Answer:
True
Explanation:
as the ph of pure water is 7
(-)log(10^-7) = 7
The statement if the pH of pure water is 7.0, the hydroxide ion concentration in pure water is 1 × 10⁻⁷M is true.
How do we calculate the hydroxide ion concentration?Hydroxide ion concentration in the solution will be calculated by using the below equation as:
pOH = -log[OH⁻]
Relation between pH and pOH is :
pH + pOH = 14
Given that, pH = 7
So, pOH = 14 - 7 = 7
By using first equation, we have
7 = -log[OH⁻]
[OH⁻] = 10⁻⁷M
Hence, hydroxide ion concentration in pure water is 1×10⁻⁷M.
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Why does increasing temperature increase the rate of reaction?
Answer:
Explanation:
Reaction rate measures the speed of chemical reaction and how they proceed with time.
The theories that have been propounded about reactions rates shows that increasing temperature is very important in chemical reactions.
From observation, chemical reaction rates are controlled by:
Nature of the reactantsConcentration of the reactants or pressure for gasesTemperaturePresence of catalystSunlightIncreasing temperature temperature releases heat energy to drive reactions into completing faster. Collisions between reacting particles becomes more as a result of increase in energy. This energy when greater than the activation energy of the reaction would further influence the effectiveness of collisions between reacting particles. This would therefore make reactions proceed faster with more increase in temperature.
Diamonds are mostly composed of what element?
Answer:
Diamonds are composed almost entirely of the element carbon, often with some other impurities in them, such as nitrogen (i.e., pure diamonds are entirely carbon). The element carbon comes in three different natural forms, or allotropes: diamond, graphite, and amorphous.
Explanation:
Hydrazine (N2H4), a rocket fuel , reacts with oxygen to form nitrogen gas and water vapor. The reaction is represented with the equation:
N2H4(l) + O2(g) → N2(g) + 2H2O(g)
At STP, if 4.20L of O2 reacts with N2H4, how many liters of water vapor will be produced?
A)
2.10L H2O(g)
B)
2.67L H2O(g)
C)
5.33L H2O(g)
D)
8.40L H2O(g)
Answer:
D) 8.40 L H₂O(g).
Explanation:
The balanced equation for the mentioned reaction is:2N₂H₄(l) + O₂(g) → N₂(g) + 2H₂O(g),
It is clear that 2.0 moles of N₂H₄ react with 1.0 mole of O₂ to produce 2.0 moles of N₂ and 2.0 moles of H₂O.
At STP, 4.20L of O₂ reacts with N₂H₄:
It is known that at STP: every 1.0 mol of any gas occupies 22.4 L.
using cross multiplication:
1.0 mol of O₂ represents → 22.4 L.
??? mol of O₂ represents → 4.2 L.
∴ 4.2 L of O₂ represents = (1.0 mol)(4.2 L)/(22.4 L) = 0.1875 mol.
To find the no. of moles of H₂O produced:Using cross multiplication:
1.0 mol of O₂ produce → 2.0 mol of H₂O, from stichiometry.
0.1875 mol of O₂ produce → ??? mol of H₂O.
∴ The no. of moles of H₂O = (2.0 mol)(0.1875 mol)/(1.0 mol) = 3.75 mol.
Again, using cross multiplication:1.0 mol of H₂O represents → 22.4 L, at STP.
3.75 mol of H₂O represents → ??? L.
∴ The no. of liters of water vapor will be produced = (3.75 mol)(22.4 L)/(1.0 mol) = 8.4 L.
So, the right choice is: D) 8.40 L H₂O(g).
Final answer:
Using the balanced chemical equation, stoichiometry, and Avogadro's law, we determine that if 4.20 liters of O₂ reacts, it will produce 8.40 liters of H₂O vapor. The correct answer is 8.40L of H₂O vapor.
