Answer:
∵
Explanation:
điện phân nóng chảy hoàn toàn 14,9 gam muối clorua của 1 kim loại kềm R thu đc 2,24 lít khí . R là kim loại gì ?
Answer:
d
Explanation:
nCl2 = 0,1 -> nRCI = 0,2
M muéi = R + 35,5 = 14,9/0,2
-> R = 39: R la K
Answer:
d
Explanation:
nCl2 = 0,1 -> nRCI = 0,2
M muéi = R + 35,5 = 14,9 / 0,2
-> R = 39: R la K
After mixing the solutions in a separatory funnel, the stopper should be ______ and the liquid should be _______ and the layers allowed to separate. When you get close to the interface between the layers, ______ the funnel and turn over _______ heat up until the first layer is collected get eye level with to collect the second layer. _______
Answer:
Hence,
1) removed
2) drained through the stopcock
3) get eye level with
4) slow the draining
5) switch to a new flask
Explanation:
After mixing the solutions in a separatory funnel, the stopper should be removed and the liquid should be drained through the stopcock, and the layers allowed to separate. When you get close to the interface between the layers, get eye level with the funnel and turn over to slow the draining heat up until the first layer is collected. Switch to a new flask get eye level with it to collect the second layer.
Stomach acid is approximately 0.10 M HCl. How many mL of stomach acid can be neutralized by one regular antacid tablet that contains 500 mg of solid CaCO3 (100.09 g/mol)?
Answer:
100 mL
Explanation:
The reaction that takes place is:
CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂First we convert 500 mg of CaCO₃ into mmoles, using its molar mass:
500 mg ÷ 100 mg/mmol = 5 mmol CaCO₃Then we convert 5 mmoles of CaCO₃ into HCl mmoles, using the stoichiometric coefficients of the balanced reaction:
5 mmol CaCO₃ * [tex]\frac{2mmolHCl}{1mmolCaCO_3}[/tex] = 10 mmol HClFinally we calculate the volume of a 0.10 M HCl solution (such as stomach acid) that would contain 10 mmoles:
10 mmol / 0.10 M = 100 mLWrite any two drawbacks of the octet theory.
Answer:
Octet rule fails to explain the following:
(1) The stability of incomplete octet molecules, i.e., the molecules with the central atom containing less than eight electrons. (2) The stability of expanded octet molecules, i.e., the molecules with the central atom containing more than eight electrons.
Consider these two cases.
Case 1: An electron jumps from energy level 1 to energy level 2 in an atom.
Case 2: An electron jumps from energy level 1 to energy level 3 in an atom.
For case 1, what happens when an electron jumps from energy level 1 to energy level 3 in an atom?
A. A photon is absorbed by the atom.
B. A photon is emitted by the atom.
C. A proton is absorbed by the atom.
D. A proton is emitted by the atom.
Assuming that both cases describe Hydrogen-like atoms with one electron, for which case is more energy emitted or absorbed?
A. The energy is the same for both cases.
B. More energy is emitted or absorbed for case 2
C. It is impossible to tell.
D. More energy is emitted or absorbed for case 1
Answer:
A photon is absorbed by the atom.
More energy is emitted or absorbed for case 2
Explanation:
According to the Bohr model of the atom, electrons occur in energy levels. The energy of each level is fixed. However, electrons can absorb photons and move from a lower to higher energy level or emit photons and move from a higher to a lower energy level.
In each case, the energy absorbed or emitted is equal to the difference in energy between the two energy levels.
Since energy level 3 is much higher than energy level 2, the electron absorbs more energy in moving from energy level 1 to energy level 3 than it absorbs when moving from energy level 1 to energy level 2.
What is the oxidation (charge) number of tin in Sno?
Ο Α. -2
OB. +4
O C. +2
O D. 4
Explanation:
+2
hope it helps................
GC-mass spectrometry is used to find the ________ of each compound in a ________. Group of answer choices none of these molecular formula, mixture of compounds molecular weight, mixture of compounds B and C molecular formula, mixture of alkanes
Answer:
mixture of compounds molecular weight
Explanation:
Gas Chromatography-mass spectrometry is used to find the mixture of compounds of each compound in a molecular weight. The Gas Chromatography also known as Mass Spectrometry (GC/MS) is an instrument that is used to separate chemical mixtures and identifies the components at a molecular level. It is one of the most accurate tools used for analyzing samples of the environment.
