You want to decaffeinate your coffee by extracting the caffeine out with dichloromethane (they don't do it that way anymore, but they used to). It's too late to extract the caffeine from the coffee beans, because you've already brewed yourself a 200 mL cup of coffee. Your particular brand of coffee contains 100 mg of caffeine in that 200 mL cup. The partition coefficient of caffeine in dichloromethane/water is 9.0 (it is more soluble in the dichloromethane).
How much caffeine would still be in your 200 mL if you did:_____.
A. One extraction using 200 mL ofdichloromethane
B. Two extractions using 100 mL ofdichloromethan each.
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
Carbon dioxide ( a greenhouse gas) is breathed out by billions of people all over the world? Yes or no
Answer:
yes
Explanation:
Answer:
yes
Explanation:
Humans inhale oxygen and breath out carbon dioxide.
Assume that the ratio of moles of Cl to moles of Cu are 2.39. If we can represent the formula by CuClx, what is the value for x? Round your answer to the nearest whole number. Do NOT include units. So, if you think the formula is CuCl6, you enter the number 6.
Answer:
x=2.
Explanation:
Hello there!
In this case, since we have a mole ratio of moles of Cl to moles of Cu as 2.39, it is possible to write the following:
[tex]\frac{2.39molCl}{1molCu}[/tex]
Thus, since the two possible copper chlorides are CuCl and CuCl₂, we can therefore infer that x=2 since it is close but not as close as it should to the whole number 2.
Best regards!
3. Explain what would happen to the digestion process if enzymes were not present. SC.6.L.14.5
Calculate the speed of a marble that rolls 9 cm in 4 seconds
Answer:
2.25
Explanation:
9/4
What is chemistry
What is the bond type in CaO
Answer:
Ionic bond
CaO is an ionic bond. Two-element compounds are usually ionic when one element is a metal and the other is a non-metal. It is made up of one metal ion/cation(Ca^2+) and an non-metal ion/anion(O^2-).
help please guys i need it
Answer:
Amplitude
Explanation:
Hope I helped :)
Rick is creating a love potion for Morty. To make the potion, Rick's needs 51 mL of a mixture solution where 40% is carbonated water. After checking around his shop, Rick finds two solutions he could use. The first solution he found is 65% green tea, 15% carbonated water, and 20% whole milk. The second solution is 17% orange juice, 38% lemonade, and 45% carbonated water. How much of the first solution and second solution does Rick need to mix together to create the love potion? Round your final answers to one decimal place. You may solve this problem using any method we have learned in the class.
Answer:
The amount of the first solution rick needs to mix together to create the love portion is 8.5 mL
Explanation:
So as to make the love potion, we have;
The percentage of carbonated water in the love portion = 40%
The percentage of green tea in the first solution = 65%
The percentage of carbonated water in the first solution = 15%
The percentage of whole milk in the first solution = 20%
The percentage of orange juice in the second solution = 17%
The percentage of lemonade in the second solution = 38%
The percentage of carbonated water in the second solution = 45%
Let 'x' represent the volume in mL of the first solution added to make the love portion, and let 'y' be the volume in mL of the second solution added to make the love portion, we have;
x + y = 51...(1)
0.15·x + 0.45·y = 0.40×51 = 20.4
0.15·x + 0.45·y = 20.4...(2)
Solving the system of simultaneous equation by making 'y' the subject of each of the equation gives;
For equation (1)
y = 51 - x
For equation (2)
y = 20.4/0.45 - (0.15/0.45)·x = 136 - 3·x
y = 136/3 - (1/3)·x
Equating the two equations of 'y', gives;
51 - x = 136/3 - (1/3)·x
51 - 136/3 = x - (1/3)·x
17/3 = (2/3)·x
(2/3)·x = 17/3
x = (3/2) × (17/3) = 17/2 = 8.5
x = 8.5
y = 51 - x = 42.5
y = 42.5
Therefore, the amount of the first solution rick needs to mix together to create the love portion, x = 8.5 mL
What are the dependent and independent variables? (Picture^^)
Answer:
X axis shows the independent and Y axis shows the dependent.
