Answer:
MES for pH near to 6.0 and MOPS for pH near to 7.5.
Explanation:
Hello,
In this case, given that the Henderson-Hasselbach equation is:
[tex]pH=pKa+log(\frac{[Base]}{[Acid]} )[/tex]
Good's buffers are those having pKa's near to the required pH since we look for a [Base]/[Acid] ratio to approach 1, thus, for a pH near to 7.0 a good buffer may be MOPS as it has a pKa of 7.5 and for a pH neat to 6.0 a good buffer may be MES as it has a pKa of 6.15.
Best regards.
What is the difference between solid, liquid and ice? Use ice, water and steam as examples.
Answer: A solid is something that can hold its own shape and is hard to compress (squash). However, ice is different from most solids because its molecules are less densely packed than in liquid water so ice takes up a little more space than the same amount of liquid water. This is why ice floats.
Explanation: Hope it works!!!!!
Determine the identity of an unknown element X using the given table and following clues:
I) Element X is a solid
II) Element X will bond ionically with element O in a 1:1 ratio.
III) As a positive ion, it will have the same number of electrons as argon.
A) calcium
B) chlorine
C) potassium
D) sulfur
Answer:
calcium
Explanation:
A reaction in which A, B, and C react to form products is zero order in A, one-half order in B, and second order in C.
a. Write a rate Jaw for the reaction.
b. What is the overall order of the reaction?
c. By what factor does the reaction rate change if [A] is doubled (and the other reactant concentrations are held constant )?
d. By what factor does the reaction rate change if [B] is doub led (and the other reactant co ncen trati ons are held consta nt )?
e. By what factor does the reaction rate change if [C] is doubled (and the other reactant concen trations are held constant)?
f. By what factor does the reaction rate change if the concentrations of all three reactants are doubled?
Answer:
a. [tex]r=k[B]^{1/2}[C]^2[/tex]
b. [tex]Order=3.5[/tex]
c. It does not affect the rate.
d. [tex]\sqrt{2}[/tex].
e. 4.
f. 4[tex]\sqrt{2}[/tex].
Explanation:
Hello,
In this case, considering the given information, we have:
a. [tex]r=k[B]^{1/2}[C]^2[/tex]
b. By adding 1/2 and 2 (powers for B and C), the overall order is:
[tex]Order=\frac{1}{2} +2\\\\Order=3.5[/tex]
c. It is not changed, since the concentration of A is not affecting the rate due to its specific zeroth-order.
d. In this case, if the concentration of B is doubled, such term in the equation shows:
[tex]\sqrt[n]{x} \frac{r_f}{r_i}=\frac{[2B]^{(1/2)} [C]^2}{[B]^{(1/2)}[C]^2} \\\\\frac{r_f}{r_i}=\frac{[2B]^{(1/2)}}{[B]^{(1/2)}}\\\\\frac{r_f}{r_i}=(\frac{2}{1})^{1/2}\\\\r_f=\sqrt{2} r_i[/tex]
It means that the rate increases by a factor of [tex]\sqrt{2}[/tex].
e. In this case, if the concentration of C is doubled, such term in the equation shows:
[tex]\frac{r_f}{r_i}=\frac{[B]^{(1/2)}[2C]^2}{[B]^{(1/2)}[C]^2} \\\\\frac{r_f}{r_i}=(\frac{[2C]}{[C]})^{2}\\\\\frac{r_f}{r_i}=(\frac{2}{1})^{2}\\\\r_f=4r_i[/tex]
It means that the rate increases by a factor of 4.
f. In this case, if the concentration of both B and C are doubled, such terms in the equation shows:
[tex]\frac{r_f}{r_i}=\frac{[2B]^{(1/2)}[2C]^2}{[B]^{(1/2)}[C]^2} \\\\\frac{r_f}{r_i}=\frac{2^{(1/2)}2^2}{1^{(1/2)}1^2} \\\\\frac{r_f}{r_i}=4\sqrt{2} \\\\r_f=4\sqrt{2} r_i[/tex]
It means that the rate increases by a factor of 4[tex]\sqrt{2}[/tex].
Best regards.
Using the tools and knowledge of science to solve a problem or build new technology is called...
Answer:
Invention
Explanation:
Scientific ideas can be applied in novel was to solve new scientific problems and create new technology. This process helps to make life easier and better.
