Answer:
82.9 mL
Explanation:
1. Volume of silver
[tex]\begin{array}{rcl}\text{Density}&=& \dfrac{\text{Mass}}{\text{Volume}}\\\\\rho&=& \dfrac{m}{V}\\\\V &=& \dfrac{m}{\rho}\\\\& = & \dfrac{\text{50.0 g}}{\text{10.49 g$\cdot$mL}^{-1}}\\\\& = & \text{4.766 mL}\\\end{array}\\\text{The volume of the silver is $\large \boxed{\textbf{4.766 mL}}$}[/tex]
2. Volume of gold
[tex]\begin{array}{rcl}V& = & \dfrac{\text{50.0 g}}{\text{19.30 g$\cdot$mL}^{-1}}\\\\& = & \text{2.591 mL}\\\end{array}\\\text{The volume of the gold is $\large \boxed{\textbf{2.591 mL}}$}[/tex]
3. Total volume of silver and gold
V = 4.766 mL + 2.591 mL = 7.36 mL
4 New reading of water level
V = 75.5 mL + 7.36 mL = 82.9 mL
How many moles of O2 are needed to react completely with 35 moles of FeCl3? 4FeCl3 + 3O2 > 2Fe2O3 + 3Cl2
Answer:
26 mol
Explanation:
Step 1: Write the balanced equation
4 FeCl₃ + 3 O₂ ⇒ 2 Fe₂O₃ + 3 Cl₂
Step 2: Determine the appropriate molar ratio
The molar ratio of FeCl₃ to O₂ is 4:3.
Step 3: Use the determined molar ratio to calculate the moles of oxygen required to completely react with 35 moles of ferric chloride
[tex]35molFeCl_3 \times \frac{3molO_2}{4molFeCl_3} = 26molO_2[/tex]
Answer:
[tex]n_{O_2}=26.25molO_2[/tex]
Explanation:
Hello,
In this case, given the reaction:
[tex]4FeCl_3 + 3O_2 \rightarrow 2Fe_2O_3 + 6Cl_2[/tex]
Since oxygen and iron (III) chloride are in a 4:3 molar ratio, he required moles of oxygen to completely react with 35 moles of iron (III) chloride result:
[tex]n_{O_2}=35molFeCl_3*\frac{3molO_2}{4molFeCl_3} \\\\n_{O_2}=26.25molO_2[/tex]
Best regards.
Given the partial equation: MnO4−+ SO32− → Mn2++ SO42−, balance the reaction in acidic solution using the half-reaction method and fill in the coefficients. The missing blanks represent H2O, H+, or OH-, as required to balance the reaction. Enter the coefficients as integers, using the lowest whole numbers. If the coefficient for something is "1", make sure to type that in and not leave it blank. Enter only the coefficients.
Explanation:
MnO4−+ SO32− → Mn2++ SO42−
Splitting into half equations;
MnO4− → Mn2+
SO32− → SO42−
Balancing the electrons;
2 MnO4− + 10 e- → 2Mn2+
5SO32− → 5SO42− + 10 e-
In an acidic medium, it becomes;
2 MnO4− + 8 H+ → 2 Mn2+ + 4 H2O
5 SO32− + H2O → 5 SO42− + 2 H+
Final equation is;
2 MnO4- + 5 SO32- + 6 H+ → 2 (Mn)2+ + 5 SO42- + 3 H2O
Coefficient of H+ = 6
Coefficient of H2O = 3
Coefficient of MnO4- = 2
Coefficient of SO32- = 5
Coefficient of (Mn)2+- = 2
Coefficient of SO42- = 5
Answer:
[tex]5SO_3^{2-}+2MnO_4^{-}+6H^+ \rightarrow 5SO_4^{2-}+ 2Mn^{2+}+3H_2O[/tex]
Explanation:
Hello,
In this case, given the reaction:
[tex]MnO_4^{-}+ SO_3^{2-} \rightarrow Mn^{2+}+ SO_4^{2-}[/tex]
We first identify the oxidation state of both manganese and sulfur at each side:
[tex]Mn^{7+}O_4^{-}+ S^{4+}O_3^{2-} \rightarrow Mn^{2+}+ S^{6+}O_4^{2-}[/tex]
So we have the oxidation and reduction half-reactions below, including the addition of water and hydronium as it is in acidic media:
[tex]S^{4+}O_3^{2-}+H_2O \rightarrow S^{6+}O_4^{2-}+2H^++2e^-[/tex]
[tex]Mn^{7+}O_4^{-}+8H^++5e^- \rightarrow Mn^{2+}+4H_2O[/tex]
Next, we exchange the transferred electrons:
[tex]5*(S^{4+}O_3^{2-}+H_2O \rightarrow S^{6+}O_4^{2-}+2H^++2e^-)\\2*(Mn^{7+}O_4^{-}+8H^++5e^- \rightarrow Mn^{2+}+4H_2O)\\\\5S^{4+}O_3^{2-}+5H_2O \rightarrow 5S^{6+}O_4^{2-}+10H^++10e^-\\2Mn^{7+}O_4^{-}+16H^++10e^- \rightarrow 2Mn^{2+}+8H_2O[/tex]
Then we add the resulting half-reactions and simplify the transferred electrons:
[tex]5S^{4+}O_3^{2-}+5H_2O+2Mn^{7+}O_4^{-}+16H^+ \rightarrow 5S^{6+}O_4^{2-}+10H^++ 2Mn^{2+}+8H_2O[/tex]
We rearrange the terms in order to simplify water and hydronium molecules:
[tex]5S^{4+}O_3^{2-}+2Mn^{7+}O_4^{-}+16H^+-10H^+ \rightarrow 5S^{6+}O_4^{2-}+ 2Mn^{2+}+8H_2O-5H_2O\\\\5S^{4+}O_3^{2-}+2Mn^{7+}O_4^{-}+6H^+ \rightarrow 5S^{6+}O_4^{2-}+ 2Mn^{2+}+3H_2O[/tex]
Finally we write the balanced reaction in acidic media:
[tex]5SO_3^{2-}+2MnO_4^{-}+6H^+ \rightarrow 5SO_4^{2-}+ 2Mn^{2+}+3H_2O[/tex]
Best regards.
a hot liquid located under earth's surface?
Answer:
Magma
Explanation:
Magma is the hot liquid under earths surface
2. What are the similarities between law of triads and law of octaves?
Answer:
The similarities are the groups, triads law is a law where they are in groups or three, the octaves law is the 'best' law, is the one who every atom wants, they do everything to be in groups of eight.
Explanation:
When a chemical reaction releases energy it is called what
When a chemical reaction releases energy it is called Exothermic Reaction.
hope it helps!
When a chemical reaction energy releases then this type of reaction is called exothermic reaction. In this reaction energy is release to the atmosphere.
What is exothermic reaction?In chemistry there are various type of reaction out of which the two main types are the exothermic reaction and endothermic reaction.
Exothermic reaction is the one in which energy releases in form of heat respiration reaction is an example of exothermic reaction. In respiration food that we eat are broken down in glucose with release of energy.
Endothermic reaction is the one in which energy is taken out during the reaction. Photosynthesis is an example of endothermic reaction where sunlight energy is taken by the plants to make food.
Thus when a chemical reaction releases energy these reactions are called exothermic reaction.
To learn more about exothermic reaction, here:
https://brainly.com/question/13014923
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Porosities can have merits and demerits during manufacturing procedures of dental materials. Clarify this statement.
Answer:
The porosities in dental materials can be of merit and not merit since some dental materials need to be porous in order to reduce their weight and improve their properties and functions, whereas in those (which are the majority) porosities are not Merit, see the properties of the material, the function and can even influence dental rehabilitation.
An example of this is the use of vitreous ionomers, which is a dental material, where when it is spatulated it remains porous, it can give recurrence of infectious caries, since its permeability increases, the best cariogenic microorganisms are filtered and porosity works as a retentive site for these microorganisms that make up the dental biofilm.
In summary, the world of dental materials is very wide, some are resins, other cements, others have metallic claims, etc. To say that the presence of porosity is merit or demerit would be ideal because for some materials this is favorable and for others unfavorable since they are very versatile, with different qualities, different degrees of porosity, different molecules, different coefficients of thermal expansion, some do not set, others do not, some are light-cured, others do not, some withstand more mechanical forces and have more elastic modulus and less porosity, while others do not, and thus with many more variables.