Explanation:
As the independent variable is always plotted on the X-axis of the graph the Y-axis shows the dependent variable that is affected by the X variables Time is an independent variable and is always shown along the X-axis. Such as the image showed tells about the data of N2O biofuel emissions from 2009-10. Thus this will be plotted along the X-axis and Y-axis will show the amount of nitrogen fertilizer applied.How do the polar easterlies and the jet stream work together to affect the
weather in the United States?
Answer:
they can carry cold arctic air, producing snow and freezing weather.
Explanation:
-w- hope it helps
While performing a neutralization reaction, Jonna added 27.55 mL of 0.144 M H2SO4 to 43.84 mL of 0.316 M KOH. How many moles of OH- are unreacted in the solution after the neutralization is complete?
Answer:
5.916x10⁻³ mol OH⁻
Explanation:
The reaction that takes place is:
H₂SO₄ + 2KOH → K₂SO₄ + 2H₂OFirst we calculate the added moles of each reagent, using the given volumes and concentrations:
H₂SO₄ ⇒ 0.144 M * 27.55 mL = 3.967 mmol H₂SO₄KOH ⇒ 0.316 M * 43.84 mL = 13.85 mmol KOHNow we calculate how many KOH moles reacted with 3.967 mmol H₂SO₄:
3.967 mmol H₂SO₄ * [tex]\frac{2mmolKOH}{1mmolH_2SO_4}[/tex] = 7.934 mmol KOHFinally we calculate how many OH⁻ moles remained after the reaction
13.85 mmol - 7.934 mmol = 5.916 mmol OH⁻5.916 mmol / 1000 = 5.916x10⁻³ mol OH⁻Which postmortem parameter is fixed by 8 hours?
1)cloudiness of the eyes
2)rigor mortis
3)livor mortis
4)putrefaction
15POINTS I NEED HELP WITH THIS QUESTION PLEASE!
Answer:
12.76 g
Explanation:
Step 1: Write the balanced equation
4 Fes + 7 O₂ ⇒ 2 Fe₂O₃ + 4 SO₂
Step 2: Calculate the moles corresponding to 11.15 g of O₂
The molar mass of O₂ is 32.00 g/mol.
11.15 g × 1 mol/32.00 g = 0.3484 mol
Step 3: Calculate the moles of SO₂ produced from 0.3484 moles of O₂
The molar ratio of O₂ to SO₂ is 7:4.
0.3484 mol O₂ × 4 mol SO₂/7 mol O₂ = 0.1991 mol SO₂
Step 4: Calculate the mass corresponding to 0.1991 moles of SO₂
The molar mass of SO₂ is 64.07 g/mol.
0.1991 mol × 64.07 g/mol = 12.76 g
Tris is a molecule that can be used to prepare buffers for biochemical experiments. It exists in two forms: Tris (a base) and TrisH (an acid). The MW of Tris base is 121.14 g/mol; the MW of TrisH is 157.6 g/mol (the extra weight is due to the Cl- counterion that is present in the acid). The Ka of the acid is 8.32 X 10-9. Assume that you have TrisH in solid form (a powder), unlimited 1M HCl, unlimited 1 M NaOH and an unlimited supply of distilled water. How would you prepare 1 L of a 0.02 M Tris Buffer, pH
Solution :
The reaction :
[tex]$\text{TrisH}^+ + \text{H}_2\text{O} \rightarrow \text{Tris}^- +\text{H}_3\text{O}^+$[/tex]
We have
[tex]$K_a = \frac{[\text{Tris}^-]\times[\text{H}_3\text{O}^-]}{[\text{TrisH}^+]}$[/tex]
[tex]$=\frac{x^2}{0.02-x}$[/tex]
[tex]$= 8.32 \times 10^{-9}$[/tex]
Clearing x, we have [tex]$x=1.29 \times 10^{-5}$[/tex] moles of acid
Now to reach pH = [tex]$7.8 (\text{ pOH} = 14-7.8 = 6.2)$[/tex], we must have an [tex]$OH^-$[/tex] concentration of
[tex]$[OH^-] = 10^{-pOH}$[/tex]
[tex]$=10^{-6.2}$[/tex]
[tex]$=6.31 \times 10^{-7}$[/tex] moles of base
We must add enough NaOH of 1 M to neutralize the acid calculated above and also add the calculated base.
