The color change exhibited by phenolphthalein during a titration of aqueous acetic acid with aqueous sodium hydroxide is pink to colorless.
An indicator is an organic dye which changes color in acidic, basic and neutral medium.
Phenolphthalein is an example of an indicator. When aqueous acetic acid is titrated against aqueous sodium hydroxide, the indicator may be added to the basic solution.
Phenolphthalein has a pink color in a basic medium. As the acid is added gradually, the solution turns colorless at end point.
Hence, the color change exhibited by phenolphthalein during a titration of aqueous acetic acid with aqueous sodium hydroxide is pink to colorless.
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is a salt water solution saturated when there is undissolved salt at the bottom of the bottle?
Answer:
Yes
Explanation:
These questions are from an experiment where we had a mixture of Ferrocene, acetylferrocene and diacetyl ferrocene and we separated each by using column chromatography. Before doing the column chromatography we did TLC analysis to ensure that we did, in fact, have a mixture of these 3 compounds.
During the column chromatography we first eluted the ferrocene using pure hexane. Then we eluted the acetylferrocene using a 1:1 mixture of hexane and methylene chloride. Then we eluted the diacetylferrocene using a 9:1 mixture of hexane and methylene chloride.
1. Rank ferrocene, acetylferrocene, and diacetylferrocene in order of increasing polarity. Do the TLC results from your fractions support this ranking? Explain.
2. Rank the solvents used in the experiment in order of increasing polarity.
3. Why do you start with the least polar solvent/solvent mixture and progress to increasing polar solvent/solvent mixtures when eluting the ferrocene compounds from the column rather than starting with more polar solvent system and progressing to less polar solvents?
4. How do the thin layer and column chromatography for this experiment compare in regard to stationary and mobile phases?
5. What key feature in the IR spectrum of acetylferrocene distinguishes it from the spectrum of ferrocene?
Answer:
Explanation:
The polarity of the 3 compounds would be in the order of
Ferrocene < Acetylferrocene < Diacetylferrocene
Your TLC data has to also support this observation . This can be checked by measuring the values of Rf ( Retention factor = distance travelled by solute/solvent ) .The Rf values also has to follow this particular order: -
Ferrocene > acetylferrocene > diacetylferrocene
2) Hexane happens to be a non-polar solvent. The polarity of hexane can be increased if some polar solvents for example, ethyl and methylene chloride etc are added
Therefore, in the increasing order of solvents polarity, we have
Hexane < 1:1 mixture of hexane: methylene chloride < 9:1 mixture of methylene chloride:
3) Chromatographic techniques all have a stationary phase in addition to a mobile phase. In the case of column chromatography, the silica gel will be the stationary phase and the solvent that will be poured will be the mobile phase.
4) The TLC and column chromatography both happen to have the same stationary phase which is the silica gel. Also, the same solvent mixture is used in both the techniques. This makes the result of the 2 to be almost the same. The difference seen between them is that, TLC works against the gravity while on the other hand column chromatography works in the direction of the gravity.
5) The key feature in the IR spectra of the acetylferrocene that will be absent in the spectra of ferrocene is the presence of carbonyl stretching frequency at close to 1700 per cm(cm-1). This peak is easily differentiated between both acetyl ferrocene and ferrocene.
Which unit of measurement would best be used to measure the volume of a points a DROP of water? .
Answer:
milliliter
Explanation:
smallest form of measuring volume from all the available choices
What is the molality of 6 grams of salt in 10 grams of solution?
Answer:
maalat ang salt
Explanation:
Which element has the lowest first ionization energy?
NEED ASAP
Select one:
a. 1s22s22p63s23p5
b. 1s22s1
c. 1s22s22p63s23p6
d. 1s22s22p63s1
Answer:
C
Explanation:
there is no explanation needed
Answer:
The value of ionization energy (IE) decreases down the group due to the increasing size as the valence electrons are more loosely bound. Thus lowest IE in this case is of Bi as it is bottom most element.
Explanation:
Which is a chemical property of soda ash?
Explanation:
A chemical property of soda ash is, it is a alkaline compound
What is the reason for the trend in lonization Energy? Select all that apply.
A. larger atomic mass number
B. number of energy levels around the nucleus C. number of valence electrons.
D. number of protons in the nucleus
E. number of neutrons in the nucleus
Answer:
Explanation:
A, D,E and B i think is the correct answers
Read the information about the halogen family.
Elements within a group share similar properties. Elements in the halogen family, such as fluorine (F), chlorine (Cl), bromine (Br), and iodine (I), all have seven valence electrons. Iodine is an important element for human health. The thyroid gland uses iodine to produce hormones. One of the hormones it makes is a covalent compound called thyroxine.
Given this information, what effect do you think other halogen elements have on human health? State your prediction, and do some research on one of the halogen elements to see how it affects human health. List your findings, and then give your opinion on whether you think the element you chose should be used in food products, cleaning products, or in other manners that cause it to come in contact with humans. Be sure to provide evidence from your research to support your opinion.
