Solution :
Partition coefficient Kd
[tex]$=\frac{\frac{\text{mass of caffeine in } CH_2Cl_2}{\text{volume of } CH_2Cl_2}}{\frac{\text{mass of caffeine in water}}{\text{volume of water}}}$[/tex]
= 9.0
A). 1 x 200 mL extraction :
Let m be the mass of caffeine in the water
Mass of caffeine in [tex]$CH_2Cl_2$[/tex] = 100 - m
[tex]$\frac{\frac{100-m}{200}}{\frac{m}{200}} = 9.0$[/tex]
[tex]$=\frac{100-m}{m} = 9.0$[/tex]
[tex]$= 10 m = 100$[/tex]
m = 10
Mass remaining in coffee = m = 10 mg
B). 2 x 100 mL extraction :
First extraction :
Let [tex]$m_1$[/tex] be the mass of caffeine in the water
Mass of caffeine in [tex]$CH_2Cl_2$[/tex] = [tex]$100-m_1$[/tex]
[tex]$\frac{\frac{100-m_1}{100}}{\frac{m_1}{200}} = 9.0$[/tex]
[tex]$=\frac{100-m_1}{m_1} = 4.5$[/tex]
[tex]$ 5.5 \ m_1 = 100$[/tex]
[tex]$m_1$[/tex] = 18.18
Mass remaining in coffee = [tex]$m_1$[/tex] = 18.18 mg
Second Extraction :
Let [tex]$m_2$[/tex] be the mass of caffeine in the water
Mass of caffeine in [tex]$CH_2Cl_2$[/tex] = [tex]$18.18-m_2$[/tex]
[tex]$\frac{\frac{18.18-m_2}{100}}{\frac{m_2}{200}} = 9.0$[/tex]
[tex]$=\frac{18.18-m_2}{m_2} = 4.5$[/tex]
[tex]$ 5.5 \ m_2 = 18.18$[/tex]
[tex]$m_2$[/tex] = 3.3
Mass remaining in coffee = [tex]$m_2$[/tex] = 3.3 mg
3. What is the difference between prodation and competition?
a. Competition is the demand for the same resource, precision is when one
organism eats another
b. Competition is when one organism eats another, predation is the demand for the
same resource
C. Competition always ends with one organismiling another, while predation is
when one organism just harms another
d. None of the above
From where do the placenta and umbilical cord develop?
outer cells of the blastocyst
inner cells of the blastocyst
directly from the uterus
directly from the ovary
Answer:
When an egg is fertilized, it divides into two components — one becomes the embryo, which develops into the fetus, and the other becomes the placenta, which grows along the lining of the uterus. The umbilical cord develops from embryonic tissue and will grow about 60 centimetres long.
The umbilical cord develops from and contains remnants of the yolk sac and allantois. It forms by the fifth week of development, replacing the yolk sac as the source of nutrients for the embryo.
OR put simply
A, the oyster cells of the blastocyst.
Can someone please help me on this?
Answer:
a liquid
Explanation:
I'm not for sure but I just looked it up
Sulfur dioxide and oxygen react to form sulfur trioxide during one of the key steps in sulfuric acid synthesis. An industrial chemist studying this reaction fills a flask with of sulfur dioxide gas and of oxygen gas, and when the mixture has come to equilibrium measures the partial pressure of sulfur trioxide gas to be . Calculate the pressure equilibrium constant for the reaction of sulfur dioxide and oxygen at the final temperature of the mixture. Round your answer to significant digits.
Answer:
The answer is "[tex]\bold{4.97 \times 10^{-2}}[/tex]"
Explanation:
Please find the complete question in the attached file.
Equation:
[tex]2SO_2+O_2 \leftrightharpoons 2SO_3[/tex]
at [tex]t=0 3.3 \ \ \ \ \ \ \ \ \ \ 0.79[/tex]
at equilibrium [tex]3.3-p \ \ \ \ \ \ \ \ \ \ 0.79 - \frac{P}{2} \ \ \ \ \ \ \ \ \ \ \ \ P[/tex]
[tex]p= 0.47 \ \ atm\\\\SO_2=3.3-0.47 = 2.83 \ \ atm\\\\O_2= 0.74 -\frac{0.47}{2}=0.74-0.235=0.555 \ atm\\\\K_P=\frac{[PSO_3]^2}{[PSO_2]^2[PO_2]}\\\\[/tex]
[tex]=\frac{0.47^2}{2.83^2\times 0.555}\\\\=4.97 \times 10^{-2}[/tex]
(a)A student took a solution of copper sulphate in a beaker and put a clean iron nail into it and left it for about an hour.