Sodium fluoroacetate (NaO₂C₂H₂F) is a common poison used in New Zealand to control invasive species, such as rats. It can be prepared by the substitution of a C-Cl bond in sodium chloroacetate (NaO₂C₂H₂Cl) for a C-F bond. What is the approximate enthalpy change for this substitution reaction on a 1.500 mole sample, based on the following bond energies?
C-Cl = 339.0 kJ/mol
C-F = 485.0 kJ/mol
Answer:
-219
Explanation:
1.5(339) - 1.5(485) = -219
The approximate enthalpy change for this substitution reaction is -219 kJ.
In the case of this substitution reaction, we need to find the enthalpy change when NaO₂C₂H₂Cl is converted to NaO₂C₂H₂F.
This reaction involves the breaking of the C-Cl bond and the formation of the C-F bond.
We have to subtract the bond energy of the C-F bond from that of the C-Cl bond and multiply by the number of moles involved.
So we will have;
ΔH= 1.500 mole [339.0 kJ/mol - 485.0 kJ/mol]
ΔH= -219 kJ
Learn more: https://brainly.com/question/1301642
What waves are used to send signals because they can travel over very long distances and pass through buildings
Answer:
sound waves for used I think
Taxol is a potent chemotherapeutic agent (isolated from the Pacific Yew tree) which is especially effective against ovarian cancer. Which functional groups is not contained in taxol?
Answer:
Amine
Explanation:
The functional groups contained in Taxol are :
Ketone , Ester, Amide and Alcohol
while the functional group that is not contained in the Taxol is Amine
Taxol is a very potent anti-cancer chemotherapeutic, and it is also groped into a class called Taxanes and this makes it effective in the treatment of breast and ovarian cancer.
Guide Questions:
1. How do you compare the distance travelled by the object
when you pushed it with a weak/gentle, strong and
strongest?
Refle
2. Which amount of force applied made the materials travelled
the farthest from the starting point. Nearest the starting
point?
3. What factors do you think affected the movement of the
materials?
Answer:
Kindly check explanation
Explanation:
The force applied is directly proportional to the distance moved by an object, the larger the applied force, the greater the distance moved.
a = f/m
a = acceleration ; f = applied force ; m = mass
From the relation, we can see that acceleration is directly proportional to force applied.
The ball will travel farthest with the greatest applied force while, nearest distance will be attained with the smallest applied force.
The distance covered is affected by both the mass of the object and the applied force
Name the following ketone:
여 o
A. cyclohexyne
B. cyclohexanal
C. cyclohexanol
D. cyclohexanone
Answer:
It is D).cyclohexanone ( in acellus)
Explanation:
To determine the enthalpy and entropy of dissolving a compound, you need to measure the Ksp at multiple _______. Then, plot ln(Ksp) vs. ______. The slope of the plotted line relates to the _______ of dissolving and the intercept of the plotted line relates to the ______ of dissolving.
Answer:
To determine the enthalpy and entropy of dissolving a compound, you need to measure the Ksp at multiple temperatures. Then, plot ln(Ksp) vs. 1/T. The slope of the plotted line relates to the enthalpy (ΔH) of dissolving and the intercept of the plotted line relates to the entropy (ΔS) of dissolving.
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us use the thermodynamic definition of the Gibbs free energy and its relationship with Ksp as follows:
[tex]\Delta G=-RTln(Ksp)\\\\\Delta G=\Delta H-T\Delta S[/tex]
Thus, by combining them, we obtain:
[tex]-RTln(Ksp)=\Delta H-T\Delta S\\\\ln(Ksp)=-\frac{\Delta H}{RT} +\frac{T\Delta S}{RT} \\\\ln(Ksp)=-\frac{\Delta H}{RT} +\frac{\Delta S}{R}[/tex]
Which is related to the general line equation:
[tex]y=mx+b[/tex]
Whereas:
[tex]y=ln(Ksp)\\\\m=-\frac{\Delta H}{R} \\\\x=\frac{1}{T} \\\\b=\frac{\Delta S}{R}[/tex]
It means that we answer to the blanks as follows:
To determine the enthalpy and entropy of dissolving a compound, you need to measure the Ksp at multiple temperatures. Then, plot ln(Ksp) vs. 1/T. The slope of the plotted line relates to the enthalpy (ΔH) of dissolving and the intercept of the plotted line relates to the entropy (ΔS) of dissolving.
Regards!
Classify each amino acid by the chemical properties of its side chain (R group) at pH 7 . Select the amino acid that fits best in each category. Each amino acid will be selected only once. Which amino acid has a positively charged R group
Answer: The amino acid that has a positively charged R group are LYSINE and ARGININE.