Explanation:
The question involves a stoichiometric calculation based on the balanced chemical equation for the reaction between hydrazine (N₂H₄) and oxygen (O₂) to produce nitrogen gas (N₂) and water vapor (H₂O). At STP (standard temperature and pressure), one mole of any gas occupies 22.4 liters. According to the balanced chemical equation:
N₂H₄(l) + O₂(g) ⇒N₂(g) + 2H₂O(g)
We can see that 1 mole of O₂ reacts with 1 mole of N₂H₄ to produce 2 moles of H₂O. If 4.20 liters of O₂ are reacted, we can use Avogadro's law to determine the volume of H₂O produced, which will be twice the volume of O₂ reacted because of the 1:2 molar ratio. Therefore, the volume of water vapor produced will be:
4.20 L O₂(g) x (2 moles H₂O / 1 mole O₂) = 8.40 L H₂O(g)
The correct answer is 8.40 L H₂O(g), which corresponds to option D.
Hydrochloric acid is a strong acid that is diprotic. True or false?
Answer:
False.
Correction: Hydrochloric acid is a strong acid that is monoprotic.
Explanation:
Hydrochloric acid is a strong acid because it is completely dissociated to its ions in the solution.But it is a monoprotic acid because it produces 1 mol of H⁺ when it is dissociated. according to the reaction:HCl → H⁺ + Cl⁻.
So, the answer is: False.
And the correction is:
Hydrochloric acid is a strong acid that is monoprotic.
A solute crystal is dropped into a solution containing dissolved solute. It falls to the bottom of the beaker and does not dissolve after vigorous stirring. What does this indicate about the solution?
It is probably super saturated.
What causes an electric current in a wire
An electrical phenomenon is caused by flow of free electrons from one atom to another. The characteristics of current electricity are opposite to those of static electricity. Wires are made up of conductors such as copper or aluminum. ... Current flows from positive to negative and electron flows from negative to positive.
A container holds a pure sample of a radioactive substance with a half-life of 2 hours. Which of the following statements are true?
a) After 1 hour, less than 50 % of the original atoms in the container will have decayed.
b) After 1 hour, more than 50 % of the original atoms in the container will have decayed.
c) After 2 hours, 50 % of the original atoms in the container will have decayed.
d) After 4 hours, 25 % of the original atoms will have decayed.
e) After 4 hours, the total number of atoms in the container will be reduced by 75 %.
A container holds a pure sample of a radioactive substance with a half-life of 2 hours. The true statements are a, c and d.
a) After 1 hour, less than 50 % of the original atoms in the container will have decayed.
True. The half-life of the radioactive substance is 2 hours, which means that after 1 hour, only half of the original atoms would have decayed. Therefore, less than 50% of the original atoms will have decayed.
b) After 1 hour, more than 50 % of the original atoms in the container will have decayed.
False. As explained in statement (a), after 1 hour, less than 50% of the original atoms will have decayed, not more than 50%.
c) After 2 hours, 50 % of the original atoms in the container will have decayed.
True. The half-life of the radioactive substance is 2 hours, so after 2 hours, exactly 50% of the original atoms will have decayed.
d) After 4 hours, 25 % of the original atoms will have decayed.
True. Since the half-life is 2 hours, after 4 hours (2 half-lives), 50% of the original atoms will have decayed. Therefore, 25% of the original atoms will remain after 4 hours.
e) After 4 hours, the total number of atoms in the container will be reduced by 75 %.
False. After 4 hours, as explained in statement (d), 25% of the original atoms will remain, not 75%. So, the total number of atoms will be reduced by 100% - 25% = 75%, not 75%.
Correct statements: a), c), and d).
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Question 3(Multiple Choice Worth 4 points)
(08.04 LC)
Which of the following happens to an acid when it reacts with another substance?
It receives a hydrogen ion.
It receives a hydroxide ion.
It donates a hydroxide ion.
It donates a hydrogen ion.
Answer:
It donates a hydrogen ion
Explanation:
Under the Bronsted-Lowry definition of an acid, acids are protons donors which donate the H+ ion, or the hydrogen ion.
Answer:
The correct option is "it donates a hydrogen ion"
Explanation:
The choice for the last option being the correct answer is because of the Bronsted-Lowry definition of an acid. Bronsted-Lowry acid is a substance that donates a hydrogen ion or a proton.
