Thomson discovered the electron, the first subatomic particle. In 1904, Thomson proposed atomic model where electrons are embedded within spherically distributed, positive charge (so-called "plum pudding" model).
J.J. Thomson's experiments with cathode ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons. Thomson proposed the plum pudding model of the atom, which had negatively-charged electrons embedded within a positively-charged "soup."
☆...hope this helps...☆
_♡_mashi_♡_
Which of the following is the best example of an isolated system?
OA. A bus at a bus station
B. An astronaut in a spaceship
OC. A car on the freeway
D. A motorcycle in a garage
Answer:
B. An astronaut in a spaceship
Isolated system :-
In an isolated system, there is no transfer of energy or matter between the system and the environment.
Hope it helps!
Identify if phosphorous is paramagnetic or diamagnetic and explain why.
Due to the presence of three unpaired electrons, phosphorus is paramagnetic.
Electronic configuration of Phosphorus:-
[Ne] 3S2 3P3
What determines if an element is paramagnetic or diamagnetic?
By looking at a substance's electron configuration, one can identify whether or not it has magnetic qualities. If a substance has unpaired electrons, it is paramagnetic; if all of its electrons are paired, it is diamagnetic.
Paramagnetic:-A tiny, positive susceptibility to magnetic fields exists in materials. When exposed to a magnetic field, these materials are only weakly drawn to it; once the external field is removed, they lose their magnetic qualities.
Diamagnetic:-A weak, negative sensitivity to magnetic fields exists in materials. When exposed to a magnetic field, diamagnetic materials are partially repulsed and lose their magnetic properties when the external field is removed.
To learn more about magnetic properties refer to :-
https://brainly.com/question/16961890
#SPJ10
How many xenon atoms are contained in 1.00 moles of xenon?
Answer:
6.022 x 10²³
Explanation:
The number of atoms = the number of moles x with the Avogadro's number.
(The Avogadro's number is 6.022 x 10²³ atoms / moles)
number of atoms = 1.00 moles x 6.022 x 10²³ atoms / mole
number of atoms = 6.022 x 10²³ atoms
(There is no need to simplify?) = 6.022 x 10²³
(ps. This is my first time doing this question so im sorry if i got it wrong
(つ﹏⊂)
Calculate the mass of pure sodium chloride will yield enough hydrogen chloride gas to tralize 25 cm² of 0.5 M potassium trioxo- bonate(IV) solution. NACI=58.5, HC1 = 36.5, K,CO, = 138)
Sort the length measurements in increasing order of magnitude from smallest to largest.
The length measurements in increasing order of magnitude from smallest to largest is Nanometer, micrometer, centimeter, decimeter, dekameter, kilometer.
What is Measurement ?Measurement is the quantification of attributes of an object or event, which can be used to compare with other objects or events.
Measurement is a process of determining how large or small a physical quantity is as compared to a basic reference quantity of the same kind.
Hence, Among the given length measurements, The increasing order of magnitude from smallest to largest is Nanometer, micrometer, centimeter, decimeter, dekameter, kilometer.
Learn mopre about Measurement here ;
https://brainly.com/question/2734349
#SPJ1
What are the rows of the periodic table called?
A. Periods
B. Elements
C. Atoms
D. Groups
Answer:
i believe its called A. periods
M1 = 3M M2 = 1.25M V1 = V1=.125L unkown What is V2?
0.3 L is the final volume when M₁ = 3 M, V₁ = 0.125L, M₂ = 1.25M.
What is volume?The amount of space occupied by a three-dimensional figure as measured in cubic units.
Given data:
M₁ = 3 M
V₁ = 0.125L
M₂ = 1.25M
V₂ = ?
Solution:
M₁V₁ = M₂V₂
3 M × 0.125L = 1.25M × V₂
V₂ = 0.3 L
Hence, 0.3 L is the final volume.
Learn more about volume here:
https://brainly.com/question/15576659
#SPJ1
I need help with this one bad
Explanation:
it applies to pressure laws
Hybridization of bromine in SF4 and arsenic in SF2
Answer:
The answer is C
Define voltaic ???!!!
A voltaic cell is used to produce electrical energy with the help of chemical reactions.
