Answer:
Explanation:
Thin-layer chromatography (TLC) is a chromatography technique used to separate non-volatile mixtures. ... After the sample has been applied on the plate, a solvent or solvent mixture (known as the mobile phase) is drawn up the plate via capillary action.
According to the electron configuration, which atom will be the most reactive?
1s^2 2s^2
1s^2 2s^2 2p^6 3s^2
1s^2 2s^2 2p^6 3s^2 3p^6
1s^2 2s^2 2p^6 3s^2 3p^6 4s^2
Answer:
The fourth atom.
Explanation:
Number of valence electrons in each of the four atoms:
First atom: two ([tex]2\, s^{2}[/tex].)Second atom: two ([tex]3\, s^{2}[/tex].)Third atom: eight ([tex]3\, s^{2}\; 3\, p^{6}[/tex].)Fourth atom: two ([tex]4\, s^{2}[/tex].)Without referring to a periodic table, the first, second, and fourth atoms would all belong to the alkali-earth metal elements. The third atom would belong to a noble gas element. (The four choices are beryllium, magnesium, argon, and calcium, respectively.)
Noble gas elements are highly stable. Thus, the third atom (argon) would be the least reactive among all four choices.
On the other hand, alkali-earth metals are reactive since they tend to lose their valence electrons. The reactivity of an alkali-earth atom depends on its ionization energy (the energy required to take a valence electron away from the atom.)
Since these atoms are in the same group, ionization energy would be smaller for atoms with a larger radius. In a given group, atoms with more filled electron shells would have a larger radius.
The first atom has two filled main shells, the second has three, whereas the fourth has four.
Thus, among the three alkali-earth metals in the choices:
[tex]\begin{aligned}&\text{Number of filled electron shells:} \\ & a < b < d\end{aligned}[/tex].
[tex]\begin{aligned}&\text{Atomic radius:} \\ & a < b < d\end{aligned}[/tex].
[tex]\begin{aligned}&\text{Ionization energy:} \\ & a > b > d\end{aligned}[/tex].
[tex]\begin{aligned}&\text{Reactivity:} \\ & a < b < d\end{aligned}[/tex].
The third choice (a noble gas) is the least reactive among the four choices:
[tex]\begin{aligned}&\text{Reactivity:} \\ & c < a < b < d\end{aligned}[/tex].
Overall, the fourth choice would be the most reactive among the four choices.
Determine the reducing agent in the following reaction. Explain your answer. 2 Li(s) + Fe(C2H3O2)2(aq) → 2 LiC2H3O2(aq) + Fe(s)
The reducing agent in the reaction 2Li(s) + Fe(CH₃COO)₂(aq) → 2LiCH₃COO(aq) + Fe(s) is lithium (Li).
The general reaction is:
2Li(s) + Fe(CH₃COO)₂(aq) → 2LiCH₃COO(aq) + Fe(s) (1)
We can write the above reaction in two reactions, one for oxidation and the other for reduction:
Oxidation reactionLi⁰(s) → Li⁺(aq) + e⁻ (2)
Reduction reactionFe²⁺(aq) + 2e⁻ → Fe⁰(s) (3)
We can see that Li⁰ is oxidizing to Li⁺ (by losing one electron) in the lithium acetate (reaction 2) and that Fe²⁺ in iron(II) acetate is reducing to Fe⁰ (by gaining two electrons) (reaction 3).
We must remember that the reducing agent is the one that will be oxidized by reducing another element and that the oxidizing agent is the one that will be reduced by oxidizing another species.
In reaction (1), the reducing agent is Li (it is oxidizing to Li⁺), and the oxidizing agent is Fe(CH₃COO)₂ (it is reducing to Fe⁰).
Therefore, the reducing agent in reaction (1) is lithium (Li).
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How many of sodium (Na) are needed to make 4.5 liters of a 1.5mol/L of Na solution?
Answer:
Explanation:
First you will find the mole from the molarity and then the desired mass from the mole.
Potassium sulfate has a solubility of 15g/100g water at 40 Celsius. A solution is prepared by adding 39.0g of potassium sulfate to 225g water, carefully heating the solution, and cooling it to 40 Celsius. A homogeneous solution is obtained. Is this solution saturated, unsaturated, or supersaturated? The beaker is shaken and precipitation occurs. How many grams of potassium sulfate would you except to crystallize out?please help me to understant this
Answer:
5.25 grams of potassium sulfate will get crystallize out.
Explanation:
Solubility of potassium sulfate at 40 °C = 15 g/100 g
This means that at 40 °C 15 g of potassium sulfate will get completely dissolved in 100 of water.
