Answer:
Hello your question is incomplete the pH of the solution is unknown hence I will take the pH of the solution be = 4.7
answer : Pka = 5 i.e. > 4.7
Explanation:
Student titrates :
Unknown weak acid ( HA ) with 25 mL of 0.100 M of NaOH ( to a pale pink phenolphthalein endpoint ) then titrates with 11.0 mL of 0.100 M HCL to the solution that contains neutralized unknown acid
Assuming pH of solution = 4.7
HA + NaOH --------> H2O + NaA
at equilibrium point
0.1 * 25 * 1 = n * 1 ∴ [tex]n_{ha}[/tex] = 2.5 mmoles ------ 1
also
[tex]A^-[/tex] + HCL ---------> HA + C[tex]L^-[/tex]
at equilibrium point
[tex]n_{a}[/tex] = 1.1 mmoles --------- 2
The ratio of reaction 2 to 1
[tex]\frac{n_{a} }{n_{ha} }[/tex] = 1.1 / 2.5 ≈ 1/2 ( this show that when the pH = 4.7 approximately half of the A^- have been converted to HA )
Determine the pKa value of the solution
Given that
pH = Pka + log ( A^- / hA )
4.7 = Pka + log ( 1/2 )
therefore Pka = 4.7 - ( -0.3 ) = 5
A bottle of an unknown liquid has a volume of 6.3 mL and mass 255.15 g. What is its density?
Answer:
40.5 g/mL
Explanation:
Density is a measure of a substance's mass over its volume.
d = m/v
Therefore d = 255.15g/6.3mL = 40.5 g/mL
Mg + 2HCl ⟶ MgCl2 + H2
How many grams of MgCl2 are produced by 2.55 mol Mg?
Answer: m = nM= 242.8 g
Explanation: amount of MgCl2 is same as n(Mg)
M(MgCl2) = 95.21 g/mol
95.21 g/mol is the mass in grams of MgCl[tex]_2[/tex] are produced by 2.55 mol Mg in the reaction Mg + 2HCl ⟶ MgCl[tex]_2[/tex] + H[tex]_2[/tex].
What is mass?A body's mass is an inherent quality. Prior to the discoveries of the concept of atom as well as particle physics, it was widely considered to be tied to the amount of matter inside a physical body. It was discovered that, despite having the same quantity of matter in theory, different atoms and elementary particles have varied masses.
There are various conceptions of mass in contemporary physics that are theoretically different but physically equivalent. The resistance of the body to accelerate (change of velocity) in the presence of a net force can be measured experimentally as mass. The gravitational pull an object has on other bodies is also influenced by its mass.
m = n×M= 242.8 g
M(MgCl[tex]_2[/tex]) = 95.21 g/mol
Therefore, 95.21 g/mol is the mass in grams of MgCl[tex]_2[/tex] are produced by 2.55 mol Mg in the reaction Mg + 2HCl ⟶ MgCl[tex]_2[/tex] + H[tex]_2[/tex].
To know more about mass, here:
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#SPJ2
Please answer thank you so much!
Calculate the number of atoms
in 10.0g of He.
A. 3.83 x 1023
B. 2.41 X 1024
C. 1.51 X 1024
D. 6.02 x 1023
khan academy sucks. can someone answer this? :)
Q4
Which of the following is an example of nonpoint source pollution?
A. industrial effluent
B. Agricultural runoff
C. illegal dumping of waste
D. Oil leaking from your car
Answer:
Option C.
Ilegal dumping of waste
Explanation:
This is because non point source of pollution refers to source of pollution that are many and not directly one which is illegal or does not meet the legal term. This type of pollution does not have a point source, it has many sources and this type of pollution is cause by rainfall or precipitation. Where when the rain fall, it wash away the waste through to water bodies, causing pollution and endangering water bodies.
What causes a sharp increase in potential energy when two
atoms approach more closely to one another then their ideal
bond distance?
A. Electrostatic repulsion between electron clouds
B. Gravitational force between the atoms
C. Electrostatic repulsion between nuclei
D. Electrostatic attraction between electrons and nuclei
Circle all that apply for an anion.
a. Positively charged
b. Negatively charged
c. Metal
d. Nonmetal
e. Loses electrons when formed
f. Gains electrons when formed
g. Listed first in a compound
h. Listed second in a compound
Answer:
b. d. f. h
Explanation:
Anions are negatively charged. They are usually non metals with few exceptions. They need to gain electrons in order to form and they are always listed after cation in a compound.
a wave transfers from one place to another
Answer:
mhm
Explanation:
True or False. Chemical changes only rearrange the elements that are
already present.
True or False. The reactants and the products of a chemical equation
always have the same number of atoms.
Here's link to the answer:
tinyurl.com/wpazsebu
Convert 17oC to kelvin
Answer:
290
Explanation:
Temperature in kelvin = 273 + Temperature in ⁰C
Answer: °Celsius Kelvin
25.00 298.15
25.01 298.16
25.02 298.17
25.03 298.18
25.04 298.19
25.05 298.20
25.06 298.21
25.07 298.22
25.08 298.23
25.09 298.24
What is the experimental yield of Li2O?
