Answer:
c. 1.0 mole C5H5N and 1.5 mole C5H5NHCl
Explanation:
We can determine pH of a buffer using H-H equation:
pH = pKa + log [A⁻] / [HA]
Where [A⁻] is concentration of conjugate base and [HA] concentration of weak acid. These concentrations can be computed as moles of each species.
We need to determine pKa of both NH₃ and C₅H₅N buffers, thus:
pKb = -log Kb
NH₃ pKb = -log 1.8x10⁻⁵ = 4.74
C₅H₅N pKb = -log 1.7x10⁻⁹ = 8.77
And pKa = 14 - pKb:
NH₃ pKa = 14 - 4.74 = 9.26
C₅H₅N pKb = 14 - 8.77 = 5.23
A buffer works only under pH's between pKa-1 and pKa + 1. As pKa NH₃ buffer is 9.23 is not possible to produce a buffer with pH 5.05 for this system.
Thus, we only will compute the buffers made with C₅H₅N:
c. 1.0 mole C5H5N (Weak base) and 1.5 mole C5H5NHCl (Conjugate acid)
pH = pKa + log [A⁻] / [HA]
pH = 5.23+ log [1.0 moles] / 1.5 moles]
pH = 5.05d. 1.5 mole C5H5N and 1.0 mole C5H5NHCl
pH = pKa + log [A⁻] / [HA]
pH = 5.23+ log [1.5 moles] / 1.0 moles]
pH = 5.41Right solution is:
c. 1.0 mole C5H5N and 1.5 mole C5H5NHClHow old is a bone if it presently contains 0.3125g of C-14, but it was estimated to have originally contained 80.000g of C-14?
Half-life of C-14 is 5730 years
The age of the bone is the time taken to decay carbon -14 from a mass of 80 g to 0.3125 g. The decay time is 46209 years. That is the age of the bone.
What is carbon dating?Carbon -14 isotope is radioactive and undergoes nuclear decay by the emission of charged particles. The age of a fossil sample which contains carbon -14 can be determined using the time of decay.
Half life of C-14 = 5730 years
decay constant k = 0.693 / 5730 = 0.00012 yr⁻¹
Initial amount of C-14 = 80 g
final amount = 0.3125 g
Then the time taken to decay 80 g to 0.3125 g is t = 1/k ln (80/0.312)
t = ln (80/0.312) / (0.00012 yr⁻¹)
= 46209 years.
Therefore, the age of the bone is 46209 years.
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Cubes are three-dimensional square shapes that have equal sides. What is the density of a cube that has a mass of 12.6 g and a measured side length of 4.1 cm? (Density: D = )
Answer:
0.1828g/cm³
Explanation:
density= mass÷volume
m= 12.6g
v= 4.1×4.1×4.1 = 68.921cm³
•
density= 12.6÷68.921 = 0.1828g/cm³
What is conservation area write in 8 points
Answer:
The Conservation area is the pay way to the special architectural and historic interest these are special character.
Explanation:
Conservation area is the features of building and use that historical development to contribute to its special character material and style.
Conservation area is that contain process to the application management development process and local residents.Conservation is that the produce demolition of a building structure with the conservation area,contribute to the group in individually.Conservation area that are special protection in the trees to the dangerous tree and some of the fruit trees.Conservation area are often to the protected by their building, planning works, these character area of appearance.Development rights to the conservation area require to the planning and permission to the outside area.Conservation area is classified to the regulation and the restricted area to the department planning.Conservation area is a composed to the impact of materials and building and the setting of impact.The new development in the conservation area is to the process of the renewal and the managed in the conservation area.Balance the equation: "Sodium oxide reacts with water to form sodium hydroxide and hydrogen." I can't find the correct coefficients to balance the equation. I have written my unbalanced equation in the file attached.
Answer:
So, sodium oxide + water = sodium hydroxide + hydrogen is written Na2O+H2O-->NaOH+H.
To balance the equation it should read NaO+H2O-->2NaOH
Explanation:
Na2O+H2O-->2NaOH+0H2.......the 0H2 is dropped because there is no value
The correct balance of equation will be
Na2O + H2O - - > 2NaOH
What is a balanced chemical equation?A chemical equation where the number of atoms on both the reactant side and the product side of the reaction are equal is called a balanced chemical equation.
