Answer:
2.343 g of HEPES sodium salt is needed.
Explanation:
So, from the question above we have the following parameters which is going to help in solving this particular question.
The number of moles = 90mM, the pH = 7.50, FW for the HEPES sodium salt = 260.31, and the volume of HEPES sodium salt required = 100mL.
Therefore, the amount of HEPES sodium salt required to make the buffer = 260.31 × 9 × 0.001 = 2.343 grams of HEPES sodium salt is needed in 10mL.
26. A Grignard's reagent may be made by
reacting magnesium with which of the
following compound ?
(A)
Methyl amine
(B) Diethyl ether
(C
)
Ethyl iodide
(D)
Ethyl alcohol
All moving objects have kinetic energy. True False
Answer:
true
.......................
Answer: You're Welcome!
Oh, It's False - Kinetic energy depends upon the speed of the object; potential energy depends upon the position of the object.
Compound is a dull white smooth solid which does not conduct electricity.
a. True
b. False
Answer:
a. True.
Explanation:
Hello!
In this case, since dullness and smoothness are characteristic of materials that are not able to conduct the electricity, as they do not provide an appropriate pathway for the electrons to move around because of their amorphous structure, we realize the answer is a. True.
On the contrary, a lustrous and robust solid, is actually able to conduct electricity because it provides the pathway for the electron movements and therefore to conduct electricity.
Best regards!
fluorine is more reactive than chlorine.
Answer:
yes because of fluorine has higher electronegativity
A mixture is made by combining 1.29 lb of salt and 5.35 lb of water.
What is the percentage of salt (by mass) in this mixture?
Answer:
19.47%
Explanation:
[tex]\frac{1.29}{1.29+5.35}[/tex]
Please recheck, for this answer may not be correct
How many electrons must nitrogen gain to become like it’s closest noble gas, Neon?
Answer:
3
Explanation:
Pressure is often defined as
Answer:
Pressure is often defined as a measure of force applied on an area, or over a unit area.
Explanation:
Is Gold (Au) soluble?
Answer:
yes
Explanation:
how many 500 mg tablets of acetaminophen would be a lethal dose for a 132 lb adult
Answer:
About 2000 mg so 4 pills
could kill
Explanation:
Use your periodic table to determine which of the following is a non metal
A.Nitrogen
B. Lithium
C. Sodium
D. Gold
Copper metal reacts with silver nitrate to produce silver metal and copper (II) nitrate.
the correct equation for this reaction is:
A: Cu + SiN—> Si + Cu2N
B: 2Cu + AgNO3–> Ag +
Cu(NO3)2
C: Cu + 2 AgNO3–> Ag + Cu(NO3)2
D:Cu + AgNO3–> Ag + CuNO3
Answer:
Cu + 2AgNO₃ → 2Ag + Cu(NO₃)₂
Explanation:
The reactants are:
Copper metal = Cu
Silver nitrate = AgNO₃
The products are:
Silver metal = Ag
Copper (II) nitrate = Cu(NO₃)₂
So, the reaction equation is given as;
Cu + 2AgNO₃ → 2Ag + Cu(NO₃)₂
This is a single displacement reaction
I need help on these questions!
Answer:
See explanation
Explanation:
Given that;
E = hc/λ
h = 6.63 * 10^-34 Js
c = 3 * 10^8 ms-1
λ = ?