Explanation:
In the manufacture of dental materials, much attention is always paid to what the manufacturer indicates in these indications that come on the reverse side of the material or on a paper inside the material container.
This is important to know, because the manufacturer is the one that indicates the mode of use and working time according to the trademark and the chemical composition of the dental material.
That a dental material in its manufacture is more or less porous, makes its density, weight and volume possibly be affected, there are materials that seek to increase porosity for a certain purpose, while others seek the opposite, depending on the function that is applied, will have more or less pores.
The example we gave above about the vitreous ionomer is an example that indicates that in the case of restorative dental materials where the function is to SEAL the porosity is almost nil, since otherwise it will not seal the cavity that was formed with caries and not the infectious problem would be solved.
On the other hand, in the surgical field of dentistry there are bone grafts or porous macroparticles that are for the purpose of bone replacement, which in order to be integrated need blood vessels that run over these pores, irrigating the area of bone neoformation well, in this case the merit of porosity if necessary and it is essential that they be very porous.
the diagram above represents a reflex arc in a human. This pathway responds when someone touches something that causes pain, such as a hot stove. Which of the following shows the correct order of the body systems involved in this response?
A) Integumentary, respiratory, digestive
B) Circulatory, respiratory, nervous
C) Integumentary, nervous, muscular
D) Circulatory, digestive, nervous
Answer:
C) Integumentary, nervous, muscular
Explanation:
When a human body touches a hot stove , our sense organ which is integumen first of all receives the impulse of heat . The impulse is transformed into electrical signal which is transmitted to brain which is a part of nervous system . Then brain processes it and command signal is sent to muscle of hand to move it away from that place . Hence the order is
Integumentary, nervous, muscular .
4. A burning candle is an example of a chemical reaction taking place. What i
can be inferred about this reaction? Choose the correct answer."
A.Mass is not conserved.
B. The reaction absorbs energy. C.The reaction releases energy
D.There are reactants but no products,
Answer:
C
Explanation:
heat is energy
Using Boyle's Law solve the following: An unknown gas has a volume of 200.0 mL and a pressure of 350.0 torr, pressure were increased to 700.0 torr, what is the resulting volume?
Answer:
400 mL
Explanation:
Boyle's Law: [tex]P_1*V_1 = P_2*V_2[/tex]
Let x = the resulting volume
350 (200) = 700 (x)
x = 400 mL
Describe an autopsy table
After the body is cleaned, the body is weighed and measured before being placed on the autopsy table for reexamination. The autopsy table is typically a slanted, aluminum table with raised edges that has several faucets and drains used to wash away collecting blood during the internal investigation.
Answer:
A table used to scientifically determine the cause of death of a human or animal
Explanation:
A polymer coating of 6:0 mm thickness is cast onto a nonporous flat surface. The coating contains a residual amount of casting solvent, which is uniform at 1.0 wt% within the coating. The mass transfer of solvent through the polymer coating is controlled by molecular diffusion. The air flowing over the coating surface eliminates convective mass-transfer resistances and reduces the solvent vapor concentration in the air to nearly zero. The effective diffusion coefficient of the solvent molecules in the polymer is 2 x 10^-6 cm^2/s.
a. How many hours will it take for the solvent concentration at 1.2 mm from the surface to be reduced to 0.035 wt%?
Answer:
vent vapor concentration in the air to nearly zero. The effective diffusion coefficient of the solvent molecules in the polymer is 2 x 10^-6 cm^2/s
Explanation:
Which of the following will increase the boiling point of water?
Adding more water
Adding sugar
Removing some of the water
None of the above
Answer:
Explanation:
Adding sugar
The alcohol functional group is composed of elements
Answer:carbon, hydrogen and oxygen
Explanation:
Alcohol functional group is composed of carbon, hydrogen and oxygen
What is the hydrogen ion concentration [H+] of a HCl solution if the pH is measured to be 2.0?
Answer:
.01
Explanation:
H30+=10^-pH
- Hope that helps! Please let me know if you need further explanation.
If an insufficient amount of liquid unknown had been used, how would this have effected the value of the experimental molar mass
Answer:
Actual yield reduces the more.
