The Ka for benzoic acid is 6.5 × 10−5. Calculate the pH of a 0.12 M benzoic acid solution.
Answer:
pH=4.05
Explanation:
C7H6O2 -> C7H6O- + H+
ka= [C7H6O-] [H+]/[C7H6O2]
During equilibrium
[C7H6O-]= [H+]= x^2
[C7H6O2]=0.12-x
Replace
ka= x^2/0.12-x
6.5 x10^-5= x^2/0.12-x
7.8x10^-6 - 6.5 x10^-5x=x^2
x^2+ 6.5 x10^-5x - 7.8x10^-6
Solution of quadratic equation
x=8.8 x10^-5
pH= -log [H+]= -log 8.8 x10^-5=4.05
The pH value of the benzoic acid solution is equal to 4.05.
What is pH?pH can be defined the negative logarithm of hydrogen ion concentration. pH can be seen as an abbreviation of the power of hydrogen or the concentration of hydrogen ions in a solution.
Mathematically, pH equals the negative logarithmic value of the concentration of hydrogen ion (H⁺).
pH = -log [H⁺]
The pH scale have range from 0 to 14 when 7.0 is neutral. A low pH is acidic and a high pH is basic. Pure water has a pH of 7.0.
The partial dissociation of benzoic acid in an aqueous solution can be shown as:
[tex]C_6H_5COOH +H_2O[/tex] ⇄ [tex]C_6H_5COO^- +H_3O^+[/tex]
ka= [C₆H₅O⁻] [H₃O⁺]/[C₆H₅COOH]
At equlibrium:[C₆H₅O⁻] = [H₃O⁺] = x²
[C₆H₅COOH] = 0.12-x
The equilibrium constant: ka= x²/0.12-x
6.5 × 10⁻⁵ = x²/0.12-x
7.8 × 10⁻⁶- 6.5 × 10⁻⁵ x = x²
x²+ 6.5 × 10⁻⁵ x- 7.8 × 10⁻⁶ = 0
The solution of the given quadratic equation will be:
x = 8.8 × 10⁻⁵
pH= -log [H⁺]= -log [8.8 × 10⁻⁵] = 4.05
Therefore, the pH of the given benzoic acid solution is 4.05.
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The endocrine system sends hormones through the blood to control the activities of tissues and organs.
Group of answer choices
a. True
b. False
answer:it is false
explanation: as it is true or false I think you don't need explanation
Assuming a car (with a 70-L) gas tank can hold approximately 50,000 (5.00 * 10^4) g of octane(C8H18) or 50,000 (5.00 * 10^4) g of ethanol (C2H6O). How much carbon dioxide (CO2), in grams, is produced in one tank of gas from the combustion of each amount?
Answer:
- From octane: [tex]m_{CO_2}=1.54x10^5gCO_2[/tex]
- From ethanol: [tex]m_{CO_2}=9.57x10^4gCO_2[/tex]
Explanation:
Hello,
At first, for the combustion of octane, the following chemical reaction is carried out:
[tex]C_8H_{18}+\frac{25}{2} O_2\rightarrow 8CO_2+9H_2O[/tex]
Thus, the produced mass of carbon dioxide is:
[tex]m_{CO_2}=5.00x10^4gC_8H_{18}*\frac{1molC_8H_{18}}{114gC_8H_{18}}*\frac{8molCO_2}{1molC_8H_{18}}*\frac{44gCO_2}{1molCO_2} \\\\m_{CO_2}=1.54x10^5gCO_2[/tex]
Now, for ethanol:
[tex]C_2H_6O+3O_2\rightarrow 2CO_2+3H_2O[/tex]
[tex]m_{CO_2}=5.00x10^4gC_2H_6O*\frac{1molC_2H_6O}{46gC_2H_6O}*\frac{2molCO_2}{1molC_2H_6O}*\frac{44gCO_2}{1molCO_2} \\\\m_{CO_2}=9.57x10^4gCO_2[/tex]
Best regards.
Can someone answer these questions for me please?
15. Use bond energies to determine the ∆H for the combustion of methane (CH₄).
16. Use Hess's law to determine the ∆H for the combustion of liquid methanol (CH₃OH).
17. Using your answers from question 16, how much energy will you get from burning 245.0 g of methanol in excess oxygen?
18. The ∆S is 209.6 J/K for the following reaction:
C₂H₄ (g) + 3O₂ (g) → 2CO₂ (g) + 2H₂O (g)
• What is the absolute entropy of O₂ (g)?
