Answer:
C
Explanation:
Hope this helps :)
How many 20 mL extractions of organic solvent are needed to extract at least 99.5% of 50.0 g Compound A from 100 mL of water if K
Answer:
5 extractions to extract at least 99.5% of 50.0 g Compound A from 100 mL of water
Explanation:
If K=10...
Partition coefficient is defined as the ratio of concentrations of a compound A in two inmiscibles solvents:
K = 10 = Conc. Organic solvent / Conc. Water
Usually organic phase over aqueous phase.
In the first 20mL extraction, the organic solvent will extract:
10 = X / 20mL / (50.0g - X) / 100mL
10 = 100X / (1000-20X)
10000 - 200X = 100X
10000 = 300X
X = 33.3g of compound A are extracted in the first extraction
Remember you want to extract 99.5%, that is 50.0g*99.5% = 49.75g
In the aqueous phase remain: 50-33.3g = 16.7g:
Second extraction:
10 = X / 20mL / (16.7g - X) / 100mL
10 = 100X / (334-20X)
3340 - 200X = 100X
3340 = 300X
11.1g are extracted and will remain: 16.7g - 11.1g = 5.6g
Third extraction:
10 = X / 20mL / (5.6g - X) / 100mL
10 = 100X / (112-20X)
1120 - 200X = 100X
1120 = 300X
3.8g are extracted and will remain: 5.6g - 3.8g = 1.8g
Fourth extraction:
10 = X / 20mL / (1.8g - X) / 100mL
10 = 100X / (36-20X)
360 - 200X = 100X
360 = 300X
1.2g are extracted and will remain: 1.8g -1.2g = 0.6g
Fifth extraction:
10 = X / 20mL / (0.6g - X) / 100mL
10 = 100X / (12-20X)
120 - 200X = 100X
120 = 300X
0.4g are extracted. The total extractions gives:
33.3g + 11.1g + 3.8g + 1.2g + 0.4g = 49.8g
That means, you need to do:
5 extractions to extract at least 99.5% of 50.0 g Compound A from 100 mL of waterYou may have to recrystallize any or all of the components of your extraction mixture, benzoic acid, ethyl-4-aminobenzoate and fluorenone, depending on their purity after isolation. You should have the recystallization solvents in your protocol. They are respectively:
Answer:
the Recrystallization solvents are;
-Sodium Hydroxide Base (NaOH)
- Hydrochloric Acid (HCl)
- Sand bath when acidic and basic components are removed.
Explanation:
Recrystallization is simply a technique used to purify an impure compound in a solvent.
Now, we want to purify the mixture of benzoic acid, Ethyl-4-aminobenzoate and fluorenone.
For the benzoic acid, it can be separated out of the mixture by addition of sodium hydroxide base (NaOH).
The Ethyl - 4 - aminobenzoate will be separated from the mixture by the addition of Hydrochloric Acid (HCl).
The fluorenone would be separated out by heating the mixture in a sand bath after the basic and acidic components have already been extracted out.
Thus, the Recrystallization solvents are;
-Sodium Hydroxide Base (NaOH)
- Hydrochloric Acid (HCl)
- Sand bath when acidic and basic components are removed.
Calculate the following quantity: molarity of a solution prepared by diluting 49.16 mL of 0.0270 M ammonium sulfate to 525.00 mL.
Answer:
2.528x10⁻³M
Explanation:
Molarity is an unit of concentration used in chemistry. Is defined as the moles of solute per liter of solution.
To find the molarity of the solution we need to determine the moles of ammonium sulfate present in the initial 49.16mL solution and, with total volume, we can find the molarity, thus:
Moles ammonium sulfate:
49.16mL = 0.04916L * (0.0270 moles / L) =
1.327x10⁻³moles ammonium sulfate
These moles are present in 525.0mL = 0.525L. Thus, molarity of the solution will be:
1.327x10⁻³moles ammonium sulfate / 0.525L =
2.528x10⁻³Mwhy are copper pipes used in place of old lead pipes for plumbing systems?
What characteristics are used to clarify an area as a wetland?
10. The density of aluminum is 2.70 g/mL. If the mass of a piece of aluminum is 244 grams, what is the volume of the aluminum?
Answer:
The answer is 90.37 mLExplanation:
The volume of a substance when given the density and mass can be found by using the formula
[tex]volume = \frac{mass}{density} \\ [/tex]
From the question we have
[tex]volume = \frac{244}{2.7} \\ = 90.370370...[/tex]
We have the final answer as
90.37 mLHope this helps you
A tree frog uses plants or trees for protection from the rain. The frog is protected from the rain and the tree is neither helped nor harmed
I don't know what category to put this question in, but I attached a photo of it. Can someone please help me answer it?
Analysing the question:
To calculate the density of a material, we need its mass and volume
We are given:
Mass of sample = 21 grams
dimensions of the sample = 1 * 1 * 2 = 2 cm³
Calculating the density:
Density = Mass of sample / volume of sample
Replacing the variables
Density = 21 / 2
Density = 10.5 g / cm³
Determining the Material:
From the table provided, we can see that the density of Silver is 10.5 g/cm³
Therefore, the material is Silver
Which of the following does Electrons change when Electrons are changed?
