Answer:
A
Explanation:
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)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)
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)
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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)
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What are the rows of the periodic table called?
A. Periods
B. Elements
C. Atoms
D. Groups
Answer:
i believe its called A. periods
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:
Imagine that a single cell below goes through four cell divisions. How many cells are produced? To find out, draw the parent cell and cells present after each division. Then write the number of cells in the space below each drawing. (Hint: the number of cells doubles with each division.)
16 cells are produced from a single parent cell after the fourth division of the cell.
What is a cell?In biology, the smallest unit can live on its own and that makes up all living organisms and the tissues of the body.
In mitosis type of cell division, one parent cell is divided into two same or different daughter cells. In this way, in the first division, two cells are produced from single parent cells and in the second division, four daughter cells are produced. In the third division, 8 cells are produced from 4 parent cells and in the fourth division, 16 cells are formed from 8 cells.
So we can conclude that 16 cells are produced from a single parent cell after the fourth division of the cell.
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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.
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Which of the following is an insoluble compound that is likely to be produced by the reaction below?
CaSO4 + PbI _______
The following is an insoluble compound that is likely to be produced by the reaction below CaSO4 + PbI- CaI + PbSO4. The PbSO4 will be insoluble as The sulfates are insoluble in water besides for the sulfates of calcium, barium, mercury, and lead.
Why lead sulfate is insoluble in water?Lead sulphate ($PbS$) is insoluble in water due to the fact water's dipole electricity is simply too vulnerable to shy away the ions (each anion and cations) from the sturdy crystals of lead sulphate.Lead sulfate seems as a white crystalline solid. Insoluble in water and sinks in water. Contact might also additionally aggravate skin, eyes, and mucous membrane.
Thus, PbSO4 is insoluble. In PbSO4 , the electricity of the dipole is vulnerable to interrupting the anionic and cationic bond. So, PbSO4 stays insoluble in solution.
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One mole of hydrogen is burned in oxygen to produce water in the gas phase, H = 285.8 kJ. What is the energy change when 1 mole of water, in the gas phase, decomposes to form hydrogen and oxygen? a.142.9 kJ of heat is absorbed. b.285.8 kJ of heat is absorbed. c.142.9 kJ of heat is released. d.285.8 kJ of heat is released.
When One mole of hydrogen is burned in oxygen to produce water in the gas phase, 285.8 kJ of heat is released.Hence, option (D) is correct
What is Enthalpy change ?An enthalpy change is approximately equal to the difference between the energy used to break bonds in a chemical reaction and the energy gained by the formation of new chemical bonds in the reaction.
It describes the energy change of a system at constant pressure. Enthalpy change is denoted by ΔH.
The energy change that occurs when one mole of a compound is burnt in excess oxygen under standard bis called the standard enthalpy change of combustion.
Hence, When One mole of hydrogen is burned in oxygen to produce water in the gas phase, 285.8 kJ of heat is released.Thus, option (D) is correct
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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.
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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]
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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﹏⊂)
The heat capacity of nickel is 0.444 J/(g · °C). Calculate the amount of heat needed to raise the temperature of 12 g of nickel from 23 °C to 69 °C. Now imagine those same joules were used instead to accelerate the same mass of nickel from rest. What would be the final speed, in m/s
Answer:245.088
Explanation: you subtract final temperature with initial temperature = 46 then multiply by grams = 552 then multiplied by J = 245.088
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.
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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!
pls this this solutions
If 6.34 g of CuNO, is dissolved in water to make a 0.720 M solution, what is the volume of the solution in milliliters?
V=n/M
V=(6.34:125.55 g/mol)/0.72
V=0.07 L = 70 ml
What would be the mass, in grams, of 2.408 x 1024 molecules of tetraphosphorus decaoxide?
Answer:
1,135 grams P₄O₁₀
Explanation:
To find the mass, you need to (1) convert molecules to moles (via Avogadro's Number) and then (2) convert moles to grams (via molar mass from periodic table values). It is important to arrange the ratios/ conversions in a way that allows for the cancellation of units (the desired unit should be in the numerator). The final answer should have 4 sig figs to reflect the given value (2.408 x 10²⁴).
Avogadro's Number:
1 mole = 6.022 x 10²³ molecules
tetraphosphorus decaoxide = P₄O₁₀
Molar Mass (P₄O₁₀): 4(30.974 g/mol) + 10(15.998 g/mol)
Molar Mass (P₄O₁₀): 283.876 g/mol
2.408 x 10²⁴ molecules P₄O₁₀ 1 mole 283.876 g
------------------------------------------- x ------------------------------------ x -----------------
6.022 x 10²³ molecules 1 mole
= 1,135 grams P₄O₁₀
In a recent study, 50 males used a new weight-loss supplement, and 37 of them experienced weight loss after two weeks: In the same study, 20 females used
the same supplement, and 13 of them experienced weight loss after two weeks.
Fill in the blanks below to make the most reasonable statement possible.
The new weight-loss supplement was less effective on (Choose one) in the study. That is because only % of them lost
weight after two weeks, whereas % of the (Choose one) lost weight after two weeks.
Answer:
The new weight-loss supplement was less effective on females in the study. That is because only 65% of them lost weight after two weeks, whereas 74% of the males lost weight after two weeks.
Explanation:
37 out of 50 males lost weight after two weeks, so 74% of males lost weight ( (37 · 2)/(50 · 2) ). 13 out of 20 females lost weight after two weeks, so 65% of females lost weight ( (13 · 5)/(20 · 5) ). This means the supplement was less effective on females because males had a higher percentage of losing weight.
Hope this helps !! :D
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.
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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
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.
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I need help with this one bad
Explanation:
it applies to pressure laws
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.
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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
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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.
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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 ;
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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
Hybridization of bromine in SF4 and arsenic in SF2
Answer:
The answer is C
