Final answer:
At 0 °C, a solution with a pH of 7.25 is considered basic since the neutrality point at this temperature is approximately pH 6.31.
Explanation:
The pH of a solution at 0 °C that reads 7.25 would actually be basic. This is because the neutrality point of pH at 0 °C is not exactly 7 but approximately 6.31. At this temperature, a solution is considered neutral at pH 6.31, acidic if the pH is less than 6.31, and basic if the pH is greater than 6.31. Given that a pH of 7.25 is more than 6.31, the solution at 0 °C would be classified as basic.
He hydroxide ion concentration in household ammonia is 3.2 × 10−3 m at 25 °c. what is the concentration of hydronium ions in the solution
Answer:- [tex][H_3O^+]=4.2*10^-^1^1[/tex]
Solution:- Ammonia is a weak base. So, to calculate the hydroxide ion concentration we make the ice table:
[tex]NH_3(aq)+H_2O(l)\rightleftharpoons NH_4^+(aq)+OH^-(aq)[/tex]
I 0.0032 0 0
C -X +X +X
E (0.0032-X) X X
[tex]K_b=\frac{[NH_4^+][OH^-]}{[NH_3]}[/tex]
Kb value for ammonia is [tex]1.8*10^-^5[/tex] . Let's plug in the values and solve for X.
[tex]1.8*10^-^5=\frac{X^2}{0.0032-X}[/tex]
Kb value is very low so we can neglect the X on the bottom.
[tex]1.8*10^-^5=\frac{X^2}{0.0032}[/tex]
On cross multiply:
[tex]X^2=1.8*10^-^5*0.0032[/tex]
[tex]X^2=5.76*10^-^8[/tex]
On taking square root:
[tex]X=2.4*10^-^4[/tex]
From ice table, [tex][OH^-]]=X[/tex]
So, [tex][OH^-]=2.4*10^-^4[/tex]
hydronium ion and hydroxide ion concentrations are related to each other by the formula:
[tex][H_3O^+][OH^-]=K_w[/tex]
where, Kw is the water dissociation constant and its value is [tex]1.0*10^-^1^4[/tex]
[tex][H_3O^+]=\frac{1.0*10^-^1^4}{2.4*10^-^4}[/tex]
[tex][H_3O^+]=4.2*10^-^1^1[/tex]
Which of the following is the best definition of a chemical change?
Answer: A change in a substance where one or more new substances form
Explanation: Apex
The equation below shows hydrogen reacting with oxygen to produce water. 2H2+O2>2H2O if 16mol of oxygen were reacted with excess hydrogen gas, how many moles of water would be produced?
Answer : The number of moles of water produced would be, 32 moles.
Explanation : Given,
Moles of [tex]O_2[/tex] = 16 mole
The given chemical reaction is:
[tex]2H_2+O_2\rightarrow 2H_2O[/tex]
From the balanced chemical reaction we conclude that,
As, 1 mole of [tex]O_2[/tex] gas react to give 2 moles of [tex]H_2O[/tex]
So, 16 mole of [tex]O_2[/tex] gas react to give [tex]16\times 2=32[/tex] moles of [tex]H_2O[/tex]
Thus, the number of moles of water produced would be, 32 moles.
Sam wants to demonstrate how water changes from a solid to a gas. He places ice in a pot on a stove. What variable is causing water to change state?
A) the heat from the stove
B) the container the ice is placed in
C) the temperature of the air surrounding the ice
D) the time that has lapsed since the ice was removed from the freezer
Answer: Option (A) is the correct answer.
Explanation:
When Sam placed ice in a pot on a stove then there will be transfer of heat from the stove to the pot and then from the pot to the ice.
As a result, solid state of ice changes into liquid state of water because of melting of ice.
Thus, we can conclude that the heat from the stove is the variable that is causing water to change state.
Is oil used by other organisms on Earth? If yes, explain.
Identify the oxidizing agent in the reaction: 8h+(aq) + 6cl−(aq) + sn(s) + 4no3−(aq) → sncl62−(aq) + 4no2(g) + 4h2o(l)
The oxidizing agent in the reaction is the NO3- ions.
