Solution :
The partition coefficient
[tex]$k_d= \frac{\text{(mass of caffeine in }CH_2Cl_2 / \text{volume of }CH_2Cl_2)}{\text{(mass of caffeine in water/ volume of water)}}$[/tex]
= 9.0
A). 1 x 200 mL extraction
Let m be the mass of caffeine in water
Mass of caffeine in [tex]$CH_2Cl_2$[/tex] = 100 - m
∴ [tex]$\frac{(100-m)/200}{m/200}=9$[/tex]
[tex]$\frac{100-m}{m}=9$[/tex]
[tex]$10 \ m = 100$[/tex]
[tex]$m=\frac{100}{10}$[/tex]
= 10
Therefore, the mass remaining in the coffee is m = 10 mg
B). 2 x 100 mL extraction
First extraction :
Let [tex]$m_1$[/tex] be the mass of the caffeine in water.
Mass of caffeine in [tex]$CH_2Cl_2$[/tex] = 100 - m
∴ [tex]$\frac{(100-m_1)/100}{m_1/200}=9$[/tex]
[tex]$\frac{100-m_1}{m_1}=9$[/tex]
[tex]$5.5 \ m_1 = 100$[/tex]
[tex]$m_1=\frac{100}{5.5}$[/tex]
= 18.18
Mass remaining in the coffee after the 1st extraction [tex]$m_1$[/tex] = 18.18 mg
Second extraction:
Let [tex]$m_2$[/tex] be the mass of the caffeine in water.
Mass of caffeine in [tex]$CH_2Cl_2$[/tex] = 18.18 - [tex]$m_2$[/tex]
∴ [tex]$\frac{(18.18-m_2)/100}{m_2/200}=9$[/tex]
[tex]$\frac{18.18-m_2}{m_2}=9$[/tex]
[tex]$5.5 \ m_2 = 18.18$[/tex]
[tex]$m_1=\frac{18.18}{5.5}$[/tex]
= 3.3
Mass remaining in the coffee after the 1st extraction [tex]$m_2$[/tex] = 3.3 mg
Difference between brain and spinal cord
Pls help
calculate the molecular mass of sodium trioxocarbonate (iv) decahydrate. hints (H= 1, C=12, O=16, Na=23
Given :
A compound sodium trioxocarbonate (iv) decahydrate.
To Find :
The molecular mass of sodium trioxocarbonate (iv) decahydrate.
Solution :
We know, molecular formula of sodium trioxocarbonate (iv) decahydrate is :
Na₂CO₃.10H₂O
Now, we can calculate its molecular mass :
M = ( 2 × 23 ) + 12 + ( 3 × 16 ) + 10 × ( 1 × 2 + 16)
M = 46 + 12 + 48 + ( 10 × 18 )
M = 286 gram/mol
Hence, this is the required solution.
Please help this is due tonight
PLSS HELPP ME i dont knowww
Answer:
non polar. polar ionic substance
Which reaction represents a double replacement reaction?
A
C2H4 + 302 --> 2CO2 + 2H2O
B
NH3 + H20 --> NH4OH
с
CuBr2 + 2K --> 2KBr + Cu
D
2FeCl3 + 3Na2CO3 --> Fe2(CO3)3 + 6Naci
Answer:
D
Explanation:
D shows a double displacment reaction
the other ones show combustion, synthesis and single displacment
If a point is chosen inside the square, what
is the probability that it will also be inside the
circle?
1
Point to be present exactly at midway between center and circumference of circle (let’s say radius = r) should lie at circumference of circle of radius r/2.
Favorable outcome = 2*pi*r/2
Total outcome = Point can be anywhere inside the circle of radius r = Area of circle = pi * r * r
Probability = (2*pi*r/2) / pi * r* r = 1/r.
Not completely sure about correctness . Waiting for comments to verify.
Question 18 (Multiple Choice Worth 2 points)
(12.02 LC)
What type of adaptation relates to the stages of growth and reproduction of plants?
Inherited trait
O Life cycle difference
O Learned behavior
O Physical characteristic
Answer:
the answer should be Life Cicle Difference.
Answer: Option (D) Is the correct Life cycle difference
Explanation: Hope it helps!
Good luck!!!