E = 3.978 * 10^-19 J
λ = hc/E
λ = 6.63 * 10^-34 * 3 * 10^8 /3.978 * 10^-19
λ = 19.89 * 10^-26/3.978 * 10^-19
λ = 5 * 10^-7 m The colour is green
2. E = hc/λ
E= 6.63 * 10^-34 * 3 * 10^8 /1000 * 10^-9
E = 1.989 * 10^-19 J
But
E = hf
f = E/h
f = 1.989 * 10^-19/6.63 * 10^-34
f = 3 * 10^14 Hz The radiation is infrared
3. E = hc/λ
λ= hc/E
λ= 6.63 * 10^-34 * 3 * 10^8 /2.0 * 10^-14
λ= 995 * 10^-14 m This is gamma radiation
4. E = hc/λ
E=6.63 * 10^-34 * 3 * 10^8 /620 * 10^-9
E = 3.2 * 10^-19 J
5. E = hf
E= 6.63 * 10^-34 * 2 * 10^17
E = 1326 * 10^-19 J
E = hc/λ
λ= hc/E
λ= 6.63 * 10^-34 * 3 * 10^8 /1326 * 10^-19 = 15 * 10^-9
This is ultraviolet radiation
Need help asap
1. All nonmetals (except hydrogen) have 8 valence electrons?
True or False
2. The N^-3 ion is classified as a(n) ____ and has ____.
A. anion, 8 valence electrons
B. cation, 8 valence electrons
C. anion, 15 valence electrons
D. anion, 3 valence electrons
3. If two nonmetals react to form a compound and have very different _____ they form ____ bonds. If there is a small difference, then they form ____ bonds.
A. ionization energy; covalent; nonpolar ionic
B. electronegativity; nonpolar covalent; polar covalent.
C. ionization energy, ionic, nonpolar covalent
D. electronegativity, polar covalent, nonpolar covalent.
Answer:
1: false
2: B
Explanation:
I do not know the 3rd one
The number of calories listed on a food label always refers to the number in the entire package
Thermal energy is the energy an object has due to the _____ of the particles
Answer: Vibråtory movement.
Explanation: when particles bounce against each other the friction creates thermal energy. Think about what happens when you rub your hands together and they get warmer, that the friction between your hands making thermal energy.
Select the correct number of valence electrons, in order, for groups 13-18.
13, 14, 15, 16, 17, 18
5, 6, 4, 3, 8,7
3,4,5,6,7,8
18, 13, 15, 16, 17, 14
Answer:
3,4,5,6,7,8
Explanation:
Groups 13 - 18 are the main group on the periodic table
The group number corresponds the number of valence electrons they contains.
Valence electrons are the number of electrons in the outermost shell of an atom.
So group 13 - 18 corresponds to a valency of 3,4,5,6,7,8.
Groups with a valency of 8 are the noble gases.
Based on the number of valence electrons indicated by its location in the periodic table ,which elements behavior would you predict to be closest to that of potassium (k)
Answer:
Na sodium or Rb rubidium
Explanation:
Because Na is present in first group all members of group 1 have 1 electron in valence shell and show similar properties.
How do I round 74,000 to have only one significant figure?
Answer:
7x10⁴.
Explanation:
Hello!
In this case, when rounding big number to a representation with less significant figures than it, we need to make sure we remove the spare figures and round up whether the next digit is five or more.
In such a way, for 74,000, we notice that 4 is not enough to round up the 7, that is why the number would contain a 7 only; moreover, to get rid of the thousand places, we need to introduce an exponent in 4 places, which means that the result would be:
7x10⁴.
Best regards!
You want to determine the concentration of a phosphoric acid (H3PO4) solution using a standardized 0.0995 M NaOH solution. 10.00 mL of the H3PO4 solution needed to be titrated with 22.85 mL of the standardized 0.0995M NaOH solution to reach the equivalence point. What is the concentration of the H3PO4 solution
Answer:
Explanation:
H₃PO₄ + 3NaOH = Na₃PO₄ + 3 H₂O.
1 mole 3 mole
22.85 mL of the standardized 0.0995M NaOH solution will contain
.0995 x .02285 moles of NaOH
= 22.7357 x 10⁻⁴ moles of NaOH
3 moles of NaOH reacts with 1 mole of H₃PO₄
22.7357 x 10⁻⁴ moles of NaOH reacts with 1 x 22.7357 x 10⁻⁴ / 3 mole of H₃PO₄
= 7.5785 x 10⁻⁴ moles of H₃PO₄
7.5785 x 10⁻⁴ moles of H₃PO₄ is contained in 10 mL or 10⁻² L
molarity of H₃PO₄ solution = 7.5785 x 10⁻⁴ / 10⁻²
= 7.58 x 10⁻² M
= .0758 M .

Someone unscramble the first mystery element because I don’t know how to.
-unnecessary comments will be reported
Answer:
Calcium
Explanation:
The symbol for the element with a mass number of 27 is actually Al for Aluminum instead of Co for Cobalt. Mass number refers to atomic mass, not atomic number.
Aluminum has an atomic mass of 26.982 or 27.
The letters to unscramble are I, M, C, Al, U, and C.
The mystery element is Calcium.
Hope that helps.