In a balanced chemical equation, not only the number of atoms but the charge and the mass is the same on both sides of the equation.
A chemical equation needs to be balanced to validate the law of conservation of mass. The law of conservation of mass states that the 'mass can neither be created nor destroyed in a chemical reaction'.
If the chemical equation is not balanced, it will go against the fundamental law of law of conservation of mass.
Thus, the chemical equations need to be balanced.
Therefore to balanced the given chemical equation, we equate the number of atoms on both the reactant and the product side of the reaction.
It will be written as
Na2O + H2O - - > 2NaOH
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Chromium is dissolved in sulfuric acid according to the following equation: Cr + H2SO4 ⇒ Cr2 (SO4) 3 + H2
a) How many grams of Cr2 (SO4) 3 can be obtained by reacting 165 g of 85.67% H2SO4 of purity?
b) If 485.9 g of Cr2 (SO4) 3 are obtained, what is the yield of the reaction?
Answer:
[tex]\large \boxed{\text{a)188.4 g; b) 98.67 $\, \%$}}[/tex]
Explanation:
We will need a balanced chemical equation with masses and molar masses, so, let's gather all the information in one place.
Mᵣ: 98.08 392.18
2Cr + 3H₂SO₄ ⟶ Cr₂(SO₄)₃ + 3H₂
To solve the stoichiometry problem, you must
Use the molar mass of H₂SO₄ to convert the mass of H₂SO₄ to moles of H₂SO₄ Use the molar ratio to convert moles of H₂SO₄ to moles of Cr₂(SO₄)₃ Use the molar mass of Cr₂(SO₄)₃ to convert moles of Cr₂(SO₄)₃ to mass of Cr₂(SO₄)₃
a) Mass of Cr₂(SO₄)₃
(i) Mass of pure H₂SO₄
[tex]\text{Mass of pure} = \text{165 g impure} \times \dfrac{\text{85.67 g pure} }{\text{100 g impure}} = \text{141.36 g pure}[/tex]
(ii) Moles of H₂SO₄
[tex]\text{Moles of H$_{2}$SO}_{4} = \text{141.36 g H$_{2}$SO}_{4} \times \dfrac{\text{1 mol H$_{2}$SO}_{4}}{\text{98.08 g H$_{2}$SO}_{4}} = \text{1.441 mol H$_{2}$SO}_{4}[/tex]
(iii) Moles of Cr₂(SO₄)₃
The molar ratio is 1 mol Cr₂(SO₄)₃:3 mol H₂SO₄ [tex]\text{Moles of Cr$_{2}$(SO$_{4}$)}_{3} = \text{1.441 mol H$_{2}$SO}_{4} \times \dfrac{\text{1 mol Cr$_{2}$(SO$_{4}$)}_{3}}{\text{3 mol H$_{2}$SO}_{4}} = \text{0.4804 mol Cr$_{2}$(SO$_{4}$)}_{3}[/tex]
(iv) Mass of Cr₂(SO₄)₃ [tex]\text{Mass of Cr$_{2}$(SO$_{4}$)}_{3} = \text{0.4804 mol Cr$_{2}$(SO$_{4}$)}_{3} \times \dfrac{\text{392.18 g Cr$_{2}$(SO$_{4}$)}_{3}}{\text{1 mol Cr$_{2}$(SO$_{4}$)}_{3}} = \textbf{188.4 g Cr$_{2}$(SO$_{4}$)}_{3}\\\text{The mass of Cr$_{2}$(SO$_{4}$)$_{3}$ formed is $\large \boxed{\textbf{188.4 g}}$}[/tex]
b) Percentage yield
It is impossible to get a yield of 485.9 g. I will assume you meant 185.9 g.
[tex]\text{Percentage yield} = \dfrac{\text{Actual yield}}{\text{Theoretical yield}} \times 100 \, \% = \dfrac{\text{185.9 g}}{\text{188.4 g}} \times 100 \, \% = \mathbf{98.67 \, \%}\\\\\text{The percentage yield is $\large \boxed{\mathbf{98.67 \, \%}}$}[/tex]
boron has two naturally occurring isotopes: boron -10 (abundance = 19.8% , mass = 10.013 amu) boron -11 (abundance = 80.2%, mass= 11.009 amu) Calculate th eatomic mass of boron
Explanation:
eam=%abudance×mass+%abudance×mass
eam=19.8%×10.013/100+80.2%×11.009/100
eam=198.2574/100+882.9218/100
eam=1081.1792/100
eam=10.811792
eam=10.812
A student with a body temperature of 37°C holds a piece of ice that has a
temperature of -8°C.