Help plz:)))I’ll mark u Brainliest
Explanation:
LCCEB is the answer
Which compounds are most likely ionic? compounds A and B O compounds B and C compounds C and D O compounds D and A
Answer:
compounds D and A
Explanation:
The ionic compound can conduct electricity therefore, the compounds A and D are most likely ionic. Therefore, option (4) is correct.
What are ionic compounds?Ionic compounds can be defined as crystalline solids produced by closely packed ions with opposite charges. The formation of an Ionic compound takes place when metal reacts with non-metal.
In ionic compounds, the ions of the compound are generally linked together by ionic bonds. The ions of an atom are formed by gaining or losing electrons in order to get the noble gas electronic configuration.
In a reaction, the metals are generally electropositive so they can lose electrons to complete their octet while non-metals will gain electrons from the metals to complete their octet.
Ionic compounds can conduct electricity in a molten state and aqueous solution because then they have free ions that can move from one place to another to conduct an electric current.
Learn more about ionic compounds, here:
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What is the pH if the [H+] concentration is 3 x10^-13
Answer:
pH = 12.52
Explanation:
Given that,
The [H+] concentration is [tex]3\times 10^{-13}[/tex].
We need to find its pH.
We know that, the definition of pH is as follows :
[tex]pH=-log[H^+][/tex]
Put all the values,
[tex]pH=-log[3\times 10^{-13}]\\\\pH=12.52[/tex]
So, the pH is 12.52.
g What is the relationship between the moles of the limiting reagent and the change in temperature (i.e. directly proportional or indirectly proportional)
Answer:
number of moles is inversely proportional to the Temperature
Explanation:
As we know
PV = nRT
where P is the pressure
V is the volume
n is the number of moles
R is the gas constant
and T is the temperature
If we see the equation, we can find that n is inversely proportional to the Temperature
10. The lithium-ion in a lithium-ion battery moves from one side to the other by
A. moving through the cathode.
B. moving through the anode.
C. passing through the separator.
D. passing through the device.
ved:
Chapter
Chapter List
CH5.3
Problem
Problem List
10SMB
Printed circuit boards are used in the electronics industry to both connect and hold components in place. In production, 0.03 in. of copper foil is laminated to an insulating plastic board. A circuit pattern made of a chemically resistant polymer is then printed on the board. Next, the unwanted copper is chemically etched away by using selected reagents. If copper is treated with Cu(NH3 ) 4Cl2 (cupric ammonium chloride) and NH4OH (ammonium hydroxide), the products are water and Cu(NH3) 4Cl (cuprous ammonium chloride). Once the copper is dissolved, the polymer is removed by solvents, leaving the printed circuit ready for further processing. If a single-sided board 4 in. by 8 in. is to have 75% of the copper layer removed using these reagents, how many grams of each reagent will be consumed? Data: The density of copper is 8.96 g/cm3.
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In the reaction between CH4 and O2, if 25.0 g of CO2 are produced, what is the minimum amount of each reactant needed?
PLS HELP
Answer:
25 gram
Explanation:
the minimum amount of the reactant needed is equal to the mass of the product because of the law of conservation of mass ok
Which of the following statements is FALSE. Select one: A. Two of the statements are false. B. In the synthesis of aspirin, the main impurities are salicylic acid and acetic acid. C. Aspirin was purified in the lab by recrystallizing the crude aspirin. The melting point of the purified aspirin is expected to be lower than the melting point of crude aspirin. D. In the analysis of aspirin, the greater the amount of salicylic acid impurity in the aspirin, the smaller the amount of NaOH needed for the hydrolysis of aspirin. E. If the crude aspirin is not entirely pure, the temperature range at which it melts will be larger than pure aspirin.
Answer:
Aspirin was purified in the lab by recrystallizing the crude aspirin. The melting point of the purified aspirin is expected to be lower than the melting point of crude aspirin.
Explanation:
The presence of impurities in a sample lowers the melting point of the impure substance. Hence the melting point of an impure substance is always less than the melting point of the corresponding pure substance.