Compound A reacts with Compound B to form only one product, Compound C, and it's known the usual percent yield of C in this reaction is 72.%. Suppose 3.5g of A are reacted with excess Compound B, and 6.5g of Compound C are successfully isolated at the end of the reaction.
A. What was the theoretical vield of C?
B. How much B was consumed by the reaction?
Answer:
A. Theoretical yield of C is 9.03 g
B. Mass of B consumed is 5.53 g
Explanation:
A. Determination of the theoretical yield of C.
Actual yield of C = 6.5 g
Percentage yield of C = 72.%
Theoretical yield of C =?
Percentage yield = Actual yield /Theoretical yield × 100
72% = 6.5 / Theoretical yield
72 / 100 = 6.5 / Theoretical yield
Cross multiply
72 × Theoretical yield = 100 × 6.5
72 × Theoretical yield = 650
Divide both side by 72
Theoretical yield = 650 / 72
Theoretical yield = 9.03 g
Therefore, the theoretical yield of C is 9.03 g
B. Determination of the mass of B consumed.
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
A + B —> C
Mass of A = 3.5 g
Mass of C = 9.03 g
Mass of B =?
A + B = C
3.5 + B = 9.03
Collect like terms
B = 9.03 – 3.5
B = 5.53 g
Thus, the mass of B consumed in the reaction is 5.53 g
Why is it easier to switch to solar and wind energy as compared to other alternative energy sources? Select all that apply.
A. They are more cost-effective.
B. They require large, easily obtainable parcels of land.
C. They can be produced easily in areas with geothermal activity.
D. The land can be used for other purposes while supplying energy.
Answer:C. They can be produced easily in areas with geothermal activity.
D. The land can be used for other purposes while supplying energy.
Explanation:
Both c and d are correct
It is easier to switch to solar and wind energy as compared to other alternative energy sources because they can be produced easily in areas with geothermal activity and can be used for other purposes while supplying energy.
What is solar energy?Solar energy is any type of energy generated by the sun. Solar energy can be harnessed directly or indirectly for human use.
Generating energy that produces no greenhouse gas emissions from fossil fuels and reduces some types of air pollution.
Diversifying energy supply and reducing dependence on imported fuels. Creating economic development and jobs in manufacturing, installation, and more.
Hence, options C and D are correct.
Learn more about the solar energy here:
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which toxic gas is released in incomplete combustion?
Answer:
Incomplete combustion produces carbon monoxide (CO), a toxic gas.
Explanation:
Combustion is the rapid chemical reaction of oxygen in the air or direct oxygen, which is defined as oxidizer, with the different elements that make up the fuel (mainly carbon (C) and hydrogen (H)). These chemical reactions release energy producing local increases in temperature, which causes a flow of heat to the outside.
In other words, on the one hand you have the fuel, which is the substance that oxidizes and that you can find in a solid, liquid or gaseous state and which is made up mostly of carbon and hydrogen.
The oxidizer, for its part, is the substance that oxidizes the fuel, and it is generally the oxygen found in the air.
Certain amounts of oxidizer and fuel must come into contact for combustion to occur.
Incomplete combustion occurs when part of the fuel does not fully react. Incomplete combustion produces carbon monoxide (CO), a toxic gas.
Sn + 2HCI --> SnCl2 + Hz
a. synthesis
b. single replacement
C. combustion
d. double replacement
e. decomposition
Answer:
Option B. Single replacement reaction
Explanation:
To know which option is correct, it is important that we know the definition of each option. The definition of each option is given below:
1. Synthesis reaction is a reaction in which two different elements or compound combine together to produce a new compound different from the two starting elements or compound. An example is illustrated below:
C + D —> E
2. Single replacement reaction is a reaction in which an element replaces or displaces another element in a compound. An example is illustrated below:
D + BC —> B + CD
3. Combustion reaction is a reaction in a substance react with oxygen to generate carbon dioxide (CO₂) and water (H₂O). An example can be seen when organic compound react with oxygen to produce carbon dioxide (CO₂) and water (H₂O). This is illustrated below:
CₓHᵧ + (x + y/4) O₂ —> xCO₂ + (y/2) H₂O
4. Double replacement reaction is a reaction in which the ions of the two reacting compound replaces one another to form new products. This is illustrated below:
X⁺Y¯ + U⁺V¯ —> X⁺V¯ + U⁺Y¯
5. Decomposition reaction is a reaction in which a large compound breaks down into two or more elements or compound. An example is illustrated below:
GH —> G + H
Now, observing the equation given in the question above:
Sn + 2HCl —> SnCl₂ + H₂
We can see that Sn replaces H in HCl to produce SnCl₂.