Consider the reaction below
HCl + NH₃ ⇒ NH₄⁺ + Cl⁻
From the above, we can see that HCl is an example of Bronsted-lowry acid since it donates its hydrogen ion to NH₃ to form NH₄⁺
How is the equilibrium constant of a reaction determined?
Answer:
The molarity of products is divided by the molarity of reactants.
Explanation:
What is the basic theme of organization in the periodic table
Answer:
The basic theme of organization in the periodic table is that elements are divided into groups and periods based on their properties. Elements that exhibit similar properties are placed in the same group while elements that have the similar number of shell are placed in the same period. This arrangement is based basically on the increasing atomic number of the elements in the periodic table. Atomic number is used for the arrangement of the element because it is a fundamental property of all elements.
Chemistry help??
A student increases the temperature of a 100 cm3 balloon from 60°C to 120°C. What will the new volume of the balloon be? (Be careful with units.)
(a) 118 cm3
(b) 200 cm3
(c) 236 cm3
(d) 400 cm3
Final answer:
OPTION A.
Using Charles's Law, the temperature of the balloon is converted to Kelvin and the law is applied to find the new volume when the temperature is increased from 60°C to 120°C. The new volume is approximately 118 cm³.
Explanation:
The question involves applying Charles's Law, which states that the volume of a gas is directly proportional to its temperature when pressure is constant. To find the new volume after an increase in temperature, we convert the temperatures from Celsius to Kelvin by adding 273. The initial temperature (T1) is thus 60°C + 273 = 333K and the final temperature (T2) is 120°C + 273 = 393K. The initial volume (V1) is 100 cm³.
Charles's Law is given by the formula V1/T1 = V2/T2, where V2 is the final volume. Applying this formula, we get:
V1/T1 = V2/T2
(100 cm³) / (333K) = V2 / (393K)
Multiplying both sides by 393K, we find the final volume V2:
V2 = (100 cm³) * (393K) / (333K)
This results in:
V2 ≈ 118 cm³
Therefore, the new volume of the balloon, after increasing the temperature from 60°C to 120°C, will be approximately 118 cm³.
Which of the following conditions remain constant in Gay-Lussac's law? Temperature and number of moles Volume and number of moles Density and temperature Volume and pressure
Answer:
Volume and number of moles.
Explanation:
Gay-Lussac's law was found by Joseph Louis Gay-Lussac in 1808. It states that, for a given mass (no. of moles) and constant volume of an ideal gas, the pressure exerted on the sides of its container is directly proportional to its absolute temperature.So, no. of moles and V are constant.
P ∝ T,
∴ P1/T1 = P2/T2.
So, the right choice is: Volume and number of moles.Answer:
Volume and Number of Moles
Explanation:
I hope this helps !! :)
Base your answer to this question on the information below.During a bread-making process, glucose is converted to ethanol and carbon dioxide, causing the bread dough to rise. Zymase, an enzyme produced by yeast, is a catalyst needed for this reaction.Choose the correct structural formula for the alcohol formed in this reaction.
Answer: 1 C6H12O6===> 2 C2H5OH + 2 CO2
75 In the space in your answer booklet, draw a structural formula for the alcohol formed in this reaction. [1]
Explanation:
The correct structural formula for the alcohol formed in this reaction [tex]CH_3-CH_2-OH[/tex] is also called ethanol.
What is alcohol?Alcohol is any of a class of organic compounds characterized by one or more hydroxyl (―OH) groups attached to a carbon atom of an alkyl group (hydrocarbon chain).
Ethanol is simple alcohol produced via the fermentation of sugars (such as glucose, fructose, and sucrose) by yeasts because yeasts do this conversion in the absence of oxygen.
The correct structural formula for the alcohol formed in this reaction [tex]CH_3-CH_2-OH[/tex] is also called ethanol.
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What happens to a glucose molecule when it loses a hydrogen atom as the result of an oxidation-reduction reaction?
Answer: oxidized
Explanation:
When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction, the molecule becomes
oxidized.