39.0 g of potassium sulfate to 225 g water, carefully heating the solution.
Amount of potassium sulphate will get dissolve in 225 g of water at 40 °C will be:
[tex]\frac{15g}{100g}[/tex] × 225 = 33.75g
Amount of potassium sulfate precipitated out by the solution:
= 39.0 g-33.75 g = 5.25 g
At 40 °C 5.25 g of potassium sulfate will get precipitate out from the solution which means that solution is saturated.
Saturated solution are solution in which solute is dissolved in maximum amount. Further addition of solute results in precipitation of solute form the solution.
5.25 grams of potassium sulfate will get crystallize out.
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describe radioisotope
Answer:
It is an unstable form of a chemical element that releases radiation as it breaks down and becomes more stable.
Which solution has the same number of moles of KCl as 75.00 mL of 0.250 M solution of KCl?
25.0 mL of 0.175 M solution of KCl
129 mL of 0.145 M solution of KCl
20.0 mL of 0.200 M solution of KCl
50.0 mL of 0.125 M solution of KCl
100 mL of 0.0500 M solution of KCl
Answer:
None of them
Explanation:
The number of moles in 75ml is 0.01875moles while in 25ml is 0.004375 and in 129 ml is 0.018705.
REMEMBER: Molarity is the number of moles per litre so in order to get the number of moles you multiply the molarity of the substance by the quantity of the substance in litres.
129 mL of 0.145 M solution of KCl solution has the same number of moles of KCl as 75.00 mL of 0.250 M solution of KCl. Therefore, option B is correct.
What is molarity ?Molarity is defined as the number of moles of a solute in one liter of solution. A solution's molarity is also known as its molar concentration.
To calculate the molarity of a solution, divide the number of moles of solute by the total volume of solution in liters.
Molarity is a concentration unit that is defined as the number of moles of dissolved solute per liter of solution. Molarity is expressed as the number of millimoles per milliliter of solution when the number of moles and volume are divided by 1000.
Given:
number of mol = M ×V
= 0.250 M × 0.0750 L
= 1.87 × 10^-2 mol
volume, V = 1.29*10^2 mL
= 0.129 L
use:
number of mol,
n = Molarity × Volume
= 0.145 × 0.129
= 1.87 × 10^-2 mol
Thus, option B is correct.
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What is the net charge of C
Explanation:
Sorry, I don't know, but I can tell you that when an atom, or a body, has the same amount of positive charges (protons) and negative charges (electrons), it is said to be electrically neutral. ... The net charge corresponds to the algebraic sum of all the charges that a body possesses.
Answer: Neutral carbon-12 (or any carbon atom) has 6 electrons with a total negative charge of 6e- orbiting a nucleus with a total positive charge of 6e+, so that the total net charge is zero. The nucleus is made up of 6 protons, each with a positive charge of e+, and 6 neutrons, each with zero charge.
Explanation:
1. If the wavelength is changed, what will happen to the absorbance values?
Answer:
The longer the path length, the more molecules there are in the path of the beam of radiation, therefore the absorbance goes up. As you likely know from other experiences, a particular chemical species absorbs some wavelengths of radiation and not others
The wavelength is used to determine the concentration of a colored solution since at this wavelength a slight change in concentration allows for a significant change in the absorbance of light.
What is Wavelength?Wavelength is the distance between equal points in adjacent cycles of a wave signal that propagates in space. Each wave has a definite shape and length, so the distance between the peaks is called the wavelength.
It can be calculated by this formula-
[tex]\lambda=\frac{v}{f}[/tex]
[tex]where, \lambda =wavelength\\{v} = velocity\\{f} = frequency[/tex]
Absorbance measures the amount of light with a specific wavelength which a given substance prevents from passing through ii.
Thus, the wavelength is used to determine the concentration of a colored solution since at this wavelength a slight change in concentration allows for a significant change in the absorbance of light.
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What does a chemical reaction tell us?
Answer:
A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products. The properties of the products are different from those of the reactants.
I hope this helps.
if you are a scientific or a inventor what do you want to discover or to invent relate to electrogmagnetism
Answer:
Michal Faraday 19th century
Milkweed contains a poison known as cardenolides. Monarch butterflies eat the milkweed plant and hold on to this toxic compound. The chemical formula for cardenolides is shown below.
CH18C20H15CHCO2
How many atoms of each element are in one molecule of cardenolides?
