Answer:
D . GOD BLESS .
Explanation:
1: Given that Ka for HCOOH is 1.8×10^-4 at 25°C what is the value of b for COOH− at 25 °C?
Kb=
2: Given that b for (CH3)2 NH is 5.4×10^-4 at 25°C, what is the value of Ka for (CH3)2NH+2 at 25 °C?
Ka=
Explanation:
At 25 °C Dissociation constant of water or Kw = 1× 10^-14 mol2dm-6
Ka × Kb = Kw for all diluted solutions
Ka×Kb = 1 × 10^-14 mol2dm-6
Therefore for question 1 -
COOH- is the conjugate base for HCOOH ( we find the conjugate base by removing an H atom and the Conjugate acid by adding an H atom)
COOH- (aq) + H2O ( l) <-----> HCOOH( aq) + OH-(aq)
So we can apply the above mentioned equation to find Kb value for COOH-
Kb = 5.56 × 10^-11 moldm-3
For question 2-
We can see that (CH3)2NH+2 is the conjugate acid of (CH3)2 NH. (A H atom has been removed so the one with a H atom less is the conjugate base.)
(CH3)2NH+2 (aq) + H2O (l) <-----> (CH3)2 NH (aq) + H3O+ (aq)
So applying the previously mentioned equation we get Ka = 1.85 × 10^-11 moldm-3
Describe your observations when the paper clip was gently crushed with the pestle
Answer:
We can do an experiment with vinegar to see what happens to the calcium in an eggshell when it is exposed to an acid.
Can anybody complete this for me?
Answer:
I wish i could
Explanation:
as the solar nebula cooled which compounds were the first to condense from a gas to a solid? Rock water ice or metal
As the solar nebula cooled METAL compounds are the first to condense from a gas to a solid. The solar nebula gave birth to the Solar system.
A solar nebula is a disc-shaped cloud of gases and grain dust, which gave birth to the Sun and planets of the Solar system, approximately 4.6 billion years ago.
The solar nebula is at the beginning a mixture of interstellar gases (hydrogen and helium) and dust grains.
As the solar nebula cools, heavy elements such as metals in the disk condensate into planetesimals.
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pls help me right now
Answer:
LETTER
1. D. PURE SUBSTANCES CAN BE FURTHER BROKEN DOWN INTO SIMPLER SUBSTANCES.
2.A
PO PLEASE MARK A BRAINLIESTS ANG MARK A 5 STAR ANG HEART PO PLEASW
What instruments are used to measure moleculars vibration , rotation and translation?
Answer:
you hear
Explanation:
beautiful hear can be wonderful day in your life so to be rotations is not a big deal
2. What pressure is required to compress 196.0 L of air at 1.00 atmosphere into a cylinder
whose volume is 26 0 L? (2 points)
Answer:
7.54 atmExplanation:
The required pressure can be found by using the formula for Boyle's law which is
[tex]P_2 = \frac{P_1V_1}{V_2} \\[/tex]
where
P1 is the initial pressure
P2 is the final pressure
V1 is the initial volume
V2 is the final volume
From the question we have
[tex]P_2 = \frac{1 \times 196}{26} = \frac{196}{26} \\ = 7.538461...[/tex]
We have the final answer as
7.54 atmHope this helps you
To what volume would you have to change 6.5 Liters of a gas at 1.25 atm in order to
decrease its pressure to 1.0 atm?
Answer:
8.13 mLExplanation:
The required volume can be found by using the formula for Boyle's law
[tex]V_2 = \frac{P_1V_1}{P_2} \\[/tex]
where
P1 is the initial pressure
P2 is the final pressure
V1 is the initial volume
V2 is the final volume
From the question we have
[tex]V_2 = \frac{6.5 \times 1.25}{1} = 6.5 \times 1.25 \\ = 8.125[/tex]
We have the final answer as
8.13 mLHope this helps you
từ một dung dịch có pH=7 muốn tạo thành dung dịch có pH nhỏ hơn 7 thì cho vào dung dịch
Answer:
you lift my feet off the ground spin me around you make me crazier crazier
After being placed on the table where should the ocular lenses face?
What is the mass in grams of one mole of sulfur? (round to 3 sig figs)
Answer:
This tells you that one mole of sulfur atoms, S , has a mass of 32 g
answer this please thank you
Answer:
Explanation:
D is the correct answer
When the pressure of a gas decreases, which quantity will increase, assuming all other variables are held constant?