Answer:
See explanation
Explanation:
Chlorine is a member of the halogen family known as a toxic yellowish green gas. Inhalation of chlorine for a prolonged period of time leads to pulmonary edema. If a person comes in contact with compressed liquid chlorine the person may experience frostbite of the skin and eyes.
However chlorine is very useful in water disinfection and is preferred in water treatment because it provides residual disinfection of the treated water.
Chlorine gas may be dissolved in NaOH to form oxochlorate I which is used as a bleach in cleaning.
Answer:
Iodine
Explanation:
iodine is pretty good for you in moderation, iodine can ensure proper tyriod function but too much of it can cause thyroid gland inflammation and thyroid cancer, burning of the mouth, throat, and stomach; and coma.
What determines the speed at which a particle of matter moves
Answer:
The force exerted on it.
Explanation:
As the law of motion states, an object at rest will remain at rest an object in motion will remain in motion unless acted upon by another force.
is the center of an atom is called the nucleus?
Answer:
The center of the atom contains the nucleus so yes
Explanation:
22. The metal roof of a building has turned a light green colour. The metal roof is most likely
Ammonium phosphate NH43PO4 is an important ingredient in many solid fertilizers. It can be made by reacting aqueous phosphoric acid H3PO4 with liquid ammonia. Calculate the moles of ammonium phosphate produced by the reaction of 2.3mol of ammonia. Be sure your answer has a unit symbol, if necessary, and round it to the correct number of significant digits.
Answer:
0.767 moles of ammonium phosphate are produced
Explanation:
The reaction of ammona (NH3), with phosphoric acid is:
3 NH3 + H3PO4 → (NH4)3PO4
Where 3 moles of ammonia reacts per mole of H3PO4 to produce 1 mole of ammonium phosphate.
If 2.3 moles of ammonia reacts, the moles of ammonium phosphate produced if phosphoric acid is in excess are:
2.3 moles NH3 * (1 mole (NH4)3PO4 / 3 moles NH3) =
0.767 moles of ammonium phosphate are produced
In ethane, C2H6, ethene (ethylene), C2H4, and ethine (acetylene), C2H2, there are direct carbon-carbon bonds. Which one is the shortest?
a. The carbon-carbon bond in ethane's the longest!)
b. The carbon-carbon bond in ethene is the longest
c. The carbon-carbon bond in ethyne is the longest.
d. All of the carbon-carbon bonds have the same length.
Answer:
a. The carbon-carbon bond in ethane's the longest!)
Explanation:
Ethane is a chemical compound that is organic in nature. Its chemical formula is [tex]$C_2H_6$[/tex]. It has two carbon atoms and six of hydrogen atoms that is connected to the carbon atoms.
Ethane is odorless and colorless at the standard temperature and standard pressure.
The carbon to carbon atoms in ethane is connected by a single bond.
The length of single carbon-carbon bond is greater than carbon-carbon double bond and triple bond.
Thus, carbon-carbon bond length in ethane is the longest.
How much 1.50M KBr can be made from 15.6 mL of concentrated KBr with a molarity of 9.65 M?
Answer: 234.8 M
Explanation:
The brain combines the electrical signals sent from the what? I NEED THIS ASAP PLEASE!!
How is the charge found in an element?
Answer:
Positive charge if there are more protons than electrons. Negative charge if there are more electrons than protons. If there's the same amount of protons and electrons, it's a neutral charge.
Explanation:
All matter is made up of electrons and protons. Electrons have a negative charge, protons have a positive charge. A charge is a type of particle measurement, and it is determined based on the amount of protons or electrons in a certain thing. The charge is which one there are more of, and there’s no charge (neutral) if they’re balanced.
How many oxygen atoms will there be in the balanced equation of Al+O2-Al2O3
Answer: 10
Explanation:
4Al + 2O2 --> 2Al2O3
This is the balanced equation so there are 2*2 +2*3 = 4+6 =10
What kind of mixture is sometimes difficult to distinguish form a compound? Why?
Answer:
In a heterogeneous mixture, the parts of the mixture are noticeably different from one another. In a homogeneous mixture, the substances are so evenly distributed that it is difficult to distinguish one substance in the mixture from another.
4)
Fluorine and element Z have similar chemical properties. Element Z could have an electron
configuration of
A)
2-2
B)
2-8-1
C)
2-8-8
D)
2-8-18-7
Answer:
D) 2.8.18.7
Explanation:
because it has 7 valence electron that occupied by shells
8. What do the results tell you about your hypothesis(es)?
Answer: Results will tell you which hypothesis is true.
Explanation: The hypothesis becomes a theory if the results support it. d.A new experiment is designed to provide additional data about the hypothesis. Imagine that a team of scientists test a certain hypothesis, and the experimental results show that it is false. ... The results will show which other hypotheses must be true.
If the temperature of the water inside of the
pressure cooker is greater than 104'C, and the
water is still a liquid, then the pressure inside of the
pressure cooker must be
less than 1 atm
equal to 1 atm
c.
greater than 1 atm
Answer:
(C). Greater than 1atm
Explanation:
We are aware that water boils at 100 degree Celsius. Water can change its phase and become vapor at 100degree Celsius and at normal pressure which is 1atm.
