A 1.0 m solution of a compound with 2 ionizable groups (pka's = 6.2 and 9.5; 100 ml total) has a ph of 6.8. what are the concentrations of the relevant acid and conjugate base?
Answer:
[H₂A] = 0.2M
[HA⁻] = 0.8M
Explanation:
A compound with 2 ionizable groups has as equilbriums:
H₂A ⇄ HA⁻ + H⁺ ⇄ A²⁻ + H⁺
A pH of 6.8 is near to the first equilibrium:
H₂A ⇄ HA⁻ + H pKa = 6.2
To determine concentrations of the acid H₂A and conjugate base HA⁻ we use H-H equation:
pH = pKA + log [HA⁻] / [H₂A]
6.8 = 6.2 + log [HA⁻] / [H₂A]
0.6 = log [HA⁻] / [H₂A]
3.981 = [HA⁻] / [H₂A] (1)
As concentration of the buffer is 1.0M:
1M = [HA⁻] + [H₂A] (2)
Replacing (2) in (1):
3.981 = 1- [H₂A] / [H₂A]
3.981[H₂A] = 1 - [H₂A]
4.981 [H₂A] = 1
[H₂A] = 0.2M
And [HA] = 1M - 0.2M = 0.8M
4.One rubber tire can generate about250,000 BTUS (1BTU=.0003KW ) when it is burned. The average American home consumes about 10,000 kWh of electricity per year. How many tires would be needed to meet the annual electricity demand of ten homes for one year if the production of electricity from tires is 50% efficient??
Answer:
The number of tires required to power ten homes for one year is approximately 2,730 tires
Explanation:
The given information are;
The energy generated by burning one rubber tire = 250,000 BTUs
1 BTU = 0.0003 kW
The amount of energy consumed by the average American home = 10,000 kWh
Therefore, the amount of energy generated by burning one tire in kW can be found as follows;
The energy generated by burning one rubber tire = 250,000 BTUs
1 BTU = 0.0003 kW
∴ 1 BTU × 250,000 = 250,000 BTUs = 0.0003 kW × 250,000 = 75 kW
We note that 250,000 BTUs is equivalent to 263764 kJ
1 kWh is equivalent to 3600 kJ
10,000 kWh = 10,000 × 3600 = 36,000,000 kJ
The energy requirement for ten homes for one year = 10 × 36,000,000 kJ = 360,000,000 kJ
At 50% efficiency, the energy produced per tire = 0.5 × 263764 kJ = 131,882 kJ
The electrical energy produced per tire = 131,882 kJ/tire
The number of tires required to power ten homes for one year = 360,000,000 kJ/ 131,882 kJ/tire = 2,729.71293 ≈2,730 tires
The number of tires required to power ten homes ≈2,730 tires.
What is the mass of substance that exactly fills a 247.2 mL container? The density of the substance is 0.81 g/mL. Give the answer with two decimals.
Answer:
mass = 200.23 gExplanation:
The density of a substance can be found by using the formula
[tex]Density = \frac{mass}{volume} [/tex]
Since we are finding the mass
mass = Density × volumeFrom the question
Density = 0.81 g/mL
volume = 247.2 mL
Substitute the values into the above formula and solve for the mass
mass = 0.81 × 247.2
= 200.232
We have the final answer as
mass = 200.23 g to 2 decimal placesHope this helps you
A color-coded periodic table. Which elements are metals? Check all that apply. rhenium (Re) boron (B) lithium (Li) krypton (Kr) phosphorus (P) mercury (Hg)
Answer:
re) li) hg)
Explanation:
An example of a physical property of an element is the element's ability to
Answer:
dissolve
Explanation:
When it dissolves , no chemicals are formed and it is considered as a physical property.
Answer:
what is it ???? I need help to
An unknown solid is placed on a scale and has a mass of 2.5 grams. The solid then displaces 35 mL of water in a graduated cylinder. Find the unknown solid’s density.
