Answer:
The noble gases (Group 18) are located in the far right of the periodic table and were previously referred to as the "inert gases" due to the fact that their filled valence shells (octets) make them extremely nonreactive. The noble gases were characterized relatively late compared to other element groups.
The History
The first person to discover the noble gases was Henry Cavendish in the late 180th century. Cavendish distinguished these elements by chemically removing all oxygen and nitrogen from a container of air. The nitrogen was oxidized to NO2 by electric discharges and absorbed by a sodium hydroxide solution. The remaining oxygen was then removed from the mixture with an absorber. The experiment revealed that 1/120 of the gas volume remained un-reacted in the receptacle. The second person to isolate, but not typify, them was William Francis (1855-1925). Francis noted the formation of gas while dissolving uranium minerals in acid.
Argon
In 1894, John William Strutt discovered that chemically-obtained pure nitrogen was less dense than the nitrogen isolated from air samples. From this breakthrough, he concluded that another, unknown gas was present in the air. With the aid of William Ramsay, Strutt managed to replicate and modify Cavendish's experiment to better understand the inert component of air in his original experiment. The researchers' procedure differed from the Cavendish procedure: they removed the oxygen by reacting it with copper, and removed the nitrogen in a reaction with magnesium. The remaining gas was properly characterized and the new element was named "argon," which originates from the Greek word for "inert."
Helium
Helium was first discovered in 1868, manifesting itself in the solar spectrum as a bright yellow line with a wavelength of 587.49 nanometers. This discovery was made by Pierre Jansen. Jansen initially assumed it was a sodium line. However, later studies by Sir William Ramsay (who isolated helium on Earth by treating a variety of rare elements with acids) confirmed that the bright yellow line from his experiment matched up with that in the spectrum of the sun. From this, British physicist William Crookes identified the element as helium.
Neon, Krypton, Xenon
These three noble gases were discovered by Morris W. Travers and Sir William Ramsay in 1898. Ramsay discovered neon by chilling a sample of the air to a liquid phase, warming the liquid, and capturing the gases as they boiled off. Krypton and xenon were also discovered through this process.
Radon
In 1900, while studying the decay chain of radium, Friedrich Earns Dorn discovered the last gas in Group 18: radon. In his experiments, Dorn noticed that radium compounds emanated radioactive gas. This gas was originally named niton after the Latin word for shining, "nitens". In 1923, the International Committee for Chemical Elements and International Union of Pure Applied Chemistry (IUPAC) decided to name the element radon. All isotopes of radon are radioactive. Radon-222 has the longest half-life at less than 4 days, and is an alpha-decay product of Radium-226 (part of the U-238 to Pb-206 radioactive decay chain).
The Electron Configurations for Noble Gases
Helium 1s2
Neon [He] 2s2 2p6
Argon [Ne] 3s2 3p6
Krypton [Ar] 3d10 4s2 4p6
Xenon [Kr] 4d10 5s2 5p6
Radon [Xe] 4f14 5d10 6s2 6p
Explanation:
Describe the Bay's salinity. How does the salinity change throughout the year?
Each molecule of an olefin has at least:
a
one double bond
b
two double bonds
c
three double bonds
d
two or more single bonds
Answer:
a.
Explanation:
One double bond.
For example ethene CH2=CH2
What element in the second period has the largest atomic radius?
a
neon
b
lithium
c
carbon
d
potassium
Answer:
b) Lithium
Explanation:
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
A compound containing only carbon, hydrogen, and oxygen is analyzed using combustion analysis. When 50.1 g of the compound is burned, 91.8 g of carbon dioxide and 25.1 g of water are collected. In order to determine the moles of carbon in the compound, first determine the moles of carbon dioxide that were produced from the combustion.
