium nitrate, carbon-dioxide gas and water. In the reaction, both nitrous acid and Strontium carbonate exchange their partners with each other and forming a different products.
Answer:
Option E is correct.
The net ionic equation is given as
SrCO₃(s) + 2H⁺ → Sr²⁺ + H₂O + CO₂(g)
Explanation:
When acids react with carbonate compounds, it leads to the liberation of CO₂, hence, when an aqueous solution of HNO₂ is poured onto a solid pile of SrCO₃, the balanced overall equation is given as
SrCO₃(s) + 2HNO₂(aq) → Sr(NO₂)₂ + H₂O + CO₂(g)
But for the net ionic reaction, it is obtained by eliminating ions that occur on both sides of the overall reaction. Note that ions exist onlubone the aqueous compounds.
Hence, the two aqueous compounds that exist in the balanced overall equation are
2HNO₂(aq) on the left hand side and Sr(NO₂)₂ on the right hand side
In their ionic form, 2HNO₂ ⇌ 2H⁺ + 2NO₂⁻
And Sr(NO₂)₂ ⇌ Sr²⁺ + 2NO₂⁻
And it is evident that the ion that occurs on both sides and needs to be deleted is NO₂⁻,
Hence, the net ionic equation is
SrCO₃(s) + 2H⁺ → Sr²⁺ + H₂O + CO₂(g)
Hope this Helps!!!
What is science? Answer for brainilest
Answer:
The importance of learning is that it helps the individual to acquire the necessary skills through learning and knowledge so that he can achieve his set goals. An important fact about learning is that it is a means to improve knowledge and gain skills that will help in reaching specific goals
Explanation:
The importance of learning is that it helps the individual to acquire the necessary skills through learning and knowledge so that he can achieve his set goals. An important fact about learning is that it is a means to improve knowledge and gain skills that will help in reaching specific goals
A molecule of which compound has a multiple covalent bond?
1. CH4
2. C2H4
3. C3H8
4. C4H10
Answer:
The second one
Explanation:
Because not only did I take a castle learning in this today but c2h4 has 6 covalent bonds
There are several types of molecules that have multiple bond. A molecule of which compound has a multiple covalent bond is C2H4.
Covalent bonding is the sharing of one or more electron pairs. In many covalent bonding situations,
Multiple chemical bonds exist when there is more than one electron pair that is being shared.
A nitrogen atom often fill its octet by sharing three electrons with another nitrogen atom thereby creating three covalent bonds.
Multiple bonds are commonly found in organic compound and they have carbon molecules.
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A solution is prepared by mixing 525 mL of ethanol with 597 mL of water. The molarity of ethanol in the resulting solution is 8.35 M. The density of ethanol at this temperature is 0.7893 g/mL. Calculate the difference in volume between the total volume of water and ethanol that were mixed to prepare the solution and the actual volume of the solution. g
Answer:
[tex]\Delta V = 234.736\,mL[/tex]
Explanation:
The quantity of moles of ethanol in the solution is:
[tex]n_{C_{2}H_{5}OH} = \left(\frac{597\,mL}{1000\,mL} \right)\cdot \left(8.35\,\frac{mol}{L} \right)[/tex]
[tex]n_{C_{2}H_{5}OH} = 4.985\,mol[/tex]
The mass and volume of ethanol in the solution are, respectively:
[tex]m_{C_{2}H_{5}OH} = (4.985\,mol)\cdot \left(46.07\,\frac{g}{mol} \right)[/tex]
[tex]m_{C_{2}H_{5}OH} = 229.658\,g[/tex]
[tex]V_{C_{2}H_{5}OH} = \frac{229.658\,g}{0.7893\,\frac{g}{mL} }[/tex]
[tex]V_{C_{2}H_{5}OH} = 290.964\,mL[/tex]
The difference between the total volume of water and ethanol mixed to prepare the solution and the actual volume of solution is:
[tex]\Delta V = (525\,mL+597\,mL) - (597\,mL + 290.964\,mL)[/tex]
[tex]\Delta V = 234.736\,mL[/tex]
The difference in volume between the total volume of water and ethanol is ΔV =234.736 mL.
Calculation for moles of ethanol:The quantity of moles of ethanol in the solution is:
[tex]nC_2H_5OH=\frac{597mL}{1000mL} *8.35mol/L\\\\nC_2H_5OH=4.985 moles[/tex]
The mass and volume of ethanol in the solution are, respectively:
[tex]mC_2H_5OH=4.985moles*46.07g/mol\\\\mC_2H_5OH=229.685g[/tex]
[tex]VC_2H_5OH=\frac{229.685g}{0.7893g/mL} \\\\VC_2H_5OH=290.964mL[/tex]
The difference between the total volume of water and ethanol mixed to prepare the solution and the actual volume of solution is:
ΔV= (525mL+597mL)- (597mL + 290.964 mL)
ΔV= 234.736mL
Find more information about Moles here:
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The mass of single iridium atom is 3.19*10^-22 grams how many iridium atoms would be in 56.4 milligrams of iridium