[tex]$n \ NaOH = 1.29 \times 10^{-5} + 6.31 \times 10^{-7}$[/tex]
[tex]$=1.35 \times 10^{-5}$[/tex] moles
Vol [tex]$NaOH = 1.35 \times 10^{-5} \text{ moles} \times \frac{1000 \ mL}{1 \ mol}$[/tex]
= 0.0135 L
Tris mass [tex]$H^+ = 0.02 \text{ mol} \times 157.6 \ g/mol$[/tex]
= 3.152 g
To prepare the said solution we must mix
-- [tex]$3.152 \ g \text{ TrisH}^+$[/tex]
-- [tex]$0.0135 \ mL \ NaOH \ 1M$[/tex]
-- [tex]$\text{Gauge to 1000 mL with H}_2\text{O}$[/tex]
need help whoever answers will be awarded branliest answer
Answer:
1.used to seperate solids from liquids, and is a act of pouring a mixture onto a membrane this allows the passage of liquid and results in the collection of a solid
2. the solution would passed through without losing and solids
3 would allow them to dry or on further hearing decompose
Explanation:
what is the purpose of ash to soil conditioning.
Answer:
Question: what is the purpose of ash to soil conditioning?
answer: soil conditioner is a product that is added to soil to improve the soils physical qualities, it's usually the fertility of the soil and sometimes the mechanics of the soil. can be used to improve poor soils.
most wood ash contains a good percentage, about 25 percent, of calcium carbonate, which is an ingredient in garden lime. if your soil is highly acidic, with a pH of 5.5 or lower, amending with wood ash can raise the pH of your soil.
(80 points)
Requirements
You must include each of the following in your diagram, story/explanation:
1. precipitation
2. runoff
3. evaporation
4. condensation
5. transpiration
6. infiltration
7. groundwater
8. clouds
9. collection areas (example: ocean or lake)
Instructions
1. Complete either the diagram or written explanation – 10 points
• Diagram – you will draw the water cycle process. You must include each of the required items and label each. You are not required to color it, but it is encouraged to help differentiate between the processes.
• Written Explanation – for either of these options you need to include each of the processes. It may be beneficial to explain them in the order in which they occur but is not necessary.
2. Answer the questions
Questions
1. What process drives evaporation and transpiration? Explain how this process operates in the water cycle? (2 Points)
2. What role does gravity play in the water cycle? Hint: it is in more than 1 process (2 Points)
3. What states of matter will your find water in going through the water cycle? (1 Point)
Answer:
1.solar energy drives the cycle by evaporating water from its source and water moves from plants by the process of transpiration
2. in precipitation because the water falls from the sky
3.liquid and gas
Please answer by the number ! I will mark any correct answer brainliest :)
Answer:
36 joules is the answer
1/2mv^2
1/2* 8*3*3
4*9
36joules
Who knows how to do this please help
Answer: You forgot to zero the balance
Explanation:
What does the article “Absolute Zero” tell us about what temperature really means?
Answer:
Absolute zero, technically known as zero kelvins, equals −273.15 degrees Celsius, or -459.67 Fahrenheit, and marks the spot on the thermometer where a system reaches its lowest possible energy, or thermal motion. There's a catch, though: absolute zero is impossible to reach.
Explanation:
GIVING 21 POINTS AWAY PLEASE HELP ME WITH BOTH QUESTIONS ASAP!!!!
What is the molar mass of PbSO4?
Answer:
=303.2g
Explanation:
molar mass of Pb = 207.2g
atomic mass of S = 32g
atomic mass of O = 16g
Solution
PbSO4
= 207.2 + 32 + 4 (16)
= 239.2 + 64
= 303.2 g
The molar mass of compound lead sulfate is 207.2 g.
Molar mass of a compound or a molecule is defined as the mass of the elements which are present in it.The molar mass is considered to be a bulk quantity not a molecular quantity. It is often an average of the of the masses at many instances.