Answer:
tuttutututu and the optionsTrue or False: All cells have different basic chemical composition. *
True
False
In what ways are physical and chemical weathering alike? In what ways are they different?
The incredible catalytic power of enzymes can perhaps best be appreciated by imagining how challenging life would be without just one of the thousands of enzymes in the human body. For example, consider life without fructose-1,6-bisphosphatase, an enzyme in the gluconeogenesis pathway in liver and kidneys, which helps produce new glucose from the food we eat:
Fructose-1,6-bisphosphate + H2O → Fructose-6-phosphate + Pi
The human brain requires glucose as its only energy source, and the typical brain consumes about 120. g (or 480. calories) of glucose daily. Ordinarily, two pieces of sausage pizza could provide more than enough potential glucose to feed the brain for a day. According to a national fast-food chain, two pieces of sausage pizza provide 1260 calories, 49.0 % of which is from fat. Fats cannot be converted to glucose in gluconeogenesis, so that leaves 615 calories potentially available for glucose synthesis. The first-order rate constant for the hydrolysis of fructose-1,6-bisphosphate in the absence of enzyme is 2.00×10-20 sec-1.Calculate how long it would take to provide enough glucose for one day of brain activity from two pleces of sausage pizza without the enzyme.
Answer:
t = 7.58 * 10¹⁹ seconds
Explanation:
First order rate constant is given as,
k = (2.303 /t) log [A₀] /[Aₙ]
where [A₀] is the initial concentraion of the reactant; [Aₙ] is the concentration of the reactant at time, t
[A₀] = 615 calories;
[Aₙ] = 615 - 480 = 135 calories
k = 2.00 * 10⁻²⁰ sec⁻¹
substituting the values in the equation of the rate constant;
2.00 * 10⁻²⁰ sec⁻¹ = (2.303/t) log (615/135)
(2.00 * 10⁻²⁰ sec⁻¹) / log (615/135) = (2.303/t)
t = 2.303 / 3.037 * 10⁻²⁰
t = 7.58 * 10¹⁹ seconds
As the space in a container gets smaller, the _____
decreases.
O A) pressure
O B) temperature
O c) volume
O D) heat
Answer:
A
Explanation:
As the space in a container gets, smaller the volume decreases because volume is a measure of the space that the particles can occupies inside.
What is volume?Volume is the space occupied by a substance and which is directly proportional to temperature according to Boyles law and inversely proportional to the pressure.
As the temperature increases, volume increases whereas the pressure increases, volume get decreased. As there are more particles but the space inside a container is small, then their volume is said to be smaller.
Hence, option C is the answer.
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Describe the Bay's salinity. How does the salinity change throughout the year?
The smallest unit of an element that can exist either alone or in combination with other such particles of the same or different elements is the
А.
electron
B
proton
neutron
D
atom
Answer:
The answer is D - Atom
The smallest unit of an element that can exist either alone or in combination with other such particles of the same or different elements is the atom.
What is an atom?
An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.
The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.
Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.
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Calculate the sublimation pressure of the solid at the melting point of 400.00 K assuming that the enthalpy of sublimation is not a function of temperature.
This question is incomplete, the complete question is;
Tonksite is a solid at 300.00K. At 300.00 K its enthalpy of sublimation is 66.00 kJ/mol. The sublimation pressure at 300.00 K is 5.00 × 10⁻⁴ atm
Calculate the sublimation pressure of the solid at the melting point of 400.00 K assuming that the enthalpy of sublimation is not a function of temperature.
Answer: the sublimation pressure of the solid at the melting point is 0.3727 atm
Explanation:
Given that;
T1 = 300 K
T2 = 400 K
H_sub = 66 kJ/mol = 66000 J/mol
P1 = 5.00 × 10⁻⁴ atm
p2 = ?
now using the expression
log( p2 / 5.00 × 10⁻⁴ ) = (H_sub / R × 2.303 ) (( T2 - T1) / T1T2)
now we substitute of given values into the expression
log(p2/p1) = (66000 / 8.314 × 2.303 ) (( 400 - 300) / 300 × 400 )
p2 = 0.3727 atm
therefore the sublimation pressure of the solid at the melting point is 0.3727 atm
What type of energy is defined as the kinetic energy of the atoms of a substance?
Explanation:Thermal energy, or heat, is the energy that comes from the movement of atoms and molecules in a substance. Heat increases when these particles move faster. Geothermal energy is the thermal energy in the earth. Motion energy is energy stored in the movement of objects.
I hope this helped!
how do you find protons in an atom?
Answer:
Protons are always found in the nucleus of an atom.
Explanation:
Protons and neutrons make up the nucleus of an atom, which is in the center. The electrons "orbit" the nucleus.
Answer:
The number of protons, neutrons, and electrons in an atom can be determined from a set of simple rules.
Explanation:
The number of protons in the nucleus of the atom is equal to the atomic number (z). The number of electrons in a neutral atom is equal to the number of protons.
A factory discharges clean, warm water into a nearby stream. Fish keep dying in this part of stream. Explain why.