19. What is ∆G for the following reaction at 298 K?
2C₆H₆ (l) + 150₂ (g) → 12CO₂ (g) + 6H₂O (g)
20. If a reaction has a ∆H of -120.0 kj/mole and is spontaneous for all temperatures less than 200.0 K, what is ∆S?
Answer:
wowits too long
Explanation:
2
Next →
Physical Changes Versus Chemical Changes: Mastery Test
Submit Test
2
Select the correct answer.
The metal wire in an incandescent lightbulb glows when the light is switched on and stops glowing when it is switched off. This simple process is
which kind of a change?
ОА a physical change
B. a chemical change
ca nuclear change
OD. an lonic change
Determine whether these statements describe Geiger counters, scintillation counters, both, or neither. An amplifying device that indicates the presence of ionizing particles A device that permits determination of alpha and beta radiation emitted from a substance Film sensitive to radiation that is removed and developed to measure exposure A device used for monitoring individual cumulative exposure to ionizing radiation
Answer:
An amplifying device that indicates the presence of ionizing particles
GEIGER COUNTERS
A device that permits determination of alpha and beta radiation emitted from a substance
BOTH
Film sensitive to radiation that is removed and developed to measure exposure
NEITHER
A device used for monitoring individual cumulative exposure to ionizing radiation
NEITHER
Explanation:
1. Geiger counters and scintillation counters can be described by statements 1 and 2.
2. Statement 3 refers to film-based radiation detectors, not Geiger counters or scintillation counters.
3. Statement 4 refers to dosimeters, not Geiger counters or scintillation counters.
1. An amplifying device that indicates the presence of ionizing particles: This statement describes both Geiger counters and scintillation counters. Both types of counters use amplifying devices to detect and indicate the presence of ionizing particles.
2. A device that permits determination of alpha and beta radiation emitted from a substance: This statement describes both Geiger counters and scintillation counters. Both types of counters are capable of detecting alpha and beta radiation.
3. Film sensitive to radiation that is removed and developed to measure exposure: This statement describes neither Geiger counters nor scintillation counters. Instead, it refers to film-based radiation detectors, such as photographic film or thermoluminescent dosimeters (TLDs), which are used to measure radiation exposure.
4. A device used for monitoring individual cumulative exposure to ionizing radiation: This statement describes neither Geiger counters nor scintillation counters.
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Have scientists found any reliable predictors for earthquakes, like radon gas release or weird animal behavior?
Answer:
The "Parkfield earthquake prediction experiment" was the most heralded scientific earthquake prediction ever. It was based on an observation that the Parkfield segment of the San Andreas Fault breaks regularly with a moderate earthquake of about M 6 every several decades: 1857, 1881, 1901, 1922, 1934, and 1966.
Explanation:
this is the best I could come up with. luv u.
what is the molarity of 2.3 mol of Kl dissolved in 0.5 L of water
Answer:
[tex]4.6\,\,moL\,\,L^{-1}[/tex]
Explanation:
Molarity refers to a measure of concentration.
Molarity = moles of solute/Litres of solution
Molarity refers to number of moles of solute present in this solution.
In order to find a solution's molarity, use value for the number of moles of solute and the total volume of the solution expressed in liters
As molarity of 2.3 mol of Kl is dissolved in 0.5 L of water,
Molarity = [tex]\frac{2.3}{0.5} =4.6\,\,moL\,\,L^{-1}[/tex]
You use a 15.0 gram piece of aluminum foil to cover a pan in the oven. The specific heat for aluminum is c = 0.900 J/g o C. If the temperature is raised from 25 o C to 350 o C, how much heat was absorbed?
Answer:
Best regards.
Explanation:
Hello,
In this case, we relate the heat, mass, heat capacity and temperature when a thermal change is carried out as shown below:
[tex]Q=mCp(T_{final}-T_{initial})[/tex]
Now, for the given data, we compute the absorbed heat (due to the temperature increase) as follows:
[tex]Q=15.0g*0.900\frac{J}{g^oC}*(350^oC-25^oC) \\\\Q=4.39x10^3J=4.39kJ[/tex]
Best regards.
Answer:
4,387.5 J was absorbed
Explanation:
Calorimetry is the part of physics that is responsible for measuring the amount of heat generated or lost in certain physical or chemical processes.