Explanation:
AMINO ACIDS are the basic structural units of proteins. Each amino acid contains an amino group ( -NH2) and a carboxyl group (-COOH) in its molecule. The carbon atom of amino acid to which the functional groups are attached is know as the alpha-carbon. In neutral solution, amino acids are mainly in the form of dipolar ions. Amino acids can be prepared through hydrolysis of protein by boiling with dilute hydrochloric acid.
Amino acids can be classified according to the chemical properties of its side chain (R group) at pH 7, these include:
--> Amino acids with POSITIVELY CHARGED R group
--> Amino acids with negatively charged R group
--> Amino acids with neutral polar R group
--> Amino acids with nonpolar aliphatic R group.
Amino acids with POSITIVELY CHARGED R group are those amino acids that has side chains which contain nitrogen and resemble ammonia, which is a base. Their pKa's are high enough that they tend to bind protons, gaining a positive charge in the process. Example include LYSINE and ARGININE.
Suppose a piece of silver jewelry contains 7.49x10^22 atoms of silver (Ag). how many moles of silver are in the jewelry?
Answer:
0.124 mol Ag
General Formulas and Concepts:
Atomic Structure
MolesStoichiometry
Using Dimensional AnalysisExplanation:
Step 1: Define
[Given] 7.49 × 10²² atoms Ag
[Solve] mol Ag
Step 2: Identify Conversions
Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.
Step 3: Convert
[DA] Set up: [tex]\displaystyle 7.49 \cdot 10^{22} \ atoms \ Ag(\frac{1 \ mol \ Ag}{6.022 \cdot 10^{23} \ atoms \ Ag})[/tex][DA] Divide [Cancel out units]: [tex]\displaystyle 0.124377 \ mol \ Ag[/tex]Step 4: Check
Follow sig fig rules and round. We are given 3 sig figs.
0.124377 mol Ag ≈ 0.124 mol Ag
Topic: AP Chemistry
I am holding a balloon containing 439 mL of gas over my fireplace. The temperature and pressure of the gas inside the balloon is 317.15 K and 0.959 atm, respectively. Suppose I don't want the pressure to change, but I want to the volume to go down to 0.378 L. What is the temperature that I need to reach when I cool down the balloon?
To what temperature (in Celsius) must the balloon be cooled to reduce its volume to 0.378 L if the pressure doesn't change (remained constant)?
Answer:
-0.08 °C
Explanation:
We can solve this problem by using Charles' law, which states that at constant pressure:
V₁T₂ = V₂T₁Where in this case:
V₁ = 439 mLT₂ = ?V₂ = 0.378 L ⇒ 0.378 * 1000 = 378 mLT₁ = 317.15 KWe input the data:
439 mL * T₂ = 378 mL * 317.15 KAnd solve for T₂:
T₂ = 273.08 KFinally we convert 273.08 K to Celsius:
273.08 K - 273.16 = -0.08 °CSelenium, an element used in the manufacture of solar energy devices, forms an oxide that contains only one atom of selenium (SeOx) and is 37.8% oxygen by mass. What is the molecular formula of the oxide? (Hint: find “x”)
Answer: The molecular formula of the compound will be [tex]SeO_3[/tex]
Explanation:
The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
Let the mass of the compound be 100 g
Given values:
% of O = 37.8%
% of Se = [100 - 37.8] = 62.2%
Mass of O = 37.8 g
Mass of Se = 62.2 g
We know:
Molar mass of Se = 79 g/mol
Molar mass of O = 16 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of Se}=\frac{62.2g}{79g/mol}=0.787 mol[/tex]
[tex]\text{Moles of O}=\frac{37.8g}{16g/mol}=2.36 mol[/tex]
Calculating the mole fraction of each element by dividing the calculated moles by the least calculated number of moles that is 0.787 moles
[tex]\text{Mole fraction of Se}=\frac{0.787 }{0.787 }=1[/tex]
[tex]\text{Mole fraction of O}=\frac{2.36}{0.787 }=2.99\approx 3[/tex]
Taking the mole ratio as their subscripts.