OR
ОТ
On
OV
I don't think the answer is in one of the options- unless I am reading it wrong and there is a 'V' option.
The volume (V) of gas increases when the pressure of the gas decreases assuming all the other variables are held constant.
I hope this helps!
Calculate the moles of HCl in 15 mL of a 0.50 M solution.
Explanation:
[tex]\tiny\implies Molarity = \dfrac{no. \: of \: moles \: of \: solute \times 1000}{volume \: of \: the \: solution \: (in \: ml)} [/tex]
[tex]\tiny\implies 0.50 = \dfrac{no. \: of \: moles \: of \: solute \times 1000}{15}[/tex]
[tex]\tiny\implies no. \: of \: moles \: of \: solute \times 1000 = 0.50 \times 15[/tex]
[tex]\tiny\implies no. \: of \: moles \: of \: solute \times 1000 = 7.5[/tex]
[tex]\tiny\implies no. \: of \: moles \: of \: solute = \dfrac{7.5}{1000} [/tex]
[tex]\tiny\implies \bf no. \: of \: moles \: of \: solute = 0.075 \: mol[/tex]
Which of the following is NOT a type of evidence indicating that a chemical change has occurred? *
- fizzing/bubbling
- heat is released
- solubility
- sound is given off
Answer:
sound is given off
Explanation:
due to a number of scientific research sound that is given off of an object is not due to a chemical reaction.
Which statement best describes a mechanical wave?
Answer:
A mechanical wave is a wave that is an oscillation of matter, and therefore transfers energy through a medium.
Explanation:
While waves can move over long distances, the movement of the medium of transmission—the material—is limited. Therefore, the oscillating material does not move far from its initial equilibrium position.
--------------
hope this helped!
✼-answers by brookeangelx
The wave transmits energy from one point to another in the form of signals. Some waves require a medium for propagation while some others does not require a medium for the propagation.
What is a mechanical wave?The mechanical wave is defined as the wave which involves the oscillation of matter and it is responsible for the transfer of energy through a medium. These types of waves does not need a medium for propagation.
The mechanical waves cannot travel through vacuum. Some of the examples of mechanical waves are sound waves, water waves, seismic waves, etc. These waves are not capable of transmitting its energy through a vacuum.
The sound wave is a mechanical wave and the medium which it propagates can be solid, liquid or gas. It can travel fastest in solids and slower in gases.
Thus mechanical wave is an oscillation of matter.
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Problem 07.020 - Heat transferred from cold to hot reservoir Assume that heat in the amount of 100 kJ is transferred from a cold reservoir at 600 K to a hot reservoir at 1050 K contrary to the Clausius statement of the second law. What is the total entropy change
This problem is describing a system in which 100 kJ of energy is transferred from a cold reservior at 600 K to a hot one at 1050 K. This situation is opposed to the Clausius statement of the second law of thermodynamics, because it is widely known that heat is transferred from hot to cold systems.
However, we can calculate the total entropy change by using the following formula:
[tex]\Delta S =\Delta S _{Low}+\Delta S _{High}[/tex]
Which is broken down as follows:
[tex]\Delta S =\frac{-Q}{T_{Low}} + \frac{Q}{T_{High}}\\\\\\\Delta S =Q(\frac{-1}{T_{Low}} + \frac{1}{T_{High}})[/tex]
Since the heat is assumed to be equal for the both of them. Then, we plug in the given heat and temperatures to obtain:
[tex]\Delta S =100kJ(\frac{-1}{600K} + \frac{1}{1050K})\\\\\Delta S =-0.0714\frac{kJ}{K}[/tex]
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https://brainly.com/question/17145614https://brainly.com/question/13999732Calculate how many moles are in 63.1 grams FeCl3.
Answer: 1 grams FeCl3 = 0.0061650760770388 mole using the molecular weight calculator and the molar mass of FeCl3.
Explanation:
If such an ion is negatively charged and includes one or more oxygen atoms
Answer:
atom
Explanation:
The sodium atom has a single valence electron that it can easily lose. (If the sodium atom loses its valence electron, it achieves the stable electron configuration of neon.) The chlorine atom has seven valence electrons and can easily gain one electron.
which two types of food are homogeneous mixtures
A. mustard
B. mayonnaise
C. tossed salad
D. trail mix
the process of breaking food is to release energy is called _____
Answer:
The process by which food is broken down to release energy is called respiration
I hope it helps.