In this way, there is a direct proportional relationship between heat and temperature. Thus, the amount of heat received or transferred by a body when it undergoes a temperature variation (Δt) without there being a change of physical state (solid, liquid or gaseous) is calculated using the following expression:
Q = c * m * ΔT
Where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.
In this case:
Q= ?c= 0.900 [tex]\frac{J}{g*C}[/tex]m= 15 gΔT=Tfinal - Tinicial= 350 °C - 25 °C= 325 °CReplacing:
Q= 0.900 [tex]\frac{J}{g*C}[/tex] *15 g * 325 °C
Q=4,387.5 J
4,387.5 J was absorbed
What is the volume of the Earth in comparison to the Sun? How many Earths would
we need to equal the volume of the Sun?
Answer: The total volume of the sun is 1.4 x 10 27cubic meters. About 1.3 million Earths could fit inside the sun. The mass of the sun is 1.989 x 10 30 kilograms, about 333,000 times the mass of the Earth.
Explanation: So if you divide the volume of the Sun by the volume of the Earth, you get 1,300,000.
Compare and contrast monoprotic and polyprotic acids.
Jenna is playing with her toy cars, which are both the same size. She pushes the red car with a strong push. She pushes the blue car with a weak push. What should Jenna expect to observe?
Answer:
red car will travel a much farther distance and at a faster speed as opposed to the blue car
Explanation:
Based on the information provided within the question Jenna can expect to observe that the red car will travel a much farther distance and at a faster speed as opposed to the blue car which will travel a shorter distance and at a lower speed. This is mainly because Jenna is applying an increased amount of force on the red car thus creating more acceleration and ultimately increasing the distance.
A student dissolves 20g of potassium chloride in 100cm³ of water in a beaker. What is the concentration of the solution in g/dm³?
Answer:
The concentration of the solution is 2 g/dm³
Explanation:
The equation used to find the concentration of a solution is "c = m/v"
C= concentration
M= mass
V= volume
The question asks for the answer to be in decimeters, so you need to 100 cm³ to dm³. To do this, you divide 100 by 10, giving you 10 cm³. Then you just plug in your numbers into the formula: c = 20g/10dm³.
The concentration of the potassium chloride solution has been [tex]\rm 2\;\times\;10^-^3\;g/dm^3[/tex].
The concentration has been defined as the mass of sample present in a definite volume of the solution. The concentration has been given by the moles, molarity, g/ml, g/L etc.
The concentration attained by the student has been by dissolving 20 g of KCl in [tex]\rm 100\;cm^3[/tex] water has been given in [tex]\rm g/cm^3[/tex] as:
[tex]\rm \dfrac{g}{cm^3}=\dfrac{20\;g}{100\;cm^3}\\ \dfrac{g}{cm^3}=0.2\;g/cm^3[/tex]
The concentration of the solution obtained by the student has been [tex]\rm 0.2\;g/cm^3[/tex].
The conversion of [tex]\rm cm^3\;to\;dm^3[/tex] has been given as:
[tex]\rm 1\;g/cm^3=0.001\;g/dm^3[/tex]
The concentration of [tex]\rm 0.2\;g/cm^3[/tex] solution has been given as:
[tex]\rm 1\;g/cm^3=0.001\;g/dm^3\\0.2\;g/cm^3=0.2\;\times\;0.001\;g/dm^3\\0.2\;g/cm^3=2\;\times\;10^-^3\;g/dm^3[/tex]
The concentration of the potassium chloride solution has been [tex]\rm 2\;\times\;10^-^3\;g/dm^3[/tex].
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All chemicals pollute the environment.
True
False
Answer:
False,not all chemicals pollute the enviorment
Explanation:
Hope this helps!
Brainliest?
Answer:
False
Explanation:
Oxygen?
Consider the total ionic equation below.
Ba2+ + 2NO3 + 2Na+ + Co3 —BaCO3 + 2Na+ + 2NO3
Which is the net ionic equation for the reaction?
O Ba2+ + C03 —> BaCO3
© 2Na+ + co} → Na2CO3
NO3 + Na* —> NaNO3
O Ba2+ + 2NO3 →→ Ba(NO3)2
Answer:
Ba²⁺ + CO₃²⁻ → BaCO₃
Explanation:
A net ionic equation is a way to write a chemical reaction in which you list only the species that are participating in the reaction.