Explanation:In the given reaction,
8H+(aq) + 6Cl-(aq) + Sn(s) + 4NO3-(aq) → SnCl62-(aq) + 4NO2(g) + 4H2O(l)
The oxidizing agent is the species that gets reduced. In this reaction, the NO3- ions are reduced from a +5 oxidation state to a +4 oxidation state, so the NO3- ions are the oxidizing agent.
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In the given reaction, the nitrate ion (NO₃⁻) is the oxidizing agent as it gets reduced from an oxidation number of +5 to +4. The tin (Sn) is oxidized from 0 to +4.
The identification is based on changes in oxidation numbers during the reaction.
To identify the oxidizing agent in the given reaction:
8H⁺(aq) + 6Cl⁻ (aq) + Sn(s) + 4NO₃⁻(aq) → SnCl₆²⁻(aq) + 4NO₂(g) + 4H₂O(l)Assign oxidation numbers to each element in the reaction:
Sn (tin) in its elemental form has an oxidation number of 0.In SnCl₆²⁻ tin’s oxidation number is +4.In NO₃⁻ (nitrate ion), nitrogen has an oxidation number of +5.In NO₂ (nitrogen dioxide), nitrogen has an oxidation number of +4.Determine what is being oxidized and reduced:
sn is oxidized from 0 to +4, losing electrons.NO₃⁻ is reduced from +5 to +4, gaining electrons.Identify the oxidizing and reducing agents:
The species that gets reduced is the oxidizing agent.So, in this reaction, NO₃⁻ (nitrate ion) is the oxidizing agent.
Correct question is: Identify the oxidizing agent in the given reaction:
8H⁺(aq) + 6Cl⁻ (aq) + Sn(s) + 4NO₃⁻(aq) → SnCl₆²⁻(aq) + 4NO₂(g) + 4H₂O(l)
An unknown substance has the composition of 77.87% C, 2.63% H and 55.62% O. The compound has a molar mass of 345.2 g/mole. What is the molecular formula?
Calculate the freezing point of a solution containing 15 grams of kcl and 1650.0 grams of water. the molal-freezing-point-depression constant (kf) for water is 1.86 ∘c/m
Answer : The freezing point of a solution is [tex]-0.454^oC[/tex]
Explanation : Given,
Molal-freezing-point-depression constant [tex](K_f)[/tex] for water = [tex]1.86^oC/m[/tex]
Mass of KCl (solute) = 15 g
Mass of water (solvent) = 1650.0 g = 1.650 kg
Molar mass of KCl = 74.5 g/mole
Formula used :
[tex]\Delta T_f=i\times K_f\times m\\\\T^o-T_s=i\times K_f\times\frac{\text{Mass of KCl}}{\text{Molar mass of KCl}\times \text{Mass of water in Kg}}[/tex]
where,
[tex]\Delta T_f[/tex] = change in freezing point
[tex]\Delta T_s[/tex] = freezing point of solution = ?
[tex]\Delta T^o[/tex] = freezing point of water = [tex]0^oC[/tex]
i = Van't Hoff factor = 2 (for KCl electrolyte)
[tex]K_f[/tex] = freezing point constant for water = [tex]1.86^oC/m[/tex]
m = molality
Now put all the given values in this formula, we get
[tex]0^oC-T_s=2\times (1.86^oC/m)\times \frac{15g}{74.5g/mol\times 1.650kg}[/tex]
[tex]T_s=-0.454^oC[/tex]
Therefore, the freezing point of a solution is [tex]-0.454^oC[/tex]
Answer:
The freezing point of the solution containing 15 grams of KCl and 1650 grams of water is [tex]\rm -0.454^\circ\;C[/tex].
Explanation:
The freezing point of the solution can be calculated by:
Molarity = [tex]\rm \frac{mass\;of\;KCl\;}{molar\;mass\;of\;KCl\;\times\;Mass\;of\;water}[/tex]
Molarity = [tex]\rm \frac{15}{74.5;\times\;1650}[/tex]
Molarity = 1.2 [tex]\rm \times\;10^-^4[/tex] M
[tex]\rm \Delta\;T\;=\;i\;\times\;K_f\;\times\;Molarity[/tex]
[tex]\rm T^\circ\;\times\;T_f\;=\;i\;\times\;K_f\;\times\;Molarity[/tex]
[tex]\rm T_f=\;2\;\times\;1.86\;\times\;1.2\;\times\;10^-^4[/tex]
[tex]\rm T_f[/tex] = [tex]\rm -0.454^\circ\;C[/tex]
The freezing point of the solution containing KCl is [tex]\rm -0.454^\circ\;C[/tex].
