Answer:
a. Endothermic
b. 26.37kJ/mol
Explanation:
a. As we can see, the temperature of the water is decreasing when the reaction is occurring, that means the reaction is absorbing heat and is endothermic
b. To find the enthalpy we must find the change in heat when 12.1g of KCl are dissolved. Using the equation:
Q = -m*ΔT*C
Where Q is change in heat
m the mass of solution (250g + 12.1g = 262.1g)
ΔT is change in heat (17.1°C - 21.0°C = -3.9°C)
And C is specific heat of the solution (4.184J/g°C assuming is the same than the specific heat of water).
Replacing:
Q = -262.1g*-3.9°C*4.184J/g°C
Q = 4277J = 4.28kJ
As reaction enthalpy is the change in heat per mole of reaction, we must find the moles of 12.1g of KCl:
Moles KCl -Molar mass: 74.55g/mol-:
12.1g KCl * (1 mol / 74.55g) = 0.1623 moles KCl
The reaction enthalpy us:
4.28kJ / 0.1623mol = }
26.37kJ/mol
SUMMARY: Write a 3-4 sentence summary about molecules.
Answer:
molecules definition is that "a molecule is an electrical neutral group of two or more atoms held together by chemical bonds molecules are distinguished from ions by their lack of electrical charge." molecules have a part of many things we touch or come across in a everyday life. se example of theses things are water,nitrogen, glucose, and many other things.a molecule is an atom that forms a chemical bond with another atom.
Explanation:
there
Answer please I need help
Answer:
Explanation::::
Before spectroscopy was invented, Korner's absolute method had been used to determine whether a disubstituted benzene derivative was the ortho, meta, or para isomer. Korner's method involves adding a third group (often a nitro group) and determining how many isomers are formed. A turn-of-the-20th-century chemist isolated an aromatic compound of molecular formula C6H4Br2. He carefully nitrated this compound and purified three isomers of formula C6H3Br2NO2, one of which was obtained in very small amounts. Propose a structure for the original compound.
Answer:
Answer is explained in the explanation section below.
Explanation:
Definitely, before the invention of spectroscopy, Korner's absolute method had been in use. So, the proposed structure is a diagram, that we can not draw here. Therefore, I have drawn it separately and attached in the attachment below. Please for this answer, refer to the diagram which is a proposed structure attached in the attachment below.
Proposed Structure is:
1,3-Dibromo Benzene.
In the Korner's method, 1,3- Dibromo benzene undergoes nitration process in the presence of HNO3/H2SO4.
The original compound that undergoes nitration is a meta disubstituted aromatic compound.
After nitration, 1,3-Dibromo benzene yields three having chemical formula C6H3Br2NO2.
A gas occupies 135 cm3 at 143. K. At what Celsius temperature will its volume be 140 cm3? Assume that pressure remains constant.
Answer:
New temperature T2 = -124.7 °C
Explanation:
Given:
Old volume V1 = 135 cm³
New volume V2 = 140 cm³3
Old temperature T1 = 143 K
Find:
New temperature T2
Computation:
V1 / T1 = V2 / T2
135 / 143 = 140 / T2
New temperature T2 = 148.3 K
New temperature T2 = 148.3 - 273
New temperature T2 = -124.7 °C
A 508-g sample of sodium bicarbonate (NaHCO3) contains how many moles of sodium bicarbonate (NaHCO3)?
molar mass = (22.99) + (1.01) + (12.01) + 3(16.00)
molar mass = 84.01 g/mol
//
(508g)(1 mol/84.01 g) = 6.0
There are 6.0 moles of sodium bicarbonate
A 508-g sample of sodium bicarbonate (NaHCO3) contains 0.6 moles of sodium bicarbonate (NaHCO3)
What is mass?Mass is defined as a dimensionless quantity representing the amount of matter in a particle or object. The SI unit of mass is kg.
Mole is defined as a standard scientific unit for measuring large quantities of very small entities
Molar mass = 22.99 + 1.01 + 12.01 + 3x16.00
= 84.01 g/mole
Moles of NaHCO3
= 508 g x 1 mole / 84.01
= 6.0 moles
Thus, 508-g sample of sodium bicarbonate (NaHCO3) contains 0.6 moles of sodium bicarbonate (NaHCO3)
To learn more about mass, refer to the link below:
https://brainly.com/question/19694949
#SPJ2
During electrolysis, where do reduction reactions occur?
