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 C5H5NHCl0.024 is how many significant figures?
Answer:
24×10^-3Explanation:
[tex]Move \: the\:decimal \:point\:,\\3 \:times\:to\:the \:right = 24\\\\When \:the\:decimal\:point \: moves\\\:to\:the \:right\:it\:becomes\:a \:negative\:power\\\\0.024= 24 \times 10^-^3[/tex]
does the tendency to gain electrons decrease as we go down grp 17?
Explanation:
Hi, there!!!!
Let me simply clear you..
Yes,The tendency to gain electrons (in nonmetal) decreases when we go down group 17.
The reason for above answer is when we go downwards in periodic table then the atomic size increases with the addition of number of shells and force of attraction between the nucleus and valance shell decreases. The force of attraction between the nucleus and valance shell becomes weaker due to which the force of attracting the electrons gets decreased.
So, we can say that the tendency to gain electrons decreases as we go down in periodic table.
Hope it helps....
If two solutions with concentrations of 0.4 M sugar and 0.7 M sugar respectively are separated by a semipermeable membrane, during osmosis there is a net flow of Group of answer choices sugar molecules from the dilute to the concentrated solution sugar molecules from the concentrated to the dilute solution water molecules from the concentrated to the dilute solution water molecules from the dilute to the concentrated solution
Answer: Water molecules from the dilute to the concentrated solution
Explanation:
During Osmosis if a solution is separerated by a semipermeable membrane, the solvent (typically water) from the less concentrated solution in terms of solute goes through the semipermeable membrane to the solution with the higher concentration so that the concentrations between the solutions can be balanced.
With the above solutions therefore, water molecules would move from the solution of 0.4M of sugar to the solution with a 0.7M of sugar through the semipermeable membrane.
During osmosis, water molecules move from the dilute to the concentrated solution.
OSMOSIS:
Osmosis is the movement of water molecules from a region of higher concentration (low concentration of solute) to a region of lower concentration (higher concentration of solute). The principle of movement is based on the concentration gradient i.e. difference in concentration across a semipermeable membrane. According to this question, two solutions have sugar concentrations of 0.4 M sugar and 0.7 M respectively and are separated by a semipermeable membrane. Therefore, water molecules will move from the dilute (0.4M) to the concentrated (0.7M) solution during osmosis.Learn more at: https://brainly.com/question/13655668?referrer=searchResults
Over the period of a few days, a hospital receives an overwhelming increase in the number of patients with food poisoning. How would a scientist respond to this increase in sick patients?
Answer:
Hey there!
A scientist would try to determine the cause of the food poisoning, and see if the people who got poisoned had anything in common, for example: they ate at the same restaurant, they are all people of a certain age, etc.
Let me know if this helps :)
Which is the correct definition of metallic bonding? Select one: a. an array of positive ions in a sea of electrons b. complete transfer of valence electrons c. atoms share electrons to to be stable
Answer:
I believe it's A) an array of positive ions in a sea of electrons
When might Accurate length measurement be important?
Answer:
When you are going to measure small lengths or objects or when you are going to measure things with great accuracy.
Explanation:
100 cm^3 of oxygen diffuses through a Porous in 3second how long will it take 150 cm^3 of sulphur (iv) oxide diffuse through the same pot? ( oxygen= 16 sulphur = 32)
Answer:
3.18 seconds
Explanation:
Given the following :
Volume of oxygen (V1) = 100cm^3
Time taken (t1) = 3 seconds
Volume of Sulphur (iv) oxide (v2) = 150cm^3
From Graham's Law of diffusion:
(r1/r2) = √(m1/m2)
Where r = rate of diffusion
m = molar mass
Note rate (r) = (volume / time)
[(V1/t1) ÷ (v2/t2)] = √(m1/m2)
(v1/t1) * (t2/v2) = √(m1/m2)
m1 = 02 = (16 * 2) = 32
m2 = SO2 = (32 + (16 * 2)) = 64
(100/3) * (t2/150) = √(32/64)
100t2 / 450 = √(32/64)
100t2 / 450 = √32 / 8
100t2 / 450 = √32 / 8
100t2 * 8 = 450 * √32
800t2 = 2545.5844
t2 = 2545.5844 / 800
t2 = 3.1819805
t2 = 3.18 seconds
It will take 3.18s for 150cm^3 of Sulphur (iv) oxide to diffuse through the same pot.
if 193 ml of chlorine gas was collected at 21 celsius, what volume would it have if the temperature dropped to 0 celsius
Answer:
New volume of chlorine gas (V2) = 179 ml (Approx)
Explanation:
Given:
Volume of chlorine gas (V1) = 193 ml
Temperature of chlorine gas (T1) = 21°C = 21 + 273 = 294 k
New temperature of chlorine gas (T2) = 0°C = 0 + 273 = 273 k
Find:
New volume of chlorine gas (V2) = ?