Explanation:
An actual yield of the course of a chemical reaction is the mass of a product actually obtained from the reaction.
In practice you see it and It is usually less than the theoretical yield.
Various reasons may come up to explain this away but here is one:
• incomplete reactions, simply put here some of the reactants do not react to form the product.
The same applies in the question about the actual yield will reduce significantly in molar mass now that insufficient amount of reagent are used.
Considering the limiting reactant, what is the mass of zinc sulfide produced from 0.250 g of zinc and 0.750 g of sulfur? Zn(s)+S(S) ZnS(s)
Answer:
The mass of zinc sulfide produced is [tex]M_{ZnS} = 0.76 \ g[/tex]
Explanation:
From the question we are told that
The mass of zinc is [tex]m_z = 0.750 \ g[/tex]
The mass of sulfur is [tex]m_s = 0.250 \ g[/tex]
The molar mass of [tex]Zn_{(s)}[/tex] is a constant with value 65.39 g /mol
The molar mass of [tex]S_{(s)}[/tex] is a constant with value 32.01 g/mol
The molar mass of [tex]ZnS_{(s)}[/tex] is a constant with value 97.46 g/mol
The reaction is
[tex]Zn_{(s)} + S_{(s)} ------> ZnS_{(s)}[/tex]
So from the reaction
1 mole of [tex]Zn_{(s)}[/tex] react with 1 mole of [tex]S_{(s)}[/tex] to produce 1 mole of [tex]ZnS_{(s)}[/tex]
This implies that
65.39 g /mol of [tex]Zn_{(s)}[/tex] react with 32.01 g/mol of [tex]S_{(s)}[/tex] to produce 97.46 g/mol of [tex]ZnS_{(s)}[/tex]
From the values given we can deduce that the limiting reactant is sulfur cause of the smaller mass
So
0.250 g of [tex]Zn_{(s)}[/tex] react with 0.250 of [tex]S_{(s)}[/tex] to produce [tex]x \ g[/tex] of [tex]ZnS_{(s)}[/tex]
So
[tex]x = \frac{97.46 * 0.250}{32.01}[/tex]
[tex]x = 0.76 \ g[/tex]
Thus the mass of the mass of zinc sulfide produced is
[tex]M_{ZnS} = 0.76 \ g[/tex]
234.
In the equation:
Th →
90
particle is presented by.X?
234
Pa + X, which
91
0
1
1.
3.
-70
TH
0
4
He
2.
4.
*70
Answer:
the answer woul be 89 if you do the math right
Explanation:
A gas occupies 18.7 L at standard temperature. What is its volume at 200.5 °C
Answer:
32.4 L
Explanation:
Note 1:
The Standard Temperature and Pressure (STP) is defined by IUPAC as air at 0 gradius Celcius and 1 bar.
Note 2:
The Ideal Gas Law is used for solving this problem.
......
Please see the step-by-step solution in the picture attached below.
Hope this answer can help you. Have a nice day!
A loud classroom demonstration involves igniting a hydrogen-filled balloon. The hydrogen within the balloon reacts explosively with oxygen in the air to form water. If the balloon is filled with a mixture of hydrogen and oxygen, the explosion is even louder than if the balloon is only filled with hydrogen. The intensity of the explosion depends on the relative amounts of oxygen and hydrogen within the balloon. Look below at the molecular views representing different amounts of hydrogen and oxygen in four different balloons. Based on the balanced chemical equation, which balloon will make the LOUDEST explosion and why?
Answer:
See explaination
Explanation:
When ignited, hydrogen gas combines with oxygen gas explosively in proportions ranging from 4.1 - 71.5% hydrogen - ignition temperature is 580 °C. The gaseous reaction is
2 H2(g) + O2(g) → 2 H2O(g)
This exothermic reaction yields 232 kJ/mol of water formed. The rapid release of a considerable amount of energy causes the surrounding air to expand suddenly, resulting in a sharp expolsion. When pure hydrogen is ignited, the reaction with the surrounding air is less rapid, the sound is less loud, and a significantly larger flame is produced.
The amount of water produced directly influences the amount of heat produced and the amount of energy released. If the two gases are in the correct ratio of 1 oxygen to 2 hydrogen we get the loudest sound as the maximum amount of water is produced for the same volume of the balloon.