The application of scientific knowledge to solve new problems and create new technology is generally referred to as invention.
Theories in science can be disproved through new or extended research.
1. True
2. False
Answer:
True
Explanation:
This is true because technology advances all the time and even Newton's "Laws" could be disproved in the future.
Answer:
True
Explanation:
Based on new research we find out new things
What period is Zn (zinc) in?
O A. 2A
O B. 12
O C. 30
D. 4
Answer:
D. 4
Explanation:
How does your Skeletal and Muscular Systems work together?
Muscles move your bones
Bones move your muscles
Heart pumps blood throughout the body
Your bones protect your muscles
Answer:
Answer would be A, Muscles move your bones
Explanation:
Without the Muscular System, your bones would not be connected properly
Based on Chromium's position on the periodic table, which statement describes the element
chromium (Cr), atomic number 24?
A. chromium is a nonmetal and therefore a good conductor of heat and electricity
B. chromium is a metal that is more reactive than potassium
C. chromium is a metal that is less reactive than sodium
D. chromium is a noble gas that is not reactive
Answer:
C. chromium is a metal that is less reactive than sodium.
Explanation:
Hello.
In this case, since chromium is in period 4 group VIB we infer it is a transition metal which slightly reacts with acids and poorly reacts with oxygen and other oxidizing substances. Thus, in comparison with both sodium and potassium which are highly reactive even with water as they get on fire, we can say that it is less reactive than both potassium and sodium, therefore, answer is: C. chromium is a metal that is less reactive than sodium.
Best regards.
Hafnium (Hf) has six naturally occurring isotopes: 0.16% of 174Hf, with an atomic weight of 173.940 amu; 5.26% of 176Hf, with an atomic weight of 175.941 amu; 18.60% of 177Hf, with an atomic weight of 176.943 amu; 27.28% of 178Hf, with an atomic weight of 177.944 amu; 13.62% of 179Hf, with an atomic weight of 178.946 amu; and 35.08% of 180Hf, with an atomic weight of 179.947 amu. Calculate the average atomic weight of Hf.
Answer:
178.463 amu
Explanation:
Average atomic weight of Hafnium is calculated as follows;
[(0.0016 × 173.940) + (0.0526 × 175.941) + (0.186 × 176.943) + (0.2728 × 177.944) + (0.1362 × 178.946) + (0.3508 × 179.947)] =0.278 + 9.234 + 32.911 + 48.543 + 24.372 + 63.125 = 178.463 amu
Therefore, average atomic weight of Hafnium is 178.463 amu
When of a certain molecular compound X are dissolved in of dibenzyl ether , the freezing point of the solution is measured to be . Calculate the molar mass of X. If you need any additional information on dibenzyl ether, use only what you find in the ALEKS Data resource. Also, be sure your answer has a unit symbol, and is rounded to significant digit.
This question is incomplete, the complete question is;
When 4.28 g of a certain molecular compound X are dissolved in 60.0 g of dibenzyl ether [(C₆H₅CH₂)₂0] , the freezing point of the solution is measured to be -3.2°C . Calculate the molar mass of X.
If you need any additional information on dibenzyl ether, use only what you find in the ALEKS Data resource. Also, be sure your answer has a unit symbol, and is rounded to significant digit.
Answer: molar mass of solute (X) is 88.03 g/mol
Explanation:
Given that;
mass of solute = 4.28 g
mass of solvent = 60.0 g = 0.060 kg (Dibenzyl ether)
depression constant kf = 6.17 °CKg/mol
Freezing Point of solvent T₀ = 1.80°C (Dibenzyl ether)
freezing point of solution Tsol = -3.20°C
Now we know that
Depression in freezing point ΔTf = depression constant kf × molaity m
and (ΔTf = T₀-Tsol)
so T₀ - Tsol = kf × m
we substitute
1.80 - (-3.20) = 6.17 × m
5 = 6.17 × m
m = 5 / 6.17
m = 0.8103 kg/mol
so molaity m = 0.8103 kg/mol
we know that
Molaity of solute m = (mass of solute / M.wt of solute) × ( 1 / mass of solvent in Kg)
solve for molar mass of solute
molar mass of solute = (mass of solute / molaity) × ( 1 / mass of solvent in Kg)
now we substitute
molar mass = (4.28g / 0.8103 kg/mol) × (1 / 0.060kg)
molar mass = ( 5.2839 × 16.66 ) g/mol
molar mass = 88.0297 g/mol ≈ 88.03 g/mol
Therefore molar mass of solute (X) is 88.03 g/mol
Which phrase is evidence of the limits of what science can study?