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When hydrogen is burned, it reacts with oxygen and produces _____. carbon dioxide water oil helium
The balanced net ionic equation for the neutralization reaction involving equal molar amounts of hno3 and koh is ________.
Final answer:
The balanced net ionic equation for the neutralization reaction involving equal molar amounts of HNO3 and KOH is H+(aq) + OH−(aq) → H2O(l), illustrating the direct interaction between hydrogen and hydroxide ions to form water.
Explanation:
The balanced net ionic equation for the neutralization reaction involving equal molar amounts of HNO3 and KOH is represented by the equation:
H+(aq) + OH−(aq) → H2O(l)
This equation demonstrates that the hydrogen ion (H+) from nitric acid (HNO3) combines with the hydroxide ion (OH−) from potassium hydroxide (KOH) to form water (H2O). The potassium ion (K+) and the nitrate ion (NO3−) are spectator ions and do not participate in the reaction. Therefore, they are not included in the net ionic equation. Neutralization reactions like this involve the combination of an acid and a base to produce water as one of the products.
In which relationship stage are the individuals in the following scenario?
Heather and Mona became good friends about ten years ago. For the last year, though, things haven't been the same. They no longer make the effort to meet up for lunch or go shopping together. They try to remember to call on birthdays and holidays, but sometimes they forget.
terminating
differentiating
stagnating
circumscribing
avoiding
Differentiating is a process of loosing or separating. During this stage, variations between the relationship associates are highlighted and what was considered to be connections starts to crumble. The people avoid discussing the relationship because they believe they understand what the other will respond.
What concentration of the barium ion, ba2+, must be exceeded to precipitate baf2 from a solution that is 1.00×10−2 m in the fluoride ion, f−? ksp for barium fluoride is 2.45×10−5 . express your answer with the appropriate units?
Answer is: concentration of the barium ion is 0.245 M.
Chemical reaction: BaF₂ → Ba²⁺ + 2F⁻.
[F⁻] = 1.00·10⁻² M.
Ksp = 2.45·10⁻⁵.
Ksp = [Ba²⁺] · [F⁻]².
[Ba²⁺] = Ksp ÷ [F⁻]².
[Ba²⁺] = 2.45·10⁻⁵ ÷ (1.00·10⁻² M)².
[Ba²⁺] = 0.245 M.
Answer: The concentration of barium ions that must exceed to precipitate the salt is 0.245 M
Explanation:
Solubility product is defined as the product of concentration of ions present in a solution each raised to the power its stoichiometric ratio. It is represented as [tex]K_{sp}[/tex]
Barium fluoride is an ionic compound formed by the combination of 1 barium ion and 2 fluoride ions.
The equilibrium reaction for the ionization of barium fluoride follows the equation:
[tex]BaF_2(s)\rightleftharpoons Ba^{2+}(aq.)+2F^-(aq.)[/tex]
The solubility product for the above reaction is:
[tex]K_{sp}=[Ba^{2+}]\times [F^-]^2[/tex]
We are given:
[tex][F^-]=1.00\times 10^{-2}M\\\\K_{sp}=2.45\times 10^{-5}[/tex]
Putting values in above equation, we get:
[tex]2.45\times 10^{-5}=[Ba^{2+}]\times (1.00\times 10^{-2})^2[/tex]
[tex][Ba^{2+}]=\frac{2.45\times 10^{-5}}{(1.00\times 10^{-2})^2}=0.245M[/tex]
Hence, the concentration of barium ions that must exceed to precipitate the salt is 0.245 M
A mixture is two or more substances that are mixed together but not chemically combined. The substances in a mixture each keep their own properties and can be separated from the mixture.
Identify the substance in a mixture of sand, salt, sawdust, and iron filings that can easily be separated by dissolving the mixture in water.