Which statement best explains what happens?
1. Thermal energy transfers coldness from the student's hand to the ice.
2. Heat transfers coldness from the ice to the student's hand.
3. Heat transfers thermal energy from the student's hand to the ice.
4. Thermal energy transfers heat from the student's hand to the ice.
Answer:
Thermal energy transfers hear from the students hand to the ice
Explain the reaction that would occur in a galvanic cell between solutions of Al 3+and Pb 2+ . Identify the oxidation and reduction reactions and the location of each reaction. Then, use the standard reduction potential tables to determine the cell potential.
Answer:
Al ==> Al^3+ + 3e
Pb^2+ + 2e ==> Pb
Oxidation is the loss of electrons. Reduction is the gain of electrons. Which half rxn above lost and which gained?
For the potential of the cell, look up the reductions potentials, change the sign of the Al half cell, add in the potential for the Pb and add them.
Explanation:
Calculate the pressure drop over a 100m length due to friction when a slurry made from 1.0-mm silica particles is pumped through a horizontal 6-cm diameter pipeline (smooth pipe) at 2.5 m/s. The slurry contains 25 per cent silica by volume. The density of silica is 2700 kg/m3, rhow = 1000 kg/m3, μw = 0.001 kg/ms. Use a value of 82 for Ω. Drag coefficient for these particles,CD, may be taken as 0.44 .
For the slurry/Pipe system in question 1, estimate the deposition velocity.
Answer:
The answer is "2.78".
Explanation:
Given values:
CD= 0.44
Formula:
[tex]\bold{f_r= \frac{v^{2}}{ g(s-1)D}}[/tex]
g=9.8
s= 2.7
D= 0.06
[tex]\to f_r=\frac{2.5^2}{9.8(2.7-1)0.06}\\\\[/tex]
[tex]=\frac{2.5 \times 2.5}{9.8 \times 1.7 \times 0.06 }\\\\=\frac{6.25}{.9996 }\\\\=6.252501[/tex]
[tex]\phi = \frac{82\times v}{ \sqrt{cD} \times f_r^{-1.5}}\\\\[/tex]
[tex]= \frac{82 \times 0.25 }{ \sqrt{0.44} \times 6.25^{1.5}}\\\\=2.4285\\[/tex]
[tex]\frac{\bigtriangleup P f_1 s_1}{L} = \frac{\bigtriangleup Pf_w}{L}(1+\phi)\\[/tex]
[tex]=\frac{2fwSwv^2 (1+2.4285)}{D}\\\\[/tex]
[tex]Re= \frac{D \bar v Sw}{M_w}\\[/tex]
[tex]=\frac{0.06 \times 2.5 \times 1000 }{0.001}\\\\=\frac{150 }{0.001}\\\\= 150 \times 10^{3}\\\\= 1.50 \times 10^{5}\\\\[/tex]
[tex]fw= 0.00389[/tex]
[tex]\to \frac{\bigtriangleup P f_1 s_1}{L}[/tex]
[tex]\to \frac{2 \times 0.00389 \times 1000 \times2.5^2 \times 3.4265}{0.06}\\\\\to 2.78[/tex]
what is local unit?
.
Answer:
Explanation:
Local unit means a county, city, village, or township.
26. Calculate the mass of hydrogen formed when 25 grams of aluminum reacts with excess hydrochloride acid. 2AI + 6HCl →l Al2Cl6 + 3H2
Answer:
2.76 gram
Explanation:
2AI + 6HCl → 2AlCl3 + 3H2
get the mol of aluminum => n = m / M = 25 / 27 = 0.925 (mol)get the ratio mol of Hydro => nH2 = 0.925 * 3 / 2 = 1.38 (mol)get weight of hydro mH2 = n x M = 1.38 x 2 = 2.76 (gram)Answer
Al +2 HCl - AlCl2 + H2
what does porous mean
Answer:
porous = allowing liquid or air to pass through slowly
I hope it's helpful
Answer:
It is a rock or or other materials, having minutes interstices through which liquid or air may pass.