Good luck! and sorry if is not the answer ur looking 4!
Answer:
The glucose molecule is oxidized
Explanation:
When glucose loses a hydrogen atom it is losing 1 proton and 1 electron. As it is losing an electron, the glucose is oxidized.
How is the equilibrium constant of a reaction determined
Answer:
It is given by the concentration of the products divided by the concentration of the reactants
What is the balanced equation for the combustion of sulfur
Answer:
There are three possible chemical equations for the combustion of sulfur:
2S (s) + O₂ (g) → 2SO (g)S (s) + O₂ (g) → SO₂ (g)2S (s) + 3O₂ (g) → 2SO₃ (g)Explanation:
Combustion is a reaction with oxygen. The products of the reaction are oxides, and energy is released in the form of heat and light.
Sulfur iis a nonmetal, so the oxide formed is a nonmetal oxide.
The most common oxidation numbers of sulfur are -2, + 2, + 4, and + 6.
The combination of sulfur with oxygen may be only with the positive oxidation numbers (+2, + 4, and +6).
Then you have three different equations for sulfur combustion:
1) Oxidation number +2:
S(s) + O₂(g) → SO(g)Which when balanced is: 2S(g) + O₂(g) → 2SO(g)
2) Oxitation number +4:
S(s) + O₂(g) → SO₂(g)That equation is already balanced.
3) Oxidation number +6:
S(s) + O₂(g) → SO₃(g)Which when balanced is: 2S(s) + 3O₂(g) → 2SO₃(g)
The balanced equation for the combustion of sulfur is [tex]\[ \text{S}(s) + \text{O}_2(g) \rightarrow \text{SO}_2(g) \][/tex]
To balance this equation, we need to ensure that the number of atoms of each element is the same on both sides of the equation. Sulfur (S) is present as a diatomic molecule [tex](S_2)[/tex] when it reacts with oxygen [tex](O_2)[/tex] to form sulfur dioxide [tex](SO_2)[/tex]. The balanced equation considering the diatomic nature of sulfur is:
[tex]\[ \text{S}_2(s) + \text{O}_2(g) \rightarrow 2\text{SO}_2(g) \][/tex]
Here's the step-by-step process to balance the equation:
1. Start by writing the unbalanced equation with the correct formulas for the reactants and products:
[tex]\[ \text{S}_2 + \text{O}_2 \rightarrow \text{SO}_2 \][/tex]
2. Count the number of atoms of each element on both sides of the equation:
On the left side, there are 2 sulfur (S) atoms and 2 oxygen (O) atoms.
On the right side, there is 1 sulfur (S) atom and 2 oxygen (O) atoms.
3. To balance the sulfur atoms, we need to have the same number of sulfur atoms on both sides. Since there are 2 sulfur atoms on the left, we need to multiply the sulfur dioxide [tex](SO_2)[/tex] by 2 on the right side:
[tex]\[ \text{S}_2 + \text{O}_2 \rightarrow 2\text{SO}_2 \][/tex]
4. Now, count the number of oxygen atoms again. There are 2 oxygen atoms on the left and 4 on the right (2 molecules of [tex]SO_2[/tex], each with 2 oxygen atoms).
5. To balance the oxygen atoms, we need to have 4 oxygen atoms on the left side as well. Since we already have 2 oxygen atoms in one [tex]O_2[/tex] molecule, we need to add another [tex]O_2[/tex] molecule:
[tex]\[ \text{S}_2 + 2\text{O}_2 \rightarrow 2\text{SO}_2 \][/tex]
6. Finally, count the atoms on both sides to confirm that the equation is balanced:
Left side: 2 S atoms and 4 O atoms.
Right side: 2 S atoms (2 molecules of [tex]SO_2[/tex], each with 1 S atom) and 4 O atoms (2 molecules of [tex]SO_2[/tex], each with 2 O atoms).
The equation is now balanced with 2 sulfur atoms and 4 oxygen atoms on both sides."