A) sand
B) salt
C) sawdust
D) iron filings
Plz help!
The nucleus of the atom contains what subatomic particle(s)? Protons only Neutrons only Electrons only Protons and neutrons Protons and electrons
Answer:
c
Explanation:
Consider the following equilibrium:
4KO2(s) + 2H2O(g) 4KOH(s) + 3O2(g)
Which of the following is a correct equilibrium expression?
Keq=[KOH]4[O2]3[KO2]4[H2O]2
Keq=[H2O]2[O2]3
Keq=[KO2]4[H2O]2[KOH]4[O2]3
Keq=[O2]3[H2O]2
Answer:
[tex]Keq=\frac{[O_{2}]^{3} }{[H_{2}O]^{2} }[/tex]
Explanation:
The equilibrium constant (Keq) is equal to the product of the concentrations of the products raised to their stoichiometric coefficients divided by the product of the concentrations of the reactants raised to their stoichiometric coefficients. In Keq we include gases and aqueous species, but not solids nor pure liquids because their concentration remains almost constant over time.
Let's consider the following reaction.
4 KO₂(s) + 2 H₂O(g) ⇄ 4 KOH(s) + 3 O₂(g)
Then, the equilibrium constant is:
[tex]Keq=\frac{[O_{2}]^{3} }{[H_{2}O]^{2} }[/tex]
When assigning electrons to orbitals, which would be the most likely 'address' for the next electron following the 5s2 electron? 5s3 5p1 4d1 5d1
Filling of electrons in an orbitals takes place by using following rules:
Aufbau rule: Filling of electrons takes place in an energy levels in the increasing order of energy that is the one having lowest energy will fill first.
Hunds rule: No second electron will be filled in an orbital until each orbital occupies a single electron.
Pauli exclusion principle: No two electrons can have same spin in an orbital.
So here also also the rules must be applied in filling electrons , by Aufbau rule, energy level that is having lower energy in this case after 5s it will be 4d¹, will fill first. So the answer is 4d¹.
The decomposition of hi has a rate constant of 1.80 × 10-3 m-1s-1. how much hi remains after 8.50 min if the initial concentration of hi is 4.78 m?
Which atomic model proposed that electrons move in specific orbits around the nucleus of an atom?
Dalton’s atomic model
Thomson’s atomic model
Rutherford’s atomic model
Bohr’s atomic model
quantum atomic model
Answer: The correct answer is Bohr's atomic model.
Explanation:
For the given options:
Dalton's atomic model: This model states that every matter is made up of smallest unit known as atom.
Thomson's atomic model: He proposed a model known as plum pudding model. He considered atom to be a pudding of positive charge in which negative particles are embedded such as plum.
Rutherford's atomic model: He gave an experiment known as gold foil experiment. In his model, he concluded that in an atom, there exist a small positive charge in the center.
Bohr's atomic model: This model states that electron revolve around the nucleus in discrete orbits in an atom.
Quantum atomic model: This model determines the location of electrons in an atom in a 3-D space.
Hence, the correct answer is Bohr's atomic model.
When a collision occurs between two reactant particles that, between them, have the required minimum kinetic energy, or activation energy, a product does not always form. Which of the following reasons explains this?
a.low temperature
b.small surface area
c.unfavorable geometry
d.low concentration
c.unfavorable geometry
Answer: C. Unfavorable geometry
Explanation: When collision occurs between two reactants in order to make a reaction possible there are 3 factors which are responsible.
a) Orientation factor
b) Energy factor
c) rate of collision
Thus out of the given options, unfavorable geometry is the correct one as temperature and concentration as well as surface area will have very little effect on the reaction.
If the geometry of the reactant is not complementary then the reaction would not lead successfully.
Write the name of the following compound MgSO4 • H20
which of the following substances has a molar mass of 208g
What is the molality of a solution that contains 75.2 grams of AgClO4 in 885 grams of benzene? Question 5 options: 0.41 m 4.10 m 8.20 m 0.83 m
The molality of the solution is 0.41 molal and the correct option is option 1.
What is Molality?