The diameter of neutral atoms generally decreases going left to right across one period on the periodic table. What change causes this decrease in diameter of atoms?
Explanation:
Atomic size gradually decreases from left to right across the periodic table because within a period of elements, all electrons are added to the same shell. However, at the same time, protons are being added to the nucleus, making it more positively charged. The effect of increasing proton number is greater than that of the increasing electron number. Therefore, there is a stronger nuclear attraction. This means that the nucleus attracts the electrons more strongly, pulling the atom's electron shells closer to the nucleus. As a result, the atomic diameter of the atom decreases.
List the metals Mg, Cu, Au, Na and Al in the decreasing order of their reactivity with air.
Answer:
Na is most reactiveAlcuAu is less reactiveIN HEREAnswer:
Potassium (K)
Sodium (Na)
Calcium (Ca)
Magnesium (Mg)
Aluminium (Al)
Iron (Fe)
Lead (Pb)
Copper (Cu)
Silver (Ag)
Gold (Au)
what is the mass of 1 mole of chlorine ion
Answer:
35.453 g
Explanation:
one mole of chlorine is 34.453 g
Answer:
One mole of chlorine atoms has a mass of 35.453g. A mole of something means that you have 6.023×1023 units of that something. So if you have a mole of Cl atoms you have 6.023×10
Hope this helps <3
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How much does 9.8 liters of ammonia (NH3) weigh at standard temperature and pressure (273 K and 100 kPa)?
A. 13.84 grams
B. 7.44 grams
C. 17 grams
D. 12.91 grams
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Can someone tell me the advantages and disadvantages of Ceramics? I need scientific, good and clear points! :)
Explain the bonding that occurs between sodium and chlorine. Specifically, what kind of bonding takes
place, what’s the name of the resulting compound, and what properties would you expect this compound to
have with respect to water?
Answer:
About bonding
Explanation:
A chemical bond is a lasting attraction between atoms, ions or molecules that enables the formation of chemical compounds. The bond may result from the electrostatic force of attraction between oppositely charged ions as in ionic bonds or through the sharing of electrons as in covalent bond.
Answer:
An ionic bond occurs between sodium and chlorine where sodium has one electron while chlorine has seven electrons. The electron from sodium is lost and transferred to a chlorine atom which results in a sodium ion with a charge of one+ and a chloride ion with a charge of one-. These oppositely charged ions attract each other making a balanced charge to make a compound that is electrically neutral.. Sodium cation (Na+) and chlorine anion (Cl-) are attracted to each another to form sodium chloride (table salt). When dissolved in water, the sodium and chloride ions are strongly attracted to the polar water molecules because of ion-dipole interactions.
Explanation:
3.490x 10^-3 + 1.100x10^-2
[?]x10^[?]
[tex]1.44\times 10^{-2}[/tex]
Explanation:
We need to find the value of [tex]3.49\times 10^{-3}+1.1\times 10^{-2}[/tex].
Here,
The first number is [tex]3.49\times 10^{-3}[/tex]
The second number is [tex]1.1\times 10^{-2}[/tex]
To add these numbers as follows :
[tex]3.49\times 10^{-3}+1.1\times 10^{-2}=0.01449\\\\=1.44\times 10^{-2}[/tex]
So, the value of [tex]3.49\times 10^{-3}+1.1\times 10^{-2}[/tex] is [tex]1.44\times 10^{-2}[/tex]
Plsss help with this ASAP TT
Answer: lithium- 3 protons, 3 electrons, 3 neutrons
Oxygen- nucleon no. 16, Atomic no. 8, 8 protons, overall charge (-2)
Sorry I don't the others. Hope this helps
The number of ATPs per NADH generated by the electron transport system is higher than the number generated per FADH2 because __________. The number of ATPs per NADH generated by the electron transport system is higher than the number generated per FADH2 because __________. NADH is converted to NAD , which increases the charge gradient for ATP synthesis FADH2 has a higher (more negative) redox potential than NADH does electrons from FADH2 are not oxidized all the way to water FADH2 has a lower (less negative) redox potential than NADH does
Answer:
FADH2 has a lower (less negative) redox potential than NADH does
Explanation:
Flavin Adenine Dinucleotide (FAD) and Nicotinamide Adenine Dinucleotide (NAD) are redox cofactors that play important functions for mitochondrial activity and cellular redox balance. Both coenzymes exist in two forms: an oxidized and a reduced, which are abbreviated as NAD/FAD and NADH/FADH2, respectively. These reduced forms (NADH and FADH2) are produced in the Krebs cycle during respiration. FADH2 has lower redox potential than NADH because FADH2 is only capable of activating 2 proton pumps, while NADH can activate 3 proton pumps during the electron transport chain, thereby FADH2 generates a minor number of ATP molecules than NADH.