Answer:
the fish can't survive in that warm water
Explanation:
when the factory puts that warm water into the stream where the fish live they changed their environment. by adding unknown chemicals and changing the temp of the water the fish start to die.
The fish aren't used to living in that warm water, and if they can't adapt fast enough they will die, also the unknown chemicals that could be in the water will act as a poison for them making that stream unable to support any life.
How many grams of sodium hypochlorite (NaClO)is required to make abuffer with pH= 7.35 if you had 500 mL of a 0.1M solution of hypochlorous acid with pKa=7.54.(Assume the addition of NaClO does not change the volume.)
Answer:
2.4g of NaClO must be added
Explanation:
To find the pH of a buffer we must use H-H equation:
pH = pKa + log [A⁻] / [HA]
Where pH is the pH of the buffer, 7.35
pKa of the HClO buffer is 7.54
[A⁻] could be taken as moles of NaClO
And [HA] moles of the weak acid: 500mL = 0.500L * (0.1mol/L) = 0.05 moles
Replacing:
pH = pKa + log [A⁻] / [HA]
7.35 = 7.54 + log [A⁻] / [0.05moles]
0.6457 = [A⁻] / [0.05moles]
0.03228 moles = Moles of NaClO we need to make the pH = 7.35 buffer.
To convert these moles to grams we use the molar mass of NaClO (74.44g/mol):
0.03228 moles * (74.44g/mol) =
2.4g of NaClO must be added
which dissolved first in acetone? food coloring or liquid paint?
Answer:
Liquid paint.
Explanation:
Liquid paints are dissolved first in acetone. Most of the food dyes are not soluble in acetone.
What is acetone?Acetone is an organic compound comes under the category of ketones. It contains a carbonyl group and can dissolve most of the organic solvents.
The active ends in acetone easily forms hydrogen bonds with other solvents with polar or nonpolar groups.
Xylene, benzene, toluene, aromatic azo dyes etc. are common components in paint. Which are easily miscible with acetone.
Hence, liquid paints dissolve in acetone and food dyes are hard o dissolve in it.
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Which neutral atom is isoelectronic with Cl-??
And we can see that the potassium ion, K+, has the same electronic configuration as the chloride ion, Cl-, and the same electronic configuration as an atom of argon, Ar. Therefore, Ar, Cl-, and K+ are said to be isoelectronic species.
what isotope of an atom if it has 29 protons and 36 neutrons
Answer:
POTASSIUM
Explanation:
2 8 8 1________ 1A
8. Besides landforms, the other large features that cover the
surface of the earth are ______.
A. islands
B. waterways
C. deserts
D. lakes
Answer:
A landform is a feature on the Earth's surface that is part of the terrain. Mountains, hills, plateaus, and plains are the four major types of landforms. Minor landforms include buttes, canyons, valleys, and basins. Tectonic plate movement under the Earth can create landforms by pushing up mountains and hills.
Explanation:
"Waterways" are the other large features that cover the surface of the earth.
Waterways
A canal would be any body of water throughout which boats may move. Waterways, on the other hand, comprise waterways that seem to be expansive as well as shallow enough already to allow freight-carrying watercraft just to travel through.
Some bodies of water are usually regularly dredged to maintain an appropriately deep course throughout all circumstances. Dams change the depth of other rivers in particular parts.
Thus the response above i.e., "Option B" is correct.
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Which element is classified as a noble gas?
Answer:
The elements with completely filled shells are classified as noble gases
That is why we only see noble gases on the rightmost corner of the periodic table, it is because they have the maximum number of electrons in a shell
Examples of noble gases
Helium , Neon , Argon and Krypton are some examples of noble gases
Answer:
D. (Xe) XenonExplanation:
I JUST TOOK THE TEST!
Please help. The question is in the picture
According to Avogadro's law, what is characteristic of 1 mole of gas at STP?
A. It occupies 22.4 L.
B. It occupies no volume.
C. It occupies 1 L.
D. It will expand to any volume.
Answer:
A. It occupies 22.4 L
Explanation:
STP (Standard Conditions for Temperature and Pressure) = 22.4 L per mole at 1 atm
Avogadro's Law states that 1 mol at 1 atm occupies 22.4 L.
True or False: The exact location of an electron can be measured thanks to
modern science.
Answer:
false you can not get a exact location of electrons from just modern science
What is the atomic mass of element X
Answer:
Which one of the table is element X?
Explanation:
I have no idea and help!!!!!!!!!!!!!!!!!!!!!!!!!
Two students apply force to a box at rest on the floor.
Left
Right
40 Newtons
30 Newtons
What is the total amount of force in Newtons acting on the box and in which direction?
10 N Left
10 N Right
• 70 N Left
70 N Right
Answer:
10 N Left
Explanation:
Given parameters;
Forces acting on the box
Left force = 40N
Right force = 30N
Unknown:
Net force on the box and the direction = ?
Solution:
Force is a pull or push on a body;
← BODY →
40N 30N
The forces acting on the body are in the opposite directions, the greater force will determine the direction of pull.
Net force = Left force - Right force = 40 - 30 = 10N
The force will be directed left with a net value of 10N