Carbohydrates are nutrients that supply the main energy source for the body. True or False
Answer:
false
Explanation:
The chart shows the path reactants take to become products. Which statement best describes the chart? A. Heat was removed from the activation energy to create the product. B. Heat was added to create the product. C. The products have less energy than the reactants. D. The products have the same energy as the reactants.
Answer:
B
Explanation:
The final position of the curve is higher than the original height of the curve, meaning the products have more energy than the reactants.
Hence energy was added for the reactants to become the products. This is why the reaction is endothermic, because the products retained some of the supplied energy.
Part of the energy supplied was used to overcome the activation energy (the peak of the curve). However, this extra energy is recuperated as heat once the product is formed.
Answer:
B-
Heat was added to create the product
Explanation:
Just did the quiz on edg
What kind of weather would an occluded front likely bring?
a.
sunny and warm
c.
thunderstorms
b.
much precipitation
d.
cold and dry
Answer:
The answer is b. much precipitation
Explanation:
A front is a strip in which two air masses of different temperatures are separated. An occluded front occurs when a cold front that generally moves more quickly reaches a hot front and merges. The cold air mass, being heavier, stays below, forcing the warmer to rise. When this happens it cools and condenses, causing heavy precipitation.
The occluded fronts cause weak and continuous rains at first with stratiform-type clouds, and later the rains intensify with the arrival of vertically developing clouds, which cause storms.
Answer:
The answer is B.
Explanation:
What is the term for the direction and angle of a handwriting sample?
A) fluidity
B) lift
C) slant
D) spacing
Answer:
slant
Explanation:
In the lab, a chemist adds 3.6 grams of sodium chloride to 100.0 g of water. what is the molality of the solution?
Answer:
0.616 m.
Explanation:
Molality (m) is defined as the no. of moles of solute dissolved in a 1.0 kg of the solvent.m = (no. of moles of solute)/(mass of the solvent (kg))
m = (mass/molar mass) NaCl / (mass of the solvent (kg))
mass of NaCl = 3.6 g, molar mass of NaCl = 58.44 g/mol, mass of water = 100.0 g = 0.1 kg.
m = (mass/molar mass) NaCl / (mass of the solvent (kg)) = (3.6 g / 58.44 g/mol) / (0.1 kg) = 0.616 m.
The molality of a solution if a chemist adds 3.6 grams of sodium chloride to 100.0 g of water is 0.615m.
What is molality?Molality is defined as the no. of moles of solute dissolved in a 1.0 kg of the solvent.
m = no. of moles of solute ÷ mass of the solvent (kg)
no of moles of NaCl = 3.6g ÷ 58.5g/mol = 0.0615mol
Molality = 0.0615mol ÷ 0.1kg
Molality = 0.615m
Therefore, the molality of a solution if a chemist adds 3.6 grams of sodium chloride to 100.0 g of water is 0.615m.
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The reaction depicted in the figure would take place in which of the following?
Answer: Option (a) is the correct answer.
Explanation:
Nuclear fission is defined as a reaction in which a heavy nucleus splits into two or more small nuclei along with emission of energy.
For example, [tex]^{235}_{92}U + ^{1}_{0}n \rightarrow ^{139}_{56}Ba + ^{95}_{36}Kr + 3^{1}_{0}n[/tex]
So, the given diagram shows a large nucleus is splitting into two small nuclei. Therefore, it is a nuclear fission reaction.
Whereas a nuclear reaction in which two small nuclei combine together to result into the formation of a large nucleus is known as a nuclear fusion reaction.
Thus, we can conclude that the reaction depicted in the figure would take place in fission reactor.
Which combination is the best choice to prepare a buffer with a ph of 9.0? which combination is the best choice to prepare a buffer with a of 9.0? nh3; nh4cl (pkb for nh3 is 4.75) hcho2; nacho2 (pka for hcho2 is 3.74) c5h5n; c5h5nhcl (pkb for c5h5n is 8.76) hno2;nano2 (pka for hno2 is 3.33)?
Answer:
[tex]\boxed{\text{NH$_{3}$; NH$_{4}$Cl}}[/tex]
Explanation:
The best choice to prepare a buffer of pH 9.0 is a conjugate acid/base pair in which the acid has pKₐ = 9.0 ± 1.
