Consider the following data on some weak acids and weak bases:
acid base
name formula Ka name formula Kb
hydrocyanic acid HCN 4.9 x 10^-10 hydroxylamine HONH2 1.1 x 10^-1
hypochlorous acid HCIA 3.0 x 10^-18 ethylamine C2H5NH2 6.4 x 10^-4
Use this data to rank the following solutions in order of increasing pH. In other words, select a '' next to the solution that will have the lowest pH, a '' next to the solution that will have the next lowest pH, and so on.
a. 0.1 M HONH3Br
b. 0.1 M NaNO3
c. 0.1 M C2H5NH3Cl
d. 0.1 M NaF
Answer:
a < c < b < d
Explanation:
The weak acid with the lowest pKa will be the most acidic. In the other way, the conjugate base which the acid is weakest will be strongest.
The weak base with the lowest pKb will be the most basic. And the conjugate base of the weakest base will be a strongest acid.
Using the values:
Ka HCN = 4.9x10⁻¹⁰
Kb HONH2 = 1.1x10⁻⁸
Ka HClA 3.0x10⁻⁸
Kb C2H5NH2 = 6.4x10⁻⁴
The NaNO3 is the conjugate base of a strong acid as HNO3. That means its solutions are almost neutral
The HONH3Br is the conjugate acid of a weak base. Its solutions will be acidics
C2H5NH3Cl is the conjugate acid of a weak base as ethylamine, its solutions will be acidic.
As ethylamine has a lower pkb than hydroxylamine, the conjugate acid of hydroxylamine will be more acidic.
NaF is the conjugate base of a weak acid as HF. Its solutions will be basics
The order in increasing pH is:
HONH3Br < C2H5NH3Cl < NaNO3 < NaF
a < c < b < d24.3 2 An artifact classified as seeds, found in a site at Newlands Cross, Ireland, is found to have a 14C radioactivity of 0.103 counts per second per gram of carbon. If living carbon-containing objects have an activity of 0.255 counts per second per gram of carbon, estimate the age of the artifact?
The half-life of 14C is 5730 years.
______ years
Answer:
Age ≅ 7500 years
Explanation:
All radioactive decay is 1st order kinetics and described by the expression
A = A₀e^-kt => t = ln(A/A₀) / -k
k = 0.693 / t(half life) = (0.693 / 5730)yrs⁻¹ = 1.21 x 10⁻⁴ yrs⁻¹
t = Age = [ln(0.103/0.255) / - 1.21 x 10⁻⁴] yrs = 7500 years
Λλ(Lamda) Represents what??
Answer:
λ Represents:-
one wavelength of electromagnetic radiationthe decay constant in radioactivityfunction expressions in the lambda calculusa general eigenvalue in linear algebrathe expected number of occurrences in a Poisson distribution in probabilitythe arrival rate in queueing theorythe failure rate in reliability engineeringthe Lagrange multiplier in mathematical optimization, known as the shadow price in economicsthe Lebesgue measure denotes the volume or measure of a Lebesgue measurable setlongitude in geodesylinear densityecliptic longitude in astronomythe Liouville function in number theorythe Carmichael function in number theorythe empty string in formal grammara formal system in mathematical logicthermal conductivitythe Lorentz transformation-TheUnknownScientist
Rank the following solutions from lowest to highest vapor pressure.
Rank from lowest to highest. To rank items as equivalent, overlap them.
10.0 g of potassium acetate KC2H3O2 in 100.0 mL of water
20.0 g of sucrose (C12H22O11) in 100.0 mL of water
20.0 g of glucose (C6H12O6) in 100.0 mL of water
Solution :
When non volatile solute is added to solvent, vapor pressure gets lowered.
Relative lowering in vapor pressure is given :
[tex]$\frac{P^0-P}{P^0}$[/tex] = [tex]$\text{mole fraction}$[/tex] of solute
[tex]$\frac{P^0-P}{P^0}=x_B$[/tex]
[tex]$P^0$[/tex] = vapor pressure of pure solvent
P = vapor pressure of solution
[tex]$x_B$[/tex] = mole fraction of solute
[tex]$x_B=\frac{n_B}{n_A+n_B}$[/tex]
[tex]$n_B $[/tex] = [tex]$\text{number of moles of solute}$[/tex]
[tex]$n_A$[/tex] = [tex]$\text{number of moles of solvent}$[/tex]
Number of moles [tex]$=\frac{\text{weight}}{\text{molecular weight}}$[/tex]
[tex]$\frac{P^0-P}{P^0}=\frac{w_B/M_B}{w_A/M_A+w_B/M_B}$[/tex]
[tex]$\approx \frac{w_B/M_B}{w_A/M_A}$[/tex]
1. For 10 g of [tex]$CH_3COOK$[/tex]
[tex]$CH_3COOK \rightarrow CH_3COO^- + K^+$[/tex]
Ions = 2
It will affect colligative property.