Computation:
Using charle's law
V1 / T1 = V2 / T2
193 / 294 = V2 / 273
V2 = 179.21
New volume of chlorine gas (V2) = 179 ml (Approx)
ocean in ionnic bonding, during the transfer of electrons between two neutrally charged atoms, one electron moves from one atom to another. What are the new relative charges between two atoms
Answer: The new relative charges between two atoms are +1 and -1 for cation and anion respectively.
Explanation:
When an atom accepts an electron, negative charge is created on atom and is called as anion.
When atom loses an electron, positive charge is created on atom and is called as cation.
For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
Thus when one electron is lost by an atom it forms one positive charge and when one electron is gained by an atom it forms one negative charge.
Foe example: sodium atom loses its one valance electron and form cation [tex]Na^+[/tex]. Chlorine atom gain one electron and form anion [tex]Cl^-[/tex]. they both combine to form sodium chloride through ionic bond.
What is ionic bond and explain it
Answer:
An ionic bond is a chemical bonding involving the attraction between oppositely charged ions
Explanation:
On the periodic table, elements from group 1 and 7 are attracted to each other and when they bond, it's called ionic bonding. This is because of their valence electrons and ions.
Answer:
Ionic bonding is a type of chemical bonding that involves the electrostatic attraction between oppositely charged ions, and is the primary interaction occurring in ionic compounds. It is one of the main types of bonding along with covalent bonding.
How many moles are present in 136 grams of MgCl2? 1.46 mol 1.43 mol 2.27 mol
Answer:
1.43 mol
Explanation:
How many gram of zinc will have to be treated with dilute hydrochloric acid to liberate 1.85 dm³ of hydrogen at 27°C and 750mmHg?
Answer:
Explanation:
given
volume=1.85 d m^3
T=27 degree C=27+273 k=300 k
P=750 mmHg
mass of zinc=?
we know that PV=nRT
n=m/M
PV=mRT/M
M for zinc=65.4
PVM=mRT
m=PVM/RT
m=750*1.85*65.4/0.0821*300
m=90742.5/24.63
m=3684
hope this will help u
compare the activity of sodium and iron with water and dilute acid
Answer:
Reactions of sodium with water and dilute acid
Sodium reacts explosively with dilute HCl(aq) to produce NaCl(aq) and H₂(g)
2Na (s) + 2HCl(aq) → 2NaCl(aq) + H₂(g)
Sodium reacts violently with cold water to produce NaOH(aq) and H₂(g)
2Na (s) + H₂O(l) → 2Na(OH)(aq) + H₂(g)
The produced hydrogen may become ignited and explode
Reactions of iron with water and dilute acid
Iron reacts very slowly with dilute acid to produce iron (II) chloride and hydrogen gas
Fe (s) + 2 HCl (aq) → FeCl₂ (aq) + H₂ (g)
Iron does not react with cold water. Iron reacts only with steam
Explanation:
Tips for memorizing the first 20 elements of the periodic table?
Answer:
hydrant flying with balloon, balloon has lithp letting air out, bee: really yum balloon
= = = =
hydrogen helium lithium beryllium
be bore on the balloon, balloon pops, hydrant drops and makes a car bomb
= =
boron carbon
night row general gets hurt by car bomb nearby, that general gets off boat
=
nitrogen
wearing oxygen mask, mask is full of fluride gel, then he got neon teeth
= = =
oxygen fluorine neon
(try making a story out of the elements, use your imagenation)
I will give u tips to learn whole periodic table
1. Break down the table into sections
2. Spread out the memorisation process
3. Learn the elements in a song
4. Make none sense words made from element symbols
5. Use colour to learn element groups
6. Use mnemonic device to help remember the order of elements
I am sure this will be helpful for uuu
Explanation:
What is the term for the belief that one's own culture is superior to other
cultures?
O A. Cultural behavior
O B. Cultural competence
C. Cultural relativism
D. Cultural absolutism
Cultural absolutism is the term for the belief that one's own culture is superior to other cultures.
What is cultural absolutism?Cultural absolutism is one of the perspectives which is common in anthropology, but it can also be applied to non-scientific thoughts also. It assumes that there is a set of universal values which are objectively valid in every situation.