(i) What type of colour change do you observe?
(ii) Identify the type of reaction.
(iii) Write a word equation for the above change.
Answer: (i) blue colour fades away
(ii) Single replacement
(iii) copper sulphate + iron [tex]\rightarrow[/tex] iron sulphate + copper
Explanation:
Single replacement reaction is a chemical reaction in which more reactive element displaces the less reactive element from its salt solution.
[tex]CuSO_4+Fe\rightarrow FeSO_4+Cu[/tex]
Here iron being more reactive than copper can easily displace copper from its salt solution and form iron sulphate and copper in elemental form.
The blue colour of the copper sulphate solution fades away.
The word equation is :
copper sulphate + iron [tex]\rightarrow[/tex] iron sulphate + copper
Lets be honest here no one would help me with these 3-4 questions but anyways
Answer:
Continental drift was a theory that explained how continents shift position on Earth's surface. Set forth in 1912 by Alfred Wegener, a geophysicist and meteorologist, continental drift also explained why look-alike animal and plant fossils, and similar rock formations, are found on different continents.
Explanation:
nun
Answer:
Continental drift or tectonic plates is a theory that explains the formation of the current surface structure of the Earth.
Continental drift is also understandable if you take pictures of each continents map and try to join them with another, for example, try to fit the map of western south India with Oman's southern region you will see they exactly fit each other, Science explains this as that the land had split and drifted to form what we see now, and this is known as continental drift or tectonic plates. This form was brought up by Alfred Wegener in 1912.
This theory is also the reasoning for the rising of mountains like the Himalayan mountains, which are having a rise in their height over time, the Himalayan mountains are believed to be belonging to a boundary of two plates that move towards each other and this is believed as the rise of India.
Predict the product of the following Wittig reaction: You may want to draw out the reaction of a separate piece of paper before submitting your response. 2-butanone reacts with (C2H5O)2P=O--CHC.Hs with added heat in a potassium salt solution
a) Potassium diethyl phosphate
b) (z)-stilbene
c) 2-methylbut-1-enyl-benzene
d) 2-methylbutene diethyl phosphate
Answer:
c) 2-methylbut-1-enyl-benzene
Explanation:
From the information given:
Wittig reaction is essential for the creation of carbon-carbon bonds which results in the production of alkenes. The presence of the ketone compound ( 2-butanone) is because of its high electrophilic character of the carbonyl carbon. The reaction between 2-butanone with triethylamine in the presence of potassium salt is to catalyze the reaction. This reaction proceeds to yield the product 2-methylbut-1-enyl-benzene.
How many grams of water can be made from 6 moles of oxygen
The iodide (I2) content of a commercial mineral water was measured by two methods that produced wildly different results.6 Method A found 0.23 milligrams of I2 per liter (mg/L) and method B found 0.009 mg/L. When Mn21 was added to the water, the I2 content found by method A increased each time that more Mn21 was added, but results from method B were unchanged. Which of the Terms to Understand describes what is occurring in these measure- ments? Which result is more reliable?
Answer:
Results from method B is more reliable than method A.
Explanation:
The two method that are used for the analysis produced different results. The first method that is method A gives higher value of the iodine content than the method B.
When [tex]$Mn^{2+}$[/tex] was added to water, method A showed an increased in the iodine content and it increases with the increase in the amount of [tex]$Mn^{2+}$[/tex] .
Where as in the method B, there is no change in the results. Therefore the measurements provided by the method A shows an inference of [tex]$Mn^{2+}$[/tex] ion.
The measurement of the iodine content is affected by the presence of the ion [tex]$Mn^{2+}$[/tex] in water.
Since in method B there is no change in measurement, it is independent of the presence [tex]$Mn^{2+}$[/tex] ion in water.
As higher iodine content is given by method A, so [tex]$Mn^{2+}$[/tex] ion must be present in original water that must be interfering the measurement. Hence, method B is more reliable.
Method B is more reliable as its value is not altered by external factors such as contamination.
What is water analysis?Water analysis is done to test the quality of water.
The method employed in water analysis is titrimetric analysis.
In the test iodide (I⁻) content of a commercial mineral water using the two methods, the results of the test showed different values for the iodide content.
However, since addition of Mn²⁺ to the mineral water increases the iodide content value from Method A while that of Method B remains unchanged, Method B is more reliable as its value is not altered by external factors such as contamination.