This question is incomplete; here is the complete question:
Which phrase is evidence of the limits of what science can study?
A. Only a phenomenon that a scientist can observe with instruments
B. Only a phenomenon that a scientist can observe without instruments
C. Only a phenomenon that a scientist will be able to explain with certainty
D. Any phenomenon that a scientist can observe or model
The correct answer is D. Any phenomenon that a scientist can observe or model
Explanation:
Science focuses on phenomena that can be objectively studied or witnessed. This includes any phenomenon a scientist can register using observation, instruments, or that can be represented through models. This is because, through observations or instruments, it is possible to prove the phenomenon occurs and understand how this happens; also, models can represent or recreate the phenomenon itself, which is essential to understand and explain the phenomenon. Moreover, science has an objective focus and due to this, aspects such as personal beliefs that cannot be represented through a model or be observed are not part of science. According to this, the correct answer is D.
what is the molar mass of PbCO₄
Answer:
283.211
Explanation:
How many molecules are in 237 g (about a cup) of water? a. 1513.1 b. 4267 c. 6.02 * 1023 d. 93 * 1024 e. 7.93 * 10 24
Answer:
7.93E24 molecules of water
Explanation:
determine no. of moles of water: 237 g/18 g/mole H2O= 13.17 moles H2O
13.17 moles H2O x 6.02E23 molecules/mole= 7.93E24 molecules of water
Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore, 7.93×10²⁴ molecules are in 237 g (about a cup) of water. The correct option is option E.
What is mole?The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity or amount of substance. We know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number.
Mathematically,
number of moles of water=237 g÷18 g/mole
number of moles of water = 13.17 moles
number of atoms/molecules=number of moles × 6.022×10²³(Avogadro number)
molecules of water=13.17 moles x 6.02×10²⁴
molecules of water=7.93×10²⁴ molecules of water
Therefore, 7.93×10²⁴ molecules are in 237 g (about a cup) of water. The correct option is option E.
To know more about mole, here:
https://brainly.com/question/15209553
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If the atom has a MASS of 127 and 45 NEUTRONS, then it contains how many
PROTONS

Answer:
53
Explanation:
because minus 3
When finding the density of a solid, which situation prevents us from being
able to accurately find the volume displacement?
a) if the solid floats
b) if we use an analytical balance
c) if the solid sinks
d) if we use a graduated cylinder
Answer:
a) if the solid floats
Explanation:
Hello,
In this case, since the determination of the volume of a solid when submerged in water requires to use an analytical balance to measure the mass, but also it is necessary that the solid sinks in order to completely displace the what in the graduated cylinder which accurately provides the volume of the solid via its scale. Therefore, a draw back is a) if the solid floats since the water is not completely displaced.
Best regards.
Question 3 of 10
Which of the following is an example of a phase change from liquid to solid?
A. Ice melting
B. Water freezing
C. Water evaporating
D. Water condensing
Answer:
the answer is B
Explanation:
B is the answer
Strontium-90 is radioactive and has a half life of 28.8 years. How much of a 2.90mg sample would be left after 137. years?
Round your answer to 2 significant digits. Also, be sure your answer has a unit symbol.
Answer:
0.11 mg
Explanation:
From the question given above, the following were obtained:
Half life (t½) = 28.8 years
Original amount ((N₀) = 2.90 mg
Time (t) = 137 years
Amount remaining (N) =?
Next, we shall determine the rate of disintegration (K). This can be obtained as follow:
Rate of decay (K) = 0.693/ half life (t½)
K = 0.693 / t½
Half life (t½) = 28.8 years
Rate of decay (K) =?
K = 0.693 / t½
K = 0.693 / 28.8
K = 0.0241 /year
Finally, we shall determine amount remaining after 137 years as follow:
Original amount ((N₀) = 2.90 mg
Time (t) = 137 years
Rate of decay (K) = 0.0241 /year
Amount remaining (N) =?