What is a voltaic cell?Relating to, or producing direct electric current by chemical action.
A Voltaic Cell (also known as a Galvanic Cell) is an electrochemical cell that uses spontaneous redox reactions to generate electricity. It consists of two separate half-cells.
Learn more about voltaic cells here:
https://brainly.com/question/861659
#SPJ1
In the reaction of 675.9 grams of barium chloride and excess silver(I) nitrate, how many grams of silver(I) chloride should get formed?
i dont understand, show work pls ty
Taking into account the reaction stoichiometry, the mass of silver(I) chloride formed is 930.37 grams.
Reaction stoichiometryIn first place, the balanced reaction is:
2 AgNO₃ + BaCl₂ → 2 AgCl + Ba(NO₃)₂
By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:
AgNO₃: 2 moles BaCl₂: 1 moleAgCl: 2 molesBa(NO₃)₂: 1 moleThe molar mass of the compounds is:
AgNO₃: 169.87 g/moleBaCl₂: 208.24 g/moleAgCl: 143.32 g/moleBa(NO₃)₂: 261.34 g/moleThen, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:
AgNO₃: 2 moles ×169.87 g/mole= 339.74 grams
BaCl₂: 1 mole ×208.24 g/mole= 208.24 grams
AgCl: 2 moles ×143.32 g/mole= 286.64 grams
Ba(NO₃)₂: 1 mole×261.34 g/mole= 261.34 grams
Mass of silver(I) chloride formedThe following rule of three can be applied: if by reaction stoichiometry 208.24 grams of barium chloride form 286.64 grams of silver(I) chloride, 675.9 grams of barium chloride form how much mass of silver(I) chloride?
[tex]mass of silver(I) chloride=\frac{675.9 grams of barium chloride x286.64 grams of silver(I) chloride }{208.24 grams of barium chloride}[/tex]
mass of silver(I) chloride= 930.37 grams
Finally, the mass of silver(I) chloride formed is 930.37 grams.
Learn more about the reaction stoichiometry:
brainly.com/question/24741074
brainly.com/question/24653699
#SPJ1
What information does a net ionic equation give that the complete ionic equation does not show?
A complete ionic equation shows ions formed from each of the species. It also show the charge on each of the ions.It also shows all reactants as compounds or elements. The ions formed and their charges can only be inferred from this equation.
What is a Net Ionic equation ?The net ionic equation shows the chemical species involve in chemical reaction while the complete ionic equation also involve the spectator ions.
What are Spectator ions ?These ions are same in both side of chemical reaction and thus cancels out each other.
Their presence can not effect the equilibrium of reaction that's why these ions are omitted in net ionic equation.
The net ionic equation state that whether precipitation is occur or not.
If the chemical reaction have no net ionic equation it means all are in aqueous from not precipitation occur.
Consider the following example:Balanced Chemical equation:
HClO₂(aq) + NaOH(aq) → H₂O(l) + NaClO₂ (aq)
Ionic equation:
H⁺(aq) + ClO₂⁻(aq) + Na⁺(aq) + OH⁻(aq) → H₂O(l) + Na⁺(aq) + ClO₂⁻ (aq)
Net ionic equation:
H⁺(aq) + OH⁻(aq) → H₂O(l)
The ClO₂⁻(aq) and Na⁺ (aq) are spectator ions that's why these are not written in net ionic equation.
The water can not be splitted into ions because it is present in liquid form.
Hence, The net ionic equation shows the chemical species involve in chemical reaction while the complete ionic equation also involve the spectator ions.
Learn more about Ionic equation here ;
https://brainly.com/question/15467502
#SPJ1
How much heat (in joules) does it take to heat 180 g of water from 24 °C to 66 °C? The heat capacity of water is 4.184 J/(g · °C). You may round your answer to the nearest 100 J
Answer:31,631.04
Explanation: multiply final temp with initial temp = 42 then multiplied by grams = 7,560 then multiplied by J = 31,631.04
How many grams of hydrogen gas are produced from 2.50 mol of water?