Let's examine each of the choices.
A. NH₃/NH₄Cl
For NH₃, = pK_b = 4.75
For NH₄⁺, pKₐ 14.00 - 4.75 = 9.25
B. HCHO₂/NaCHO₂
For HCHO₂, pKₐ = 3.74
C. C₅H₅N/ C₅H₅NHCl
For C₅H₅N, = pK_b = 8.76
For C₅H₅N⁺, pKₐ 14.00 – 8.76 = 5.21
D. HNO₂/NaNO₂
For HNO₂, pKₐ = 3.33
The only acid with a pKₐ close to 9.0 is the ammonium ion.
The best buffer to prepare a buffer with pH 9.0 is [tex]\boxed{\text{NH$_{3}$; NH$_{4}$Cl}}[/tex]
From the given options, the best combination to prepare a buffer with a PH of 9.0 is given by;
Option 1; NH₃;NH₄Cl
A buffer solution is defined as an aqueous solution that consists of a mixture of a weak acid and its conjugate base or mixture of a weak base and its' conjugate acid.Now, we want to find the best choice to prepare a buffer of pH 9.0. Thus, let us look at each option;
Option 1; NH₃;NH₄Cl
We are given that pK_b for NH₃ is 4.75
Thus pKₐ for NH₄ is;
NH₄; pKₐ = 14.00 - 4.75
NH₄; pKₐ = 9.25
Option 2; HCHO₂; NaCHO₂
We are given that pK_a for HCHO₂ is 3.74
HCHO₂; pKₐ = 3.74
Option 3; C₅H₅N; C₅H₅NHCl
We are given that pK_b for C₅H₅N is 8.76
Thus
For C₅H₅N, = pK_b = 8.76
Thus, pKₐ for C₅H₅N is;
C₅H₅N; pKₐ = 14.00 – 8.76
C₅H₅N; pKₐ = 5.21
Option 4; HNO₂;NaNO₂
We are given pKₐ for HNO₂ as 3.33
HNO₂; pKₐ = 3.33
Looking at all the pKₐ values, the only acid that has a pKₐ close to 9.0 is NH₄ with a pKₐ of 9.25.
In conclusion, the best combination to prepare a buffer with pH of 9.0 is
NH₃;NH₄Cl
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Assuming equal concentrations and complete dissociation, rank these aqueous solutions by their freezing points.
Li_2SO_4 NH_4l CoCl_3
Highest freezing point Lowest freezing point
Answer:
CoCl₃ > Li₂SO₄ > NH₄I.
Explanation:
Adding solute to water causes depression of the boiling point.The depression in freezing point (ΔTf) can be calculated using the relation:ΔTf = i.Kf.m,
where, ΔTf is the depression in freezing point.
i is the van 't Hoff factor.
van 't Hoff factor is the ratio between the actual concentration of particles produced when the substance is dissolved and the concentration of a substance as calculated from its mass. For most non-electrolytes dissolved in water, the van 't Hoff factor is essentially 1.Kf is the molal depression constant of water.
m is the molality of the solution.
(1) Li₂SO₄:
i for Li₂SO₄ = no. of particles produced when the substance is dissolved/no. of original particle = 3/1 = 3.
∴ ΔTb for (Li₂SO₄) = i.Kb.m = (3)(Kf)(m) = 3(Kf)(m).
(2) NH₄I:
i for NH₄I = no. of particles produced when the substance is dissolved/no. of original particle = 2/1 = 2.
∴ ΔTb for (NH₄I) = i.Kb.m = (2)(Kf)(m) = 2(Kf)(m).
(3) CoCl₃:
i for CoCl₃ = no. of particles produced when the substance is dissolved/no. of original particle = 4/1 = 4.
∴ ΔTb for (CoCl₃) = i.Kb.m = (4)(Kf)(m) = 4(Kf)(m).
So, the ranking of the freezing point from the highest to the lowest is:CoCl₃ > Li₂SO₄ > NH₄I.