Log (N₀/N) = kt/2.3
Log (2.9/N) = 0.0241 × 137 / 2.3
Log (2.9/N) = 3.3017 / 2.3
Log (2.9/N) = 1.4355
Take the antilog of 1.4355
2.9/N = antilog (1.4355)
2.9/N = 27.26
Cross multiply
2.9 = N × 27.26
Divide both side by 27.26
N = 2.9/27.26
N = 0.11 mg
Therefore, the amount remaining after 137 years is 0.11 mg
0.400 mole of sucrose, C 12H 22O 11, contains ________ C atoms.
Answer:
2.89x10²⁴ atoms of Carbon are contained in 0.400 moles of sucrose
Explanation:
The formula of sucrose is C₁₂H₂₂O₁₁, that means per mole of sucrose you will have 12 moles of carbon. In 0.400 moles of sucrose you will have:
0.400 moles Sucrose * (12 moles C / 1 mole Sucrose) = 4.8 moles of Carbon
To convert moles to atoms you must use Avogadro's number (1 mole contains 6.022x10²³ atoms):
4.8 moles Carbon * (6.022x10²³ atoms / 1 mole) =
2.89x10²⁴ atoms of Carbon are contained in 0.400 moles of sucrose0.4 mole of sucrose, C₁₂H₂₂O₁₁ contains 2.89×10²⁴ carbon atoms
How to determine the mole of carbon1 mole of C₁₂H₂₂O₁₁ contains 12 mole of C.
Therefore,
0.4 mole of C₁₂H₂₂O₁₁ will contain = 0.4 × 12 = 4.8 mole of C
How to determine the atoms of carbonFrom Avogadro's hypothesis,
1 mole of C = 6.02×10²³ atoms
Therefore,
4.8 mole of C = 2.89×10²⁴ atoms
Thus, 0.4 mole of sucrose, C₁₂H₂₂O₁₁ contains 2.89×10²⁴ carbon atoms
Learn more about Avogadro's number:
https://brainly.com/question/26141731
Which element has fewer than 4 dots In its Electron dot diagrams
Answer:Strontium (Sr) and Gallium (Ga)
Explanation:
Strontium (Sr) and Gallium (Ga) are the elements which have fewer than four dots in the electron dot diagrams. Explanation: Electron dot diagrams are the diagrams which represent the valence electrons in an element. The electrons are represented by the dots in these diagrams.
Which expression correctly describes energy using SI units? A. 1 J=1kg•m^2/s^2 B. 1 J= 1kg•m/s^2 C. 1 J= 1kg• m/s D. 1 J= 1kg•m^2/s
Answer:
A. 1 J=1kg•m^2/s^2
Explanation:
Energy refers to the capacity to do work. According to the International System of units (SI units), energy is measured in Joules.
Energy is represented by the force applied over a distance. Force is measured in Newton (N) and distance in metres (m). Hence, energy is Newton × metre (N.m)
Newton is derived from the SI units of mass (Kilograms), and acceleration (metres per seconds^2) i.e Kg.m/s^2, since Force = mass × acceleration.
Since; Energy = Newton × metres
If Newton = Kg.m/s^2 and metres = m
Energy (J) will therefore be; Kg.m/s^2 × m
1J = Kg.m^2/s^2
Which element is the
most reactive?
A . Silicon
B. oxygen
C. lithium
D . Aluminum
An atom or ion has 41 neutrons, 36 protons, and 36 electrons. Identify the element symbol, and determine the mass number
and charge for this atom or ion.
Answer:
Element symbol: Kr.
Mass number: 77.
Charge : 0.
Explanation:
Hello,
In this case, since such substance has the same amount of protons and electrons we can infer it is an atom whose number of neutrons is defined by considering its atomic mass or mass number and atomic number which is actually equal to the number of protons and electrons (36):
[tex]neutrons=atomic\ mass - atomic\ number[/tex]
In such a way, solving for the atomic mass we obtain:
[tex]atomic\ mass=neutrons+ atomic\ number\\\\atomic\ mass=41+36=77[/tex]
It means that the element is krypton (Kr) as it has 36 electrons and protons so its charge is 0.
Best regards.
How many moles is 90.93 grams of aluminum?