A)
34 carbon atoms, 43 hydrogen atoms, and 2 oxygen atoms
B)
42 carbon atoms, 23 hydrogen atoms, and 2 oxygen atoms
C)
20 carbon atoms, 33 hydrogen atoms, and 2 oxygen atoms
D)
23 carbon atoms, 34 hydrogen atoms, and 2 oxygen atoms
Answer:
the answer is D) 23 carbon atoms, 34 hydrogen atoms, and 2 oxygen atoms
Explanation:
i took the test and got a 100%
What is the [H+] if pOH =9.50
will it be acid or basic?
Taking into account the definition of pH and pOH, the [H⁺] is 3.16×10⁻⁵ M and the solution will be acid.
First of all, pH is a measure of acidity or alkalinity that indicates the amount of hydrogen ions present in a solution or substance.
The pH is defined as the negative base 10 logarithm of the activity of hydrogen ions, that is, the concentration of hydrogen ions or H₃O⁺:
pH= - log [H⁺]= - log [H₃O⁺]
Similarly, pOH is a measure of hydroxyl ions in a solution and is expressed as the logarithm of the concentration of OH⁻ ions, with the sign changed:
pOH= - log [OH⁻]
The following relationship can be established between pH and pOH:
pH + pOH= 14
In this case, being pOH= 9.50, pH is calculated as:
pH + 9.40= 14
pH= 14 - 9.50
pH= 4.50
Replacing in the definition of pH the concentration of H⁺ ions is obtained:
- log [H⁺]= 4.50
Solving :
[H⁺]= 10⁻⁴ ⁵
[H⁺]= 3.16×10⁻⁵ M
The numerical scale that measures the pH of the substances includes the numbers from 0 to 14, being acidic solutions with a pH lower than 7, and basic those with a pH greater than 7. The pH = 7 indicates the neutrality of the solution.
In this case, the pH has a value of 4.50. So, the solution is acidic.
In summary, the [H⁺] is 3.16×10⁻⁵ M and the solution will be acid.
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brainly.com/question/16032912?referrer=searchResults brainly.com/question/13557815?referrer=searchResultsUsing chemical equations, show how the triprotic acid H3PO4 ionizes in water. Phases are optional.
Ka1:
Ka2:
Ka3:
Explanation:
H3PO4 is a weak acid so it partially dissociates in water
Ka1
H3PO4 (aq) + H2O(l) <----> H2PO4-(aq) + H3O+ (aq)
Ka2
H2PO4- (aq) + H2O(l) <----> HPO4 2- (aq) + H3O+ (aq)
Ka3
HPO4 2- (aq) + H2O(l) < ---> PO4 3- (aq) + H3O+ (aq)
What are the bond angles found in germanium disulfide ?
Answer:
Every germanium atom is tetrahedrally linked to four sulphur atoms, with an interatomic distance of 2.19A. The angle between the two sulphur bonds is 103°.
hope this helps
An interatomic distance of 2.19A exists between each germanium atom and the four sulphur atoms that are tetrahedrally connected to it. The two sulphur bonds form a 103° angle.
What is bond angle ?A complex molecule's or ion's bond angle is the angle between the two bonds, or the angle between two orbitals that contain bonding electron pairs surrounding the central atom. It is determined using a spectroscopic approach and measured in degrees.
Any angle between two bonds that share an atom is known as a bond angle, and it is often measured in degrees. The distance along the straight line between the nuclei of two bound atoms is known as a bond distance.
Bond angles also have a role on a molecule's structure. The angles between neighboring lines that form bonds are known as bond angles. The difference between linear, trigonal planar, tetrahedral, trigonal-bipyramidal, and octahedral crystals may be determined by the bond angle.
Thus, The two sulphur bonds form a 103° angle.
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Atomic mass is an average of the elements_____.
Specific chemical element
Answer:
The atomic mass of an element is the average mass of the atoms of an element measured in atomic mass unit (amu, also known as daltons, D). The atomic mass is a weighted average of all of the isotopes of that element, in which the mass of each isotope is multiplied by the abundance of that particular isotope.
Explanation:
g Element X is an element in period 4. Identify X given that in the molecule XH3. It exhibits hybridization sp3. WHat is the element
Answer:
XF3 is our compound. X is unknown For the problem I am using the periodic table at this ...
Explanation:Solution for Element X is an element in period 3. Identify X given that in the molecule XH3, it exhibits hybridization sp2 . Indicate the symbol and not ...
Two or more than two atoms with different physical or chemical properties can not combine together to form an element. The element X in period 4 with covalency 3 is Arsenic (As).
What is element?Element generally consist of atoms or we can atoms combine to form element. Atoms of an element is always same, means all the properties of all atoms of one type of element is same. The periodic table is divided into groups and periods. depending on the number of valence electrons and the number of outermost orbit respectively.