Learn more about titrimetric analysis at: https://brainly.com/question/8463543
Rocks are classified as sedimentary, metamorphic, or igneous on the basis of
the
a. age of the rocks.
b. way the rocks were formed.
c. types of fossils the rocks contain.
d. number of minerals found in the rocks.
While performing a blatant flop togain a foul called on the opposing team, LeBron James scrapes his knee and begins to bleed. His personal doctor bursts ontothe court with hydrogen peroxide (H2O2) in to clean up his wound. If the doctor applied 6.43 x 1029 molecules of hydrogen peroxide to the infected area, how many grams of hydrogen peroxide (H2O2) were used?
A)3.14 g H2O2B)1.317 x 1055g H2O2C)3.63 x 107 g H2O2D)1.138 x 1052g H2O
Answer:
i hope u find what your looking for
Question 1 (4 points)
What is the molecular weight of Magnesium nitride, Mg3N2 (OR Mg3 N2). Report
your answer to two decimal places.
Do not include units with your answer.
The atomic weight of Mg is 24.31 grams/mole
The atomic weight of N is 14.01 grams/mole
Which system is affected by the process of weathering?
the hydrosphere
the atmosphere
the biosphere
the geosphere
[tex] \huge \colorbox{pink}{Answer☟︎︎︎}[/tex]
When ice melts, liquid water performs the act of erosion by carrying away the tiny rock fragments lost in the split. This specific process (the freeze-thaw cycle) is called frost weathering or cryofracturing. Temperature changes can also contribute to mechanical weathering in a process called thermal stress.
What are the the basic cloud types?
Answer:
they are 10 but I'll be listing three
Explanation:
cirrus,cirrocumulus and cirrostratus
I hope this helps....good luck with the rest...again, I hope this helps
The gleaming metallic appearance of the Gateway Arch in St. Louis, Missouri, comes from the stainless steel used in its construction. This steel is made mostly of iron, but it also contains 19% (by mass) chromium and 9.0% (by mass) nickel. Stainless steel maintains its metallic sheen because the chromium and nickel in it combine with oxygen from the atmosphere, forming a layer of Cr2O3 and NiO that is too thin to detract from the luster of the steel but that protects the metal beneath from further corrosion. What is the mole ratio of chromium to nickel atoms in this steel?
Answer:
the mole ratio of chromium to nickel atoms in the steel is 2.383
Explanation:
Given the data in the question;
Chromium = 19% ( by mass )
Nickel = 9% ( by mass )
now, let the mass of the steel = 100 g
so mass of Chromium = 19g
mass of nickel = 9g
We know that; Atomic mass of Cr is 52 g/mol, Atomic mass of Ni is 58.7 g/mol
Moles of Cr = mass/atomic number = 19/52 mol
Moles of Ni = mass/atomic number = 9/58.7 mol
The mole ratio of of Cr to Ni atom will be;
⇒ Moles of Cr / Moles of Ni
= (19/52) / (9/58.7)
= 19×58.7 / 9×52
= 2.383
Therefore, the mole ratio of chromium to nickel atoms in the steel is 2.383
At room temperature, oxygen is a gas and hydrogen is a gas. When they combine at room temperature, they form a _______________.
Answer: they can combine to form water or hydrogen peroxide.
Explanation:
sorry if it wrong i just looked it up lol. hope this helps tho
To make some oatmeal, Sally combined 40 grams of oatmeal, 10 grams of maple syrup, and some warm water. If the combined mass was 100 grams, how much water did she add?
ANSWER THIS EMEDIATLY PLEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEAAAAAAAAAASE
thank you
(ps.this is the closest subject to science (that deals with volume, mass, and matter you know that kind of stuff )that I could find
Calculate the speed of a marble that rolls 9 cm in 4 seconds
Answer:
2.25
Explanation:
9/4
Lithium and nitrogen react to produce lithium nitride:
6Li (s) + N2 (g) = 2Li3N (s)
How many moles of lithium nitride are produced when 0.400 mol lithium are used in this reaction?
a. 1.28 mol
b. 0.133 mol
c. 0.800 mol
d. 0.0667 mol
Answer:
B : 0.133 M
Explanation:
moles Li3N3 = 0.4 mol Li x (2 moles Li3N/6 moles Li) = 0.133 M
1. At an environmental testing lab, a lab technician calculated the known concentration of the calibrating solution three times too high. How will this affect the results of the samples run using this calibration solution
Answer:
The deviation in the results will be too large when compared with the actual result
Explanation:
The effect this will have on the results of the samples run using this Calibration solution is that the deviation in the results will be too large when compared with the actual result that was supposed to be obtained. and this will also lead to wrong analysis by the technician .