Answer:
The unknown solid’s density is 0.071 [tex]\frac{g}{mL}[/tex]
Explanation:
Density is defined as the property that matter, whether solid, liquid or gas, has to compress into a given space. In other words, density is a quantity that allows us to measure the amount of mass in a certain volume of a substance. Then, the expression for the calculation of density is the quotient between the mass of a body and the volume it occupies:
[tex]density=\frac{mass}{volume}[/tex]
From this expression it can be deduced that density is inversely proportional to volume: the smaller the volume occupied by a given mass, the higher the density.
Archimedes' principle states that every body immersed in a fluid experiences a vertical and upward thrust equal to the weight of fluid dislodged. In other words, this principle says that the volume of the object is equal to the volume of the water displaced or displaced. So:
mass= 2.5 gramsvolume=35 mLReplacing in the definition of density:
[tex]density=\frac{2.5 g}{35 mL}[/tex]
you get:
[tex]density=0.071\frac{g}{mL}\[/tex]
The unknown solid’s density is 0.071 [tex]\frac{g}{mL}[/tex]
Answer: The answer would be 0.071 g/cm^3
Explanation:
a sample of a substance has a mass of 52.5g and displaces a volume of 4.2ml. what is the density of the substance
Answer:
Density = 12.5 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]Density = \frac{mass}{volume} [/tex]
From the question
mass = 52.5 g
volume = 4.2 mL
Substitute the values into the above formula and solve for the density
We have
[tex]Density = \frac{52.5}{4.2} \\ [/tex]
We have the final answer as
Density = 12.5 g/mLHope this helps you
What is the volume of 88.2 g of silver metal (density = 10.50 g/cm^3)
Answer:
The answer is
8.4 mLExplanation:
The volume of a substance when given the density and mass can be found by using the formula
[tex]volume = \frac{mass}{density} [/tex]
From the question
mass = 88.2 g
density = 10.5 g/cm³
The volume is
[tex]volume = \frac{88.2}{10.5} [/tex]
We have the final answer as
8.4 mLHope this helps you
Answer:
8.4 km
Explanation:
examples of white bloodcell
Answer: White blood cells help the immune system and help fight infection and disease.
Which type of scientist
studies everything
from the tiniest
organisms to human
beings?
Answer:
Biology
Explanation:
Biology is the study of all living beings. From the smallest algae or micro organism to the biggest living being is all covered under biology. How micro organisms live, how do they function and how they affect other living beings is studied in biology.
Answer:
Micro bioligist
Explanation: hope this helps
Which part of an atom is mostly empty space?
A) Nucleus
B) Proton cloud
C) Electron cloud
D) Neutron
Answer:
Answer is C. Electron cloud
Explanation:
<3
If the density of a substance is d=2.1g/cm^3 what is the mass of 20.0mL of this substance
Answer:
Explanation:
density = mass (g)/ volume (cm3)
2.1 = mass / 20 cm3
mass = 42 g
be attention that each 1 ml =1cm3
It takes Serina 0.25 hours to drive to school. Her route is 16 meters long. What is
Serina's average speed on her drive to school? *
Answer:
60 (1 hour) × 0.25 = 15 minutes
15 ÷ 16 = 0.9375 meters per minute
what does H2CO3 mean on the periodic table
Answer:
Carbonic acid
Best of luck
If a falling rock undergoes a Δv of 112ms due to an a¯¯¯ of 9.8 m/s2, how long did it fall? A. 6.7 seconds B. 11.4 seconds C. 0.09 seconds D. 9.8 seconds
Answer:
11.4
Explanation:
You wont fail your quiz .
If a falling rock undergoes a Δv of 112ms due to a speed of 9.8 m/s2, it will take 11.4 seconds to fall.
What is speed?The speed is the rate of change of position of an object with a given time of interval or per unit time then it is known as speed and it is the ratio of distance traveled to the time taken unit is meter per second.
