why is it important to select a good stationary phase
Selectivity is relatively easy to alter, with mobile phase composition and stationary phase being the primary means of adjustment. The hydrophobicity, polarity and nature of the chosen stationary phase all play a crucial role in analyte interaction and directly affect the selectivity of a separation.
In chromatography, it is important to select a good stationary phase so as to ensure proper separation of components.
What is chromatography?Chromatography is a separation technique which is generally used for separating substances based on their solubilities. The technique makes use of two phases the mobile phase and the stationary phase.
The components are separated from each other based on their solubility in the mobile phase. Component which is least soluble does not travel along the mobile phase while component which is highly soluble travels with the mobile phase.
The difference in the solubility of the components is measured with the reference to the solvent front and is expressed in terms of Rf value.Chromatography finds application in forensics, separation of organic compounds,etc.
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What isotope forms when radon-215 emits two alpha particle and three gamma rays
why are magnesium fluoride and calcium allowed in water
Answer:
calcium allowed in
Explanation:
Why are magnesium, fluoride, and calcium allowed in water?
✓ They’re naturally occurring elements in many springs & aquifers used for water supply purposes - calcium and magnesium are also essential minerals
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Answer:
option B it was captured by earth's gravity
Explanation:
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what is chemical formula of water, carbon dioxide, oxygen and hydrogen
Answer:
water= H20 , carbondioxide= co2 , oxygen=o2 , hydrogen=h2Explanation:
Answer:
water: H2O,
carbon dioxide: CO2
oxygen:O₂
hydrogen: H2
Explanation:
Is table salt dissolved in water a homogeneous or heterogeneous mixture
Answer:
heterogeneous
Explanation:
I said so jit
Which option would be an appropriate model of nuclear fusion?
A adding a drop of water to a glass of water
B sewing one piece of fabric to another
C mashing two marshmallows together
D putting a puzzle together
Mashing two marshmallows together can be an appropriate model to explain nuclear fusion.
Nuclear fusion is the reaction that occurs when two or more light elements combine to form heavier elements with the release of energy.
Nuclear fusion reactions occur mainly in the production of stars and the main-sequence star, The Sun by the fusion of hydrogen nuclei into helium.
Therefore,The following cannot be a model of Nuclear fusion, because they do not follow the basic concept of nuclear fusion which two light nuclei react to form a single heavy nuclei.
Adding a drop of water to a glass of waterSewing one piece of fabric to anotherPutting a puzzle togetherMarshing two marshmallows together can be a good model to explain nuclear fusion because it follows the basic concept of nuclear fusion
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Answer:
mashing two marshmallows together
Explanation:
i've taken the test
Which of these is an example of chemical digestion?
(a person cutting food into small pieces with a knife)
(B
saliva breaking down molecules in the mouth)
(C bones leaching calcium into the bloodstream
)
(D a blender mixing solid food into a paste)
Answer:
B. Saliva breaking down molecules in the mouth
Explanation:
I'm pretty sure it's this because saliva contains enzymes and enzymes use chemicals to break down food in your mouth. For example, your mouth has an enzyme called amylase which helps to break down starches.
Answer:
B. Saliva breaking down molecules in the mouth
Explanation:
I'm pretty sure it's this because saliva contains enzymes and enzymes use chemicals to break down food in your mouth. For example, your mouth has an enzyme called amylase which helps to break down starches.Explanation:
half of the earth is in the light and the other half is in the shadow because
Answer:
the sun doesn't shine on that half
Explanation:
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Answer: Is it sewage checks
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The example of a unicellular organism is amoeba
cacs hạt cấu tạo nên hầu hết cac nguyên tử là
How many grams of H2O is needed to produce 0.75 moles of HCL ?
2 moles of HCl solution reacts with one mole Calcium Hydroxide
Ca
(
O
H
)
2
One mole of HCl has mass : 36.5 g/mol, two moles of HCl will have mass, 73 g.
One mole of Ca
(
O
H
)
2
has mass 74.1 g
as per equation; 73 g of HCl reacts with 74.1 g of Ca
(
O
H
)
2
1g of HCl reacts with 74.1g / 73 of Ca
(
O
H
)
2
1g of HCl reacts with 1.015 g of Ca
(
O
H
)
2
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Answer:
wow only six points, you have to amp it up a little
Explanation: because
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Answer:
Answer is the third one
Explanation:
All living organisms are made up of one or more cells, which are considered the fundamental units of life. Even unicellular organisms are complex! Inside each cell, atoms make up molecules, which make up cell organelles and structures.
when two or more elements are combined, the substance produced is a:
A compound is formed when two or more elements are chemically combined.
Ex: [tex]H{2}O[/tex]
A mixture is formed when two or more elements and/or compounds are physically combined.
Ex: [tex]NaCl + H{2}O[/tex]
H2F5BLi
How many atoms are in the chemical formula?