In the given scenario we have enough temperature to convert water into vapor phase but we don't want it rather we want it to remain in liquid state. This can be achieved by increasing the pressure which was earlier required for vapor phase conversion. So the pressure should be greater than 1atm.
When we increase the temperature the molecules will get enough energy to escape into vapor phase, but when we will increase the pressure, it will provide hindrance to those molecules and will maintain them into Liquid state.
In the US, nutritional energy is reported in Calories (Cal). One nutritional Calorie is equal to one kilocalorie (kcal). If a food package reports 250.0 Calories (Cal) per serving, how many calories (cal) are in each serving?
Answer:
2.500 × 10⁵ cal
Explanation:
1kcal= 1000 cal
From the analysis, the number of calories in each serving of a food with 250 Calories would be 250,000 calories.
According to the illustration:
1 Calories = 1 kilocalories
The food package reports 250 Calories
Hence, 250 Calories = 1 x 250 kilocalories
= 250 kilocalories
According to metrics, 1 kilocalories = 1,000 calories
Thus, 250 kilocalories = 250 x 1000 calories
= 250,000 calories
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Determine the number of Au atoms found in 5.18 grams of gold.
A.1.02x1022 atoms
B. 3.84 x 1022 atoms
C.2.13 x 1022 atoms
D.4.58x1022 atoms
1.58 x 1022. atoms
Please let me know
Answer:
1.58× 10²² atoms of Au
Explanation:
Given data:
Mass of gold = 5.18 g
Number of atoms of gold = ?
Solution:
First of all we will calculate the number of moles of gold.
Number of moles = mass/molar mass
Number of moles = 5.18 g/196.96 g/mol
Number of moles = 0.0263 mol
Number of atoms:
Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ atoms of Au
0.0263 mol × 6.022 × 10²³ atoms of Au / 1mol
0.158× 10²³ atoms of Au
1.58× 10²² atoms of Au
Which of the following molecules has a covalent bond?
A) H-F
B) H-Cl
C) H-Br
Ultraviolet light A (UVA) can penetrate deeper layers of skin than UVB. If UVA has a wavelength of 400 nm, how much energy would be in this wave? 2 x 10-17)
Answer:
E = 5×10⁻¹⁹ J
Explanation:
Given data:
Wavelength = 400 nm (400×10⁻⁹ m)
Energy of wave = ?
Solution:
Formula:
E = h c/λ
c = 3×10⁸ m/s
h = 6.63×10⁻³⁴ Js
Now we will put the values in formula.
E = 6.63×10⁻³⁴ Js × 3×10⁸ m/s /400×10⁻⁹ m
E = 19.89×10⁻²⁶ J.m / 400×10⁻⁹ m
E = 0.05×10⁻¹⁷ J
E = 5×10⁻¹⁹ J
Arrange in order of decreasing atomic radii: Kr, K, Ge, Ca
Answer:
K > Ca > Ge > Kr
Explanation:
The elements given are all in the 4th period on the periodic table.
Kr, k, Ge, Ca;
Arranging their order from left to right;
K, Ca, Ge, Kr
Atomic radius is taken as half the of the inter-nuclear distance (d) between two covalently bonded atoms of non-metallic elements or half the distance between two nuclei in the solid state of metals.
Across the periodic table atomic radii decreases progressively from left to right. This is due to progressive increase in the nuclear charge (number of protons in the nucleus) without an attendant increase in the number of electronic shells.
From the left to right; decreasing radii;
K > Ca > Ge > Kr
I NEED HELP ASAP PLEASE I BEG
with what?..................
How many different principal quantum numbers can be found in the ground-state electron configuration of nickel?A) 2.B) 3.C) 4.D) 5.E) 6.
Answer:
C) 4.
Explanation:
Hello!
In this case, since the electron configuration of nickel at its ground-state, considering 28 as its atomic number and the number of electrons it has in one atom, is:
[tex]Ni^{28}:1s^2,2s^2,2p^6,3s^2,3p^6,4s^2,3d^8[/tex]
We can see it has four energy levels, 1, 2, 3 and 4, which are related to the following principal quantum number, that describes the energy of an electron in the atom and its most probable distance with respect to the nucleus.
Therefore, nickel has C) 4 different principal quantum numbers.
Best regards!
In the nucleus of an atom, there are 17 protons and 18 neutrons. What is the atomic number? What is the atomic mass? How many electrons are there?
Answer:
atomic number =17
mass number = 17+18= 35
How many grams of N2 are required to react with 2.30 moles of Mg in the following process? 3 Mg + N2 → Mg3N2? (Mg = 24.3 g/mol, N = 14.0 g/mol)
Answer: 10.73 g
Explanation:
2.3 mol Mg * (1 mol N2 / 3 mol Mg) * (14 g Mg / 1 mol g) = 10.73