Today, pure cultural absolutism is seen as a harmful effect of ethnocentrism focusing on the belief that one's own culture is superior and the practice of holding other's cultures to the standard of our own. However, purely relativist anthropologists have also been critiqued for going too far, by denying any common humanity and being too lenient towards morally questionable practices. Contemporary approaches try to find a balance between the universal values, such as human dignity, and a more inclusive and relativistic side of culture.
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What is the equilibrium constant of aA+bB cC +dD?
Explanation:
{c}^C . {d}^D / {a}^A . {b}^B
Which fact was most likely discovered between the time of Mendeleev’s table and the time of Moseley’s table that helped Moseley develop his version?
Answer:
The number of protons in an atom is different than the atom’s total mass.
Explanation:
Mendeleev knew only that, with some anomalies, the properties of elements varied periodically with their atomic masses.
Moseley's X-ray experiments enabled him to remove these anomalies and to show that the properties of elements varied with their atomic numbers.
Chadwick later discovered that the mass differences were caused by the presence of neutrons.
What are the properties of alkynes
In human cells, a dynamic equilibrium exists between carbonic acid (H2CO3) and carbon dioxide (CO).
H2CO3(aq) = CO2() + H200
When a person exercises, the body's cells metabolize glucose to gain energy. This metabolism also causes an increase in the
concentration of carbon dioxide.
Le Chatelier's principle states that stresses applied to a system in dynamic equilibrium will cause the system to change in order to
alleviate those stresses. According to this principle, how would an increase in carbon dioxide concentration affect the system?
A. There would be a decrease in the concentration of carbonic acid.
В. There would be an increase in the concentration of glucose.
C. There would be an increase in the concentration of water.
There would be an increase in the concentration of carbonic acid.
D There would be an increase in the concentration of carbonic acid.
There would be an increase in the concentration of carbonic acid - this is how an increase in carbon dioxide concentration influences the system.
What is dynamic equilibrium?In chemistry, a dynamic equilibrium lives once a reversible reaction occurs. Substances transition between the reactants and products at equal rates, indicating there is no net change. Reactants and products exist formed at such a rate that the concentration of neither changes. It is a precise example of a system in a steady state. After a time, a reversible reaction in a closed system can get what we call a dynamic equilibrium.
The correct answer is option D.
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A baseball has a mass of 135 grams and a softball has a mass of 270 grams. In which of the following situations would they have the same momentum? The baseball and softball are thrown at the same speed in the same direction.
Answer:
The baseball is thrown twice as fast as the softball in the same direction.
Explanation:
Calcula el %m/v de alcohol en una mezcla utilizada para la desinfección de manos formada por: 15 ml de agua (densidad=1g/ml), 105 g de etanol (densidad: 0,798 g/ml) y 4,5 gramos de jabón líquido (densidad= 1,5 g/ml)
Answer:
%m/v =70%
Explanation:
El %m/v es una unidad de concentración que se define como cien veces la división entre la masa de una sustancia (En gramos) y el volumen total en el que esta sustancia se encuentra (en mL).
En el problema, debemos hallar la masa de etanol (Alcohol) y el volumen total de la solución.
Masa alcohol:
Ya te la dan en el problema: 105g
Volumen solución:
Volumen agua: 15mL
Volumen etanol: 105g × (1mL / 0.798g) = 131mL
Volumen Jabón líquido: 4.5g × (1mL / 1.5g) = 3mL
Volumen: 15mL + 131mL + 3mL
149mL
Así, el %m/v de alcohol en la solución es:
%m/v = (105g / 149mL) × 100
%m/v =70%
3. How did ethanol use affect the shortage of corn available to consumers during and
after the drought of 2012? Do you think that commodities in one sector should be used
in another economic sector? How might the concept of needs and wants affect your
analysis of this issue?
Due to drought, the production of corn decreases and shortage of it occurs.
Effects of droughtYes, commodities in one sector should be used in another sector because scientist invented methods in which one commodity is used in several sectors for the production of new products.
Corn was used for the production of ethanol which causes the shortage of corn that was available to consumers during and after the drought condition of 2012 so we can conclude that due to drought, the production of corn decreases and shortage of it occurs.
Learn more about drought here: https://brainly.com/question/12686086
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What happens when two objects when they are brought closer together The mass of both objects decrease The mass of both objects increase The gravitational force between them decreases The gravitational force between them increases
Answer:
The correct option is
The gravitational force between them increases
Explanation:
According to Newton's law of universal gravitation states that the force of attraction between two bodies is directly proportional to the product of the masses of the bodies and inversely proportional to the square of the distance of their centers from each other.