Answer:
eight atoms
hope it helps
Someone pls help me I will make you brain
Answer:
As shown in the attachment,
Explanation:
is the moon bigger than neptune
Answer:
Neptune is bigger than the moon
Explanation:
The circumference of the moon is 6,783.5 miles
The circumference of Neptune is 96,129 miles
This means neptunes circumference is about 14 times the size of the moons
What is the difference between a molecule and compound?
A compound is a special type of molecule where the atoms that form the molecule are of different elements.
Can someone please help me
Explanation:
Solids have a definite shape and volume. Liquids have a definite volume, but take the shape of the container. Gases have no definite shape or volume.
The kinetic theory of matter (particle theory) says that all matter consists of many, very small particles which are constantly moving or in a continual state of motion.
Determine mass contribution for the following isotopes of the same element.
At the end, tell me the atomic mass of the element using the mass contributions.
Do not forget your units or the question will be marked incorrect.
Isotope 2 amu: 186.956
percent abundance: 62.6%
Atomic Mass of the element ?
Answer: Not possible to find average amu with only the information provided.
Explanation:
Is there more information about the other isotopes? I don't see how one could calculate an overall atomic mass with only one isotope is known. An isotope of 186.956 with abundance of 62.6% isn't enough information. We're not told anything about the other isotopes: are they larger, smaller, and at what percentage. If one has an amu of 204.956 at 37.4%, the overall atomic mass would be quite different than if it had an atomic mass of 182.956 at 37.4%. More infornmation is required.
Is carbon mixed with sand a homogeneous or heterogeneous mixture
Answer:
homogeneous
Explanation:
because I said so
A carbon mixed with sand is a heterogenous mixture.
What is heterogenous mixture?
Mixture is defined as a combination to two or more simpler substances.
There are two types of mixture
Homogenous mixture - A homogenous mixture is defined as a mixture of two or more component which is uniform throughout the mixture. They include water, air, steel etc.Heterogenous mixture - A heterogenous mixture is defined as a mixture of two or more phase which is not uniform throughout the mixture. They include sand and water, salt and oil etc. They are a non uniform mixture with visible or invisible particles.Thus, carbon mixed with sand is a heterogenous mixture.
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Fossil fuels—such as coal, oil, and natural gas—come from ancient, and long dead, plant and animal matter. These fuels have been generated through millions of years of the Earth's geologic processes. Most fossil fuel reserves are found underground, relatively close to the Earth's surface.
At the current rate that human civilization is burning fossil fuels for energy, the Earth's geologic processes have no chance of keeping pace. This means that fossil fuels are a _______ energy resource.
A.
synthetic
B.
nonrenewable
C.
plentiful
D.
renewable
Answer:
Nonrenewable
Explanation:
There is a finite supply of fossil fuels
What is an atomic nucleus?
the outer part of an atom in which electrons move
the outer part of an atom in which neutrons move
the central part of an atom, composed of protons and neutrons
the central part of an atom, composed of protons and electrons
Answer:-
the central part of an atom compsed of protons and neutrons.
when an atom become a negative ion, where do the extra electrons come from?
Answer:
Valence Shell
Explanation:
Some atoms have nearly eight electrons in their valence shell and can gain additional valence electrons until they have an octet. When these atoms gain electrons, they acquire a negative charge because they now possess more electrons than protons.
Which of the following describes a low viscosity liquid
Answer:
a liquid that is thick and sticky
Explanation:
a) Give the reaction that occurs when 1 gram of sodium is added to 100 ml of ethanol.
b) This solution is then heated with 5 grams of 1-bromobutane. What is the maximum yield of the final product from this reaction?
Compare and contrast Dalton's atomic theory with modern atomic theory.
Answer:
Postulates of Dalton's Atomic Theory:
1) Atoms can neither be created nor destroyed.
2) During chemical reaction, atoms combine or separate or re-arrange. They combine in simple ratios.
3) All elements are composed of the indivisible particles called atoms.
4) Atoms of a particular element are identical. They have the same mass and volume.
Postulates of modern atomic theory:
1) All matter is composed of atoms.
2) Atoms consist of protons, electrons and neutrons.
3) Atoms of an element may differ in masses. (as in isotopes)
4) The ratio in which elements combine may not be simple.
Similarities:
1) All elements/matter are/is composed of atoms.
2) Atoms can neither be created nor destroyed.
3) During chemical reactions, atom combine or separate or rearrange.
Differences:
1) Dalton's theory said that atoms are indivisible particles but modern theory denies it and calls atom a divisible particle consisting of sub-atomic particles, protons, electrons and neutrons.
2) Dalton's theory said that atoms of the same element have same mass and volume but according to modern theory, it is said that atoms of the same element can differ in mass (as in isotopes).
3) Dalton said that atoms combine in simple ratio but modern theory denies it.
[tex]\rule[225]{225}{2}[/tex]
Hope this helped!
~AH1807identify two ways in which carbon-12 carbon-13 and carbon-14 are alike
Answer:
identify two ways in which carbon-12, carbon-13, and carbon-14 are alike. they each have 6 protons and neutrons and they're all carbon atoms. what is a chemical compound?