Which statement defines an ore?
Answer:
The third one
Explanation:
An ore is a naturally occurring solid material from which a metal or valuable mineral can be profitably extracted.
What is 16.30 to the 100th gram
Answer:
1.65485688 × 10121 grams
Explanation:
Aside from those discrete items, anything like rice or flour can be measured out to make up 100 grams. For example, 1/2 cup (125 ml or about 4 and 1/2 fl. oz) of dry rice weighs very close to 100 grams.
500kg, 42m, 675g, and 10m/s are all examples of what typed of data?b
500kg, 42m, 675g, and 10m/s are all examples of a: continuous data.
A numerical data can be defined as a data set that is expressed in numbers only or a data set consisting of numbers rather than words. A numerical data is also known as a quantitative data.
Generally, numerical data are classified into two (2) main categories and these are;
Discrete data: a discrete data is a data set in which the number of possible values are either finite or countable. Some examples are; the value of a fair die, number of pen in a box, number of eggs in a crate, etc.Continuous data: a continuous data is a data set that has infinitely many possible values and as such those values cannot be counted, which simply means they are uncountable. Any data (quantity) such as mass, height, volume, weight, density, velocity, length, pressure, temperature, speed, distance, time are generally classified as continuous data.In conclusion, mass (500 kg), height (42m), mass (675g), and speed (10m/s) are all examples of a: continuous data.
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What are differences between viruses and bacteria?
Answer:
viruses are computer program that replicate itself and distribute itself to another computer but bacteria is micro organism that contaminate our food and can make us sick
What are the requirements of any hypothesis in science?
Answer:
A scientific hypothesis must meet 2 requirements:
Explanation:
A scientific hypothesis must be testable, and;
A scientific hypothesis must be falsifiable.
What does empirical fomula means with examples
Suppose you were given a substance and asked
to determine whether or not it was a plasma. Write
the characteristics you would look for to identify
the substance.
Answer:Particles in plasmas collide more often.
Plasma particles have high kinetic energy (they move quickly).
Plasma particles are far apart.
The ionized particles have no fixed volume
Explanation:
Plasma is the fourth form of matter which has freely moving electrons in it. The substance can be identified as plasma if its particles collide often and are far apart.
What is plasma?Plasma is a type of matter other than solids, liquids, and gas. They have similar properties to that of gas. Plasma particle collides are often like gases as they move freely in space. Like gases that have no definite shape and volume.
The plasma particles have ionic charges, positive and negative resulting in high kinetic energy. This property allows them to show electromagnetism and electrical conductivity.
The ionized particles are due to the high temperature that allows them to have the property of electrical conductivity and compression.
Therefore, the particles of plasma are ionized and have high kinetic energy.
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In the figure a cyclist moves A to B and then to C.he could also go through the shortest path AC. Depending on this fact solve the following questions: Find the length of AC .Find the displacement and total distance covered.
Answer:
hope it helps you see the attachment for further information
what is the correct electron configuration for an element with five electrons in the third energy level
[tex]1s^2 2s^2 2p^6 3s^2 3p^3[/tex] is the correct electron configuration for an element with five electrons in the third energy level.
What are elements?Elements are the simplest substances which cannot be broken down using chemical methods.
The shell nearest to the nucleus, 1n, can carry two electrons, while the next shell, 2n, can carry eight, and the third shell, 3n, can carry up to eighteen.
The third shell carries 18 electrons; 2 in a 3s orbital; 6 in three 3p orbitals; and 10 in five 3d orbitals. The fourth shell carries 32 electrons; 2 in a 4s orbital; 6 in three 4p orbitals; 10 in five 4d orbitals; and 14 in seven 4f orbitals.
The element would be phosphorus. Its electron configuration is [tex]1s^2 2s^2 2p^6 3s^2 3p^3[/tex]
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