The speed of an object is 9.8 m/s² distance traveled is 112m/s so the time will be,
Speed = distance / time
Substituting the value,
Time = distance/ speed
Time = 9.8 m/s² / 112m/s
Time = 11.4 seconds
Therefore, it will take 11.4 seconds to fall, if a falling rock undergoes a Δv of 112ms due to a speed of 9.8 m/s².
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Which particles contribute to the atomic number and why ??
Answer:
the number of protons in the nucleus that are found in an atom is what determines an element's atomic number.why you may ask and thats because Protons contribute to the mass of an atom.(along with neutrons but they dont have a charge)but protons provide a positive charge to the nucleus.
Explanation:
because the atom is electrically neutral, the number of electrons must equal the number of protons.
The particles that contribute to the atomic number are the number of protons. Protons contribute to the atomic number because it is positively charged and present inside the nucleus. The correct option is c.
What is the atomic number?The quantity of protons in an atom's nucleus is known as the atomic number. The number of protons determines an element's identity. The atomic number contributes to the number of protons.
There are three subatomic particles present inside the particles. These are electrons, protons, and neutrons. The electron is negatively charged, a proton is positively charged, and a neutron is neutral.
Because the atom is electrically neutral, the number of electrons must equal the number of protons.
Thus, the correct option is c. protons.
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The question is incomplete. Your most probably complete question is given below:
a. atoms
b. neutrons.
c. protons.
d. electrons.
71. Chloroform is a liquid once used for anesthetic. What is the volume of 5.0 g of chloroform. The density of chloroform is 1.49 g/mL.
Answer:
Volume, V = 3.35 mL
Explanation:
Given that,
The density of chloroform is 1.49 g/mL
We need to find the volume of 5.0 g of chloroform. Let V is its volume.
Density is equal to mass per unit volume.
[tex]d=\dfrac{m}{V}\\\\V=\dfrac{m}{d}\\\\V=\dfrac{5\ g}{1.49\ g/mL}\\\\V=3.35\ mL[/tex]
So, the volume of 5 g of chloroform is 3.35 mL.
1. What is one example of a chemical reaction?
Answer:
AN EXPLOSION
Explanation:
What has mass?
A. Energy
B. Heat
C. Light
D. Matter
Answer:
matter
Explanation:
Answer:
matter is your answer
hope this helped
what is Alkanoic acid
Answer:
an aliphatic acid (such as hexanoic acid) regarded as derived from an alkane and containing the same number of carbon atoms as the alkane.
Explanation:
Answer:
Acetic acid, systematically named ethanoic acid, is a colourless liquid organic compound with the chemical formula CH₃COOH. When undiluted, it is sometimes called glacial acetic acid. Vinegar is no less than 4% acetic acid by volume, making acetic acid the main component of vinegar apart from water.
A small snail makes a journey that takes him in a circle of area 0.750square meters in one day. What is the area of the circle that the snail makes in square inches? Round to three significant figures. Do not give the units in your answer.
Answer:
1160
Explanation
1 square meter = 1550 square inches
[tex].0750 square meters * \frac{1550 square inches}{1 square meter}[/tex] = 1162.5 becomes 1160 when rounded to 3 sig figs.
The area of the circle of 0.750 m² is equivalent to 1.16 × 10³ in².
We want to convert 0.750 m² to in². We will use the conversion factor 1 in = 0.0254 m, squared.
[tex]0.750 m^{2} \times (\frac{1in}{0.0254m} )^{2} = 1.16 \times 10^{3} in^{2}[/tex]
The area of the circle of 0.750 m² is equivalent to 1.16 × 10³ in².
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a nickel atom (atomic symbol Ni) has an atomic number of 28 and has an atomic mass of 59. how many neutrons does it have ??
Answer: 31 neutrons
Explanation:
What is a joule?