Final answer:
The aqueous solutions ranked from highest to lowest freezing point, based on the number of ions they produce upon dissociation, is NH4I (highest freezing point), followed by Li2SO4, and then CoCl3 (lowest freezing point).
Explanation:
To rank aqueous solutions by their freezing points when they have equal concentrations and are completely dissociated, we look at the number of ions each compound dissociates into when dissolved. The more ions produced, the lower the freezing point of the solution due to a greater freezing point depression effect. The given solutions are Li2SO4, NH4I, and CoCl3. Li2SO4 dissociates into 3 ions (2 Li+ + SO42-), NH4I dissociates into 2 ions (NH4+ + I-), and CoCl3 dissociates into 4 ions (Co3+ + 3 Cl-). Therefore, the order from highest to lowest freezing point is: NH4I > Li2SO4 > CoCl3.
Plastic is made from ____. a leachates produced by bioenzymes b melted silica sand grains c byproducts of coal mining d extraction of inorganic solids oil and natural gas e organic molecules derived from oil and natural gas
Answer:
plastic is made from polymers.
Which best describes nuclear fission?
Are there choices to pick from?
What happens to a reaction at equilibrium when more reactant is added to the system?
Answer:
When more reactant is added to a system at equllibrium more product is produced.Explanation:
Provided all other conditons remain constant (e.g. volume and temperature), the addition of more reactant means the increase of the concentration of the reactant, and so, at constant temperature, more product must be produced to compensate such addition of more reactant.
An equlibrium reaction may be represented by the general expression:
aA + bB ⇄ cC + dDAnd the equilibrium constant is given by:
[tex]Keq=\frac{[C]^c.[D]^d}{[A]^a.[B]^b}[/tex]Thus, since at constant temperature Kea is constant, the increase of a reactant concentration (A or B are in the denominator) means that the concentration of the products (C and D in the numerator) must increase.
Since, the molecular point of view what happens is that the increase of the concentration of reactions increase the rate of the direct (forward) reaction yielding to the production of more products.
Final answer:
Adding more reactant to a reaction at equilibrium causes the system to shift right, increasing the rate of the forward reaction and leading to the formation of more products until a new equilibrium is established, with the equilibrium constant (Kc) remaining unchanged.
Explanation:
When a chemical reaction has reached equilibrium, adding more reactant to the system causes the equilibrium to shift. The concepts behind this phenomenon are encapsulated by Le Châtelier's Principle, which states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium moves to counteract the change.
In the case where more reactant is added, the equilibrium will shift to the right, meaning that the reaction system will respond by forming more products to relieve the stress caused by the added reactant. This increase in reactant concentration results in a temporary increase in the rate of the forward reaction compared to the reverse reaction, leading to a consumption of the added reactant and an increase in product concentration until a new equilibrium is established.
After the system readjusts, the reaction quotient (Qc) will once again equal the equilibrium constant (Kc), which remains unchanged as it is only affected by temperature. This adjustment process continues until the rate of the forward reaction and the rate of the reverse reaction are equal again. In essence, by adding more of a reactant, one can temporarily push the reaction to produce more products, a strategy often used in industrial processes to increase yield.
Hydrogen gas has a density of , and at normal pressure and one mole of it takes up . how would you calculate the moles in of hydrogen gas? set the math up. but don't do any of it. just leave your answer as a math expression. also, be sure your answer includes all the correct unit symbols.
To calculate the moles in 5L of hydrogen gas at STP, divide the volume in liters by the volume occupied by one mole of any gas at STP, which is 22.4 L/mol.
To calculate the number of moles in 5L of hydrogen gas at standard temperature and pressure (STP), you can apply the ideal gas law. To set up the calculation, use that at STP, 1 mole of a gas occupies 22.4 L. Use the following mathematical expression for your conversion:
Number of moles = Volume of gas (L) / Volume of 1 mole at STP (L/mol)
For your specific question:
Number of moles of H2 = 5 L / 22.4 L/mol
Make sure to leave your answer as a math expression with the correct units of L for liters and mol for moles.
There are 3 beakers each of which contains saline solution.