For any ration away from 1 oxygen to 2 hydrogen by volume and mole we will get a less louder sound. The farther we are away from this ratio the lesser amount of water is formed and thus lesser heat released and lesser sound.
To demonstrate let us take 4 balloons
Balloon A 1: 2 oxygen to hydrogen
Baloon B 1.2 : 1.8 oxygen and hydrogen
Balloon C 1:1 oxygen to hydrogen
Balloon D 2:1 oxygen to hydrogen
So we will see A is the loudest followed by B, C and least loud is D.
The periodic table of the elements lists the elements in order of increasing atomic number. Each element has its own unique square in the periodic table. Numbers in an element's square are used to tell how many protons, neutrons and electrons a typical atom of each element has.

Based on the information shown, which of the following is true about magnesium atoms?
A.
They all have 12 protons.
B.
Some have 24 protons and others do not.
C.
They all have 24 protons.
D.
Some have 12 protons and others do not.
Answer:
A) They all have 12 protons.
Explanation:
Magnesium has an atomic number of 12 which means it has 12 protons. All Magnesium atoms have 12 protons, the neutrons however may differ which produces things called isotopes where the atoms have same protons but neutrons change.
Keep in mind the atomic number is unique to each element, so 12 atomic number will always be Magnesium, 1 will always be Hydrogen and so on.....
Lewisite (2-chloroethenyldichloroarsine) was once manufactured as a chemical weapon, acting as a lung irritant and a blistering agent. During World War II, British biochemists developed an antidote which came to be known as British anti-Lewisite (BAL) (2,3-disulfanylpropan-1-ol). Today, BAL is used medically to treat toxic metal poisoning. Complete the reaction between Lewisite and BAL by giving the structure of the organic product and indicating the coefficient for the number of moles of HCl produced in the reaction.
Answer:
2 HCl
Explanation:
Please kindly check attachment for the step by step solution of the given problem.
Please help! BRANLIEST to right answer
Answer:
Endothermic, positive
Explanation:
Ascorbic acid (H2C6H6O6), also known as Vitamin C, is a polyprotic acid found in fruit, tomatoes, potatoes and leafy vegetables. The pKa's of the ascorbic acid are pKa1 = 4.10 and pKa2 = 11.80 at 25 °C. When ascorbic acid is titrated with NaOH and it takes 60.0 mL to remove all protons possible. In the titration curve, how many mL of NaOH are required to reach the first pKa? Another way of asking this is when presented with a titration curve of ascorbic acid where on the x-axis should one look (which volume of NaOH), if one wants to determine the first pKa?
Answer:
as when we add 60 ml it removes all the protons it means it is 2nd equivalence point of Ascorbic acid
and we know that pH = pKa1 when moles of NaOH is half of the 1st equivalence point
1st equivalence point = 2nd equivalence point / 2 = 60/2 =30ml
1st half equivalence point = 30/2 = 15ml
so when we add 15ml of NaOH
pH = pKa1 =15mL
A 99.8 mL sample of a solution that is 12.0% KI by mass (d: 1.093 g/mL) is added to 96.7 mL of another solution that is 14.0% Pb(NO3)2 by mass (d: 1.134 g/mL). How many grams of PbI2 should form?