__Ca(s) + __H2O(l) → __Ca(OH)2(aq) + __H2(g)
Answer:
2.52 g H₂
Explanation:
To find the mass of hydrogen gas, you need to (1) convert moles H₂O to moles H₂ (via mole-to-mole ratio from reaction coefficient) and then (2) convert moles H₂ to grams H₂ (via molar mass from periodic table values). When multiplying the given value by the mole-to-mole ratio, you need to use the coefficients of the balanced equation. An reaction is balanced once there is an equal amount of each element on both sides.
(Step 1)
The unbalanced equation:
Ca(s) + H₂O(l) ----> Ca(OH)₂(aq) + H₂(g)
Reactants: 1 calcium, 2 hydrogen, 1 oxygen
Products: 1 calcium, 4 hydrogen, 2 oxygen
The balanced equation:
1 Ca(s) + 2 H₂O(l) ----> 1 Ca(OH)₂(aq) + 1 H₂(g)
Reactants: 1 calcium, 4 hydrogen, 2 oxygen
Products: 1 calcium, 4 hydrogen, 2 oxygen
(Step 2)
Molar Mass (H₂): 2(1.008 g/mol)
Molar Mass (H₂): 2.016 g/mol
(Step 3)
2.50 moles H₂O 1 mole H₂ 2.016 g
--------------------------- x ------------------------- x ---------------------- = 2.52 g H₂
2 moles H₂O 1 mole
Pure water boils at 100°C.
What happens to the water particles when water
boils?
A They gain energy and move further apart.
B They gain energy and stay close together.
C They lose energy and move further apart.
D They lose energy and stay close together.
Answer:
A
Explanation:
a 20.0mL sample of 0.15M hydrochloric acid (HCI) is needed to neutralize a 10.0mL sample of potassium hydroxide (KOH). what is the molarity of KOH solution?
Answer: .75 M
Explanation:
Na2 C6H6O7 (sodium hydrogen citrate)
Express the mass of sodium to three significant figures.
mNa =
The exact mass of one Na - atom is 22.98977 amu and thus, the weight of two sodium atoms in present in Na₂C₆H₆O₇ is 45.979539 g/mol.
What is Molar mass ?The molar mass of a substance is the mass in grams of 1 mole of the substance.
We can obtain a substance's molar mass by summing the molar masses of its component atoms.
Mass of one Na atom = 22.98977
Mass of two Na atom = 22.98977 x 2
= 45.97954
= 45.9 (up to 3 Significant figures)
Learn more about significant figure here ;
https://brainly.in/question/11059319
#SPJ1
If 44.7 g of KCI (MM = 74.55 g/mol) are added to a 500.0 mL volumetric flask, and water is added to fill the flask, what is the concentration of KCI in the resulting solution?
1.199 M is the concentration of KCI in the resulting solution.
What are moles?A mole is defined as 6.02214076 × [tex]10^{23}[/tex] of some chemical unit, be it atoms, molecules, ions, or others. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance.
No.of moles of KCI
[tex]Moles = \frac{mass}{molar \;mass}[/tex]
[tex]Moles = \frac{44.7 g}{74.5513 g/mol}[/tex]
= 0.599 moles
Vol.of the solution,V= 500 ml
= 0.5 liter
Molarity
[tex]Molality = \frac{Moles \;solute}{Volume \;of \;solution \;in \;litre}[/tex]
[tex]Molality = \frac{0.599 moles}{0.5 liter}[/tex]
= 1.199 M
Hence, 1.199 M is the concentration of KCI in the resulting solution.
Learn more about moles here:
https://brainly.com/question/8455949
#SPJ1
In the laboratory you dissolve 12.2 g of iron(II) iodide in a volumetric flask and add water to a total volume of 500 mL.
What is the molarity of the solution?
M.
What is the concentration of the iron(II) cation?
M.
What is the concentration of the iodide anion?
M.
In the laboratory you dissolve 16.8 g of iron(III) sulfate in a volumetric flask and add water to a total volume of 250 mL.
What is the molarity of the solution?
M.
What is the concentration of the iron(III) cation?
M.
What is the concentration of the sulfate anion?
M.