Beaker A initially contains 3 liters of 10\% salt solution.
Beaker B initially contains 2 liters of 20\% salt solution.
Beaker C initially contains 4 liters of 0\% salt solution.
Two liters are transferred from A to B and the result is thoroughly mixed. Then one liter is transferred from B to C and the result mixed. Finally two liters are transferred from C back to A. What is the percentage concetration of salt in A after all this?
Percentage concentration of salt in A=____ \%
Answer:
Percentage concentration of salt in A = 5.3%Explanation:
Assume all the concentrations are expressed in volumetric terms, i.e 10% = 10 liter salt / 100 liter solution, 20% = 20 liter salt / 100 liter soluton, 0% = 0 liters salt.
1) First transformation: 2 liters are from A to B
Solution A:
Concentration: 10 % salt ⇒ 10 liter salt / 100 liter solutionVolume of solution: 3 litersVolume of salt: 3 liters × 10 liter / 100 liters = 0.300 liter saltVolume of water: 3 liters - 0.300 liters = 2.700 liters solventSolution B:
Concentraion: 20%Volume of solution: 2 literVolume of salt: 2 liter × 0.20 = 0.4 liter saltVolume of water: 2 liter - 0.4 liter = 1.6 liter waterResultant mixture in beaker B: 2 liters of solution A plus 2 liters of solution B
Salt: 2 liter × 0.10 + 2 liter × 0.20 = 0.20 + 0.4 = 0.6 liter saltWater: 2 liter × 0.90 + 2 liter × 0.80 = 3.40 liter waterSolution: 2 liter + 2 liter = 4 liter solutionConcentration: 0.6 liter salt / 4 liter solution = 0.15 = 15%
2) Second transformation: 1 liter transferred from B to C
Salt: 1 liter × 0.15 + 0 = 0.15 liter salt↑ ↑
(from B) ( in C)
Solution: 1 liter + 4 liter = 5 liter solutionConcentration: 0.15 liter salt / 5 liter solution = 0.03 = 3.0%
3) Third transformation: 2 liters are from C to A.
Salt: 0.03 liter salt × 2 liter solution + 1 liter × 0.10 = 0.16 liter salt↑ ↑
(from C) (in A)
Solution: 2 liter + 1 liter = 3 liter solution% of salt in A = (0.16 liter salt / 3 liter solution) × 100 =5.3 %What change will be caused by addition of a small amount of hcl to a solution containing fluoride ions and hydrogen fluoride?
Answer:
The addition of a small amount of HCl to a solution containing fluoride ions and hydrogen fluoride will cause the equilibrium shift to the production of more hydrogen fluoride.Explanation:
The solution containing fluoride ions and hydrogen fluoride (a weak acid) may be chemically represented by this equilibrium equation:
F⁻ (aq) + H⁺ (aq) ⇄ HF (aq)The HCl, a strong acid, added will ionize in water according to this chemical equation:
HCl (aq) → H⁺ (aq) + Cl⁻ (aq)Then, following Le Chatelir's principle, the addtion of H⁺ ions coming from the HCl dissociation, will increase the concentration of H⁺ in the solution, driving to the consumption of some F⁻ ions, and the production of more HF acid. This is a shift of the equilbrium toward the HF side.
Adding hydrochloric acid to a solution of fluoride ions and hydrogen fluoride will decrease the pH and increase the concentration of hydrofluoric acid while decreasing the concentration of fluoride ions.
When hydrochloric acid (HCl) is added to a solution containing fluoride ions and hydrogen fluoride, it will cause a decrease in the pH of the solution. This is because HCl is a strong acid and it will dissociate completely in water to release hydronium ions (H3O+), resulting in an increase in the solution's acidity. Furthermore, according to Le Chatelier's principle, the addition of HCl will push the equilibrium of the reaction:
HF(aq) + H2O(l) ⇌ H3O+(aq) + F¯(aq)
to the left, meaning that the concentration of hydrofluoric acid (HF) will increase, while the concentration of fluoride ions (F−) will decrease, due to the additional supply of common ions from HCl.