[tex]$\frac{P^0-P}{P^0} = \frac{i \times 10/98}{w_A/M_A}$[/tex]
Relative lowering in vapor pressure will be :
[tex]$=\frac{2 \times 10/98}{w_A/M_A}$[/tex]
[tex]$=\frac{0.20}{w_A/M_A}$[/tex]
2. For 20 g sucrose
Sucrose is non electrolyte, i = 1
[tex]$\frac{P^0-P}{P^0} = \frac{ 20/342}{w_A/M_A}$[/tex]
[tex]$=\frac{0.050}{w_A/M_A}$[/tex]
3. For 20 g of glucose.
Glucose is a non electrolyte, i = 1
[tex]$\frac{P^0-P}{P^0} = \frac{20/180}{w_A/M_A}$[/tex]
[tex]$=\frac{0.11}{w_A/M_A}$[/tex]
[tex]$w_A/M_A$[/tex] is same in all three solutions.
Hence, lowering in vapor pressure is maximum in [tex]$CH_3COOK$[/tex] and minimum is Sucrose.
Vapor pressure from lowest to highest.
10 g of [tex]$CH_3COOK$[/tex] < 20 g of glucose < 20 g of sucrose
The pressure exerted by vapor to the other gas is called vapor pressure.
The formula used to solve the question is as follows:-
[tex]\frac{P^o -P}{P^o}[/tex]
The water vapor depends on the following:-
Water pressureTemperature.After solving the equation, the correct sequence is as follows:-
[tex]CH_3COOK > GLUCOSE > SUCROSE[/tex]
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The object shown is made of glass. What is it called?
Answer: prism
Explanation: A prism is a polyhedron, with two parallel faces called bases. The other faces are always parallelograms. The prism is named by the shape of its base.
Consider pure water separated from an aqueous sugar solution by a semipermeable membrane, which allows water to pass freely but not sugar. After some time has passed, the concentration of sugar solution: a. will have decreased b. will be the same on both sides of the membrane c. might have increased or decreased depending on other factors d. will not have changed e. will have increased
Answer:
it will be the same on both sides of the membrane
When the pure water is separated from the aqueous sugar solution when the sugar cannot pass through the semipermeable membrane. So the water moves through the membrane to the sugar solution. Therefore, the concentration of sugar solution will be decreased.
What is osmosis?Osmosis can be described as the spontaneous net movement or diffusion of solvent molecules through a permeable membrane from a region of lower solute concentration to a higher solute concentration in a direction that tends to balance the solute concentrations on both sides.
A physical process in which any solvent moves across a selectively permeable membrane separating two solutions of different concentrations.
Osmotic pressure can be described as the external pressure needed to be applied so that there is no net movement of a solvent across the membrane. Osmotic pressure can be defined as a colligative property because it depends on the molar concentration of the solute but not on its identity.
Therefore, option (A) is correct.
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Which of the following accurately describes the function of the muscular
system?
O A. To prevent and fight disease
B. To provide support for the body
C. To get rid of wastes and excess water
D. To allow the body to move
Will give brainliest
In an experiment, the molar mass of the compound was determined to be 228.276 g/mol. What is the molecular formula of the compound?
But Are Punnett square percentages always correct?
Answer:
yes
Explanation:
cuz is a square and if all angles are equal of a square then it is correct
i need help with number 3
(THANKS FOR HELPING)
(I WILL BRAINLEST FORGOT HOW TO SPELL IT AND AGAIN THANKS FOR HELPING)
Answer:
Gymnosperm and Angiosperms both are plant groups but Gymnosperm is just very large leaves that come out of the ground and Angiosperms have flowers. Gymnosperm produce seeds in pine cones for example. Some plants in the Gymnosperm group of plants are pines. They produce naked seeds which means that they aren't protected by a ovary (Fruit like an apple) to help them get planted. Angiosperms have seeds that come out of their flowers and are called covered seeds. When the plant is about to die, it's seeds fall out and either float away and grow later of fall where the plant is. Also, insects carry them places too.