You wish to make a 0.271 M hydrobromic acid solution from a stock solution of 12.0 M hydrobromic acid. How much concentrated acid must you add to obtain a total volume of 50.0 mL of the dilute solution?
mL
Question 1
1) The formula of iron(II) iodide is [tex]\text{FeI}_{2}[/tex] and has a formula mass of 309.654 g/mol. This means that in 12.2 grams, there are
12.2/309.654 = 0.039398812868557 mol.So, the molarity is (0.039398812868557)/(0.5) = 0.0788 M (to 3 sf)
2) In 0.039398812868557 mol of iron(II) iodide, there are 0.039398812868557 moles of iron(II) iodide cations, and thus the molarity is still 0.0788 M (to 3 sf)
3) In 0.039398812868557 mol of iron(II) iodide, there are
2(0.039398812868557) = 0.078797625737114 moles of iodide anionsThus, the molarity is (0.078797625737114)/(0.5) = 0.158 M (to 3 sf)
Question 2
1) The formula of iron(III) sulfate is [tex]\text{Fe}_{2}\text{(SO}_{4})_{3}[/tex] and has a formula mass of 399.9 g/mol. This means that in 16.8 grams, there are
16.8/399.9 = 0.042010502625656 molSo, the molarity is (0.042010502625656)/(0.25) = 0.168 M (to 3 sf)
2) In 0.042010502625656 moles of iron(III) sulfate, there are 2(0.042010502625656)=0.084021005251312 moles of iron(III) cations, so the molarity is:
0.084021005251312/0.25 = 0.336 M (to 3 sf)3) In 0.042010502625656 moles of iron(III) sulfate, there are 3(0.042010502625656)=0.12603150787697 moles of sulfate anions, so the molarity is:
0.12603150787697/0.25 = 0.504 M (to 3 sf)Question 3
Since we need 50.0 mL of solution at 0.271 M,
0.271 = (moles of HBr)/(0.05) moles of HBr = 0.01355 molSo, we need this from 12.0 M HBr so, meaning that:
12.0 = (0.01355)/(liters of 12.0 M HBr stock solution)liters of 12.0 M HBr stock solution = 0.0011291666666667 L = 1.13 M (to 3 sf)We do not want all staff being able to access all records that we hold. How can you ensure traceability and accessibility to the data stored?
To ensure data traceability and accessibility is to complete a study beginning-to-end on a closed system or platform.
How can you ensure traceability and accessibility to the data stored ? Lean On Self-Service Business Intelligence. Embed Dashboards Into Your Teams' Tools. Facilitate Data Literacy Throughout the Company. Embrace Your Changing Role.Learn more about Data accessibility here ;
https://brainly.com/question/3973929
#SPJ1
Need ASAP please and thank you
The empirical formula would be [tex]C_2H_3O_2[/tex] and the molecular formula would be [tex]C_4 H_6 O_4[/tex]
Empirical and molecular formulaFrom the illustration:
C = 40.6 g H = 5.1 g O = 54.2 g
Divide each element by its molar weight:
C = 40.6/12 = 3.4 H = 5.1/1 = 5.1 O = 54.2/16 = 3.4
Divide by the smallest:
C = 3.4/3.4 = 1 H = 5.1/3.4 = 1.5 O = 3.4/3.4 = 1
Thus, the empirical formula is [tex]C_2H_3O_2[/tex]
To find the molecular formula:
[ [tex]C_2H_3O_2[/tex]]n = molecular formula
where n = molar mass/empirical formula mass
Empirical formula mass = 24 + 3 + 32 = 59
n = 118.084/59 = 2
Thus, the molecular formula is [tex]C_4 H_6 O_4[/tex] which is more or less the same as the empirical formula.
More on empirical formula can be found here: https://brainly.com/question/14044066
#SPJ1
The Empirical formula will be C₂H₃O₂ and the Molecular formula would be C₄H₆O₄
What is Empirical and Molecular Formula ?Empirical formula is a formula giving the proportions of the elements present in a compound but not the actual numbers or arrangement of atoms.
Molecular formula is a chemical formula that gives the total number of atoms of each element in each molecule of a substance.