Molality is also known as molal concentration. It is a measure of solute concentration in a solution. The solution is composed of two components; solute and solvent.
The number of moles of solute in a solution corresponding to 1 kg or 1000 g of solvent is known as molality.
Molality = number of moles of solute ÷ mass of solvent in kg
Given,
Mass of AgClO₄ = 75.2g
Mass of benzene = 885g
Molality = number of moles of solute ÷ mass of solvent in kg
moles of AgClO₄ = 75.2 / 207
= 0.363 moles
Molality = 0.363 / 0.885
= 0.41 molal
Therefore, the molality of the solution is 0.41 molal and the correct option is option 1.
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Radon (rn) is the heaviest and the only radioactive member of group 8a(18), the noble gases. it is a product of the disintegration of heavier radioactive nuclei found in minute concentrations in many common rocks used for building and construction. in recent years, health concerns about the cancers caused from inhaled residential radon have grown. if 1.00 × 1015 atoms of radium (ra) produce an average of 1.373 × 104 atoms of rn per second, how many liters of rn, measured at stp, are produced per day by 9.64 g of ra?
The amount of Rn produced per day by 9.64 g of Ra is 1.13 [tex]\rm \times\;10^-^8[/tex] L.
Moles of Radon (Ra) in 9.64 g of Ra are;
Moles = [tex]\rm \dfrac{weight}{molecular\;weight}[/tex]
Moles of Ra = [tex]\rm \dfrac{9.64}{226}[/tex]
Moles of Ra = 0.0426
Number of atoms of Ra in 0.0426 moles of Ra are:
Number of atoms = moles [tex]\times[/tex] Avagadro number
= 0.426 [tex]\times\;6.203\;\times\;10^2^3[/tex]
number of atoms of Ra produced by 9.64 g of Ra are 2.56 [tex]\rm \times\;10^2^3[/tex]
the proportion of atoms : atom\sec will be:
[tex]\rm \dfrac{atoms\;of\;Ra}{atoms\;of\;Ra/sec}\;=\;\dfrac{atoms\;of\;Rn}{x}[/tex]
[tex]\rm \dfrac{1\;\times\;10^1^5}{1.373\;\times\;10^4}\;=\;\dfrac{2.56\;\times\;10^2^2}{x}[/tex]
Atoms of Rn produced per second are 3.53 [tex]\rn \times\;10^1^0[/tex] atoms/sec.
Moles of Rn produced = [tex]\rm \dfrac{atoms\;per\;sec}{avagadro\;number}[/tex]
Moles of Rn produced = [tex]\rm \dfrac{3.52\;\times\;10^1^0}{6.023\;\times\;10^2^3}[/tex] moles
Moles of Rn produced = 5.85 [tex]\rm \times\;10^-^1^4[/tex] mol/sec.
From the ideal gas equation,
PV = nRT
The volume of Rn produced = [tex]\rm \dfrac{nRT}{P}[/tex]
= [tex]\rm \dfrac{5.85\;\times\;10^-^1^4\;\times\;0.0821\;\times\;273.15}{1}[/tex]
= 1.31 [tex]\rm \times\;10^-^1^3[/tex] liter/sec.
The amount of Rn produced per day = amount produced per second [tex]\times[/tex] 3600
The amount of Rn produced per day = 1.31 [tex]\rm \times\;10^-^1^3[/tex] [tex]\times[/tex] 24 [tex]\times[/tex] 3600 L
The amount of Rn produced per day by 9.64 g of Ra is 1.13 [tex]\rm \times\;10^-^8[/tex] L.
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How many grams of sodium metal are needed to react completely with 25.8 liters of chlorine gas at 293 Kelvin and 1.30 atmospheres? Ideal gas law after stoichiometry I don't need the answer please don't give it just explain how to solve it.
How do impulses travel from one neuron to another?
At high pressures, real gases do not behave ideally. calculate the pressure exerted by 18.0 g h2 at 20.0°c in a 1.00 l container assuming in part 1 non-ideal behavior and in part 2 ideal behavior.