A. in the anode of an electrolytic cell
B. in the cathode of an electrolytic cell
C. in the power source of an electrolytic cell
D. in the salt bridge of an electrolytic cell
Answer:
B)
Explanation:
HOPE IT WILL HELP YOU
WAITING FOR YOUR RESPONSE
Answer:
( : The correct option is, (a) anode
Explanation:
According to the combined gas law, pressure is inversely proportional to volume and directly proportional to temperature, and volume is directly proportional to temperature.
True
B. False
Save & Cont
Heats makes particles vibrate _________ (btw the options are in the pic)
Answer:ok so When heat is added to a substance, the molecules and atoms vibrate faster. As atoms vibrate faster, the space between atoms increases. The motion and spacing of the particles determines the state of matter of the substance. The end result of increased molecular motion is that the object expands and takes up more space.
hope this helps have a nice day❤️
Explanation:
PLEASE HELP!!
How many moles are contained in 7.88 x 10^24 atoms of Iron?
Answer:
Explanation:
9.55 mol of Al
Explanation:
To obtain the number of moles of a certain element given the number of atoms only, you have to divide it with Avogadro's number,
Answer: mutiply them
Explanation:
balance kclo3-kcl+02
Which of the following are more likely to form a solution? (select all that apply)
A) When both solute and solvent are polar
B) When both solute and solvent are nonpolar
C) When solute is polar and solvent is nonpolar
D) When solute is nonpolar and solvent is polar
Answer:A and B
Explanation:
A substance is said to be polar when it is having a dipole (a delocalised positive and negative charge) or it is ionic (dissociate into ions when dissolved in water)
which planet in are solar system haves most moons
Answer:
Jupiter
Explanation:
Diffusion of Sucrose in Gelatin. A layer of gelatin in water 5 mm thick and con-taining 5.1 wt % gelatin at 293 K separates two solutions of sucrose. The concentra-tion of sucrose in the solution at one surface of the gelatin is constant at 2.0 g sucrose/100 mL solution, and 0.2 g/100 mL at the other surface. Calculate the flux of sucrose in kg sucrose/s
Answer:
the flux of sucrose is 9.072 × 10⁻⁷ kg sucrose / m² sec
Explanation:
Given the data in the question;
water-gelatin solution separating two different concentration solutions of sucrose; 5.1 wt % gelatin at 293 K; at this conditions diffusivity of sucrose in water gelatin solution is;
[tex]D_{AB}[/tex] = 0.252 × 10⁻⁹ m²/sec.
we know that; 1 L = 0.001 m³, 1mL = 0.001 L
[tex]C_{A1}[/tex] = 2.0 g sucrose/100 mL = 2.0 × 10⁻³ kg sucrose / 100 × 10 ⁻³ L
[tex]C_{A1}[/tex] = 2.0kg sucrose / 100 L
[tex]C_{A1}[/tex] = 2.0 kg sucrose / 100 × 10⁻³ m³
[tex]C_{A1}[/tex] = 20 kg sucrose / m³
[tex]C_{A2}[/tex] = 0.2 g sucrose/100 mL = 0.2 × 10⁻³ kg sucrose / 100 × 10⁻³ × 10⁻³ L
[tex]C_{A2}[/tex] = 2 kg sucrose / m³
Thickness ß = 5 mm = 5 × 10⁻³ m
Now, flux of sucrose in kg sucrose / m³sec will be;
using the formula, [tex]N_{A}[/tex] = [tex]D_{AB}[/tex] /ß ( [tex]C_{A1}[/tex] - [tex]C_{A2}[/tex] )
we substitute
[tex]N_{A}[/tex] = (0.252 × 10⁻⁹ m²/sec / 5 × 10⁻³ m) ( 20 kg sucrose / m³ - 2 kg sucrose / m³ )
[tex]N_{A}[/tex] = (0.252 × 10⁻⁶ / 5) × 18 kg sucrose / m² sec
[tex]N_{A}[/tex] = 4.536 × 10⁻⁶ / 5 kg sucrose / m² sec
[tex]N_{A}[/tex] = 9.072 × 10⁻⁷ kg sucrose / m² sec
Therefore, the flux of sucrose is 9.072 × 10⁻⁷ kg sucrose / m² sec
Describe the process for the separation of water and water soluble matter.
Sive an important difference of each of the following pair.
Solid and liquid
b. Liquid and gas
Solid and gas
d. Melting and freezing
Vapourization and condensation. f. Melting and sublimation.