Given ;
C = 40.6 gH = 5.1 gO = 54.2 gDivide each element by its molar weight:
C = 40.6 / 12 = 3.4H = 5.1 / 1 = 5.1 O = 54.2 / 16 = 3.4Divide by the smallest Value:
C = 3.4/3.4 = 1H = 5.1/3.4 = 1.5 O = 3.4/3.4 = 1Thus, the Empirical formula is C₂H₃O₂
Now, to find the molecular formula ;
[C₂H₃O₂ ]n = molecular formula
where n = molar mass / empirical formula mass
Empirical formula mass = 24 + 3 + 32 = 59
n = 118.084 / 59 = 2
[C₂H₃O₂ ]n = molecular formula
[C₂H₃O₂ ]2 = C₄H₆O₄
Thus, the Molecular formula is C₂H₃O₂
Learn More about Empirical formula here ; brainly.com/question/14044066
#SPJ1
An unknown gas effuses at a rate of 2.0 times the rate of Cl₂. What is the molar mass of the unknown gas?
The molar mass of the unknown gas is determined as 17.75 g.
Rate of gas diffusionThe rate of gas diffusion is given by Graham's law.
R₁√M₁ = R₂√M₂
where;
R₁ is the rate of diffusion of the unknown gasM₁ is the molecular mass of the unknown gasR₂ is rate of diffusion of chlorine gasM₂ is the molecular mass of chlorine gas[tex]\frac{R_1}{R_2} = \sqrt{\frac{M_2}{M_1} } \\\\\frac{2R_2}{R_2} = \sqrt{\frac{71}{M_1} }\\\\2 = \sqrt{\frac{71}{M_1} }\\\\2^2 = \frac{71}{M_1} \\\\M_1 = \frac{71}{4} \\\\M_1 = 17.75 \ g[/tex]
Learn more about rate of diffusion here: https://brainly.com/question/11197959
#SPJ1
Sunspot populations quickly rise and more slowly fall on an irregular cycle about every 11 years. Significant variations of the 11-year period are known over longer spans of time. For example, from 1900 to the 1960s the solar maxima (the period of greatest activity in the solar cycle of the sun) trend of sunspot count has been upward; from the 1960s to the present, it has diminished somewhat. The Sun is presently at a markedly heightened level of sunspot activity and was last similarly active over 8,000 years ago.
The number of sunspots correlates with the intensity of solar radiation over the period (since 1979) when satellite measurements of absolute radiative flux were available. Since sunspots are darker than the surrounding photosphere it might be expected that more sunspots would lead to less solar radiation and a decreased solar constant. However, the surrounding margins of sunspots are hotter than the average, and so are brighter; overall, more sunspots increase the sun's solar constant or brightness. During the Maunder Minimum in the 17th Century there were hardly any sunspots at all. The Maunder Minimum is the name given to the period roughly from 1645 to 1715, when sunspots became exceedingly rare, as noted by solar observers of the time. It is named after the solar astronomer Edward W. Maunder (1851-1928) who discovered the dearth of sunspots during that period by studying records from those years. During one 30-year period within the Maunder Minimum, for example, astronomers observed only about 50 sunspots, as opposed to a more typical 40,000-50,000 spots. This coincides with a period of cooling known as the Little Ice Age.
1) Which of the following is a true statement?:
A. There were more sunspots in 1965 than in 1701
B. The Little Ice Age had nothing to do with sunspots
C. The Sun is presently at a low level of sunspot activity
D. No one is counting sunspot activity any more
The Sun is presently at a low level of sunspot activity. Hence, option C is correct.
What is solar radiation?Solar radiation is often called the solar resource for the electromagnetic radiation emitted by the sun.
The Sun is presently at a low level of sunspot activity is the correct answer.
Hence, option C is correct.
Learn more about the solar radiation here:
https://brainly.com/question/16525532
#SPJ1
The average speed of a diatomic fluorine molecule at 25 ∘C is 442.4 m⋅s−1 . What is the average wavelength of a fluorine molecule at this temperature? Assume that the molecule acts as a single particle
The average wavelength of the fluorine molecule will be 2.36 × 10⁻¹¹ metres.