The formula for universal gravitation is given as follows;
[tex]F_{1} = F_{2} =G \times \dfrac{m_{1} \times m_{2}}{r^{2}}[/tex]
Where;
F₁, and F₂ = The gravitational forces of attraction on each mass
G = The gravitational constant
m₁ = The mass of one body
m₂ = The mass of the body
r = The distance between the centers of the two bodies
Therefore, the gravitational force of attraction on each object is inversely proportional to the as the distance between the centers of the two bodies
When the distance between the centers of the two bodies decreases, the two objects are brought closer together, the gravitational force of attraction between them increases.
Answer:
Gravitational force between two objects of masses m1/m2
Explanation:
is defined by Gm1xm2/r^2, where G is a universal constant, and r is the distance between the masses. This shows you why B is wrong; it would increase. Also, A is not a good choice, as shown. In the case of B, it would increase by say, 2/1 to 4/1 by doubling ones mass. In C's case the bottom would decrease on the fraction alot (square) if they were moved closer, thus the force would be greater.
Explanation:
in other words the answer is The gravitational force between them increases
45. The following data was collected for 3 compounds:
Mass of Nitrogen that combines with 1 g of Oxygen
Compound A 1.750 g
Compound B 0.8750 g
Compound C 0.4375 g
Show whether these are the same or different compounds. What chemical law is being observed here?
Answer:
The three compounds are different compounds
Explanation:
The mass of Nitrogen that combines with 1 gram of Oxygen in Compound A = 1.750 g
The mass of Nitrogen that combines with 1 gram of Oxygen in Compound B = 0.8750 g
The mass of Nitrogen that combines with 1 gram of Oxygen in Compound C = 0.4375 g
According to the law of multiple proportions, when atoms of two different elements react to form compounds, the masses of one of the elements that combines with a fixed mass of the other element are in small whole number ratios.
The ratio of the masses are;
Mass of Nitrogen in Compound B/(Mass of Nitrogen in Compound C = 0.8750/0.4375 = 2
Mass of Nitrogen in Compound A/(Mass of Nitrogen in Compound C = 1.750/0.4375= 4
Mass of Nitrogen in Compound A/(Mass of Nitrogen in Compound B = 1.750/0.8750= 2
Given that the masses of Nitrogen in the three compounds are in small whole number ratios, the three compounds, Compound A, Compound B, and Compound C are different compounds.
In a reversible reaction, the endothermic reaction absorbs ____________ the exothermic reaction releases.
A. None of these, endothermic reactions release energy
B. more energy than
C. the same amount of energy as
D. less energy than
Answer:
C. the same amount of energy as
Explanation:
Firstly, a chemical reaction can either absorb energy from its surroundings to occur or release energy into its surroundings as a product. The former and latter descriptions are called ENDOTHERMIC and EXOTHERMIC reactions respectively. An exothermic reaction is that which transfers energy, in form of heat, to its surroundings while an Endothermic reaction is that which absorbs energy (heat) from its surroundings.
However, a reversible reaction is that reaction in which the formation of products from reactants and reformation of the reactants from products occur simultaneously. Hence, the products of a reversible reaction can become the reactants and move in the opposite direction. For example:
Reversible reaction: A + B ⇆ C + D means;
A + B → C + D and;
C + D → A + B
In a case whereby the opposite reactions consist of an endothermic and exothermic reactions, the endothermic reaction absorbs the same amount of energy as the exothermic reaction releases.
According to the law of conservation of energy, no energy is lost during a reversible reaction. Hence, in order to achieve an equilibrium, the amount of energy absorbed by the endothermic reaction is the same as the amount of energy released in the opposite exothermic reaction.
In the lab, Amanda has two solutions that contain alcohol and is mixing them with each other. She uses twice as much Solution A as Solution B. Solution A is 11% alcohol and Solution B is 18% alcohol. How many milliliters of Solution B does she use, if the resulting mixture has 320 milliliters of pure alcohol?
Answer:
1,103.47 milliliters
Explanation:
The total percentage of alcohol from solution A and solution B is 29. In a solution that is a mixture of solution A and B, the percentage of alcohol that would be contributed by solution A would be:--
11/29 x 100% = 37.93%
--while the percentage of alcohol that would be contributed by solution B would be:
18/29 x 100 = 62.07%
Hence, if a mixture of A and B has 320 milliliters of alcohol, the amount of alcohol contributed by B would be:
320 x 62.07/100 = 198.624 milliliters
Now, remember that solution B is 18% alcohol. This means that the 18% alcohol content of solution B is 198.624 milliliters. Thus, the total volume of solution B would be:
198.624 x 100/18 = 1,103.47 milliliters.