This will cause a result that is very different from the actual result, which will lead to errors in the analysis.
We can arrive at this answer because:
A laboratory test must be done accurately and all calibrations must follow the test protocol.Changing the calibration will cause inaccurate and incorrect results, which differ from the actual result.This will promote an analysis that is unreal, false, and far from true, which will leave the entire test inaccurate.As we can see from the question above, the lab technician used a much higher calibration than what was recommended in the lab. This will lead to inaccurate and incorrect results.
More information:
https://brainly.com/question/957129?referrer=searchResults
What information in the passage helps answer the question asked previously?
Gravity smooths out even the lumpiest black hole.
A symmetrical collapse forms a smooth hole.
Erratic gravity pulls a black hole in different directions.
A collapse can be symmetrical or lopsided.
Please Hurrry
Answer:
D. A collapse can be symmetrical or lopsided.
Explanation:
I hope this helps
-Have a wonderful day
-Tell me if it is wrong :)
-ED Language Arts
-Questioning in A Black Hole Is NOT a Hole
-Assignment
Thank you
A collapse can be symmetrical or lopsided. Therefore, the correct option is option D among all the given options.
What is black hole?The event horizon of a black hole is an area of spacetime wherein gravity is so intense that nothing, not even light or even other electromagnetic waves, have the energy to cross it. According to general relativity theory, a compact enough mass can bend spacetime into a black hole.
The event horizon is the line beyond which there is no escape. Despite having a significant impact on the outcome and conditions of an object traversing it, general relativity states that it lacks any locally observable characteristics. A black hole behaves in many ways like a perfect black body since it does not reflect light. A collapse can be symmetrical or lopsided. This helps answer the question asked previously.
Therefore, the correct option is option D.
To know more about black hole, here:
https://brainly.com/question/16470114
#SPJ3
Your question is incomplete but most probably your full question was,
If the star was spinning before the collapse, then the black hole will spin, too. If the collapse is perfectly symmetric, a smooth black hole forms. On the other hand, even a slightly lopsided collapse leads to a lumpy black hole, with erratic gravitational effects. The gravity might be strong in some places and weak in others, and pull in different directions. However, a lumpy hole won't stay lumpy for long, because its own gravity will work to smooth it out. —A Black Hole Is NOT a Hole, Carolyn Cinami DeCristofano What information in the passage helps answer the question asked previously? Gravity smooths out even the lumpiest black hole. A symmetrical collapse forms a smooth hole. Erratic gravity pulls a black hole in different directions. A collapse can be symmetrical or lopsided.
At what minimum temperature do rocks melt into lava?
A) 3,500 degrees Celsius
B) 6,332 degrees Fahrenheit
C) 800 degrees Fahrenheit
OD 800 degrees Celsius
I need help please with the drop down menus
Answer:
When the archer releases the arrow, the elastic potential energy in the bowstring transforms into kinetic energy for the arrow.
Explanation:
When the string of a bow and arrow is pulled from equilibrium, the elastic potential energy in the bow is converted to kinetic energy of the arrow when the string is released.
What is the gravitational force on a 35.0kg object standing on the earth's surface ?
Answer:
Explanation:
F=mg
F=35*9.81
F=343.35N
Carbohydrates are formed by plants converting water a d carbon dioxide into glucose and oxygen, in the photocatalyzed process is called?
2. I need to find the angle of corner of a room, what tool could I use?
a. Combination square
b. Plumb-bob
c. Sliding t-bevel
d. Tri-square
Which of the following explains why a longer bond is also a weaker bond? Help plz
Answer:
Longer bonds have lower attractive force
Which element, when combined with fluorine, would most likely form an
ionic compound?
A. phosphorus
B. lithium
C. carbon
D. chlorine
please help me
is for my daughter
Answer:
I think you have to freeze the water itself then take the temp with a thermometer ️of each one then record how long it takes each one to start freezing then how long it takes for it to melt
Explanation:
sorry if I'm wrong but you have to do the experiment yourself then fill it out
How does shaking or stirring a mixture of solute and solvent affect a solution?
CA. It increases the solubility of the solute.
CB. It increases the rate of dissolving.
C C. It decreases the solubility of the solute.
D. it decreases the rate of dissolving.