O A. A unit of measurement for mass
O B. A unit of measurement for power
C. A unit of measurement for energy
O D. A unit of measurement for gravity
Answer:
C. A unit of measurement for energy
Explanation:
Joule is the SI unit of
EnergyWorkAnd HeatUnit of measurement of mass: Kilogram(Kg)
Unit of measurement of Power: Watt(W)
Unit of measurement of Gravity: m/s^2
Hope this helps ;) ❤❤❤
Answer:
C. A unit of measurement for energy
Explanation:
a p e x 2021!
what is the atomic number, mass number, element symbol, group number, and period number for oxygen?
Answer:
Atomic no. = 8
Mass no. = 16
Period no. = 2
Group no. = 6
Which of the folling ion or atom has smallest size?
a. CI
b. CI-
c. K
d. K+
14C is an isotope of carbon that possesses:_______ a) 6 protons, 8 neutrons, and 2 electrons. b) 6 protons, 6 neutrons, and 2 electrons. c) 6 protons, 8 neutrons, and 6 electrons. d) 8 protons, 6 neutrons, and 2 electrons. e) 6 protons, 2 neutrons, and 6 electrons.
Answer:
Option C. 6 protons, 8 neutrons and 6 electrons.
Explanation:
14C has the following:
Mass number = 14
Atomic number = 6
Next we shall determine the number of protons in 14C. This can be obtained as follow:
Atomic number is simply the number protons in an atom. Thus,
Proton = Atomic number
Atomic number = 6
Proton = Atomic number = 6
Proton = 6
Next, we shall determine the number of neutrons in 14C. This can be obtained as follow:
Mass number = proton + neutron
Mass number = 14
Proton = 6
Neutron =.?
Mass number = proton + neutron
14 = 6 + neutron
Collect like terms
Neutron = 14 - 6
Neutron = 8
Finally, we shall determine the number of electrons in 14C.
This can be obtained as follow:
Since the isotope i.e 14C has no charge, it means that the atom is in it's ground state. Hence, the number of protons and the number of electrons are the same i.e
Electron = proton
Proton = 6
Electron = proton = 6
Electron = 6
From the above calculations, 14C has
6 protons, 8 neutrons and 6 electrons.
Why are the trends and exceptions to the trends in ionization energy observed? Check all that apply. -Ionization energy tends to increase down a group because the electrons get farther away from the nucleus. -Ionization energy tends to increase across a period because the nuclear charge increases. -Ionization energy tends to increase across a period because electrons are added to the same main energy level. -The ionization energies of the elements in Group 16 tend to be slightly smaller than the elements in Group 15 because the fourth electron is added to an unfilled p orbital. -The ionization energies of elements in Group 13 tend to be lower than the elements in Group 2 because the full s orbital shields the electron in the p orbital from the nucleus.
Answer:
2, 3, 5
Explanation:
just the person above
The correct answer is the Ionization energy tends to increase across a period because electrons are added to the same main energy level and the ionization energies of elements in Group 13 tend to be lower than the elements in Group 2 because the full S orbital shields the electron in the p orbital from the nucleus.
What is causing the ionization energy trend?The first ionization energy increases as you move left to right across a period on the periodic table. This is because when the nuclear charge rises, the outermost electron has become more tightly connected to the nucleus.Learn more about Ionization energy here:
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4) Which is a characteristic of a solution? * Its particles scatter light. Its particles are evenly distributed. Its particles settle out.
Answer: The correct answer is B. It’s particles are evenly distributed. (:
Explanation:
Answer:
b
Explanation:
225 mm=_____hm
this is a 2-step problem
To find how many hectometers this is, we can divide the amount by 100,000.
225 / 100000 = 0.00225
Therefore, 225mm = 0.00225hm
Best of Luck!
You are making sweet tea. You add 56g of sugar into 78g if tea. What is the mass percent of sugar ?
Answer:
Approximately 72%
Explanation:
[tex]Sugar = 56g\\Tea's \:mass = 78g\\\\Sugar\:mass\:percentage = \\\frac{56}{78} \times 100\\\\\frac{5600}{78} \\\\=71.79\\Approximately \:72\%[/tex]