You should develop the TLC (thin layer chromatography) plate orthogonally (under a 90-degree angle) to the original direction of development (along its width, while the original development was along the length of the TLC plate).
This technique is called 2D TLC (two-dimensional thin layer chromatography) and is usually employed to analyze and preparatively separate very complex mixtures that cannot be separated using only one solvent system. The initial development (along the length of the TLC plate) enables crude separation into groups of compounds with similar retention factor (Rf). These groups can then be further separated using a different solvent system by developing the same TLC plate along its width.
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two compounds might have spots with the same rf value in a chromatography experiment and not be identical compounds. which proposed chromatography experiment could best help determine whether the compounds are identical? select one: repeat the original experiment with a different solvent system repeat the original experiment with the development chamber jar open repeat the original experiment with larger spots of each compound repeat the original experiment with a mixture of the compounds in a single spot
The chromatography experiment which would best decide whether the compounds are identical or not is to Repeat the original experiment once more with various solvent systems;
If two things have the same Rf value, they are probably the same compound, but not always. They are definitely distinct compounds if their Rf values differ.
Compounds with a low polarity have higher Rf values than compounds with higher polarity. Compounds' absorptivity typically rises in tandem with their polarity—that is, the more polar a compound is, the more strongly it binds to the adsorbent. Solvents' eluting power increases with polarity. In diverse solvents, different compounds with identical Rf values might behave differently.
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which of the following statements is false? gas molecules collide with each other without loss of energy. gas molecules collide with the container walls without loss of energy. the pressure of a gas at constant temperature in a sealed container will gradually decrease. because of the relationship between temperature and average molecular speed, the temperature of a gas would drop if energy were lost in collisions. friction does not slow down gas particles and cause them to stop moving.
The pressure of a gas at a constant temperature in a sealed container will gradually decrease. Option C.
Gases are made up of particles molecules or atoms in constant random motion. Gas particles constantly collide with each other and with the walls of the container. These collisions are elastic. That is, there is no net energy loss due to collision. The pressure of a constant temperature gas in a closed container gradually decreases.
The above statement is incorrect because the pressure of a gas at a constant temperature depends on the volume of the gas. If the container is sealed, the volume of gas is also constant. Collisions are completely elastic. When two molecules collide, they change direction and kinetic energy, but all kinetic energy is conserved. Collisions are not sticky. The average kinetic energy of gas molecules is directly proportional to absolute temperature.
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a soluble iodide was dissolved in water. then, an excess of silver nitrate, , was added to precipitate all of the iodide ion as silver iodide, . a question content area if 2.940 g of the soluble iodide gave 1.329 g of silver iodide, how many grams of iodine are in the sample of soluble iodide?
In the sample of soluble iodide, 0.7183 grams iodine are present.
To find the concentration of iodine in grams we must known about molar mass of Silver and molar mass of Iodine.
Molecular weight of Ag = 107.86
Molecular weight of I = 126.90
Molecular weight of = 107.86 + 126.90 = 234.76
Percentage of I in [tex]AgI[/tex] is = (126.90/234.77) x 100 = 54.05%
so we can convert percentage of Iodine in silver iodide into grams by using formula percentage of Iodine/100x grams of silver Iodide.
so,Concentration of Iodine in grams=[tex]\frac{54.05}{100}[/tex]×1.329
=0.5405x1.329
=0.7183g
1.329g of [tex]AgI[/tex] contains 0.7183g of iodine in soluble Iodide.
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atmospheric pressure at sea level is equal to a column of 760 mm hg. oxygen makes up 21 percent of the atmosphere by volume. the partial pressure of oxygen (po2) in such conditions is .
The partial pressure of oxygen in such conditions is equal to 160 mm Hg.