Hope this helps.
The mass of an atom of element x is equivalent to the total mass of 7 hydrogen atoms
Answer: I'm not sure what your question is but i'll answer as best as I can.
Explanation:
Since X is equal to 7 H and we know that H is equal to 1.008, we can just do 7x1.008 = 7.056 g. I hope i helped and please clarify more in the future.
The atomic mass of an element is given by the sum of the mass of protons and neutrons. The element X is lithium as it has a mass of 6.941 u.
What is atomic mass?Atomic mass is the sum of the masses of the isotopes of that element and is given by adding the masses of the number of protons and neutrons of the elemental atom.
The atomic mass of one hydrogen atom is 1.008, so seven hydrogens will be, 7 x 1.008 = 7.056 g. Now, from the periodic table, it can be seen that an atomic mass of 7.056 g is closest to the atomic mass of a lithium atom (6.941 u).
From the mass, it can be said that seven hydrogen atom has an equivalent mass as that of one lithium atom in the periodic table. The lithium atom has atomic number 3 and an atomic mass of 6.941 g/mol.
Therefore, element X is lithium.
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Terry, a student, performs a titration. He completes these steps as part of his titration procedure: 1. He cleans and rinses a burette with standardized base. 2. He fills the burette with standardized base solution. 3. He reads and records the initial burette volume. 4. He adds a base from the burette to an acid. 5. He observes a color change in the Erlenmeyer flask. 6. He stops the addition of base from the burette. 7. He reads and records the final burette volume. Which steps will provide information needed to calculate the volume of base needed to reach the equivalence point? A. 1 and 6 B. 3 and 7 C. 3, 4, and 6 D. 1, 2, and 7
Answer:
D
Explanation:
D is the answer because 2 is needed to know
Answer:
B) 3 and 7
Explanation:
i just took the test
Soil comes in different colors.
Answer: yes they come in different colors.
Explanation:
Most shades of soil is mostly black,brown,red,gray,and white the color of soil and other properties including texture, structure, and consistency are used to distinguish and identify soil.
Match the element with its oxidation number (charge).
1. +1 O
2. -1 Ca
3. -3 Si
4. -2 Al
5. +2 N
6. +3 Na
7. +/- 4 F
Answer:
The answer is in the problem
Explanation:
As general rule of number of oxygen is -2:
O → -2
Alkali metals (Li, Na, K) are always +1
Na → +1
Alkali earth methals (Be, Mg, Ca...) are always +2
Ca → +2
The halogen group (F, Cl, Br...) is always -1
F → -1
The oxidation number of Si (+/- 4)
Aluminium is, usually +3
And to complete the octet rule in nitrogen, 3 electrons are required. That means:
N → -3
At a certain temperature the rate of this reaction is first order in HI with a rate constant of 0.0632 s
2HI g = H2 g + I2 g
Suppose a vessel contains HI at a concentration of 1.28M. Calculate how long it takes for the concentration of HI to decrease to 17.0% of its initial value.
Answer:
[tex]28.037\ \text{s}[/tex]
Explanation:
[tex][A]_0[/tex] = Initial concentration = 1.28 M
[tex][A][/tex] = Final concentration = [tex]0.17[A]_0[/tex]
k = Rate constant = 0.0632 s
t = Time taken
For first order reaction we have the relation
[tex]kt=\ln\dfrac{[A]_0}{[A]}\\\Rightarrow t=\dfrac{\ln\dfrac{[A]_0}{[A]}}{k}\\\Rightarrow t=\dfrac{\ln\dfrac{[A]_0}{0.17[A]_0}}{0.0632}\\\Rightarrow t=28.037\ \text{s}[/tex]
Time taken to reach the required concentration would be [tex]28.037\ \text{s}[/tex].
Write the overall balanced equation for the reaction:
N2O4(g) + CO → NO(g) + CO2(g)+NO2(g)
Answer:
This reaction has infinite ways to be balanced
Explanation:
To balance this equation we can use the algebraic method:
N2O4(g) + CO → NO(g) + CO2(g)+NO2(g)
Where we write each molecule as a letter:
A + B → C + D + E
Then, we write the equations according the number of atoms of each molecule. That is:
Oxygen → 4A + B = C + 2D + 2E (1)
Nitrogen → 2A = C + E (2)
Carbon → B = D (3)
Then, we have to give 1 arbitral number for a letter. For example:
B = 1; D = 1
(1) 4A + 1 = C + 2 + 2E
4A = C + 2E + 1
2A = C + E (2) Twice (2):
4A = 2C + 2E
Subtracting (1) in (2)
C + 2E + 1 = 2C + 2E
C + 1 = 2C
1 = C
Si 1 = C:
4A + 1 = 1 + 2 + 2E
4A = 2 + 2E (1)
y:
2A = 1 + E (2)
Twice:
4A = 2 + 2E
As (1) and (2) are the same equation:
This reaction has infinite ways to be balancedFor example:
N2O4(g) + CO → NO(g) + CO2(g)+NO2(g)
What is Carbonate ion?