Bearing this in mind, the statement "Aspirin was purified in the lab by recrystallizing the crude aspirin. The melting point of the purified aspirin is expected to be lower than the melting point of crude aspirin." is found to be false since impure substances tend to have a slightly lower melting point than the pure substance, and a broader melting temperature range.
hydrogen iodide is not produced by the same method is for hydrogen chloride why with reaction
Using Phosphoric acid will work perfectly for producing Hydrogen halides because its not an Oxidizing agent. ...
Using an ionic chloride and Phosphoric acid
H3PO4 + NaCl ==> HCl + NaH2PO4
H3PO4 + NaI ==> HI + NaH2PO4
H2SO4 + NaCl ==> HCl + NaHSO4
This method(Using H2So4) will work for all hydrogen hydrogen halide except Hydrogen Iodide and Hydrogen Bromide.
The Sulphuric acid won't be useful for producing Hydrogen Iodide because its an OXIDIZING AGENT. Whist producing the Hydrogen Iodide... Some of the Iodide ions are oxidized to Iodine.
2I-² === I2 + 2e-
How many grams of oxygen are necessary to react completely if you have 4.0 moles of oxygen
Answer:
1.3 × 10² g
Explanation:
Step 1: Given data
Moles of oxygen: 4.0 mol
Step 2: Calculate the mass corresponding to 4.0 moles of oxygen
For a given chemical reaction, we need 4.0 moles of oxygen and we want to find what mass in grams it represents. To convert moles to mass, we need a conversion factor: the molar mass. The molar mass of oxygen is 32.00 g/mol.
4.0 mol × 32.00 g/mol = 1.3 × 10² g
A water bottle is cooled to -115c. What is the new pressure
Answer:
129
Explanation:
Los catalizadores sirven para detener una reacción química ?
Answer:
si
Explanation:
Los catalizadores son sustancias que aceleran una reacción química, proporcionando una ruta alternativa para romper y formar nuevos enlaces entre átomos. Su importancia reside en el hecho de que este nuevo camino requiere menos energía que el original, lo que facilita el proceso.
Look at the reaction below. Upper H subscript 2 upper S upper O subscript 4 (a q) plus upper C a (upper O upper H) subscript 2 (a q) right arrow upper C a upper S upper O subscript 4 (a q) plus 2 upper H subscript 2 upper O (l). Which substance is the base in the reaction? A. 2H2O (l) B. H2SO4 (aq) C. CaSO4 (aq) D. Ca(OH)2 (aq)
Answer:
Its D
Explanation:
Did it on edge
According to the reaction: H₂S0₄ + Ca(OH)₂ → CaSO₄+ 2H₂O, the base is Ca(OH)₂.
What is a base?Base is defined as a substance which can accept protons or any chemical compound that yields hydroxide ions (OH-) in solution.
Generally, base are substances that produces hydroxide ion when dissolve in water.
Base are substances that reacts with acid to produce salt and water. Example of base includes sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide etc.
Therefore, according to the reaction:
H₂S0₄ + Ca(OH)₂ → CaSO₄+ 2H₂O
The base is Ca(OH)₂.
learn more on chemical reaction here: https://brainly.com/question/14575718
If the half-life of Carbon-14 is 5700 years, how many years would it take a sample to decay from 1 gram to 31.3 mg
Answer:
28500 years
Explanation:
Applying,
A = A'([tex]2^{x/y}[/tex])............... Equation 1
Where A = Original mass of Carbon-14, A' = Final mass of carbon-14 after decaying, x = total time, y = half-life.
From the question,
Given: A = 1 g, A' = 31.3 mg = 0.0313 g, y = 5700 years.
Substitute these values into equation 1
1 = 0.0313([tex]2^{x/5700}[/tex])
[tex]2^{x/5700}[/tex] = 1/0.0313
[tex]2^{x/5700}[/tex] = 31.95
[tex]2^{x/5700}[/tex] ≈ 32
[tex]2^{x/5700}[/tex] ≈ 2⁵
Equating the base and solve for x
x/5700 ≈ 5
x ≈ 5×5700
x ≈ 28500 years
Calculate the molecular mass of sodium trioxocarbonate (iv) decahydrate
Answer:
106.180
Explanation:
maybe this is the correct answer
I SAID MAYBE
El osmio es un metal sólido que tiene una densidad
de 22 600 kg/m?, ¿qué volumen ocuparán 100 g de
este metal?