As the percentage of oxygen in the air is 21 percent, the mole fraction of oxygen in the air can be calculated as follows;
mole fraction of oxygen in air = 21 ÷ 100 = 0.21
Now we can determine the partial pressure of oxygen by using the equation given by Raoult's law as follows;
partial pressure of oxygen = total pressure of air × mole fraction of oxygen
As the atmospheric pressure at sea level is stated to be 760 mm hg and the calculated value of the mole fraction of oxygen is 0.21, substituting these values in the equation as follows;
partial pressure of oxygen = 760 mm hg × 0.21
partial pressure of oxygen = 160 mm hg
Therefore, the partial pressure of oxygen is calculated to be 160 mm hg.
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What is the conjugate base of H2BO3- (I am confused because one has - and +. I dont understand which one the answer would be)
The conjugate base of a compound is what this compound will be after donating a H⁺.
The comopund in question is H₂BO₃⁻. After it loses 1 H⁺, it will have one less H atom and its charge decrease by one. Its charge is only with a "-" sign, which means its chargeis 1-. After decreasing by one, the charge becomes 2-.
So, the conjugate base will be HBO₃²⁻
A compound conducts electricity in the solid state and does not dissolve in water. It isshiny and malleable. What type of bonding does it likely have?b. Ionicc. metallica.Covalent
Metallic solids,
the atoms within such a metallic solid are held together by a unique force known as metallic bonding that gives rise to many useful and varied bulk properties. All exhibit high thermal and electrical conductivity, metallic luster, and malleability.
Answer: c. metallic
what is the ph of the soil in your backyard?
which is the correct answer?
The true statement about the reaction is that the reaction reaches equilibrium around 1.5 seconds.
What is a reversible reaction?We say that a reaction is reversible if the reaction can proceed both in the forward and the reverse directions. Let us recall that it is possible for a reversible reaction to attain a status of dynamic equilibrium. The status of dynamic equilibrium is the status where the rate of the forward reaction is equal to the rate of reverse reaction.
If we look at the graph as we have it we would notice that there is such a point of dynamic equilibrium as we survey the system around 1.5 seconds.
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The true statement about the reaction is the reaction reaches equilibrium around 1.5 seconds. Thus option D is correct.
What is reversible reaction?Reversible reaction is defined as a reaction in which the transformation of both reactants and products into one another takes place simultaneously.
If a response may occur in both the forward and reverse directions, we say that it is reversible. Let's not forget that a reversible reaction can reach a state of dynamic equilibrium. The condition known as dynamic equilibrium occurs when the forward reaction rate and the backward reaction rate are equal.
If we were to examine the graph as it currently stands, we would see that the system reaches a point of dynamic equilibrium after 1.5 seconds of observation.
Thus, the true statement about the reaction is the reaction reaches equilibrium around 1.5 seconds. Thus option D is correct.
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How can photochemical smog impact the environment? PLS HURRY ASAP
It can increase the number of insects in the area.
It can reduce the amount of plastic in the ocean.
It can increase tree and plant growth in a city.
It can decrease the crop yield in a region
Photochemical smog effects largely the growth of plants by interfering in nitrogen cycle and by causing atmospheric pollution.Thus option D is correct.
What is photochemical smog?Photochemical smog is a brown haze in the atmosphere formed by the burning of fuels and from naturally released pollutants when exposed to UV radiation undergo a series of hydrocarbon reactions to produce photochemical smog.
The main composition of photochemical smog is oxides of nitrogen and it further undergo further reaction with hydrocarbons entered into he atmosphere by burning fuels produce secondary pollutants.
These secondary pollutants again creates air pollution and serious other issues such as reduction in plant growth because they interfere the atmospheric nitrogen cycle which is essential for crop yield.
Hence, photochemical smog can decrease the crop yield in a region and option D is correct.
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IN THE FIRSTSTAGE OF CHOLERA, THE BACTERIUM FINDS A HOST CELL IN THE SMALL INTESTINE. THE BACTERIUM THEN RELEASES TOXIC PROTEINS CALLED TOXINS NEAR THE HOST CELL. THROUGH WHICH PROCESS COULD A LARGE MOLECULE SUCH AS A PROTEIN LEAVE THE CHOLERA CELL?