Therefore, the reaction is a single replacement reaction.
Crude oil has many applications once it has been distilled at a refinery. According to the diagram, what process is used to distill crude oil into its various components to use energy distribution?
A) separation by density
B) separation by boiling points
C) separation by the porosity of the components
D) separation by the organic content or each component
Answer:
B) separation by boiling points
Explanation:
According to the diagram depicted, crude oil is separated into its different units using boiling points.
The boiling points of a compound is the temperature at which it begins to boil. The process of fractional distillation is used in the oil industry to separate crude oil into its components. When the boiling point of a oil fraction is reached, it becomes vaporized and rises within the columnhow many electrons does a covelent bond consist of?
Answer: 2 electrons
Explanation: Good luck! :D
which soil would be the best for growing plants?
Honestly, its based on your preference but the best recommended one would be loam. I use loam too, and it is really good for growing the plants.
:)
Construct an explanation using Newton's Laws of Motion to describe the effects of balanced and unbalanced forces on the motion of an object.
Answer:
The manner in which objects will move is determined by the answer to this question. Unbalanced forces will cause objects to change their state of motion
Explanation:
Since these two forces are of equal magnitude and in opposite directions, they balance each other.
Answer:
balance force are those force whose resultant force is zero and unbalanced force are those whose resultant are non zero
The data below shows the change in concentration of dinitrogen pentoxide over time, at 330 K, according to the following process.
2N2O5(g) = 4NO2(g) + O2
[N2O5] Time (s)
0.100 0.00
0.066 200.00
0.044 400.00
a) Find the rate of disappearance of N2O5 from t=0 s to t=200s
b) Find the rate of appearance of NO2 from t=0 s to t =200s
Answer: a) [tex]1.7\times 10^{-4}[/tex]
b) [tex]3.4\times 10^{-4}[/tex]
Explanation:
The reaction is :
[tex]2N_2O_5(g)\rightarrow 4NO_2(g)+O_2(g)[/tex]
Rate = Rate of disappearance of [tex]N_2O_5[/tex] = Rate of appearance of [tex]NO_2[/tex]
Rate = [tex]-\frac{d[N_2O_5]}{2dt}[/tex] = [tex]\frac{d[NO_2]}{4dt}[/tex]
Rate of disappearance of [tex]N_2O_5[/tex] = [tex]\frac{\text {change in concentration}}{time}[/tex] = [tex]\frac{0.100-0.066}{200-0}=1.7\times 10^{-4}[/tex]
a) Rate of disappearance of [tex]N_2O_5[/tex] = [tex]-\frac{d[N_2O_5]}{2dt}[/tex]
Rate of appearance of [tex]NO_2[/tex] = [tex]\frac{d[NO_2]}{4dt}[/tex]
b) Rate of appearance of [tex]NO_2[/tex] = [tex]\frac{d[NO_2]}{dt}=2\times 1.7\times 10^{-4}}=3.4\times 10^{-4}[/tex]
A) Find the rate of disappearance of [tex]N_2O_5[/tex] from t = 0 s to t = 200s
[tex]Rate = \frac{1}{2}(\frac{-\delta N_2O_5}{\delta t})\\\\Rate = -\frac{1}{2}(\frac{0.066 - 0.100}{200 - 0})\\\\Rate = 8.5*10^{-5}[/tex]
B) Find the rate of appearance of [tex]NO_2[/tex] from t = 0 s to t = 200s
According to rate law,
[tex]\frac{1}{2}(\frac{-\delta N_2O_5}{\delta t}) = \frac{1}{4}(\frac{\delta NO_2}{\delta t})\\\\8.5*10^{-5} = \frac{1}{4}(\frac{\delta NO_2}{\delta t})\\\\\frac{\delta NO_2}{\delta t} = 4 * 8.5*10^{-5}\\\\Rate = 3.4*10^{-4}[/tex]
For more information on rate of disappearance
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the man is being warmed by?
radiation
convention
conduction
Answer:
Comvection
Explanation:
The movement causes the density to rise and therefore transfer more heat