The ratio of Se : O = 1 : 3
Hence, the molecular formula of the compound will be [tex]SeO_3[/tex]
What mass of hydrochloric acid that reacted with zinc will produced 0.15dm3 of hydrogen at st.p? Equation for this reaction:
Zn + 2HCl ------> ZnCl2 + H2
Answer:
[tex]{ \tt{22.4 \: dm {}^{3} \: contains \: 1 \: mole \: of \: hydrogen }} \\ { \tt{0.15 \: {dm}^{3} \: will \: contain \: ( \frac{0.15}{22.4} \times 1) \: moles }} \\ = 0.0067 \: moles \\ { \bf{mole \: ratio = 1 :1 }} \\ { \tt{1 \: mole \: weighs \: 65.38 \: g}} \\ { \tt{0.0067 \: moles \: weighs \: (0.0067 \times 65.38) \: g}} \\ = 0.44 \: g[/tex]
the total pressure in a mixture of gases is equal to the partial pressures of
Answer:
"The total pressure in a mixture of gases is equal to the sum of partial pressures of each gas"
Explanation:
Dalton's law of partial pressures state that, in a mixture of gases, the total pressure is equal to the sum of the partial pressure exerted by each gas of the mixture. The equation is:
Total pressure = Partial pressure Gas 1 + Partial pressure Gas 2 + .... + Partial pressure Gas n
To complete the sentence we can say:
"The total pressure in a mixture of gases is equal to the sum of partial pressures of each gas"
Considering the Dalton's partial pressure, the total pressure in a mixture of gases is equal to the sum of partial pressures of each gas.
The pressure exerted by a particular gas in a mixture is known as its partial pressure. So, Dalton's law states that the total pressure of a gas mixture is equal to the sum of the pressures that each gas would exert if it were alone:
[tex]P_{T} =P_{A} +P_{B}[/tex]
This relationship is due to the assumption that there are no attractive forces between the gases.
Dalton's partial pressure law can also be expressed in terms of the mole fraction of the gas in the mixture. The mole fraction is a dimensionless quantity that expresses the ratio of the number of moles of a component to the number of moles of all the components present.
So in a mixture of two or more gases, the partial pressure of gas A can be expressed as:
[tex]P_{A} =x_{A} P_{T}[/tex]
In summary, the total pressure in a mixture of gases is equal to the sum of partial pressures of each gas.
Learn more:
https://brainly.com/question/14239096?referrer=searchResultshttps://brainly.com/question/25181467?referrer=searchResultshttps://brainly.com/question/14119417Help for both questions please and thanks
Answer:
hey can you re post this and zoom in i can see what it say its not allowing me to zoom thx
Explanation:
Select the statement(s) that describe the characteristics of transition metals. a. Transition metals have partially filled d subshells. b. Transition metals give rise to cations that have completely filled d subshells. c. Group 2B elements are not transition metals because they neither have nor readily acquire partially filled d orbitals.
Answer: The correct option is A,
--> a.) Transition metals have partially filled d subshells.
Explanation:
Transition elements are all metals of economic importance. They are found in the d- lock of the periodic table between group 2 and 3. They occupy three rows, with ten elements in each row. The term 'transition metals' refers only to an element which has PARTIALLY filled d orbitals. Typical example of transition metals include iron (Fe).
They have partially filled 3d orbitals which are responsible for the special properties of the metals. These include:
--> Physical properties: the transition metals have high boiling and melting points. They are hard, dense and lustrous. They are also good conductors of heat and electricity.
--> Chemical reactivity: In the s- block and p-block, the chemical properties of the elements in the same period vary, often quite markedly, from left to right. This does not happen with the transition metals because electrons are added progressively to the inner d-orbitals.
--> Variable oxidation states: they have variable oxidation states because 3d electrons are available for bond formation.
Solids that have particles arranged in a regular, repeating patterns are known as crystalline solids.
True or False
Answer: The answer is false
Explanation:
they are arranged in a structure
called a crystalline.
Ch3-ch2-o-ch2-ch2-och3
Explanation:
ethoxypropane
Ch3-ch2-o-ch2-ch2-och3
What is the pH of a solution with a 7.8 × 10−13 M hydronium ion concentration?
A) 1.9
B) 2.8
C) 11
D) 12
Answer:
12Explanation:
The pH of a solution can be found by using the formula
[tex]pH = - log [ { H_3O}^{+}][/tex]
From the question we have
[tex]ph = - log(7.8 \times {10}^{ - 13} ) \\ = 12.1079...[/tex]
We have the final answer as
12Hope this helps you
The pH of this solution with a 7.8 × 10⁻¹³ M concentration of hydronium ion is equal to: D. 12.
Given the following data:
Concentration of hydronium ion = 7.8 × 10⁻¹³ M.
What is pH?pH is literally the power of hydrogen ions and it can be defined as a measure of the molar concentration of hydrogen ions in a given solution.
How to calculate the pH of a solution?We would determine the pH of this solution by using this formula;
pH = -log[H⁺]
pH = -log(7.8 × 10⁻¹³).
pH = -(-12.1)
pH = 12.1 ≈ 12.