A process through which a large molecule such as a protein could leave the cholera cell is generally referred to as: c) exocytosis.
What is cholera?Cholera can be defined as a type of disease which is typically caused by a bacteria that is referred to as Vibrio cholerae. Also, cholera gets into the body of a living organism through an ingestion of contaminated food or water.
What is exocytosis?Exocytosis simply refers to a process which typically involves a cell releasing a large amount of a material (bulk transport) outside of the cell, especially through the use of vesicles.
This ultimately implies that, exocytosis can be defined as a biological process in which living organisms release (expel) large amount of unwanted material by using the vesicles.
Additionally, exocytosis is a biological process that is initiated by the Golgi apparatus and it can be used to expel a large molecule such as protein from cholera cells.
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Complete Question:
In the first stage of cholera, the bacterium finds a host cell in the small intestine. The bacterium then releases toxic proteins called toxins near the host cell. Through which process could a large molecule such as a protein leave the cholera cell?
a) osmosis
b) diffusion
c) exocytosis
d) endocytosis
Need this done by 10:20
Question is located on the picture below
Describe the composition of calcite
Answer:
CaCO3
Explanation:
Pure calcite has the composition CaCO3. However, the calcite in limestone often contains a few percent of magnesium. Calcite in limestone is divided into low-magnesium and high-magnesium calcite, with the dividing line placed at a composition of 4% magnesium. High-magnesium calcite retains the calcite mineral structure, which is distinct from that of dolomite, MgCa(CO3)2.[18] Calcite can also contain small quantities of iron and manganese.[19] Manganese may be responsible for the fluorescence of impure calcite, as may traces of organic compounds
In carrying out the first standardization in this experiment, a student used 0.5793 g of potassium hydrogen phthalate (khp) and 24.55 ml of a naoh solution are needed to reach the equivalence point. what is the concentration (in mol/l) of the student's naoh solution? include only the numerical answer (no units).
In carrying out the first standardization in this experiment, a student used 0.5793 g of potassium hydrogen phthalate (khp) and 24.55 ml of a NaOH solution are needed to reach the equivalence point then the concentration of student NaOH solution is 0.02455 L
Standardization is the process in which determining the exact concentration of molarity of the solution and here given data is
Mass of potassium hydrogen phthalate (C₈H₅KO₄) = 0.5793 g
Molar mass of potassium hydrogen phthalate (C₈H₅KO₄) = 204.22g/mol
The number of mole of potassium hydrogen phthalate present then,
Number of moles = mass/molar mass
Number of moles = 0.5793 g/204.22g/mol = 0.002836 mole
Volume of NaOH present = 24.55 ml
1 ml = 0.001 L then, 24.55 ml = 24.55 ml×0.001 L = 0.02455 L
The concentration (in mol/l) of the student's naoh solution is 0.02455 L
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how do we know the amount of electrons that an element has?
I need help
Answer:
The easiest way to find the number of neutrons, protons, or electrons is to look at the element's atomic number on the periodic table, that number is equal to the number of protons. Which is equal to the number of electrons unless there's an ion superscript listed after the element.
Explanation:
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how much volume in ml will you need to take from 2.7 m concentrated stock solution if you would like to prepare a diluted 0.8 solution with 100 ml? report and round your answer to a whole integer.