1 point
have specific requirements that need to be met in order for an
entrepreneur to be considered.
O Loans
O Investments
O None of the other answers
O Grants
1. How many liters of a 0.50 M solution are needed to give 3.5 moles of solute?
Answer:
The volume of solution in liters required to make a 0.250 M solution from 3.52 moles of solute is 14.08 liters of solution
Explanation:
The question relates to the definition of the concentration of a solution which is the number of moles per liter (1 liter = 1 dm³) of solution
Therefore we have;
The concentration of the intended solution = 0.250 M
Therefore, the number of moles per liter of the required resolution = 0.250 moles
Therefore, the concentration of the required solution = 0.250 moles/liter
The volume in liters of the required solution that will have 3.52 moles of the solute is given as follows;
The required volume of solution = The number of moles of the solute/(The concentration of the solution)
∴ The required volume of solution = 3.52 moles/(0.250 moles/liter) = 14.08 liters
The required volume of solution to make a 0.250 M solution from 3.52 moles of solute = 14.08 liters.
Therefore the number of liters required to make a 0.250 M solution from 3.52 moles of solute = 14.08 liters.
8. If a chemical reaction such as photosynthesis begins with 6 atoms of carbon (C), how many atoms of carbon (C) should be in the products? A. 12 atoms of carbon (C) B. 6 atoms of carbon (C) c. 3 atoms of carbon (C) D. 2 atoms of carbon (C)
A. 12 atoms of carbon (C)
B. 6 atoms of carbon (C)
C. 3 atoms of carbon (C)
D. 2 atoms of carbon (C)
Answer
b
Explanation:
Can you please help me it’s not a hard question
Which of the following items are factors that influence reaction rates? Select all that apply.
Question 2 options:
Surface Area
Concentration
Temperature
Catalyst
Light
Answer:
temperature
catalyst
surface area
How many grams of Ag2S
are produced from 10.0
grams of AgI?
10
AgI + Nazs
Ag2S +NaI
Answer:
10.0 g of AgI will produce 5.28 g of Ag₂S
Explanation:
The balanced equation of the reaction is given below:
2AgI + Na₂S ----> Ag₂S + 2NaI
From the equation of reaction, 2 moles of AgI produces 1 mole of Ag₂S
The moles of a substance is related to its mass by a quantity known as molar mass which is defined as the mass of one mole of that substance.
Molar mass of AgI = (108 + 127) g = 235 g
Molar mass of Ag₂S = (108 × 2 + 32) g= 248 g
Mass of 2 moles of AgI = 2 × 235 g = 470 g
470 g of AgI produces 248 g of Ag₂S
10 g of AgI will produce 248 /470 × 10 g of Ag₂S = 5.28 g
Therefore, mass of Ag₂S produced = 5.28 g
A forecaster studying the climate of an area would find which of the following most helpful?
A. average yearly precipitation
B. today's barometric pressure
C. temperature changes in one month
D. how often natural disasters occur
A forecaster studying the climate of an area would find average yearly precipitation most helpful.
What is forecaster studying of climate?Forecaster studying of climate tells about the changes which will occur in the atmosphere in the upcoming future time.
Forecasting is done by measuring various environmental factors for the prediction of atmosphere. As it will given information about the percent of rainfall in the upcoming days, amount of precipitation, snowfall and so on.
Hence, option (A) is correct.
To know more about Forecaster studying of climate, visit the below link:
https://brainly.com/question/13407372
An artificial vesicle containing a 1 M glucose solution is composed of a phospholipid bilayer lacking any protein components other than aquaporin channels. Assuming an ideal solution, what is the ratio of the osmotic pressure measured immediately after immersion of the vesicle in de-ionized water to the osmotic pressure measured immediately after immersion of an identical vesicle containing the original volume of 1 M glucose solution added to an equal volume of 1 M KCl solution in deionized water
Answer:
A: 0.67
The situation described in the question is analogous to a semipermeable membrane. Water is able to pass through aquaporin channels present in the liposome, but large uncharged particles (glucose) and ions (K+ and Cl -) are impermeable and will remain trapped within the liposome. If assumed to be ideal, the osmotic pressure, π, exerted by the solution due to molarity differences across the membrane is defined as π = iMRT, where i is the van't Hoff factor, M is the molarity of the solution, R is the universal gas constant, and T is the absolute temperature of the solution. A change in osmotic pressure at constant temperature is due to changes in iM, a term that is equivalent to the concentration of dissolved particles produced by solute in solution. When compared to the original volume of 1 M glucose, the new combined solution has twice the volume and three times the number of dissolved particles (1 M KCl, a strongly electrolytic solution, produces 1 M concentrations of both K+ and Cl- in solution), or an increase in the concentration of dissolved particles by a factor of 1.5. This is equivalent to a combined molarity of dissolved particles of 1.5 M. The ratio of osmotic pressure is then [1 M dissolved glucose] / [1.5 M dissolved glucose + KCl] = 0.67
Explanation:
I went for a walk the other day. I went four blocks east, then seven blocks south, then one block west and finally
eight blocks north
a.What distance did I travel?
b. What's my displacement?