Molar masses of an element are given as relative atomic masses while that of compounds is the sum of relative atomic masses which are present in the compound.
atomic mass of S = 32g
atomic mass of O = 16g
PbSO₄= 207.2 + 32 + 4 (16)= 239.2 + 64 = 303.2 g.
Learn more about molar mass,here:
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How many moles of KBr are present in 1000 ml of a 0.02 M KBr solution?
1. .00002
2. 20
3. 50000
4. .02
5. 50
Answer:
4. .02
Explanation:
Hello there!
In this case, since the molarity of a solution is defined as the moles of the solute divided by the volume of the solution, we can see we are given the molarity and volume and are asked to compute moles; thus, we can solve as shown below:
[tex]M=\frac{n}{V}\\\\n=M*V[/tex]
Whereas the volume must be in liters (1 L in this case); in such a way we can plug in the volume and molarity to obtain:
[tex]n=0.02mol/L*1L\\\\n=0.02mol[/tex]
Therefore, the answer is 4. .02 .
Best regards!
Elizabeth REALLY didn’t study, and she also wrote the formula for dicarbon tetrafluoride as “C2F5”. Describe why her answer is incorrect.
Answer:
correct formula: C2F4
Explanation:
tetra means 4. There are 2 C and 4 F in dicarbon tetrafluoride.
After you set up your apparatus for the second part of the experiment, your group begins to add the textbooks on top of the plunger. It appears that the plunger continues to drop with every added book and does not return to its original place after the books are removed. What possible sources of error could be given for this experimental outcome? Be specific and give at least two reasons.
The possible sources of error that could be given for this experimental outcome is the change in the density of the air.
What is an experiment?An experiment simply means the procedure that is carried out in order to refute a particular hypothesis. It should be noted that experiments are important to provide insights into the cause and effect of a particular situation.
In this situation, with every added book, the volume of that air column will reduce. It is just important that the temperature should remain constant when the gas compression is taking place.
Another source of error is the assumption of moles that was assumed was constant during the experiment. In this scenario, it's possible that some gas could have escaped while the compression was taking place.
Learn more about experiments on:
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What would be the mass in amu of 150 atoms of carbon?
Answer:
Do you mean the periodic table? The atomic mass of carbon is 12 and oxygen is 16.
If I understand you right though, what you’re looking for is what oxygen’s mass would be in a certain unit of measurement with which carbon weighs 150 units.
In regular atomic mass units carbon’s mass is 12 and oxygen’s is 16, so oxygen’s mass is 4/3 times carbon’s mass. In our new unit of measurement where carbon weights 150 units, oxygen would weigh 150 * 4/3 = 200 units.
is clorox an acid or base?
Answer:
Chlorine bleach is strongly basic. We actually make it by dissolving chlorine gas in a concentrated solution of sodium hydroxide, which forms sodium hypochlorite and sodium chloride, in the following equilibrium.
Explanation:
BTS ARMY
helppppppppppppppppp
Answer:
b
Explanation:
A cylinder of oxygen (O2) gas at STP has a volume of 2.75 L. How many oxygen molecules does it contain?
Answer:
7.40×10²² molecules.
Explanation:
From the question given above, the following data were obtained:
Volume of oxygen = 2.75 L
Number of molecules of oxygen =?
Next, we shall determine the number of mole of oxygen present. This can be obtained as follow:
22.4 L contains 1 mole of oxygen at STP.
Therefore, 2.75 L will contain = 2.75 / 22.4 = 0.123 mole of oxygen at STP.
Finally, we shall determine the number of molecules of oxygen present. This can be obtained as follow:
From Avogadro's hypothesis:
1 mole of oxygen = 6.02×10²³ molecules
Therefore,
0.123 mole of oxygen = 0.123 × 6.02×10²³
0.123 mole of oxygen = 7.40×10²² molecules.
Thus, the cylinder contains 7.40×10²² molecules of oxygen.
PLS HELP THIS IS DUE IN 10 MINS!
Compare and contrast floods and droughts. Give two examples of how they are the same and two examples of how they are different.