Answer:
[tex]{\huge\blue{\fbox{{࿐ᑕᗩᖇᗷOᑎᗩTᗴ IOᑎ࿐}}}}[/tex]
Explanation:✏The fizz in the club soda, the foaming effect in the washing soda are all due to carbonate ions. Carbonate is a salt of carbonic acid possessing the molecular formula CO32–. The main group of elements used as carbonates are alkali and alkaline earth metals.
Formula:✏ [tex]CO3 ^{2 - } [/tex]
ʰᵒᵖᵉ ⁱᵗ ʰᵉˡᵖˢ
At a pressure of 1.76 atm and 305 K, a certain gas has a volume of 350.0 mL. What will be the new volume of this gas under STP.
Answer:
hi
Explanation:
I'm just figuring this out
How many liters of 3.6 M solution can be made using 110 grams of
lithium bromide (LiBr)?
Answer:
0.2878 liters
Explanation:
It is possible to make 0.2878 liters of 4 M solution of lithium bromide using 100 grams of the compound.
If you had 15 molecules of H2 and an unlimited supply of N2, how many
NH3 molecules can you make?
N2 + 3H2 --> 2NH3
Answer:
10 molecules of NH₃.
Explanation:
N₂ + 3H₂ --> 2NH₃
As the N₂ supply is unlimited, what we need to do to solve this problem is convert molecules of H₂ into molecules of NH₃. To do so we use the stoichiometric coefficients of the balanced reaction:
15 molecules H₂ * [tex]\frac{2moleculesNH_3}{3moleculesH_2}[/tex] = 10 molecules NH₃10 NH₃ molecules could be prepared from 15 molecules of H₂ and unlimited N₂.
FeCI2 + Na2CO3 = FeCO3 + NaCI Balance this equation please
No links
FeCl2 + Na2CO3 = FeCO3 + 2NaCl
How many liters would you need to make a 0.8 M solution with 20 grams of lithium chloride?
Answer:
0.5875L
Explanation:
concentration = mole/ volume
n(LiCl) = 20 / (7 + 35.5) = 0.47 mol
volume = mole / conc.
volume = 0.47 /0.8
= 0.5875 dm³ = 0.5875L
How does publishing in scientific journals help ensure that science leads to
reliable results?
A. It allows results to be reviewed and reproduced by other
scientists.
B. It allows the public to decide if science is worthwhile.
C. It shows which experiments are the most popular with scientists.
D. It gives scientists a reason to do more experiments.
Answer:
A. it allows results to be reviewed and reproduced by other scientists.
Explain why people tend to wear light- colored clothing during the warmer months of the year. Use evidence and scientific reasoning to support your answer
Answer:
because dark colours like black attract light (sun) and heat. light colors reflect more light, (it absorbs less energy and heat from the sun)
Answer:
Because Black color absorbs light better than light-colored.
for example have you ever seen the black car on the road if you touch it very hotter than white car
1. White is the most reflective color. Does not absorb heat like black Make the house not hot.
2. White has the least radiation exposure. Therefore, during the winter night, it will help retain heat for a while. 3. Because white absorbs light as little as possible. Causing the pigment to deteriorate slowly Unlike black that absorbs light well. Causing the color to deteriorate and fade quickly until noticeable
4. If the house next to you is painted white during the day, it will help reflect light into the house.
Why that black color absorbs heat? Even though it abosrbs the light? It comes from the principle that (Substance or material) Black is what absorbs (absorbs) light in every technology.
It absorbs all widths of light, including infrared light. (The infrared itself is hot.)
Black repels self-heating the most because of all colors of light. But there is justice.
The pressure on 200 milliliters of a gas at constant
temperature is changed from 380 torr to 760 torr. The new
volume of the gas is
answerA) 100 mL
Explanation:
At constant temperature and number of moles, Using Boyle's law
Given ,
V₁ = 200 mL
V₂ = ?