Answer:
a) distance is 4+7+1+8=20 blocks
b) displacement is 10 blocks
Explanation:
find displacement: x and y
x axis displacement = 4-1 = 3 blocks
y axis displacement = -7+8= 1 block
displacement = the square root of 3^2 + 1^2
= 9+1 = 10 blocks.
You can find the angle of displacement with respect to the initial position using trig identities, if you wish.
that isssssss? (thank you whoever answers in advance)
Answer:
c
Explanation:
A pathogen or infectious agent is a biological agent that causes disease or illness to its host. The term is most often used for agents that disrupt the normal physiology of a multicellular animal or plant. However, pathogens can infect unicellular organisms from all of the biological kingdoms.
Answer:
Harmful to living organisms
Explanation:
tbh, quizzlet lol
13 Consider this neutralization reaction.
H2SO4 + 2KOH → K2SO4 + 2HOH
Which compound is the salt produced in this
reaction?
(1) KOH
(2) H2SO4
(3) K2SO4
(4) HOH
Explanation:
The answer to the question is (3) K2SO4
NEED HELP ASAP 50 POINTS WILL MARK BRAINLIEST!
Answer:
156748
Explanation:
The first number is on the magnetism card 1
The combination contains only the numbers found on the cards showing techniques to separate mixtures 1,5,6,7,8
The last number is on the filtering card
The red is in the middle half of 8 is 4
HELPP ILL GUVE YOU LOTS OF POINTS EVERYTHING U WANT I REALLY NEED HELP
Answer:
jupiter is your answer
Explanation:
you weigh more there
1. A wave has a frequency of 800 Hz and a wavelength of 2000 cm. What speed
is this wave traveling?
Answer:
V=f*(wavelength)
V= (800)(20m)
16000m/s
Explanation:
How many grams of sodium metal must be introduced to water to produce 3.3 grams of hydrogen gas?
Answer:
The mass of sodium metal that must be introduced to water to produce 3.3 grams of hydrogen gas, H₂, is approximately 18.82 grams of sodium metal
Explanation:
The given mass of hydrogen gas produced = 3.3 grams
The molar mass of hydrogen gas, H₂ = 2.016 g/mol
The number of moles of hydrogen gas in 3.3 grams of H₂, 'n', is given as follows;
n = Mass/(Molar mass)
n = 3.3 g/(2.016 g/mol) = 1.63690476 moles of H₂
The reaction of sodium and water can be written as follows;
2Na + 2H₂O → 2NaOH + H₂ (g)
2 moles of sodium produces 1 mole of hydrogen gas, H₂
Therefore;
1.63690476/2 moles of sodium will produce 1.63690476 moles of hydrogen gas, H₂
The molar mass of sodium, Na ≈ 22.989 g/mol
The mass of 1.63690476/2 moles of sodium, 'm', is given as follows;
m = 1.63690476/2 moles × 22.989 g/mol ≈ 18.8154018 grams ≈ 18.82 grams
The mass of sodium that will produce 3.3 grams of hydrogen, m ≈ 18.82 grams of sodium metal.
What ratio of NaCN to HCN is needed to prepare a pH 9.40 buffer? (Ka of HCN is 4.9 × 10⁻¹⁰)
Answer: The ratio of NaCN to HCN is, 1.26
15. _____ is the breakdown of rocks into smaller particles by natural processes.
A. Deposition
B. Weathering
C. Erosion
Answer:
B
Explanation:
Weathering is the physical and chemical breakdown of rock at the earth's surface. ... The physical breakdown of rock involves breaking rock down into smaller pieces through mechanical weathering processes. These processes include abrasion, frost wedging, pressure release (unloading), and organic activity.
De la reacción 3Zn+ 2H2PO4----> Zn3(PO4)2 +2H2 por cada 9 moles de zinc cuantos moles de fosfato de zinc se producen
Answer:
Por cada 9 moles de zinc, 9 moles de fosfato de zinc se producen.
Explanation:
La reacción balanceada es:
3 Zn+ 2 H₂PO₄ → Zn₃(PO₄)₂ + 2 H₂
Por estequiometria de la reacción (es decir, la relación entre la cantidad de reactivos y productos en una reacción química), las siguientes cantidades de moles de cada compuesto participan de la reacción:
Zn: 3 moles H₂PO₄: 2 moleZn₃(PO₄)₂:1 mole H₂: 2 molesEntonces podes aplicar la siguiente regla de tres: si por estequiometria 3 moles de zinc produce 1 mol de fosfato de zinc, 9 moles de zinc cuántos moles de fosfato de zinc producirá?
[tex]moles de fosfato de zinc=\frac{9 moles de zinc*1 mole de fosfato de zinc}{3 moles de zinc}[/tex]
moles de fosfato de zinc= 9
Por cada 9 moles de zinc, 9 moles de fosfato de zinc se producen.