Fluorine Molecule's Speed = 442.4 m/s
The Molar Mass of the F₂ = 38 g/mol
Now as we know that any molecule's
1 mole contain = 6.022 × 10²³ Molecule
So, 1 Fluorine molecule mass =
Fluorine's Molar mass / Number of Fluorine molecule in 1 mole
So, 1 Fluorine molecule mass = 38 / ( 6.022 × 10²³ )
1 Fluorine molecule mass = 6.31 × 10⁻²³ g
1 Fluorine molecule mass = 6.31 × 10⁻²⁶ Kg
So molecule's momentum = Molecule's mass × Molecule's Velocity
So molecule's momentum = ( 6.31 × 10⁻²⁶ ) × 442.4
So molecule's momentum = 2.8 × 10⁻²³ Kg.m/s
Now wavelength of Fluorine molecule = λ = planks constant / momentum
wavelength of Fluorine molecule = λ = ( 6.626 × 10⁻³⁴ ) / ( 2.8 × 10⁻²³ )
wavelength of Fluorine molecule = λ = 2.36 × 10⁻¹¹ metre
So the wavelength of the diatomic fluorine molecule came out to be 2.36 × 10⁻¹¹ metres after applying all the concepts and formulas.
Learn more about Wavelength here:
https://brainly.com/question/10750459
#SPJ10
If the balloon had a volume of 3 L at a depth of 50 m, what was the original volume of the balloon it we assume the pressure at the surface of the water is 14.7 psi? Express your answer using one significant figure and include the appropriate units.
If the balloon had a volume of 3 L at a depth of 50 m, the original volume of the balloon will be
What is Significant figures ?Significant figures are the number of digits in a value, often a measurement, that contribute to the degree of accuracy of the value.
The pressure at a depth of 40 m is the hydrostatic pressure of the water plus the atmospheric pressure.
The hydrostatic pressure P of a liquid is given by the formula ;
P = ρgh
where,
ρ = the density of the liquid (Density of water = 1000 kg m⁻³)g = the acceleration due to gravity (9.81 ms⁻²)h = the depth of the liquid (Given : 50 m)P = 1000 kg m⁻³ x 9.81 ms⁻² x 50 m
= 1000 kg m⁻¹ x 9.81 s⁻² x 50
= 4.9 x 10⁵ Pa
Lets's Convert Pa in to atm
= 4.9 x 10⁵ Pa x 1 / 103. 325 x 10³ Pa
= 4.7 atm
Mow, lets calculate P(atm) ;
P(atm) = 14.7 psi x 1 atm / 14.7 psi
= 1 atm
Total Pressure at 50 m is ;
P(total) = 4.7 atm + 1 atm
= 5.7 atm
Now we can apply Boyle's Law to calculate the volume of the balloon at the surface.
P₁V₁ = P₂V₂
V₂ = P₁V₁ / P₂
According to the question ;
P₁ = 5.7 atm P₂ = 1 atmV₁ = 3 LV₂ = ?V₂ = 3 L x 5.7 atm / 1 atm
= 17.1 L
= 20 L ( 1 significant figure)
Learn more about Boyles law here ;
https://brainly.com/question/1437490
#SPJ1
How does temperature affect Keq of a reaction
In an endothermic reaction, Keq increases as the temperature increases and vice versa.
In an exothermic reaction, Keq decreases as the temperature increases and vice versa.
Keq is the equilibrium constant of a reaction. The equilibrium constant is independent of the concentrations of the reactants and productsThe only factor that the equilibrium constant depends on is the temperature of the system of reactionIn an endothermic reaction, energy is gainedSo a higher temperature is more favourable in an endothermic reactionAs a result, more products are formed at a higher temperature, leading to a higher value of KeqIn an exothermic reaction, energy is releasedSo a lower temperature is more favourable in an exothermic reactionAs a result, fewer products are formed at a higher temperature, leading to a lower value of KeqTherefore, the temperature is the only factor that affects the equilibrium constant of a reaction.
Learn more about equilibrium constants here:
https://brainly.com/question/20344485
#SPJ10
Calculate the standard enthalpy change associated with this reaction at 25 °C using the
following enthalpies of formation:
CH4 ∆Hf = -62.7 kJ·mol–1, CO2 ∆Hf = -393.5 kJ·mol–1, H2O ∆Hf = -285.8 kJ·mol–1.
The standard enthalpy change associated with the given reaction at 25 °C using the following enthalpies of formation will be − 902.4 kJ
What is Standard Enhalpy change ?The standard enthalpy change of formation of a compound is the enthalpy change which occurs when one mole of the compound is formed from its elements under standard conditions, and with everything in its standard state.