P₁ = 60 kPa
P₂ = 120 kPa
The new volume of the gas is 100mL
Boyle's law is use to calculate the volume of a gas in relation with its pressure. The Boyle's law equation is as follows:
P1V1 = P2V2
Where;
P1 = initial pressure of the gas (torr)
P2 = final pressure of the gas (torr)
V1 = initial volume of the gas (mL)
V2 = final volume of the gas (mL)
According to the information of this question, the pressure on 200mL of a gas changed from 380 torr to 760 torr. Hence;
V1 = 200mL
V2 = ?
P1 = 380torr
P2 = 760torr
Using P1V1 = P2V2
V2 = P1V1/P2
V2 = (380 × 200) ÷ 760
V2 = 76000 ÷ 760
V2 = 100mL
Hence, the new volume of the gas is 100mL
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Cuo
+ H2 → → Cu + + H20
colorless
water
black
powder
reddish
solid
gas
vapor
Explanation:
because there is 2 hydrogen atoms in the reactions side of the equation (you can tell because the H has a 2 in the subscript) you have to have 2 hydrogen atoms in the reactants side to help balance out the equation. and since the copper and oxygen atoms are already balanced there is no coefficient needed.
Which of these statements does not describe electricity?
A. Lightning is electricity that has built up in the air and travels to the Earth.
B. Electricity cools down devices as it travels through them.
C. Electricity will naturally follow the path of least resistance.
D. Electricity is negatively charged and is attracted to positive charges.
Answer:
answer is B. Electricity cools down devices as it travels through them
Explanation
If the mass defect for a radionuclide is –8.7839×10-30 kg, what's the binding energy per atom?
Question 7 options:
A)
–7.8944×10-13 J/atom
B)
–4.76×1011 J/atom
C)
–7.8944×10-13 kJ/atom
D)
7.8944×10-13 J/atom
Answer:
A) –7.8944×10-13 J/atom
Explanation:
Mass defect of a radionuclide (m)
[tex]=-8.7839[/tex]×[tex]10^{-30} kg[/tex]
Formula for binding energy
[tex]E=mc^{2}[/tex]
[tex]=(-8.7839x10^{-30} kg)(3x10^{8} m/s)^{2}[/tex]
[tex]E=-7.8944x10^{-13} J/atom[/tex]
If the mass defect for a radionuclide is – 8.7839 × 10⁻³° kg, the binding energy per atom will be –7.8944 × 10⁻¹³ J/atom. The correct option is A.
What is radionuclide?A radionuclide is an unstable nuclide because it contains so much charge. The excess energy is used by the gamma radiation by the nucleus, the electron uses energy to move to another orbital.
Radionuclides are particles that are used to scanning or monitor the radioactive chemicals that are in the body due to swallowing or inhaling.
The binding energy per atom can be calculated by the formula
The mass of defect of a radionuclide (m) is – 8.7839 × 10⁻³° kg
E = mc²
E = – 8.7839 × 10⁻³° x 3 x 10⁸ m/s
E = –7.8944 × 10⁻¹³ J/atom.
Thus, the correct option is A. –7.8944×10-13 J/atom.
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PLEASE HELP ME classify this reaction:
your options are
1. synthesis
2. decomposition
3. combustion
4. single replacement
5. double replacement
explain your answer for brainliest
A mixture of He, Ar, and Xe has a total pressure of 2.40 atm. The partial pressure of He is 0.300 atm, and the partial pressure of Ar is 0.250 atm. What is the partial pressure of Xe?
Express your answer to three significant figures and include the appropriate units.
The partial pressure of Xe in the mixture is 1.850 atm. (partial pressure of Xe = Total pressure - Partial pressure of He - Partial pressure of Ar = 1.850 atm).
To find the partial pressure of Xe, we need to subtract the partial pressures of He and Ar from the total pressure.
Total pressure = partial pressure of He + partial pressure of Ar + partial pressure of Xe
Given:
Total pressure = 2.40 atm
Partial pressure of He = 0.300 atm
Partial pressure of Ar = 0.250 atm
Let's solve for the partial pressure of Xe:
Partial pressure of Xe = Total pressure - Partial pressure of He - Partial pressure of Ar
Partial pressure of Xe = 2.40 atm - 0.300 atm - 0.250 atm
Partial pressure of Xe = 1.850 atm
Therefore, the partial pressure of Xe in the mixture is 1.850 atm.
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