Answer:
[tex]C_{3}H_4O_2[/tex]
Explanation:
Hello,
In this case, since the carbon of the initial compound is present in the carbon dioxide product, we can compute the mass and moles of carbon in the compound:
[tex]n_C=91.8g CO_2*\frac{1molCO_2}{44gCO_2} *\frac{1molC}{1molCO_2} =2.09molC\\\\m_C=91.8g CO_2*\frac{1molCO_2}{44gCO_2} *\frac{1molC}{1molCO_2}*\frac{12gC}{1molC} =25.0gC[/tex]
Next, the mass and moles of hydrogen in the compound, is contained in the yielded amount of water, thus, we compute the mass and moles of hydrogen in the compound:
[tex]n_H=25.1gH_2O*\frac{1molH_2O}{18gH_2O} *\frac{2molH}{1molH_2O} =2.79molH\\\\m_H=25.1gH_2O*\frac{1molH_2O}{18gH_2O} *\frac{2molH}{1molH_2O} *\frac{1gH}{1molH} =2.79gH[/tex]
In such a way, the mass of oxygen comes from the mass of the compound minus the mass of carbon and oxygen:
[tex]m_O=50.1g-25.0g-2.79g=22.31gO[/tex]
And the moles:
[tex]n_O=22.31gO*\frac{1molO}{16gO}=1.39molO[/tex]
Then, we compute the subscripts by diving the moles of C, H and O by the moles of oxygen as the smallest moles:
[tex]C:\frac{2.09}{1.39}=1.5 \\\\H:\frac{2.79}{1.39}=2\\ \\O:\frac{1.39}{1.39} =1[/tex]
After that, we write:
[tex]C_{1.5}H_2O[/tex]
Which must be shown in whole number only, thereby we multiply the subscripts by 2, so the empirical formula turns out:
[tex]C_{3}H_4O_2[/tex]
Best regards.
You 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.
what isotope of an atom if it has 29 protons and 36 neutrons
Answer:
POTASSIUM
Explanation:
2 8 8 1________ 1A
Label the parts of the electric circuit that best correspond to the heart, arteries, veins, and cells.
Answer:
1 ➡️ Cells
2 ➡️ Arteries
3 ➡️ Veins
4 ➡️ Heart
Explanation:
The parts of the electric circuit that best correspond to the heart, arteries, veins, and cells have been properly labeled.
The circulatory system involves the transportation of nutrients, oxygen and water by blood to other the parts of the body.
From the electric circuit, we see that arteries transport blood away from the heart to the other cells in the body. The veins actually return the blood back to the heart from the cells. The heart pumps the blood
The electric circuity diagram has the label 1 bulb analogous to cell, label 2 analogous to arteries, label 3 analogous to veins, and label 4 cell analogous to heart.
What is an electric circuit?The electric circuit has been given as the power source and the conducting wires that allows the flow of the current in the circuit.
In the human body, the heart has been transported the oxygenated blood through the arteries to the cell and carried the deoxygenated blood from the cells back to the heart via veins.
In the circuit, the battery has been the source of the power/blood. The current has been carried from the heart to the cell/bulb through the arteries labeled, 2, and transported back to the battery via veins labeled 3.
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Cementation is part of the process of
A. igneous intrusion
B. lithification
C. igneous extrusion
D. metamorphism
SUBMIT
Answer:
The correct answer is b.
Explanation:
hope this helps u
Answer:
Bryna is correct it is B
Explanation:
Plz answer me will mark as brainliest
Answer:
Compared to the walls of the right ventricle, the walls of the left ventricles are much thicker.
The plasma carries hormones, which are the body's chemical messengers.
PLEASE HELP!!!!! CHEMISTRY
What is the formula for Maganese (IV) Oxalate ?
Answer:C2MnO4
You can get this by looking at your periodic table :)
Based on the visible cell structure, which of the following statements is true?
Answer:I think it would be the third one.
Explanation:
Why must you avoid touching the gas Spectrum tubes?
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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What characteristics are used to clarify an area as a wetland?
NEED HELP ASAP !
Which best describes an element?
A. elements are chemicals that are pure substance held together by chemical bonds
B. elements are mixtures of protons, neutrons, and electrons in different combination
C. elements are chemicals that are pure substances represented by symbols that have at least one capital letter
D. elements that are chemicals that are formed when temperature change happens or a precipitate forms
Answer:
A. Elements are pure substances.
Explanation:
Out of all four answers A would be best. Hope this helps.
Answer:
B
Explanation:
I think all options can define element in one form or another but an element is characterized by the atomic number it has i.e you will know it's Carbon due to it's number of protons, neutrons and/or electrons.