Filtration and evaporation, 1. Sedimentation and decantation,
Homogeneous and heterogenous mixture
Water insoluble and water soluble matter
Write T for true and F for false statements.
All matters are visible.
Air is a matter.
The tiny particles of matter are called molecule.
தங்கம்
Answer:
Describe the process for the separation of water and water soluble matter.
Sive an important difference of each of the following pair.
Solid and liquid
b. Liquid and gas
Solid and gas
d. Melting and freezing
Vapourization and condensation. f. Melting and sublimation.
Filtration and evaporation, 1. Sedimentation and decantation,
Homogeneous and heterogenous mixture
Water insoluble and water soluble matter
Write T for true and F for false statements.
All matters are visible.
Air is a matter.
The tiny particles of matter are called molecule.
தங்கம்
1) De los siguientes cambios indicar cuál es químico y cual es físico:
• Aplastar una lata:
• Congelar agua:
• Quemar pasto:
• Hervir agua:
• Se descompone fruta:
• Se oxida hierro:
• Derretir chocolate:
• Mezclar agua y sal:
• Pulverizar un ladrillo:
• Quemar pólvora
How many molecules are there in 10.5 grams of iron (111) sulfate trihydrate? With work shown
4)
On a hot day, your friend brings you some iced tea to cool off. Only, its unsweetened. You add sugar, but it just does not dissolve
fast enough. Which procedure would speed up the dissolving process?
A)
Add the sugar in the dark.
B)
Add larger crystals of sugar, or sugar cubes.
C)
Take the tea up to the top of a close mountain.
D)
• Take out the ice and stir it up outside where it is warmer.
Answer: D)
• Take out the ice and stir it up outside where it is warmer.
Explanation:
Answer:
thank you! I made it to an 100% on USA test prep...
the answer is: Take out the ice and stir it up outside where it is warmer.
Explanation:
I have a lot of rain last night when I go to bed. Stay safe!
How many grams of silver chloride can be produced by reacting excess silver nitrate with 2.4 moles of zinc chloride? _____AgNO3 + ____ZnCl2 ____AgCl + _____Zn(NO3)2
690 g AgCl
General Formulas and Concepts:Math
Pre-Algebra
Order of Operations: BPEMDAS
Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to RightChemistry
Atomic Structure
Reading a Periodic TableWriting CompoundsStoichiometry
Using Dimensional AnalysisLimiting Reactant/Excess ReactantExplanation:Step 1: Define
[RxN - Unbalanced] AgNO₃ + ZnCl₂ → AgCl + Zn(NO₃)₂
↓
[RxN - Balanced] 2AgNO₃ + ZnCl₂ → 2AgCl + Zn(NO₃)₂
[Given] 2.4 mol ZnCl₂
[Solve] x g AgCl
Step 2: Identify Conversions
[RxN] 1 mol ZnCl₂ → 2 mol AgCl
[PT] Molar Mass of Ag - 107.87 g/mol
[PT] Molar Mass of Cl - 35.45 g/mol
Molar Mass of AgCl - 107.87 + 35.45 = 143.32 g/mol
Step 3: Stoich
[DA] Set up: [tex]\displaystyle 2.4 \ mol \ ZnCl_2(\frac{2 \ mol \ AgCl}{1 \ mol \ ZnCl_2})(\frac{143.32 \ g \ AgCl}{1 \ mol \ AgCl})[/tex][DA] Multiply/Divide [Cancel out units]: [tex]\displaystyle 687.936 \ g \ AgCl[/tex]Step 4: Check
Follow sig fig rules and round. We are given 2 sig figs.
687.936 g AgCl ≈ 690 g AgCl
what is the overall equilibrium constant of 4NH3+7O2=4NO2+6H2O
Answer:
An apple, potato, and onion all taste the same if you eat them with your nose plugged
Explanation:
structure of 2,6-diiodo-4-methyl-5-propylheptane
Answer:
diiodo????
Explanation:
recheck the question and resend
Is ionization complete or incomplete when sodium hydroxide compounds are dissolved in water and why?
Answer: Ionization is complete when sodium hydroxide compound is dissolved in water as it is strong electrolyte.
Explanation:
Strong bases are good electrolytes as they completely dissociate to give ions which help in the conduction of electrical current.
Weak bases are those substances which dissociate partially to give hydroxide ions [tex](OH^-)[/tex] when dissolved in water.