Read more on pH here: brainly.com/question/24233266
#SJP2
When H2S(g) reacts with O2(g) to form H2O(g) and SO2(g), 124 kcal of energy are evolved for each mole of H2S(g) that reacts. Write a balanced equation for the reaction with an energy term in kcal as part of the equation.
Answer:
2H2S(g) + 3O2(g) → 2H2O(g) + 2SO2(g) + 248kcal
Explanation:
The reaction of the problem occurs as follows:
H2S(g) + O2(g) → H2O(g) + SO2(g)
To balance the reaction we must balance oxygens:
H2S(g) + 3O2(g) → 2H2O(g) + 2SO2(g)
To balance the complete reaction:
2H2S(g) + 3O2(g) → 2H2O(g) + 2SO2(g)
As the energy is evolved, 124kcal are as product in the reactio per mole of H2S. As the balanced reaction contains 2 moles of H2S, the heat evolved is:
124kcal*2 = 248kcal:
2H2S(g) + 3O2(g) → 2H2O(g) + 2SO2(g) + 248kcal
And this is the balanced equation
Which of these is a model that
represents valence electrons in
an atom as dots around the
element's chemical symbol?
g The most stable nucleon in terms of binding energy per nucleon is 56Fe. If the atomic mass of Fe-56 is 55.9349 amu, calculate the binding energy in J/nucleon and in Mev/nucleon for Fe-56. The atomic mass of a proton is 1.00782 amu and the atomic mass of a neutron is 1.00866 amu. Would the binding energy per nucleon for U-235 be larger or smaller than that of Fe-56
Answer:
The binding energy per nucleon of U-235 is lesser than that Fe-56
Explanation:
The binding energy refers to the energy required to hold the nucleons together in the nucleus of an atom.
It also corresponds to the energy that must be supplied in order to disintegrate the nucleus of an atom.
The binding energy per nucleon of elements depends on the number of nucleons present in the nucleus of the atom of that element. It is defined as the binding energy of the nucleus divided by the number of nucleons.
U-235 contains more nucleons than Fe-56, the binding energy per nucleon of U-235 is less than that of Fe-56. This is further confirmed by the fact that the greater the number of protons in the nucleus, the greater the coulumbic repulsion in the nucleus and the lesser the nuclear force of attraction between nucleons.
A TLC plate showed 2 spots with Rf values of 0.25 and 0.26. The plate was removed from the developing chamber, the residual solvent was allowed to evaporate from the plate, and then the plate was returned to the developing chamber. What would you expect to see after the second development was complete
Answer:
See explanation
Explanation:
TLC is a chromatographic method in which the solute is spotted on a plate and the plate is placed in an air tight chamber containing a solvent. The solvent is maintained below the level of the spot. The capillary movement of the solvent through the plate achieves the required separation.
If two spots have Rf values of 0.25 and 0.26 respectively and then the plate was removed from the developing chamber, subsequently, the residual solvent was allowed to evaporate from the plate, and then the plate was returned to the developing chamber.
It will be observed after the second development is complete that the new Rf values will be 0.50 and 0.52 respectively. It will just be as though the second chromatogram picked up from where the first chromatogram stopped.
According to the equation 2K(s) + CI2(g) 2kCI(s), potassium reacts with chlorine to form potassium chlorine. If 100 atoms of potassium react with chlorine gas, how many chlorine molecules will be needed to completely react?
Answer:
50 CI₂ molecules
Explanation:
2K(s) + CI₂(g) → 2KCI(s)By looking at the stoichiometric coefficients, we can tell that if 2 atoms of potassium (K) react with chlorine gas (CI₂), 1 chlorine molecule would react.
With that in mind we can calculate how many CI₂ molecules would react with 100 K atoms:
100 atoms K *[tex]\frac{1Cl_2Molecule}{2KAtom}[/tex] = 50 CI₂ molecules4. After reaching the final titration endpoint the solution will be cloudy white. As time goes on the solution will turn back to a cloudy dark purple color. Why does this occur if you have already reached the endpoint
Answer: hello some part of your question is missing below is the missing part
In an experiment to determine the % of ascorbic acid in Vitamin C Tablets by Titration with Potassium Bromate,
answer:
Oxidation half reaction of Vitamin C
Explanation:
The solution will turn cloudy dark purple even after reaching endpoint when allowed to settle with time. because of the Oxidation half reaction of Vitamin C. also during the Titration process few drops of starch solution will be added to help determine the endpoint of the experiment .