To make a 100 ml solution of 0.8 m from a 2.7 m concentrated stock solution we have to take a volume of: 30 ml of the concentrated solution
To solve this problem, the formula and the procedure that we have to use is:
c1 * v1 = c2 * v2
Where:
c1= concentration of the concentrated solutionv1 = volume of the concentrated solutionc2 = concentration of the diluted solutionv2 = volume of the diluted solutionInformation about the problem:
c1 = 2.7 mv1=?c2 = 0.8 mv2=100 mlApplying the dissolution of concentrations formula and clearing the volume of the concentrated solution (v1) we get:
c1 * v1 = c2 * v2
v1 = (c2 * v2)/ c1
v1 = (0.8 m * 100 ml)/ 2.7 m
v1= 29.6 ml
By rounding the volume to a whole integer value we have:
v1= 30 ml
What is a solution?In chemistry a solution is known as a homogeneous mixture of two or more components called:
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What is the measurement on this graduated cylinder
Answer: 4.3
Explanation:
You read from the bottom of the meniscus and each line equals .1 so it reads 4.3.
a chemist has three different acid solutions. the first acid solution contains 25 % acid, the second contains 45 % and the third contains 85 % . he wants to use all three solutions to obtain a mixture of 95 liters containing 65 % acid, using 3 times as much of the 85 % solution as the 45 % solution. how many liters of each solution should be used?
First acid solution contains 19 liters of 25% acid, second acid contains 19 liters of 45% acid, and the third contains 57 liters of 45% acid.
Let us take x as the liters of 25% acid, y as the liters of 45% acid, and z as the liters of 85% acid.
From this we get an equation:
x + y + z = 95
0.25x + 0.45y + 0.85z = (0.65)95
By equating both the equation we have:
y + 3z = 190
y = 190 - 3z
It is given that z = 3y
Solve the system of equations using eliminating or substituting we get:
x + y + z = 95
x + y + 3y = 95
x + 4y = 95
x = 95- 4y
0.25( 95 - 4y ) + 0.45y + 0.85(3y) = (0.65) 95
23.75- y + 0.45y + 2.55y = 61.75
2y = 38
y = 19
x = 95 - 4y
= 95 -76
= 19
z = 3y
= 3× 19
= 57
Therefore the chemist needs 19 liters of 25% acid, 19 liters of 25% acid and, 57 liters of 85% acid.
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potassium iodide reacts with lead (ii) nitrate to form lead (ii) iodide and potassium nitrate. what are the reactants? what are the products?
The reactant will be potassium iodide and lead (ii) nitrate. The products will be lead (ii) iodide and potassium nitrate.
In the field of chemistry, reactants can be described as starting materials that react together in order to form a product. The reactants are the starting material whereas the products are the ending material.
In the case above, potassium iodide and lead (ii) nitrate are the reacting materials as they are the starting materials. On the other hand, lead (ii) iodide and potassium nitrate are the ending products of this reaction.
While writing a chemical equation, the reactants are written on the left-hand side, before an arrow. On the other hand, the products are written on the right-hand side after the arrow.
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here are three isotopes of silicon: si-28, si-29, and si-30, with relative abundances of 92.23%, 4.67%, and 3.1%, respectively. determine the atomic mass of silicon.
The atomic mass of silicon is calculated to be 28.1087 amu if the three isotopes have relative abundances of 92.23%, 4.67%, and 3.1%, respectively.
The atomic mass of an element can be determined by first changing the percentage abundance of each isotope into decimal form, then multiplying this value by the atomic mass of that isotope. Then the resultant value of each isotope is added together to get the atomic mass of the element.
As the mass of the three isotopes of silicon is 28 amu, 29 amu, and 30 amu with relative abundances of 92.23%, 4.67%, and 3.1%, respectively, we can calculate the atomic mass of silicon as follows;
si-28 = 92.23% = 92.23/100 = 0.9223
si-29 = 4.67% = 4.67/100 = 0.0467
si-30 = 3.1% = 3.1/100 = 0.031
Now multiplying these values by the atomic mass;
si-28 = 0.9223 × 28 = 25.8244
si-29 = 0.0467 × 29 = 1.3543
si-30 = 0.031 × 30 = 0.93
Now adding these values together;
atomic mass of silicon = 25.8244 + 1.3543 + 0.93
atomic mass of silicon = 28.1087 amu
Therefore; the atomic mass of silicon is calculated to be 28.1087 amu.