Pb(NO3)2(aq) + 2 KI(aq) PbI2(s) + 2 KNO3(aq)
Answer:
[tex]m_{PbI_2}=18.2gPbI_2[/tex]
Explanation:
Hello,
In this case, we write the reaction again:
[tex]Pb(NO_3)_2(aq) + 2 KI(aq)\rightarrow PbI_2(s) + 2 KNO_3(aq)[/tex]
In such a way, the first thing we do is to compute the reacting moles of lead (II) nitrate and potassium iodide, by using the concentration, volumes, densities and molar masses, 331.2 g/mol and 166.0 g/mol respectively:
[tex]n_{Pb(NO_3)_2}=\frac{0.14gPb(NO_3)_2}{1g\ sln}*\frac{1molPb(NO_3)_2}{331.2gPb(NO_3)_2} *\frac{1.134g\ sln}{1mL\ sln} *96.7mL\ sln\\\\n_{Pb(NO_3)_2}=0.04635molPb(NO_3)_2\\\\n_{KI}=\frac{0.12gKI}{1g\ sln}*\frac{1molKI}{166.0gKI} *\frac{1.093g\ sln}{1mL\ sln} *99.8mL\ sln\\\\n_{KI}=0.07885molKI[/tex]
Next, as lead (II) nitrate and potassium iodide are in a 1:2 molar ratio, 0.04635 mol of lead (II) nitrate will completely react with the following moles of potassium nitrate:
[tex]0.04635molPb(NO_3)_2*\frac{2molKI}{1molPb(NO_3)_2} =0.0927molKI[/tex]
But we only have 0.07885 moles, for that reason KI is the limiting reactant, so we compute the yielded grams of lead (II) iodide, whose molar mass is 461.01 g/mol, by using their 2:1 molar ratio:
[tex]m_{PbI_2}=0.07885molKI*\frac{1molPbI_2}{2molKI} *\frac{461.01gPbI_2}{1molPbI_2} \\\\m_{PbI_2}=18.2gPbI_2[/tex]
Best regards.
Answer:
Mass PbI2 = 18.19 grams
Explanation:
Step 1: Data given
Volume solution = 99.8 mL = 0.0998 L
mass % KI = 12.0 %
Density = 1.093 g/mL
Volume of the other solution = 96.7 mL = 0.967 L
mass % of Pb(NO3)2 = 14.0 %
Density = 1.134 g/mL
Step 2: The balanced equation
Pb(NO3)2(aq) + 2 KI(aq) ⇆ PbI2(s) + 2 KNO3(aq)
Step 3: Calculate mass
Mass = density * volume
Mass KI solution = 1.093 g/mL * 99.8 mL
Mass KI solution = 109.08 grams
Mass KI solution = 109.08 grams *0.12 = 13.09 grams
Mass of Pb(NO3)2 solution = 1.134 g/mL * 96.7 mL
Mass of Pb(NO3)2 solution = 109.66 grams
Mass of Pb(NO3)2 solution = 109.66 grams * 0.14 = 15.35 grams
Step 4: Calculate moles
Moles = mass / molar mass
Moles KI = 13.09 grams / 166.0 g/mol
Moles KI = 0.0789 moles
Moles Pb(NO3)2 = 15.35 grams / 331.2 g/mol
Moles Pb(NO3)2 = 0.0463 moles
Step 5: Calculate the limiting reactant
For 1 mol Pb(NO3)2 we need 2 moles KI to produce 1 mol PbI2 and 2 moles KNO3
Ki is the limiting reactant. It will completely be consumed ( 0.0789 moles). Pb(NO3)2 is in excess. There will react 0.0789/2 = 0.03945 moles. There will remain 0.0463 - 0.03945 = 0.00685 moles
Step 6: Calculate moles PbI2
For 1 mol Pb(NO3)2 we need 2 moles KI to produce 1 mol PbI2 and 2 moles KNO3
For 0.0789 moles KI we'll have 0.0789/2 = 0.03945 moles PbI2
Step 7: Calculate mass of PbI2
Mass PbI2 = moles PbI2 * molar mass PbI2
Mass PbI2 = 0.03945 moles * 461.01 g/mol
Mass PbI2 = 18.19 grams
A crystal of table salt (NaCl) is dissolved in water. Which of the following statements explains why the dissolved salt does not recrystallize as long as the temperature and the amount of water stay constant?
A crystal of table salt (NaCl) is dissolved in water. Which of the following statements explains why the dissolved salt does not recrystallize as long as the temperature and the amount of water stay constant?
Na+ and Cl- ions lose their charges in the water.
Water molecules surround the Na+ and Cl- ions.
Na+ and Cl- ions leave the water through vaporization.
Water molecules chemically react with the Na+ and Cl- ions.
Your answer: -
Answer: B - Water molecules surround the Na+ and Cl- ions.
A chemist wants to increase the solubility of a solid in water. Which of the
following will NOT help? *
-increase the temperature
-decrease the particle size
-Increase stirring
-increase pressure
Answer:
- Increase pressure .
Explanation:
Hello,
In this case, during the dissolution process, the solute's molecules rearrange in order to get together with the solvent's molecules, in this case water.