In the given compound XH[tex]_3[/tex], the covalency of X is 3, means the valence electrons in the outermost shell of element X is 3. The only group that have valence electron 3 is group 15 that is nitrogen family. In the fourth period of group 15 we find Arsenic element.
Therefore the element X in period 4 with covalency 3 is Arsenic (As).
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In chemical reactions, _______ always involves the release of energy during the reaction process.
a) the breaking of bonds
b) the formation of bonds
c) the addition of a catalyst
d) overcoming activation energy
Answer:
a. the breaking of bonds
Answer:
B
Explanation:
Hey, I am almost positive that the answer to this question is B. The breaking of bonds uses the energy but when they are created it releases energy. I hope this helps, Have a good day!
Radio waves bounce off of _____________ before returning to Earth
Answer: ionosphere
Explanation: First it bounces off a top layer of the atmosphere called the ionosphere, then it bounces back to the Earth (this is reflection. It then bounces up again to the ionosphere, and continues bouncing back again until it reaches the radio receiver. This is called a skywave, which works around 3 to 30 MHz.
A metal (FW 241.5 g/mol) crystallizes into a face-centered cubic unit cell and has a radius of 1.92 Angstrom. What is the density of this metal in g/cm3
This problem provides the molar mass and radius of a metal that has an FCC unit cell and the density is required.
Firstly, we begin with the formula that relates the aforementioned variables and also includes the Avogadro's number and the volume of the unit cell:
[tex]\rho=\frac{Z*M}{V*N_A}[/tex]
Whereas Z stands for the number of atoms in the unit cell, M the molar mass, V the volume and NA the Avogadro's number. Next, since FFC is able to hold 4 atoms and M and NA are given. Next, we calculate the volume of the atom in the unit given the radius in meters:
[tex]V=a^3=(2*1.92x10^-10m*\sqrt{2} )^3=1.60x10^{-28}m^3/atom[/tex]
And finally the required density in g/cm³:
[tex]\rho=\frac{4*241.5g/mol}{1.60x10^{-28}m^3/atom*6.022x10^{23}atom/mol} \\\\\rho=10025739g/m^3=10.03 g/cm^3[/tex]
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https://brainly.com/question/12977980https://brainly.com/question/13110055There are two unknowns in this problem - the mass of potassium carbonates and the mass of sodium carbonate. Let's designate the grams of potassium carbonate as our first unknown (you may want to call it gKcarb, or x, some other variable name that makes sense to you) and the grams of sodium carbonate as our second unknown(you may want to call it gNacarb, or y, some other variable name that makes sense to you). Set up an equation for the sum of your two unknowns. Starting with 'unknown' grams of potassium carbonate, use stoichiometry to calculate the number of moles of nitric acid that would react with the potassium carbonate. Your answer will have a variable for your unknown grams of potassium carbonate in it. Starting with 'unknown' grams of sodium carbonate, use stoichiometry to calculate the number of moles of nitric acid that would react with the sodium carbonate. Your answer will have a variable for your unknown grams of sodium carbonate in it. Set up an equation for what you get if you add these two quantities.
This problem, is describing two scenarios, the first one, a reaction between potassium carbonate and nitric acid, and also this very same acid with sodium carbonate. In addition, it is asked to set up two equations whereby you can get the grams of nitric acid needed to react with the unknown grams of both carbonates.
In this case, we can start off by designating the unknown mass of potassium carbonate as X and that of sodium carbonate as Y, so that we will be able to provide a reliable answer. Next, we write the corresponding chemical equations that take place:
K2CO3 + 2HNO3 --> 2KNO3 + H2O + CO2
Na2CO3 + 2HNO3 --> 2NaNO3 + H2O + CO2
After that, we can set up the conversion by considering the following calcultion track:
g Carbonate --> mol Carbonate --> mol HNO3 --> g HNO3
The conversion from grams to moles involve the carbonates' molar mass and the conversion from moles of nitric acid to grams, its molar mass well. In addition, we need the 1:2 mole ratio of the carbonates to nitric acid that it is evidenced in the reaction.
Therefore, the resulting equations that can be set up are shown as follows:
[tex]X g K_2CO_3 *\frac{1mol K_2CO_3 }{138.2 gK_2CO_3 } \frac{2molHNO_3}{1molK_2CO_3 } *\frac{63.1gHNO_3}{1molHNO_3} \\\\Y g Na_2CO_3 *\frac{1mol K_2CO_3 }{105.99 gK_2CO_3 } \frac{2molHNO_3}{1molNa_2CO_3 } *\frac{63.1gHNO_3}{1molHNO_3}[/tex]
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https://brainly.com/question/22889208https://brainly.com/question/24384921lons form because the loss of one or more electrons makes
them less stable than their corresponding atoms; this state
requires more energy to maintain.