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when 2.0 mol h2 and 2.0 mol i2 are placed in a reaction vessel and allowed to come to equilibrium, the mixture is found to contain 2.5 mol hi. how many moles of each substance are present in the equilibrium mixture, i.e. what is the composition?
The composition of the mixture is 2.5 moles of HI, 0.75-mole I₂, and 0.75 moles of H₂.
The act of combining elements or elements to shape an entire. the ensuing nation or product. manner of being composed; structure: This portrait has an orderly composition. make-up; constitution: His ethical composition becomes impeccable.
A composition can discuss with any innovative painting, be it a quick story, poem, essay, studies paper or a piece of tune. consequently, the principle difference between essay and composition is that essay is a form of composition whereas composition refers to any innovative paintings.
H₂ + I₂ = 2HI
initial 2mol 2 0mol
final 2.5 mol
limiting reagent is I₂
2 mole of HI is produced by 1 mole of I₂
2.5 mole of I₂ is produced by = 1/2 × 2.5
= 1.25 mole
The final composition of the mixture = 2.5 moles of HI, 0.75-mole I₂, and 0.75 moles of H₂.
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can someone help me please !
The boiling point and freezing point of sulfur dioxide are -10℃ and -72.7℃ (at 1 atm), respectively. The triple point is -75℃ and 1.65 ×10-3 atm, and its critical point is at 157℃ and 78 atm. On the basis of this information, draw a rough sketch of the phase diagram of SO2.
What's phase diagram?
The phase diagram is a pressure vs temperature sketch. On the graph, the different physical states of any system at variable temperature and pressure are shown.
What's a Triple point?
A triple point is the point on a phase diagram where all three states of a system (solid, liquid, and gas) are in equilibrium.
What's a Critical point?
A critical point is that point on the phase diagram where the boundary between the liquid phase and gaseous phase vanishes away.
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what do sanding a piece of wood and rain forming into a cloud have in common
As a result, it is a natural bodily alteration. The chemical shape of the material is affected by physical changes, but not its makeup.
What kind of change is cloud formation?Since natural water undergoes a phase transformation cycle from liquid to gas and back to liquid, the production of clouds is a physical shift.
The physical conversion of water from vapour to liquid during cloud formation is known as condensation. When water evaporates during the evaporation process and condenses in the air to form clouds, there is a physical shift that takes place.
Condensation is the process by which water transforms from a gas to a liquid, whereas deposition is the process by which a gas transforms straight into a solid. Clouds are created by these two processes.
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Which is equal to 4 hectometers?
Answer:
There are 400 meters in a hectometer?
Explanation:
Answer:
there are 400 meters in a hectometer?
Explanation:
CAN someone please help me !!!!!!!!
The balloon and the comb definitely have the same electrical charge. Option 2.
Like charges repelAccording to the law of attraction in physics, like charges repel while unlike charges attract.
Going by this law:
positive and positive will repelnegative and negative will repelpositive and negative will attract.In other words, if 2 objects that have the same charges are brought close to each other, there will be a repulsion. If the 2 objects are of different charges, there will be an attractive force between them.
The students observed that the comb repelled the balloon. The implication is that the comb and the balloon are of the same charge.
This is logical considering the fact that both objects were rubbed against hair. They got their charges during the process of rubbing. An electrostatic force is generated that moves electrons from the hair to the two objects.
Thus, both the balloon and the comb are negatively charged and will, therefore, repel each other.
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suppose you perform a titration of an unknown weak acid solution. you start with 4.00 ml of the weak acid and find that it takes 18.3 ml of 0.0500 m naoh to reach the equivalence point. what is the concentration of the unknown weak acid solution? enter your answer to three significant figures in units of m.
The concentration of the unknown weak acid solution is 0.228 M.