Respuesta:
4.42 × 10⁻⁶ m³
Explicación:
Paso 1: Información provista
Densidad del osmio (ρ): 22600 kg/m³Masa de osmio (m): 100 gPaso 2: Convertir 100 g a kilogramos
Usaremos el factor de conversion 1 kg = 1000 g.
100 g × 1 kg/1000 g = 0.100 kg
Paso 3: Calcular el volumen ocupado por 0.100 kg de osmio
La densidad es una propiedad intensiva, igual al cociente entre la masa y el volumen.
ρ = m/V
V = m/ρ
V = 0.100 kg / (22600 kg/m³) = 4.42 × 10⁻⁶ m³
5. Calculate the number of molecules of carbon tetrachloride in 0.32 mol of
carbon tetrachloride.
To Find :
The number of molecules of carbon tetrachloride in 0.32 mol of
carbon tetrachloride.
Solution :
We know, 1 mole of any element/compound contains [tex]6.022 \times 10^{23}[/tex] number of atoms/molecules.
So, Number of molecules in 0.32 mol are :
[tex]n = 0.32 \times 6.022 \times 10^{23}\\\\n = 1.93 \times 10^{23}[/tex]
Therefore, number of molecules of carbon tetrachloride in 0.32 mol of
carbon tetrachloride are [tex]1.93 \times 10^{23}[/tex].
Which point defect in its crystal units alters the density of a solid?
please please answer
Answer:
Schottky defect
Explanation:
Schottky defect in crystals units alters the density of a solid.
How many total carbon atoms are in the structure 2 methyl, 3, 4 diethyl decane?
12
15
14
10
Answer:B
15 carbon atoms
What is the temperature of 0.750 mol of a gas stored in a 6,050 mL cylinder al 221 atm?
atm
Use and
molek
5.24K
138 K
246 K
Answer:
T = 246 K
Explanation:
Given that,
Number of moles, n = 0.750 mol
The volume of the cylinder, V = 6850 mL = 6.85 L
Pressure of the gas, P = 2.21 atm
We need to find the temperature of the gas stored in the cylinder. We know that,
PV= nRT
Where
R is gas constant
T is temperature
So,
[tex]T=\dfrac{PV}{nR}\\\\T=\dfrac{2.21\times 6.85}{0.75\times 0.0821}\\T=245.85\ K[/tex]
or
T = 246 K
So, the temperature of the gas is equal to 246 K.
What are 3 different ways we can preserve our ecosystem and what makes your 3 ways effective?
Answer:
1. Stop throwing trash and bottles in lakes because it can have our animals live longer and not have issues
2. Reducing the number of bags you use from the store because they can end up being on the ground and cause plenty of damage around us
3. probably trying not to having fires because there is alot of problems that are happening like the wildfires in californa which is leading to our animals and trees dying
hope this helps
have a good day :)
Explanation:
4. Suppose in the first part of the experiment you did not heat strong enough to
decompose the potassium chlorate, how would this affect your result?
when you strongly heat the potassium chlorate it leaves oxygen if you'll not heat it strongly to decompose it the oxygen would not release and the compound will remain thermally unstable.
Heating of Potassium Chlorate results into decomposition of Potassium Chloride and Oxygen gas.
When KClO₃ is heated strongly, it breaks down, releasing oxygen gas and leaving behind a thermally stable (i.e., heat-insensitive) solid residue of an ionic potassium compound.
If enough heat is not provided to potassium chlorate then it will not decompose into its substituent products and also some of the potassium chloride product splattered out of the crucible during the heating process.
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Find the horizontal range of a projectile launched at 15 degrees to the horizontal with speed of 40m/s
To Find :
The horizontal range of a projectile launched at 15 degrees to the horizontal with speed of 40 m/s.
Solution :
The horizontal range of a projectile is given by :
[tex]R = \dfrac{u^2 sin 2\theta}{g}[/tex] ( Here, g is acceleration due to gravity = 10 m/s² )
Putting all value in above equation :
[tex]R = \dfrac{40^2 \times sin (2 \times 15)}{10} \ m\\\\R = \dfrac{1600 \times 1}{2\times 10} \ m\\\\R = 80 \ m[/tex]
Therefore, the horizontal range of projectile is 80 m.