Example: [tex]NH_4OH\rightleftharpoons NH_4^++OH^-[/tex]
Strong bases are those substances which dissociate completely to give hydroxide ions [tex](OH^-)[/tex] ions when dissolved in water.
Example: [tex]NaOH\rightarrow Na^++OH^-[/tex]
When sodium hydroxide (NaOH) compounds are dissolved in water (H₂O), ionization takes place completely.
What is ionization?Ionization is a process, where compound on dissociation coverts into ions.
Dissociation of NaOH takes place as follow:
NaOH → Na⁺ + OH⁻
Here NaOH, is a strong electrolyte or strong base which completely dissociate into ions and never combine to again form NaOH. Whereas weak electrolytes are those which partially dissociate into ions and gives reaction like as:
AB ↔ A⁺ + B⁻
Complete ionization takes place when sodium hydroxide compounds are dissolved in water.
To learn more about ionization, visit below link:
https://brainly.com/question/1445179
Pl help it’s for a grade
What type of changes would you expect as you go down from the ocean's surface to
its bottom?
1.Temperature, pressure, light, and density all decrease
2.Temperature and pressure increase; light and density decrease
3.Temperature and light decrease; pressure and density increase
4.Temperature and density decrease; light and pressure increase
Answer:
answer is the 4th one
Explanation:
The type of changes one might expect as one goes down from the ocean's surface to its bottom is that temperature and light decrease; pressure and density increase.
What is pressure?Pressure is defined as the force applied on an object perpendicular to it's surface per unit area over which it is distributed.Gauge pressure is a pressure which is related with the ambient pressure.
There are various units by which pressure is expressed most of which are derived units which are obtained from unit of force divided by unit of area . The SI unit of pressure is pascal .
It is a scalar quantity which is related to the vector area element with a normal force acting on it.It is distributed over solid boundaries and across arbitary sections of fluid normal to the boundaries at every point.
Learn more about pressure,here:
https://brainly.com/question/18431008
#SPJ2
Assuming each solution to be 0.10 M , rank the following aqueous solutions in order of decreasing pH.Rank the solutions from the highest to lowest pH. To rank items as equivalent, overlap themN2H2Ba(OH)2HOCLNAOHHCL
Answer:
Ba(OH)₂ > NaOH >N₂H₂ > HOCl > HCl
Explanation:
To get a better understanding of this, we need to know what's the meaning of the pH values.
The pH value of any compound basically gives us information of how acidic or basic is a compound. If this value is higher (>7), means major basicity; if this number is lower (<7) means major acidity in the compound.
According to this, a strong acid would be the one with the lowest pH, and a strong base would be the one with the highest pH.
Among the 5 compounds we have here, only 2 of them are acid, and the rest is basic, so we can assume that both acid would have the lower pH, it's up to us to see which of them have the lowest pH.
To do that, we can use the following expression:
pH = -log[H⁺]
If all solutions have a concentration of 0.10, then the pH would be:
HCl:
pH = -log(0.1) = 1
HOCL:
This one is a weak acid, so it's not completely dissociated in solution and the [H⁺] would be <0.1 M. As its a weak acid, we can assume that it's pH would be near 4, 5 or 6. We cannot know with all certain, because we need the Ka of this acid, and see the dissociation of the acid in solution, but for this case, it's fine and HCl is one of the strongest known acid.
In this case the order is: HOCl > HCl
For the bases, we have 3 bases, 2 of them are strong bases, and 1 of them is a weak base so it doesn't dissociate completely (N₂H₂), so this would have the lowest pH among the bases. In the case of bases, we calculate pOH, (Same formula as before) and then, we substract 14 from the value of pOH. As for the other two:
Ba(OH)₂:
Concentration would be double because we have 2 OH, so:
[OH⁻] = 2 * 0.1 = 0.2 M
pOH = -log(0.2) = 0.69
pH = 14 - 0.69 = 13.31
NaOH:
pOH = -log(0.1) = 1
pH = 14 - 1 = 13
Therefore, Ba(OH)₂ is stronger than NaOH and N₂H₂. So, our order would be:
Ba(OH)₂ > NaOH >N₂H₂ > HOCl > HClHope this helps
which type of rock is rhyolite A.Intusive igneous B.Sedimentary C.Extrusive igneous D.Metamorphic
Answer:
C - Extrusive igneous
Explanation:
Rhyolite is an extrusive igneous due to the high silica content, the lava is very dangerous.