Answer:
Respiration
Explanation:
hope this helps.
explain in details what a matter is...!!!
Answer:
umm
Explanation:
matter makes up everything. everything is matter
the more matter an object has the more mass It has
Hot air balloons are open at their lower and end. A basket is suspended from the balloon and can take several passengers as well as the pilot. A propane burner fixed to the basket is used to heat up the air in the balloon A hot balloon has a volume of 1500 m3 and its volume does not change when the enclosed air is heated.
1) Use the ideal gas equation, pV=nRT. to calculate how many molecules of the balloon contains at a temperature of 10 °C and a pressure 10.1 KP.
2) Calculate the mass of air it contains, assuming an average M of 29.
(a) The number of molecules contained by the balloon at the given condition is 6,438.97 moles.
(b) The mass of air in the balloon is 186.73 kg.
The given parameters;
volume of the balloon, V = 1500 m³temperature, T = 10⁰C = 273 + 10 = 283 Kpressure, = P = 10.1 kPa = 10,100 PaThe number of molecules contained by the balloon at the given condition is calculated as follows;
[tex]PV = nRT[/tex]
where;
R is ideal gas constant = 8.314 J/mol.Kn is the number of moles air in the balloon;[tex]n = \frac{PV}{RT} \\\\n = \frac{10,100 \times 1500}{8.314 \times 283} \\\\n = 6,438.97 \ moles[/tex]
The mass of air in the balloon is calculated as;
[tex]n = \frac{m}{M} \\\\m = nM\\\\m = 6,438.97\ moles \ \times \ 29 \ g/mol\\\\m = 186.73 \ kg[/tex]
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In this photograph, a soccer player is about to kick the ball. Use the situation to explain that when two objects interact, the force between them can cause energy to be transferred. In your response, identify the type of energy that each object has before they interact, the forces exerted when the objects interact, and the type of energy that each object has after they interact.
The explanation to the question is stated as follows:
Newton's first law of motion states that: a body will continue in its state of rest or uniform motion unless an external force acts on it. So then, the ball initially possesses potential energy because it was at rest. While the leg of the soccer player possesses kinetic energy because its in motion.
Thus, when the player hits the ball, a force known as push has been applied. This would ensure that the ball compels and moves in the direction of the applied force. Therefore after the interaction, the leg of the player now possesses potential energy, since it would come to rest after hitting the ball. While the ball would start moving, now possessing kinetic energy.
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Convert the heat of neutralization of acetic acid from -49,8 kj/mmol to calories per
millimole and ROUND TO ONE DECIMAL PLACE (1 cal = 4.184 J)
DO NOT INCLUDE UNITS
This question is providing the exothermic heat of neutralization of acetic acid in units of kilojoules per mollimole (-49,8 kj/mmol) and asks for the same value but in calories per millimole which results -11,902.5 cal/mmol.
In this case, according to the given problem, it turns out necessary to solve a two-factor conversion in order to convert the kilojoules to joules and finally to calories as shown below:
[tex]-49.8\frac{kJ}{mmol}*\frac{1000J}{1kJ}*\frac{1cal}{4.184J}[/tex]
Thus, we cancel out the kJ and J, to obtain the following result, rounded to one decimal place:
[tex]-11,902.5\frac{cal}{mmol}[/tex]
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https://brainly.com/question/2731380https://brainly.com/question/2921187A 14.0 L container at 323 K holds a mixture of two gases with a total pressure of 8.00 atm. If there are 1.50 mol of Gas A in the mixture, how many moles of Gas B are present
The number of moles of gas B present in the gas mixture is 2.72 moles.