Pb12 (s) = Pb+2 (aq)
+
2 ]- (aq)
Answer:
this
Explanation:
What is the unit rate of the better deal? (Number answers only.)
LaTeX: \frac{160\:miles}{5\:gallons}\:or\:\frac{315\:miles}{9\:gallons}160 m i l e s 5 g a l l o n s o r 315 m i l e s 9 g a l l o n s
The better deal has a unit rate of [m] miles per gallon.
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.
Which Drug is used not to cure Cancer, but can kill Cancer?
(A) = Adrenaline.
(B) = Burger King.
(C) = Chemotherapy.
(D) = Deoxyribose.
(E) = Ethanol.
Answer:
chemotherapy
Explanation:
i need help filling in these 2 blanks i really need answers asap
is there a word bank so i know which words to chose from?
1st blank: command
2nd blank: messages
Explanation:
I am not too sure about the second blank, but to me it makes sense.
can someone pweaseee help me on this ??
Answer:
Be
Explanation:
The atomic radius decreases as you go from left to right in a period. Be has the largest radius out of those given elements.
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!
What is the atomic mass of element X
Answer:
Which one of the table is element X?
Explanation:
I have no idea and help!!!!!!!!!!!!!!!!!!!!!!!!!
Which of the following does Electrons change when Electrons are changed?
Answer:
tuttutututu and the optionsThe normal boiling point of benzene is 80.1°C. What is its enthalpy of vaporization if the vapor pressure at 26.1°C is 100 torr?
The heat of vaporization of benzene is required.
The heat of vaporization of benzene is 33009 J/kg.
[tex]T_0[/tex] = Normal boiling point = 80.1+273.15 K
[tex]T_B[/tex] = Boiling point at given pressure = 26.1+273.15 K
[tex]R[/tex] = Gas constant = 8.314 J/mol K
[tex]P[/tex] = Pressure at given [tex]T_B[/tex] = 100 torr
[tex]\Delta H[/tex] = Heat of vaporization
From the Clausius–Clapeyron equation
[tex]\dfrac{1}{T_B}=\dfrac{1}{T_0}-\dfrac{R\ln(\dfrac{P}{P_0})}{\Delta H}\\\Rightarrow \Delta H=\dfrac{R\ln\dfrac{P}{P_0}}{\dfrac{1}{T_0}-\dfrac{1}{T_B}}\\\Rightarrow \Delta H=\dfrac{8.314\times \ln\left(\frac{100}{760}\right)}{\frac{1}{80.1+273.15}-\frac{1}{26.1+273.15}}\\\Rightarrow \Delta H=33008.99\ \text{J/kg}[/tex]
The heat of vaporization of benzene is 33009 J/kg.
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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
Naphthalene is soluble in diethyl ether, but it is insoluble in water regardless of the solution pH. Explain why this compound cannot be readily ionized in aqueous solution.
Answer:
Naphthalene is a non polar substance
Explanation:
In chemistry, the principle of like dissolves like is the over aching principle that controls the dissolution of one substance in another.
Naphthalene dissolves in diethyl ether because diethyl ether is a non polar solvent just as naphthalene is a nonpolar substance.
Since water is a polar solvent, it can not dissolves naphthalene at any pH because naphthalene is a nonpolar substance.
What is an advantage of making plant-based products, such as cotton, instead of making petroleum-based products, such as plastics?
A Producing plant-based products requires more energy.
B Factories that make plant-based products generate more waste.
C Plants that are used to make the product can be replaced.
D All plant-based products cost more than petroleum-based products.
Answer:
Hey! sorry if im late but the
answer is :
C : Plants that are used to make the product can be replaced.
I hope this helps everyone out there!
Explanation:
i guessed lol
Answer:
C) Plants that are used to make the product can be replaced
Explanation:
Sorry I’m late I just did the test and got 100%
How does the motion of particles in the sun’s plasma compare to the motion of particles in a solid?
Particles in both the plasma and a solid move around to fill available space.
Particles in the plasma move randomly, but particles in a solid vibrate in one place.
Particles in the plasma have low kinetic energy, but particles in a solid have high kinetic energy.
Particles in both the plasma and a solid are made up of fast-moving electrons and cations.
Answer:
Particles in the plasma move randomly, but particles in a solid vibrate in one place.
Explanation:
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