For the reaction:
Ba²⁺ + 2NO₃ + 2Na⁺ + CO₃²⁻ → BaCO₃ + 2Na⁺ + 2NO₃
As you can see, NO₃ and Na⁺ are not participating in the reaction. Thus, net ionic equaation is:
Ba²⁺ + CO₃²⁻ → BaCO₃
Complete Question
Consider the total ionic equation below.
[tex]Ba^{2+} + 2NaO_3^{1 -} + 2Na^{+} + CO_3^{2-} ----> BaCO_3 + 2Na^{+} + 2NO_3^{1-}[/tex]
Which is the net ionic equation for the reaction?
A [tex]Ba^{2+} _{(aq)} + CO_3 ^{2-} _{(aq)} ----> BaCO_3_{(s)}[/tex]
B [tex]2Na^+ + CO_2 ----> Na2CO3[/tex]
C [tex]NO3 + Na ^ + ----> NaNO3[/tex]
D [tex]Ba_2^+ + 2NO3 ----> Ba(NO3)2[/tex]
Answer:
Option A is the correct option
Explanation:
The given ionic equation is
[tex]Ba^{2+} + 2NaO_3^{1 -} + 2Na^{+} + CO_3^{2-} ----> BaCO_3 + 2Na^{+} + 2NO_3^{1-}[/tex]
Looking at this complete ionic equation we see that [tex]Na^{+1} \ and \ NO_3^{1-}[/tex] did not change in the reaction so they will not be included in the net ionic equation so the net ionic equation becomes
[tex]Ba^{2+} _{(aq)} + CO_3 ^{2-} _{(aq)} ----> BaCO_3_{(s)}[/tex]
what is the type of bonding for ammonium lauryl sulfate?
Answer:
Hydrogen bonding.
Explanation:
Ammonium lauryl sulfate is also known as ammonium dodecyl sulfate there are two parts in Ammonium lauryl sulfate one is nonpolar hydrocarbon and other part polar sulfate group.
Due to polarity of sulfate group its form hydrogen bond very easily.
It is mainly used as foaming agent the main reason of its use is very much soluble in water and making hydrogen bond with water.
How much faster will Xenon escape out and opening than carbon dioxide gas?
gas with the smallest amount of molecular weight will effuse the quickest
Which describes the boundary where earthquake activity occurs along rift valleys? divergent boundary in the ocean divergent boundary on land convergent boundary in the ocean divergent boundary on land
Answer:
Divergent boundary on land
Explanation:
A rift valley is a lowland region that forms where Earth’s tectonic plates move apart (diverge), or rift. Rift valleys are found both on land and at the bottom of the ocean, where they are created by the process of seafloor spreading.
Rift valleys are created by tectonic activity and not the process of erosion.
Tectonic plates are huge, rocky slabs of Earth's lithosphere—its crust and upper mantle. Tectonic plates are constantly in motion—shifting against each other in fault zones, falling beneath one another in a process called subduction, crashing against one another at convergent plate boundaries, and tearing apart from each other at divergent plate boundaries.
The most well-known rift valley on Earth is probably the so-called "Great Rift Valley System" which stretches from the Middle East in the north to Mozambique in the south. The area is geologically active, and features volcanoes, hot springs, geysers, and frequent earthquakes.
Divergent boundary on land describes the boundary where earthquake activity occurs along rift valleys
for better understanding let's explain divergent plate boundary
Divergent plate boundary often happens only where 2 tectonic plates separate and thereafter create new land. most of them are in the ocean (Mid Atlantic Ridge). The Great Rift Valley in Africa is an example of a divergent plate boundary on thereafter the Great Rift Valley is filled of with water and product is a sea.Rift valley is commonly known as an area in a mid-ocean ridge where the plates are often separated and new crust begins to form. where plate tectonics exist, there is a divergent boundary or divergent plate boundary also called constructive boundary orfrom the above we can therefore say that the answer Divergent boundary on land describes the boundary where earthquake activity occurs along rift valleys, is correct
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if 203 mL of water is added to 5.00 mL of 4.16 M KCl solution, what is the concentration of the dilute solution
Answer:0.100
Explanation:
3. The organelle that produces materials that need to be released from the cell
is the:
A. storage granule
B. microvilli
C. chloroplast
D. vacuole
4. An organelle found in plant cells, fungi, and some protists, animal cells, and
bacteria is the:
A. storage granule
B. microvilli
C. chloroplast
Dvacuole
ANSWER IT PLEASE!!!!! A virus is a genome, or set of chromosomes, contained inside a protein capsule called a capsid. A virus can be either a single or double strand of RNA or DNA. Although viruses are made of genetic information, they do not have cells. They also need to attach to a host cell in order to live and reproduce. Host cells can be from animals, plants and even bacteria and fungi. Scientists debate whether or not viruses are considered living organisms. Most agree that viruses are not living.