The given parameters;
Volume of the gases, V = 14 LTemperature of the gases, T = 323 KTotal pressure of the gases, P = 8 atmNumber of moles of gas A = 1.5 molesThe total number of moles of the gases is calculated by applying ideal gas law;
PV = nRT
where;
R is ideal gas constant = 0.0821 L.atm./mol.K
n is the total mole of the gases
[tex]n =\frac{PV}{RT} \\\\n = \frac{8 \times 14}{0.0821 \times 323} \\\\n = 4.22 \ moles[/tex]
The number of moles of gas B is calculated as follows;
[tex]n_B = 4.22 - n_A\\\\n_B = 4.22 - 1.5\\\\n_B = 2.72 \ moles[/tex]
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A hydrochloric acid solution is standardized by titrating 0.2329 g of primary standard sodium carbonate to a methyl red end point by boiling the carbonate solution near the end point to remove carbon dioxide. If 42.87 mL acid is required for the titration, what is its molarity
HELP
The molarity of the acid, HCl solution is 0.103 M
We'll begin by calculating the number of mole in 0.2329 g of Na₂CO₃
Mass of Na₂CO₃ = 0.2329 g
Molar mass of Na₂CO₃ = (23×2) + 12 + (16×3) = 106 g/mol
Mole of Na₂CO₃ =?Mole = mass / molar mass
Mole of Na₂CO₃ = 0.2329 / 106
Mole of Na₂CO₃ = 0.0022 mole Next, we shall determine the number of mole of HCl needed to react with 0.0022 mole of Na₂CO₃Na₂CO₃ + 2HCl —> 2NaCl + H₂O + CO₂
From the balanced equation above,
1 mole of Na₂CO₃ reacted with 2 moles of HCl.
Therefore,
0.0022 mole of Na₂CO₃ will react with = 0.0022 × 2 = 0.0044 mole of HCl
Finally, we shall determine the molarity of the HCl.Mole of HCl = 0.0044 mole
Volume = 42.87 mL = 42.87 / 1000 = 0.04287 L
Molarity of HCl =?Molarity = mole / Volume
Molarity of HCl = 0.0044 / 0.04287
Molarity of HCl = 0.103 MThus, the molarity of the acid, HCl solution is 0.103 M
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A 15.0-L vessel contains 0.50 mol CH4 with a pressure of 1.0 atm. After 0.50 mol C2H6 is added to the vessel, what is the partial pressure of CH4? The temperature remains unchanged throughout the process.
Answer: Hi! The partial pressure of CH4 is
=1 atm
Explanation:
The partial pressure of methane in the mixture of methane and ethane has been 1 atm.
Partial pressure has been the pressure exerted by a gas in the solution or mixture. The partial pressure of each gas has been the total pressure of the gaseous mixture.
The partial pressure of the gas has been dependent on the volume, temperature, and concentration of the gas.
The given methane has a partial pressure of 1 atm in the 15 L vessel. The addition of ethane results in the change in the total pressure of the mixture, as there have been additional moles of solute that contributes to the solution pressure.
However, since there has been no change in the concentration and volume of methane, the pressure exerted by methane has been the same. Thus, the partial pressure of methane has been 1 atm.
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Given the ionic formula below, what is the charge on ion X? Be sure to
include the sign (+ or -). Li2 x
Answer:Charge on X = (+ 2)
Explanation:
Charge on one Cl = -1
So Charge on two Cl = -2
The molecule = Neutral = 0 charge
So, to make total charge = 0 , the X should have +2 charge
XCl2 = +2 -2 = 0
X = +2
Alkaline earth metals(Be , Mg , Ca , Sr) form such type of compounds
Explanation:
Bethany observes a white crystal that is cube shaped under a microscope.
Based on this observation, Bethany thinks the crystal could be sodium chloride, or table
salt. Because the crystal has an extended structure, she knows that sodium chloride is
not a molecule. Bethany uses gray and white spheres, representing the atoms in
sodium chloride, to make a model of the crystal’s most likely structure, as shown.
a. Provide two reasons why the model accurately represents sodium chloride. Support
your reasons with evidence from the model.
b. Predict whether the melting point should be high or low based on the model.
Answer:
In nature there are many different minerals we call "Salts". If you look very closely at the particles of table salt, you will find little cubic crystals. These salt crystals are made of sodium chloride (NaCl), and their cubic shape is due to a very specific arrangement of the atoms. As discussed earlier, all of the minerals classified as salts are held together through ionic bonds. The arrangement of atoms, the shapes of the crystals they form, and their mechanical, thermal, and electrical properties are all due to this special type of bonding
The two reasons why the model shows sodium chloride is that:
Sodium chloride crystals are cubic in their form as they have crystalline structure.Why sodium chloride does not exist as molecule?The other is that:
Sodium chloride does exist as an aggregates of a bigger number of ions that are oppositely charged as shown using gray and white spheres.The melting point will be high based on the model as because Sodium chloride is known to have high melting and boiling point.Note that a lot of Formula unit cannot exist as a single entity. Because of this, compound such as NaCl exist only as an aggregates of a more bigger number of ions that are oppositely charged .
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