Now, since we are talking about a solid whose particles are intimately held together, the only way to separate them is by increasing the temperature because the molecules start moving so they can join water's molecules, decreasing particle size since they will be more likely to separate to each other and increasing stirring since the applied energy will break the solid's intramolecular forces.
In such a way, since pressure significantly affects gases and slightly affects liquid, it is not able to modify a solid, just extreme pressures such as it needed to produce diamonds, is able to affect a solid. For that reason, increasing the pressure will not increase the solid's solubility.
Best regards.
What is the concentration of a solution if 0.450 mol of NaCl dissolved in 750 mL of water?
Answer:
.6mol/L
Explanation:
molarity = number of moles / volume of solvent (in L)
750mL / 1000mL/L = .75L
M = .450mol / .75L
M = .6mol/L
.......... water is good for formation of bones and teeth, soft water or hard water?
hard because it has calcium and magnesium
When is the small size of gas particles taken into account?
Answer:
At high pressures and low temperatures.
Explanation:
That's when the volume of the gas is quite small.
The volume of the gas particles can then be a significant proportion of the total volume.
What is the pH of a 1.4 M pyridine solution that has Kb = 1.7 × 10-9? The equation for the dissociation of pyridine is C5H5N(aq) + H2O(l) ⇌ C5H5NH+(aq) + OH-(aq). What is the pH of a 1.4 M pyridine solution that has Kb = 1.7 × 10-9? The equation for the dissociation of pyridine is C5H5N(aq) + H2O(l) ⇌ C5H5NH+(aq) + OH-(aq). 4.31 9.69 8.72 10.69
Answer:
pH = 9.69
Explanation:
When pyridine (C₅H₅N) is added to water, the equilibrium that occurs is:
C₅H₅N(aq) + H₂O(l) ⇌ C₅H₅NH⁺(aq) + OH⁻(aq) Kb = 1.7x10⁻⁹
Where Kb is defined as:
Kb = 1.7x10⁻⁹ = [C₅H₅NH⁺] [OH⁻] / [C₅H₅N]
If you have a solution of 1.4M C₅H₅N, the equilibrium concentration of each specie is:
[C₅H₅N] = 1.4 - X
[C₅H₅NH⁺] = X
[OH⁻] = X
Where X represents the reaction coordinate
Replacing in Kb expression:
1.7x10⁻⁹ = [X] [X] / [1.4 - X]
2.38x10⁻⁹ - 1.7x10⁻⁹X = X²
0 = X² + 1.7x10⁻⁹X - 2.38x10⁻⁹
Solving for X:
X = -0.0000488M → False answer, there is no negative concentrations
X = 0.0000488M → Right answer
Thus, [OH⁻] = 0.0000488M. As pOH = -log [OH⁻]
pOH = 4.31
Knowing pH = 14 - pOH
pH = 9.69
The pH of a 1.4 M pyridine solution is 9.69. When pyridine (C₅H₅N) is added to water, the equilibrium occurs. The rate of forward reaction is equals to the rate of backward reaction.
Equilibrium for pyridine:When pyridine (C₅H₅N) is added to water, the equilibrium that occurs is:
C₅H₅N(aq) + H₂O(l) ⇌ C₅H₅NH⁺(aq) + OH⁻(aq) Kb = 1.7x10⁻⁹
Where Kb is defined as:
Kb = 1.7x10⁻⁹
Kb= [C₅H₅NH⁺] [OH⁻] / [C₅H₅N]
If you have a solution of 1.4M C₅H₅N, the equilibrium concentration of each specie is:
[C₅H₅N] = 1.4 - x
[C₅H₅NH⁺] = x
[OH⁻] = x
Where x represents the reaction coordinate
Replacing in Kb expression:
1.7*10⁻⁹ = [x] [x] / [1.4 -x]
2.38*10⁻⁹ - 1.7x10⁻⁹x = x²
0 = x² + 1.7*10⁻⁹x - 2.38*10⁻⁹
Solving for x:
x = 0.0000488M
Thus, [OH⁻] = 0.0000488M.
As pOH = -log [OH⁻]
pOH = 4.31
Knowing pH = 14 - pOH
pH = 9.69
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