Therefore, the total milliliters of solution B Amanda used would be 1,103.47.
how many significant figures are in 820 400.0 L
Answer:
7 significant numbers
A 46.9 gram sample of a substance has a volume of about 3.5 centimeters3. It is solid at a room temperature of 23ºC. Out of the four substances whose properties are given, which is the most likely identity of this substance?
THIS IS THE COMPLETE QUESTION BELOW
46.9 gram sample of a substance has a volume of about 3.5 centimeters3. It is solid at a room temperature of 23ºC. Out of the four substances whose properties are given, which is the most likely identity of this substance?
Substance Density (g/cm3) Melting Point (°C) Boiling Point (°C)
molybdenum 10.28 2,623 4,639
mercury 13.53 -39 357
hafnium 13.31 2,233 4,603
lead 11.34 327 1,749
A.
molybdenum
B.
mercury
C.
hafnium
D.
lead
Answer :
The correct option is OPTION C.
(C) Hafnium
Explanation;:
We were given the mass of substance as (m) = 46.9 g
The Volume of substance as (V) = 3.5 Cm^3
But we know Density of substance.= Mass/it's Volume
Then Density=46.9/3.5
=13.4g/Cm^3
From the questionthe given substance is solid at room temperature, and let us take Mercury as an example , Mercury is liquid at room temperature. ThenMercury cannot be the answer.
Base on the determined density which is 13.4 and the density of Hafnium also is 13.31 g/cm3 and it is solid at room temperature. Therefore, Hafnium is the only likely element here.
Compound A, C6H12O2, was found to be optically active, and it was slowly oxidized to an optically active carboxylic acid B, C6H12O3, by Ag(NH3)2. Oxidation of A by anhydrous CrO3 gave an optically inactive compound D that reacted with Zn amalgam/HCl to give 3-methylpentane. With aqueous H2CrO4, compound A was oxidized to an optically inactive dicarboxylic acid C, C6H10O4. Give structures for compounds A, B, and C; do not specify stereochemistry.
Answer:
kindly check the attach file for the drawing of the chemical structures.
Explanation:
So, we are going to start from the compound D, which is stated in the question to be optically active. Therefore, we will have that:
STEP ONE: THE OXIDATION OF COMPOUND A, C6H12O2 TO GIVE COMPOUND C.
The oxidation of compound A,C6H12O2 gives another chemical compound that is chemical compound C which is a optical inactive di-carboxylic acid. The chemical equation is given below:
C6H12O2 + H2Cr2O4 --------------------------------------------> HOOCCH2CHCH3CH2COOH.
STEP TWO: THE OXIDATION OF COMPOUND A, C6H12O2 TO GIVE COMPOUND B.
The oxidation of compound A,C6H12O2 gives another chemical compound that is chemical compound C which is a optically active acid. The chemical equation is given below:
C6H12O2 + Ag(NH3)2^+ -----------------------------> C6H12O3.
Since the question asked us to give the structures of Compound A,B and C there is no need to to show the chemical reaction for compound D.
Kindly check the picture below for the chemical structures.
Select the correct answer from each drop-down menu. At chemical equilibrium, the amount of because .
Answer:
The answer that completes the question are in BOLD:
At chemical equilibrium, the amount of PRODUCT AND REACTANT REMAIN CONSTANT because the RATES OF THE FORWARD AND REVERSE REACTIONS ARE EQUAL.
Explanation:
In a reversible chemical reaction, an equilibrium is said to be achieved when the rates of the forward reaction is equal to that of the reverse reaction. A reversible reaction is one in which products are formed from reactants simultaneously with the formation of reactants from products.
The combination of two or more substances called REACTANTS gives rise to another substance called PRODUCT, which can in turn give rise to Reactants again. With time, the rate at which the reactants give rise the products, which is called the FORWARD REACTION will be equal to the rate at which the products give rise to the reactants, which is called REVERSE REACTION. At this point, the chemical reaction is said to be in a STATE OF EQUILIBRIUM.
When the rate at which both reaction occurs becomes equal i.e. at an equilibrium state, the concentration of both the reactants and the products becomes constant i.e. no longer changes. Hence, the amount of the reactants forming the products is the same as the amount of products forming the reactants.
N.B: At chemical equilibrium, the amount of the reactants and products does not necessarily equals zero (0). It simply means that there is no net change in the concentration/amount of both reactants and products.