What is true about the element Francium (Fr, atomic number 87)? choose 3
A. It has seven valence electrons
B. It is likely to form ionic bonds
C. It is a nonmetal
D. It is in period Seven
E. It is a metal
Answer :
(B) It is likely to form ionic bonds
(D) It is in period seven
(E) It is a metal
Explanation :
Francium is an element whose symbol is 'Fr' and atomic number is 87.
Group 1 alkali metals consists elements Lithium, Sodium, Potassium, Rubidium, Caesium and Francium. Periodic table also shown below.
Francium belongs to the group 1 (alkali metal) and it is in period seven.
It has one valence electron, the electronic configuration of Francium is [Rn} [tex]7s^{1}[/tex].
Alkali metals have tendency to form ionic compounds because they have +1 charge.
The correct statements about Francium (Fr, atomic number 87) are that it is likely to form ionic bonds, is in period seven, and is a metal.
Explanation:The element Francium (Fr, atomic number 87) has several characteristics based on its position in the periodic table. Firstly, as an element in Group 1, it has one valence electron which makes statement A incorrect. This single valence electron also means Francium is highly probable to form ionic bonds with nonmetals seeking to gain electrons, making statement B true. Francium is not a nonmetal, so statement C is false. Statement D is correct as Francium is located in period seven of the periodic table. Lastly, because Francium is in Group 1, it is indeed an alkali metal, making statement E true. Therefore, the correct statements about Francium are B, D, and E.
2no2(g)⇌n2o4(g) kp=6.7at298k a 2.35-l container contains 0.053 mol of no2 and 0.084 mol of n2o4at298k. is the reaction at equilibrium? if not, in what direction will the reaction proceed?
Q> K hence the reaction proceeds in the reverse direction.
First we must obtain the concentration of each of the species;
NO2 - 0.053 mol/2.35-l = 0.023 M
N2O4 - 0.084 mol/2.35-l = 0.036 M
Hence;
Q = [N204]/[NO2]^2
Q = [0.036]/[0.023]^2
Q = 68.05
Since Q > K, it follows that the reaction moves towards the left hand side.
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The reaction quotient Q was found to be 69.86, which is greater than the equilibrium constant Kp of 6.7. Therefore, the reaction will shift towards the formation of NO2 (g) to reach equilibrium.
Explanation:To determine whether the reaction is at equilibrium, we need to calculate the reaction quotient (Qp) and compare it with the given equilibrium constant (Kp). The reaction we are analyzing is:
2 NO2 (g) ⇌ N2O4 (g), with Kp = 6.7 at 298 K.
The reaction quotient Qp is defined similarly to Kp but for an initial or non-equilibrium state and is calculated using partial pressures. Since we are given the number of moles and the volume of the container, we can use the ideal gas law to find the partial pressures of NO2 and N2O4. However, the student question provides moles instead of partial pressures, so we will assume ideal gas behavior and calculate the reaction quotient (Q) with concentrations, which can be used in place of Qp for our rough estimation, knowing they are related in the circumstance of gasses at same temperature and pressure.
The molar concentrations are:
Now we calculate the reaction quotient Q using the given concentrations:
Q = [N2O4]1 / [NO2]2
= 0.0357 / (0.0226)2
= 0.0357 / 0.000511
= 69.86
Since Q (69.86) is greater than Kp (6.7), the reaction will proceed in the direction that reduces Q to equal Kp, which is towards the formation of NO2 from N2O4.
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substract 10x +9 from 7x-10
This is a subtraction of expression. You should remember the rules in subtracting or adding expression. You can only add or subtract two terms if they are similar terms which mean they have the same variable with the same exponents.
(7x – 10) – (10x + 9)
You have to distribute the negative to the parenthesis.
7x – 10 – 10x – 9
7x – 10x – 10 – 9
-3x - 19
Vitellium (Vi) has the following composition:
Vi–188: 187.9122 amu; 10.861%
Vi–191: 190.9047 amu; 12.428%
Vi–193: 192.8938 amu; 76.711%
Based on this data, what can you predict about the average atomic mass of vitellium?
A.)It will be equal to the arithmetic mean of the masses of the three isotopes.
B.)It will be closer to the mass of Vi–188.
C.)It will be closer to the mass of Vi–193.
D.)It will be equal to the mass of Vi–193.
And I am a PLATO user so I already know it's not A!