How to Calculate the of concentration?Acid dissociation constant, K a K text a Ka, and weak acids. Acids that don't entirely dissociate in solution are referred to as weak acids. In other words, any acid that is not a strong acid qualifies as a weak acid. The amount of dissociation determines how strong an acid is; the more dissociation, the stronger the acid.
Equivalent point:
Since the volume is 4.00 mL of the weak acid, and it takes 18.3 mL of 0.0500 M NaOH to reach the equivalence point.
We know that
In the equivalence point, [H⁺] = [OH⁻].
here the given formula C₁V₁=C₂V₂ is used
Here
C₁ = 0.0500 M
V₁ = 18.3 mL
C₂ = ?
V₂ = 4.00 mL
So, the C₂ is
0.0500 M * 18.3mL = C₂ * 4.00 mL
C₂ = 0.228M
The concentration of the unknown weak acid solution is 0.228 M
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Four atoms of element X have the same mass as one atom of bromine.
(i) What is the relative atomic mass of element X?
80
(ii) Name element X.
(c) Eight atoms of element Y have the same mass as two atoms of silicon.
(i) What is the relative atomic mass of element Y?
56
(ii) Name element Y.
Answer:
Neon and lithium.
Explanation:
4x = 79.9 atomic mass
x = 19.98 atomic mass
The element having the nearest atomic mass to 19.98 is neon with an atomic mass of 20.180.
==
8y = 2*(28.085)
8y = 56.17
y = 7.021
The element having the nearest atomic mass to 7.021 is lithium with an atomic mass of 6.94..
What is the weighted average of a
nail in the sample data given?
Nail Size
3d
16d
Number of
Nails
24
176
Percent
Abundance
12
88
Mass of One
Nail (g)
3. 30
12. 25
Weighted
Average
[?]
Hint: The percent abundance takes into account
the relative number of each type of nail.
Weighted Average
Enter
The weighted average of the nail size in the sample data is 0.0571 d.
To calculate the weighted average of the nail sizes in the given data, we need to first calculate the total mass of all the nails in the sample. We can do this by multiplying the number of nails of each size by the mass of one nail of that size and then adding up the results:
Total mass = (24 nails of size 3d) x (3.30 g/nail) + (176 nails of size 16d) x (12.25 g/nail)
Total mass = 79.20 g + 2156.00 g
Total mass = 2235.20 g
Next, we can calculate the weight fraction of each nail size by dividing the mass of nails of each size by the total mass:
Weight fraction of 3d nails = (24 nails) x (3.30 g/nail) / 2235.20 g = 0.000360
Weight fraction of 16d nails = (176 nails) x (12.25 g/nail) / 2235.20 g = 0.007901
Finally, we can calculate the weighted average of the nail sizes by multiplying each weight fraction by the corresponding nail size and then adding up the results:
Weighted average = (0.000360 x 3d) + (0.007901 x 16d) = 0.0571 d
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Which group in the Periodic Table contains elements that are all gases?
1. 11
2. 17
3. 12
4. 18
Answer:
d
Explanation:
the group's name is called noble gases. hence they are all gases.
Identify the period, group, and valence electrons block of each element.
Problem:
[Ne] 3s² 3p5
P-5, G-17, p
P-6, G-6, d
P-7, no group, f
P-3, G-17, p
P-3, G-14, p
The period, group, and valence electrons block of the given element with the electronic configuration [Ne] 3s² 3p5 is Period 3, Group 7, p-block.
What are the periods and groups in the Periodic Table?The periods in the periodic table are the horizontal rows found in the periodic table.
There are 7 periods in the Periodic Table.
Elements in the same period have the same number of electron shells.
The groups in the periodic table are the vertical columns found in the periodic table.
There are 18 periods in the Periodic Table.
Elements in the same group have the same number of valence electrons.
The electronic configuration of atoms can be used to identify the group and period each element belongs to.
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