A)2453.47 moles
B)6.02x1023 moles
C)3.37 moles
D)2.107x1024 moles
Answer:
C) 3.37 moles .
Explanation:
Hello,
In this case, considering that the atomic mass of aluminum is 27.0 g/mol, the moles in 90.93 g of aluminum are computed via the following dimensional analysis:
[tex]n=90.93 gAl*\frac{1molAl}{27.0gAl} \\\\n=3.37molAl[/tex]
Thus, answer is C) 3.37 moles .
Best regards.
what happens when the net forces are the same, do you add or subtract it
Answer:
If two forces act on an object in the same direction, the net force is equal to the sum of the two forces.
Explanation:
google is my explanation
Answer:
Answered by Oreo!
Explanation:
So a net force is the sum of all forces acting on an object! The question u asked is if the net forces are the same, do u add or subtract it.. <= the answer to that would be:
If it’s the same than the net force is the sum of the forces...
The net force = to the sum of two forces
Hope this helps! Sorry if something didn’t go right, I’m new to brainly! :)
What property of water makes it possible for water from the ground to travel all the way up to leaves in the tops of tall trees?
Answer:
cohesion-tension
Explanation:
i did the quiz.
Which of the following solutions is basic?a. [H3O+] = 1.0 x 10-10 Mb. [OH-] = 1.0 x 10-10 Mc. [H3O+] > 1.0 x 10-7 Md. [OH-] < 1.0 x 10-10 Me. [OH-] = 1.0 x 10-7 M
Answer:
[H3O+] = 1.0 x 10-10
Explanation:
A basic solution is any solution whose pH is above 7.0.
If we carefully calculate the pH of each of the species listed among the options, we will discover that it is only [H3O+] = 1.0 x 10-10 that has a pH of 10.0. This pH corresponds to a basic solution. Hence the solution having [H3O+] = 1.0 x 10-10 is a basic solution.
A farmer applies 1455 kg of a fertilizer that contains 10.0% nitrogen to his fields each year. Fifteen percent (15.0%) of the fertilizer washes into a river that runs through the farm.If the river flows at an average rate of 0.175 cubic feet per second, what is the additional concentration of nitrogen (expressed in milligrams of nitrogen per liter) in the river water due to the farmer's fertilizer each year?
Answer:
the additional concentration of nitrogen in the water = 0.1396 mg/L
Explanation:
Given that a farmer uses 1455 kg of fertilizer → 10% nitrogen
15% of the fertilizer is said to be washed into the river,
i.e.
(15/100) × 1455 = 218.25 kg
The amount of nitrogen molecule in the washed fertilizer is :
10% of 218.25 kg
= (10/100) × 218.25 kg
= 0.1 × 218.25 kg
= 21.825 kg in a year.
The river flows at an avg. rate of 0.175 ft³/sec
Then the amount of river water in a year = [tex]0.175 \dfrac{ft^3}{sec}\times 3.155 \times 10^7 \ sec[/tex]
since 1 ft³ = 28.3168 L
the amount of river water in a year = [tex]0.175(28.3168)\times 3.155 \times 10^7 \ L[/tex]
the amount of river water in a year = 156344132
The concentration of nitrogen molecule= mass/volume
= [tex]\dfrac{ 21.825 \times 10^6 \ mg}{ 156344132 \ \ L }[/tex]
= 0.1396 mg/L
Thus, the additional concentration of nitrogen in the water = 0.1396 mg/L
help me ill give brainliest i need help with a b c d and to see if i got propene and methane right please help :(
Answer:Yes, you got it right
Explanation:
Pls give brainliest
PLEASE HELP WILL MARK BRAINLIEST!!!!!!!!
Explanation:
1. 4×10^5
2. 6×10^-4
3. 2.1995×10^7
4. 5.050×10^-2
5. 7280
6. 0.00003608
7. 940.9
8. 0.0015
Marks as brainest
Answer:
not sure
Explanation:
water is denser than oil. When frozen, the oil sinks to the bottom. Why?
Answer: When water freezes it gets larger and becomes a solid but it still weighs the same as when it was a liquid form. When it becomes larger it takes up space but makes it less dense. Ok so getting to the point- oil unlike water becomes more dense when frozen so this is why oil sinks in water. Sorry if this was confusing but I hope it helped have a great day and god bless you :3