Answer:
Its C
Explanation:
A P E X
The reaction for luminol is basically luminol and hydrogen peroxide. In the instructions for the preparation of the chemicals, I found that the hydrogen peroxide is 44 times more concentrated than the luminol. The fact that there are two reactants, should make you wonder if the reaction is second order overall. However, in class, we presented data that showed that the natural log of the amount of light change over time was a straight line with a negative slope. This would tend to make you think that the reaction is first order, given the information here, you can confidently say that this reaction is:
A. zeroth order
B. first order
C. pseudo first order
D. second order
E. third order
Answer:
pseudo first order
Explanation:
We know that for a first order reaction, the plot of the natural log of the amount of reactant against time is a straight line with a negative slope. In this case the amount of substance is monitored using the amount of light change. Hence, the plot of the natural log of the amount of light change against time was a straight line with a negative slope.
The statement above characterizes a first order reaction. However, we must remember that the reaction is bimolecular; it involves luminol and hydrogen peroxide. The hydrogen peroxide is 44 times more concentrated than the luminol making the reaction a pseudo first order reaction.
A Pseudo first-order reaction can be defined as a second-order or bimolecular reaction that is made to behave like a first-order reaction(Byjus).
As illustrated, the below manometer consists of a gas vessel and an open-ended U-tube containing a nonvolatile liquid with a density of 0.993 g/mL. The difference in heights of the liquid in the two sides of the manometer is 32.3mm when the atmospheric pressure is 765 mm Hg. Given that the density of mercury is 13.6 g/mL, the pressure of the enclosed gas is ________ atm. Group of answer choices
Answer:
1.01atm is the pressure of the gas
Explanation:
The difference in heights in the two sides is because of the difference in pressure of the enclosed gas and the atmospheric pressure. This difference is in mm of the nonvolatile liquid. The difference in mm Hg is:
32.3mm * (0.993g/mL / 13.6g/mL) = 2.36mmHg
As atmospheric pressure is 765mm Hg and assuming the gas has more pressure than the atmospheric pressure (There is no illustration), the pressure of the gas is:
765mm Hg + 2.36mm Hg = 767.36 mmHg
In atm:
767.36 mmHg * (1atm / 760 mmHg) =
1.01atm is the pressure of the gas
Given:
Density of mercury = 13.6 g/mLDensity of nonvolatile liquid = 0.993 g/mLDifference in height = 32.3mmAtmospheric pressure = 765 mm HgNow,
The density of Hg will be:
= [tex]\frac{13.6}{0.791}[/tex]
= [tex]17.2 \ mm[/tex]
then,
= [tex]32.3\times (\frac{1 \ mm \ Hg}{17.2} )[/tex]
= [tex]18.73 \ mm \ Hg[/tex]
hence,
The pressure will be:
= [tex]765-18.73[/tex]
= [tex]746.27 \ mm \ Hg[/tex]
= [tex]0.993 \ atm[/tex]
Thus the above answer is right.
Learn more about gas vessel here:
https://brainly.com/question/7205294
where do coal,oil and natural gas came from?
Answer:
I hope it will help you
plz mark me as brainliest
plz thank my answer
how many oxygen (0) atoms are in a molecule C3H4O3
Answer: 3
Explanation: A P E X
When running an experiment, it is essential to record data and observations within your lab notebook. The data and observations are then discussed and analyzed, results and discussion. However, as you write a conclusion, some data are more important to include than others. Which of the following data would you include if you had to write a conclusion in for outcome of this week's LLE experiment?
a. MP range of product
b. mass of product
c. mass of flask and cork support
d. instrument used to evaporate the solvent
e. volume of crude reaction mixture used
f. % recovery
g. volume of acid and base used
h. theoretical MP
i. mass of flask, cork support, and product
Answer:
% recovery
MP range of product
mass of product
Explanation:
Liquid–liquid extraction (LLE) is a process of transferring one (or more) solute(s) which are present in a feed solution to another immiscible liquid (solvent). The other solvent that becomes enriched in the target solute(s) is called extract. The original feed solution that is depleted in solute(s) is subsequently referred to as the raffinate.
This method is used to purify compounds and separate mixtures of compounds. This is very important when we want to isolate a product from a reaction mixture.
The percent recovery is the amount of solute that is transferred to the extract. This is the most important data to be recorded in an LLE experiment.
The melting point range necessarily helps us to identify the product and the mass of solid tells us the quantity of the solid obtained after extraction.