According to the balanced chemical equation ;
CH₄(g) + 2O₂(g) ⟶ CO₂(g) + 2H₂O(l)
Now,
ΔH⁰ = ΔH⁰f(products) − ΔH⁰f(reactants)
= [ΔH⁰(CO₂) +ΔH⁰(H₂O)] − [ΔH⁰(CH₄) + 2ΔH⁰(O₂)]
= [−393.5 + 2 x (−285.8)] − [−62.7 + 2 x 0]
= − 902.4 kJ
Hence, The standard enthalpy change associated with the given reaction at 25 °C using the following enthalpies of formation will be − 902.4 kJ
Learn more about enthalpy here ;
https://brainly.com/question/16720480
#SPJ1
What is the pH of a 0.640 M solution of C₅H₅NHBr (Kb of C₅H₅N is 1.7 × 10⁻⁹)?
The pH of a 0.64 M solution of pyridine (C₅H₅N) is 9.52.
What is pH ?A figure expressing the acidity or alkalinity of a solution on a logarithmic scale on which 7 is neutral, lower values are more acid and higher values more alkaline.
The equation for the protonation of the base pyridine is the following:
C₅H₅N + H₂O ⇄ C₅H₅NH⁺ + OH⁻ (1)
Kb = 1.7 × 10⁻⁹ (Given)
To calculate the pH of the solution we need to use the following equation:
pH + pOH = 14
pH = 14 - pOH
=14 - [-log[OH⁻]]
= 14 + log[OH⁻]
Now, we need to find the concentration of the OH⁻ ions. Since pyridine is a weak base, at the equilibrium we have (eq 1):
C₅H₅N + H₂O ⇄ C₅H₅NH⁺ + OH⁻
0.64 - x x x
After entering the values of [C₅H₅N] = 0.64-x, [C₅H₅NH⁺] = x, and [OH⁻] = x, into equation (2) we can find the concentration of OH⁻:
1.7 × 10⁻⁹ =[C₅H₅NH⁺] [OH⁻] / [C₅H₅N]
= x . x / 0.64-x
1.7 × 10⁻⁹ (0.64-x) - x² = 0
Solving the above quadratic equation for x, we have :
x₁ = -3.32 x 10⁻⁵x₂ = 3.32 x 10⁻⁵Now, We can calculate the pH, after taking the positive value, x₂, (concentrations cannot be negative) and entering into above equation :
pH = 14 + log[OH⁻]
= 14 + log (3.32 x 10⁻⁵)
= 9.52
Therefore, the pH of the solution of pyridine is 9.52.
Find more about pH here:
brainly.com/question/8834103?referrer=searchResults
#SPJ1
1. Write the reaction rate expressions for the following reactions in terms of the disappearance of the reactants and the appearance of products: 1-(aq)+ OCI-(aq)-CI-(aq)+OI-(aq)
In terms of the disappearance of the reactants, the rate equations are R= -kd[I-]/dt and -kd[OCl-]/dt.
What is an ionic reaction?The term ionic reaction refers to the reaction that takes place between two ions. In this case, the ionic reaction is; I-(aq) + OCl-(aq) -------> Cl-(aq) + OI-(aq).
The rate equations in terms of the disappearance of the reactants is;
R= -kd[I-]/dt
And
R = -kd[OCl-]/dt
Learn more about ionic reaction:https://brainly.com/question/12164558
#SPJ1
What quantity in moles of silver atoms do you have if you have 2.49 × 10²¹ atoms of silver. (The mass of one mole of silver is 107.87 g.)
Answer:
0.004136 moles
Explanation:
From our question we have been asked to determine the quantity in moles of silver atoms having 2.49 × 10²¹ atoms of silver.
We know that from Avogadro's constant, one mole of silver contains 6.02 x 10²³ atoms.
Thus,
1 mole of silver contains 6.02 x 10²³ atoms.
x moles of silver contains 2.49 × 10²¹ atoms
Cross multiply to obtain the number of moles of silver,
x moles = (2.49 × 10²¹ x 1)/(6.02 x 10²³)
= 0.004136 moles
Therefore the quantity of silver in moles is 0.004136 moles