TRUE
FALSE
This statement lons form because the loss of one or more electrons makes them less stable than their corresponding atoms; this state requires more energy to maintain is FALSE.
An ion forms when an atom loses or gains one more electrons. This loss or gain of electrons causes the ion to gain the stable octet configuration. This stable octet configuration requires less energy to maintain than the corresponding atom.So, since the stable octet configuration of the ion requires less energy than the corresponding atom, the statement is false.
So, the statement lons form because the loss of one or more electrons makes them less stable than their corresponding atoms; this state requires more energy to maintain is FALSE.
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A local water retention pond was found to have elevated mass concentration of mercury of 14 ng per liter. You would like to collect some mercury for your homemade perpetuum mobile machine. How many moles of mercury can you get you collect and process the entire volume of 1250 m3 of the water in the pond?
The number of moles of mercury can you get you collect and process the entire volume of 1250 m3 of the water in the pond is 8.7 × 10^-5 moles.
First, we must convert the concentration of mercury in the pond to molar concentration using the relation;
Mass concentration = Molar concentration × molar mass
Molar concentration = Mass concentration /molar mass
Molar mass of mercury = 201 g/mol
Molar concentration = 14 × 10^-9 g/201 g/mol = 6.97 × 10^-11 M
Volume of solution = 1250 m3 or 1250000 L
Number of moles = concentration × volume
Number of moles = 6.97 × 10^-11 M × 1250000 L
Number of moles = 8.7 × 10^-5 moles
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Calculate the number of molecules present in 11 moles of H2O.
Answer:
[tex]11 \times 6.022 \times {10}^{23} \\ = 66.242\times {10}^{23} \: of \: \\ water \: molecules[/tex]
Which stage of a fire can be described as follows: The flames are not visible and the combustible item no longer generates heat or combustion products
Fire extinguishment is referred to the stage in which flames are not visible
and the combustible item no longer generates heat.
This stage refers to when the fire has been put out through a fire
extinguisher or other compounds. When fire is put out, there is no longer
flames present.
The absence of flames also means that there is no heat generation or
combustion products due to the absence of a heat source.
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Grace wanted to find out the best conditions for growing lettuce plants.
She took 4 trays and planted 8 lettuce plants in each.
The results of her investigation are shown below.
How many days did the investigation last?
Use the table to help you.
Explanation:
the investigation lasts for 7 days.
hope this helps you.
A buffer solution was prepared by mixing 50.0 mL of a 0.100 M solution of CH3COOH with 0.500 grams of NaCH3COO. The resulting mixture is diluted to 100.0 mL. What is the pH of the solution
Answer:
100.0
Explanation:
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4. Use the atomic model to answer the following questions
A. How many protons?
B. How many neutrons?
C. What is the name of this atom?
Answer:
´protons: 16
neutrons: 16
name: sulfur
Explanation:
The elements chlorine and iodine have similar chemical properties
because they
Answer:
They are both halogens and have the same number of electrons on their outer shell.
Any element with 7 electrons in the outermost shell will have similar properties. Thus other elements in the same column of the periodic table as chlorine will have similar properties.
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The boiling point of a substance is tested. After 10 tests, the result is given as 37+/−3°C. Which conclusion can be drawn from this result? (1 point)
The scientists do not need to collect more data because they have narrowed down the range of the results.
The scientists should not report these results until they have the exact number.
The actual boiling point is either 34°C or 40°C.
The actual boiling point is probably between 34°C and 40°C.
Answer:
Explanation:
The actual boiling point is probably between 34C and 40C.
Temperature measures the average kinetic energy of particles of the substances. Therefore, the correct option is option D that is the actual boiling point is probably between 34°C and 40°C.
What is temperature?Temperature is used to measure degree or intensity of heat of a particular substance. Temperature is measured by an instrument called thermometer.
Temperature can be measured in degree Celsius °c, Kelvin k or in Fahrenheit. Temperature is a physical quantity. Heat always flow from higher temperature source to lower temperature source.
We can convert these units of temperature into one another. The relationship between degree Celsius and Fahrenheit can be expressed as:
°C={5(°F-32)}÷9
The actual boiling point is probably between 34°C and 40°C.
Therefore, the correct option is option D.
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Explain why caesium is more reactive than sodium.
You should answer in terms of electrons.