Which of these statements is true based on the information in the passage?
Answer:
?
Explanation:
What are the statements? You've given the passage but not the statements
Oxygen decays to form nitrogen.
3
150
->
19N + e
8
1
This type of nuclear decay is called
Answer:
Radioactive isotopes ranging from 11O to 26O have also been characterized, all short-lived. The longest-lived radioisotope is 15O with a half-life of 122.24 seconds, while the shortest-lived isotope is 12O with a half-life of 580(30)×10−24 seconds (the half-life of the unbound 11O is still unknown).
Please help
What causes a wave to have a higher amplitude?
Answer:
More energy
Explanation:
Wave amplitude is determined by the energy of the disturbance that causes the wave. A wave caused by a disturbance with more energy has greater amplitude.
Answer:
energy of the disturbance
Explanation:
........ btw bts paved the way I saw you was army and thought I would say that
what causes different colors to appear in the sky?
Answer:
Molecules and small particles in the atmosphere change the direction of light rays, causing them to scatter. Scattering affects the color of light coming from the sky.
Explanation:
please help its due today..!
Answer:
This all should be correct:
c
a
c
a
Answer:
C, A, B, B
Explanation:
Question 1: C. inner core
Why? Because the inner core is literally the center of the Earth. Meaning it is the hottest part of the Earth.
Question 2: A. crust
Why? The crust is the outer most layer which is the layer we walk on so to speak. The Earth can be broken up into four layers and as said before the crust is the outer part of it. It is actually amounts to less than 1% of Earth's volume.
Question 3: B. basalt
Why? If we were to average the oceanic crust we would get something around six kilometers and this is the thickness. This is mostly made up of basalt.
Question 4: B. outer core
Why? Due to difference in pressure and temperature the outer core tends to release dense matter which sinks while warm (less dense rises). This causes the Coriolis force, resulting from the Earth's rotations.
what are the rules for calculating protons
Answer:
Find the element,
Explanation:
Finding the element will tell you how many protons there are. For example, if you are given an atom of oxygen, you can figure out the number of protons by looking it up on a periodic table, which gives you 8.
If an atom is neutral, find the number of electrons. This number will also be the number of protons.
Of these four liquids, which has the lowest viscosity? options: A. Pancake syrup at room temperature B. Motor oil that is in the refrigerator C.Liquid mercury at room temperature D. A glass of lemonade at room temperature
Answer: B. Motor oil that is in the refrigerator
Explanation:
Viscosity can be defined as the resistance provided by the fluid against its movement or flow. It restricts the resistance to change in shape or movement of fluid. The water has high viscosity as the water molecules do not restrict movement on the surface.
According to the given problem, motor oil has lowest viscosity because it may contain heavy hydrocarbons, which may restrict its flow also when kept in refrigerator, the bonds between hydrocarbons get compact hence, viscosity decreases.
Answer:
Option C, .Liquid mercury at room temperature
Explanation:
The viscosity of liquid mercury at room temperature is 1.526 cP. While the visocsity of lemonade at room temperature ranges between 15.10 to 17.44 cP. Viscosity of Motor oil kept in the refrigerator is equal to 1328.0 cP. And Viscosity of Pancake syrup at room temperature is 5,000 cp. Hence, out of all the four liquids, mercury has the lowest viscosity
Hence, option C is correct
Which is the control center for the endrocrine system?
Answer:
hypothalamus
Explanation:
How many joules of heat are needed to raise the temperature of 1.5 g of aluminum at 45°C, if the specific heat of aluminum is 0.75 J/g°C? Group of answer choices
Answer:
50.6 J
Explanation:
We have to use the formula
H= mcθ
Where
H= quantity of heat absorbed in joules
m= mass of aluminum= 1.5g
c= specific heat capacity of aluminum= 0.75 J/g°C
θ= rise in temperature of aluminum = 45°C
Substituting into H= mcθ
We have ;
H= 1.5g × 0.75 J/g°C × 45°C
H= 50.6 J
Several atmospheric gases contribute to global warming: carbon dioxide, methane, and nitrous oxide. Considering this, which choice would do the LEAST to directly reduce atmospheric carbon dioxide.
Answer:
A
help u and it's A
Explanation:
