Answer:
Moles of KOH in 1000 mL solution = 0.255 moles
Moles of KOH in 1 mL solution = 0.255/1000 = 0.000255 moles
Moles in 95 mL solution = (95 * 255)/1000000 = 24225/1000000
Moles of KOH in 95 mL 0.255M solution = 0.024225 moles
The number of moles of KOH present in 95.0 ml of 0.255 M solution is 0.024mol
HOW TO CALCULATE NUMBER OF MOLES:
The number of moles of a substance can be calculated by multiplying the molarity/concentration of the substance by its volume:no. of moles = molarity (M) × volume (L)
According to this question, 95.0 ml of KOH is present in 0.255 M solution, hence, the number of moles can be calculated as follows:Volume of KOH = 95.0ml = 0.095Lno. of moles = 0.095 × 0.255no. of moles = 0.024molTherefore, the number of moles of KOH present in 95.0 ml of 0.255 M solution is 0.024mol.Learn more at: https://brainly.com/question/21085277?referrer=searchResults
Suppose you buy some inflated party balloons that are at room temperature (about 20°C). What will happen to those
balloons if you take them outside on a cold day? Explain
Answer: Balloons taken outside on a cold day will shrink because, as the temperature decreases, the pressure and volume decrease also.
Explanation:
Question 1
Ernest Rutherford completed his famous gold foil experiment in 1911. In this experiment, alpha particles were fired at a thin sheet of gold foil. He observed that most of the alpha particles passed straight through the gold foil unimpeded, but a small number of alpha particles were deflected. Which of the following conclusions about atomic structure were made from Rutherford’s gold foil experiment?
Answer: gold foil. It's in the experiment's name
chemist must prepare of hydrobromic acid solution with a pH of at . He will do this in three steps: Fill a volumetric flask about halfway with distilled water. Measure out a small volume of concentrated () stock hydrobromic acid solution and add it to the flask. Fill the flask to the mark with distilled water. Calculate the volume of concentrated hydrobromic acid that the chemist must measure out in the second step. Round your answer to significant digits.
Answer:
32 mL
Explanation:
A chemist must prepare 500.0mL of hydrobromic acid solution with a pH of 0.50 at 25°C. He will do this in three steps: Fill a 500.0mL volumetric flask about halfway with distilled water. Measure out a small volume of concentrated (5.0M) stock hydrobromic acid solution and add it to the flask. Fill the flask to the mark with distilled water. Calculate the volume of concentrated hydrobromic acid that the chemist must measure out in the second step. Round your answer to 2 significant digits.
Step 1: Calculate [H⁺] of the dilute solution
pH = -log [H⁺]
[H⁺] = antilog -pH = antilog -0.50 = 0.32 M
Step 2: Calculate [HBr] of the dilute solution
HBr is a strong acid that dissociates according to the following equation.
HBr ⇒ H⁺ + Br⁻
The molar ratio of HBr to H⁺ is 1:1. The concentration of HBr is 1/1 × 0.32 M = 0.32 M.
Step 3: Calculate the volume of the concentrated HBr solution
We will use the dilution rule.
C₁ × V₁ = C₂ × V₂
V₁ = C₂ × V₂ / C₁
V₁ = 0.32 M × 500.0 mL / 5.0 M
V₁ = 32 mL
3. When two or more substances are physically combined, the result is a(n)
A. chemical change. B. element
C. compound
D. mixture
Nonmetals are ___.
O part of group 18
O are always gases
O good conductors of heat
O poor conductors of heat
Answer:
D. Poor conductors of heat
Explanation:
What volume (in mL) of a 0.150 M HNO3 solution will completely react with 35.7 mL of a 0.108 M Na2CO3 solution according to the following balanced chemical equation?
Na2CO3(aq)+2HNO3(aq)→2NaNO3(aq)+CO2(g)+H2O(l)
In the reaction in Part A, what mass (in grams) of carbon dioxide forms?
Answer:
Explanation:
where are the anwser choices
Answer:
First part: volume of HNO3 solution = 51.4 mL
Second part: mass of CO2 = 0.170 g
Explanation:
First part:
Based on the volume and concentration of the Na2CO3 solution, there is 3.86 mmol of Na2CO3 available to react with HNO3 . Considering the stoichiometric relationship, you then calculate the volume of a 0.150 M solution that contains 7.71 mmol of HNO3 .
51.4 mL
Second part:
Since the reactant and product have a stoichiometric relationship that is 1:1, 0.00386 mol of Na2CO3 can react to form 0.00386 mol of CO2 . The molar mass of CO2 (44.01 g/mol ) is then used to convert the moles to the corresponding mass in grams.
0.170 g
What is a scientific law?
Answer:
Scientific laws or laws of science are statements, based on repeated experiments or observations, that describe or predict a range of natural phenomena. The term law has diverse usage in many cases across all fields of natural science.
Which of the following contains the most electrons?
multiple choice
A - Sn2+
B - Sna+
C - Both have the same number of electrons
Why is the atomic mass of iron, 55.845 amu, most similar to the mass of iron-56, yet less than 56 amu? The atomic mass is the simple average of the masses of the two most abundant isotopes. Iron‑56 is the most abundant isotope, so the atomic mass of iron is most similar to the mass of iron‑56. The second most abundant isotope is iron‑54, which reduces the atomic mass to less than 56 amu. The atomic mass is the weighted average of the masses of all of the isotopes. Iron‑56 is the most abundant isotope, so the atomic mass of iron is most similar to the mass of iron‑56. The second most abundant isotope is iron‑54, which reduces the atomic mass to less than 56 amu. The atomic mass is the weighted average of the masses of the two most abundant isotopes. Iron‑56 is the most abundant isotope, so the atomic mass of iron is most similar to the mass of iron‑56. The second most abundant isotope is iron‑54, which reduces the atomic mass to less than 56 amu. The atomic mass is the simple average of the masses of all of the isotopes. Iron‑56 is the most abundant isotope, so the atomic mass of iron is most similar to the mass of iron‑56. The second most abundant isotope is iron‑54, which reduces the atomic mass to less than 56 amu.
Answer:
Iron‑56 is the most abundant isotope, so the atomic mass of iron is most similar to the mass of iron‑56.
Explanation:
The atomic abundance of the isotopes of Iron is:
⁵⁴Fe: 5.82%
⁵⁶Fe: 91.66%
⁵⁷Fe: 2.19%
⁵⁸Fe: 0.33%
Where the Iron-56 is the most abundant isotope of Iron atom
As atomic mass is defined as the sum of the masses of the ions multiplied by its abundance, and the Iron-56 is the most abundance isotope, the atomic mass of Fe most be similar to the ⁵⁶Fe mass because is the most abundant isotope.
Right option is:
Iron‑56 is the most abundant isotope, so the atomic mass of iron is most similar to the mass of iron‑56.Iron‑56 is the most abundant isotope, so the atomic mass of iron is most similar to the mass of iron‑56.
the atomic abundance of the isotopes of Iron is:
⁵⁴Fe: 5.82%
⁵⁶Fe: 91.66%
⁵⁷Fe: 2.19%
⁵⁸Fe: 0.33%
Since the Iron-56 is the most abundant isotope of the Iron atom
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How many mL of a 1.50 M solution of cobalt(III) sulfate are required to make 400.0 mL of a 0.850 M solution of cobalt(III) sulfate? Determine the molarities of the ions in 1.50 M cobalt(III) sulfate.
Answer:
Answer. 600 g CaCl2 would be required to make 2 L of a 3.5 M solution.
Which of the following notations is the correct noble gas configuration for
Co?
A. [Ar]48237
B. [Ar]4524p63d
O C. [Kr]4s24p64d
D. [Co]48237
Answer:
The notation of configuration of Co is [tex][Ar] 3d^7 4s^2[/tex]
(A) is correct option.
Explanation:
Given that,
The following notations is the correct noble gas configuration for Co.
(A). [Ar] 3d⁷ 4s²
(B). [Ar] 4s² 4p⁶ 3d
(C). [Kr] 4s² 4p⁶ 4d
(D). [Co] 3d⁷ 4s²
We know that,
Cobalt :
Co is the symbol of cobalt which is a chemical element.
Atomic number of Co is 27.
We need to find the notation of the configuration of noble gas Co
Using configuration
[tex]Co_{27}=2, 8, 15, 2[/tex]
[tex]Co_{27}=1s^2, 2s^2,2p^6, 3s^2 3p^6 3d^7, 4s^2[/tex]
So, we can write as the notation of noble gas configuration
[tex]Co_{27}=[Ar] 3d^7 4s^2[/tex]
Hence, The notation of configuration of Co is [tex][Ar] 3d^7 4s^2[/tex]
(A) is correct option.
n a coffee cup calorimeter, 100.0 mL of 1.0M NaOH and 100.0 mL of 1.0M HCl are mixed. Both solutions were originally at 24.6 degrees Celsius. After the reaction, the final temperature is 31.3 degrees Celsius. Assuming that all the solution have a density of 1.0g/cm3 and a specific heat capacity of 4.18 J/oCg, calculate the enthalpy change for the neutralization of HCl by NaOH. Assume that no heat is lost to the surroundings or to the calorimeter.
Answer:
Explanation:
mass of the solution = volume x density = 200 x 1 = 200 gm
heat absorbed = m x s x Δ t , s is specific heat , Δt is rise in temperature
= 200 x 4.18 x ( 31.3 - 24.6 )
= 5601 J .
This is the enthalpy change required.
How can density be used to determine the identity of a pure substance?
Answer:
Explanation:
You can identify an unknown substance by measuring its density and comparing your result to a list of known densities. Density = mass/volume. Assume that you have to identify an unknown metal.
Which of the following best describes the discovery of the atom?
Its existence was hypothesized based on observations of larger samples of matter.
O Its existence was proven with the understanding of quantum mechanics.
O Its existence was determined by an English scientist studying nature.
Its existence was established after the invention of the microscope.
Answer:
Its existence was determined by an English scientist studying nature.
Its existence was established after the invention of the microscope.
Explanation:
I know because atoms are made up by a scientist study chemicals while trying to learn about atoms as well.
Its existence was hypothesized based on observations of larger samples of matter best describes the discovery of the atom. Therefore, option A is correct.
What is an atom ?A chemical element is uniquely defined by its atoms, which are tiny pieces of substance. An atom is made up of a core nucleus and one or more negatively charged electrons that orbit it. The positively charged, comparatively hefty protons and neutrons that make up the nucleus may be present.
But when it comes to the name atom, we must travel back to 400 B.C. ancient Greece. The Greek word atomos, which meaning "uncuttable," was proposed by Democritus, a renowned philosopher. In the end, all matter could be reduced to distinct, tiny particles, or atomos, he said.
Atoms are made up of a nucleus in the middle that is surrounded by protons, neutrons, and electrons.
Thus, option A is correct.
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16H + 2MnO4 + 5C2O4 = 2Mn + 10CO2 + 8H2O MnO4 mol in 20 mL
Answer:
Titration of 50.00 mL of 0.0521 M sodium oxalate, Na2C2O4, required 38.71 mL of a potassium permanganate solution: 5 C2O42- + 2MnO4- + 16H+ = 2Mn2+ + 10 CO2 + 8H2O Calculate the molarity of the potassium permanganate solution.
Explanation:
If m and n are integers, which of the following must be an even integer? A. 2mn B. mn C. mn+2 d. mn-2 e. 3mn
Which structures are found only in plant cells, not in animal cells? O A and B O Band C O Cand D B D OD and A А с
Answer:B and C
Explanation:did the assignment
How many kilojoules are needed to raise the temperature of 234 g of water from 19.8 C to 33.1 C?
Answer:
13 kJ
Explanation:
Use the following formula where Q is the Joules needed, m is the mass of the substance, c is the heat capacity, and ΔT is the change in temperature.
Q = mcΔT
The heat capacity of water is 4.186 J/g°C. The mass of water is 234 g. The change in temperature is 13.3°C.
Q = mcΔT
Q = (234 g)(4.186 J/g°C)(13.3°C)
Q = 13,027 J
Since the answer is in Joules, convert to kiloJoules.
13,027 J = 13.027 kJ ≈ 13 kJ
An object has a variable volume and shape before it changes state. After the
change, it can still change in shape but has a fixed volume. Which change of
state has occurred
According to the concept of forces of attraction , the change of state that has occurred is gas to liquid.
What are forces of attraction?Forces of attraction is a force by which atoms in a molecule combine. it is basically an attractive force in nature. It can act between an ion and an atom as well.It varies for different states of matter that is solids, liquids and gases.
The forces of attraction are maximum in solids as the molecules present in solid are tightly held while it is minimum in gases as the molecules are far apart . The forces of attraction in liquids is intermediate of solids and gases.
The physical properties such as melting point, boiling point, density are all dependent on forces of attraction which exists in the substances.
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A sea turtle is 3feet below the surface of the sea ??? Help me ple
How is energy related to the change of state represented
by the model?
Atoms gain energy as a solid changes to a liquid.
Atoms gain energy as a solid changes to a gas.
O Atoms lose energy as a solid changes to a liquid.
O Atoms lose energy as a solid changes to a gas.
Answer:
Energy is related to the change of state represented by the model in this way - C. Atoms lose energy as a gas changes to a solid.
Explanation:
As a certain gas is changing its state into that of a solid material, its atoms are going to lose some energy.
Answer:
the answer is c
Explanation:
the person before me literally tells you that it's C!!
If 2.03 g of oxygen react with carbon monoxide, how many grams of CO2 are formed?
Answer:
The suitable equation for this reaction is
2CO + O₂ -----> 2CO₂
Here, we are given that we have 2 grams of O₂
From the equation, we can see that 2 * Moles of O₂ = Moles of CO₂
Moles of O₂:
2/32 = 1/16 moles
Therefore, the number of moles of CO₂ is twice the moles of O₂
Moles of CO₂ = 2 * 1/16
Moles of CO₂ formed = 1/8 moles
Mass of CO₂ formed = Molar mass of CO₂ * Moles of CO₂
Mass of CO₂ formed = 44 * 1/8
Mass of CO₂ formed = 5.5 grams
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What is the limiting reactant in the following reaction if 1.63g of NH3 is reacted with 3.47g of Cl2 ?
4 NH3 + 3 Cl2 → 3 NH4Cl + NCl3
a. Cl2
b. NCI3
c. NH4Cl
d. NH3
Answer:
B
Explanation:
you will have to find the number of moles for each 4Nh3 and 3cl2
4NH3
m= 1.63
mr= 14+1x3= 17
n.of moles = 1.63/17=0.09588
3CL2
m=3.47
mr=35.5x2=71
nof moles = 3.47/71= 0.04887
after getting the number of moles you will divide your answer by its ratio
4NH3 3CL2
0.09588/4=0.02397 0.04887/3= 0.0133
the smaller number will be the limiting reagent while the bigger number is the excess reagent
Why are measurements always at least a little uncertain?
Answer:
because measuring instruments have an uncertainty of +-1 or mor
How many elements are there in CH3 CH2COONa
Answer:
There are
Explanation:
There are 10 elements in CH3CH2COONa.
Conclusion of Newton law of motion
Answer:
Hope this helps
Explanation:
All object continues to be in its state of rest or uniform motion unless acted upon by an external unbalanced force. The rate of change of momentum of an object is proportional to the unbalanced force in the direction of the force. 3rd law every action has an equal and opposite reaction.
To prepare a sample in a capillary tube for a melting point determination, gently tap the tube into the sample with the_____________
a) open,
b) closed end of the tube down.
Continue tapping until the sample____________
a) completely fills the tube
b) is a couple millimeters high,
c) has a single crystal in the tube.
Then, with the _________
a) closed,
b) open end of the tube down,
tap the sample down slowly or ________
a) heat the tube up,
b) drop the tube into a longer tube,
c) shake the tube in the air to move the sample down faster.
Answer:
1. A
2. B
3. A
4. B
Explanation:
In Chemistry, one of the ways to test for the purity of a substance is to determine its melting point. Generally, a pure substance has its melting point between the temperature range of 1 - 2 (°C). In order to determine the melting point of a substance, we can use the procedure stated below;
To prepare a sample in a capillary tube for a melting point determination, gently tap the tube into the sample with the open end of the tube down. Continue tapping until the sample is a couple millimeters high. Then, with the closed end of the tube down, tap the sample down slowly or drop the tube into a longer tube. Lastly, you should ensure that you can see some or perhaps all of the sample in the viewfinder (magnifier) when it is placed on the melting point apparatus, then you can turn on the heat.
Additionally, in taking your readings, you should record the temperature for when the melting starts to when it ends.
A 4.24 kg marble slab has a volume of 1564 cm³ what is its density in grams per centimeters cubed
Answer:2.71g/cm3
Explanation:
What is the mass of an atom with seven protons, seven neutrons, and eight electrons?
Answer:
14
Explanation:
mass number = protons + neutrons
Mercury(II) oxide decomposes to form mercury and oxygen, like this:
2HgO(s)--------Hg(l) + O2(g)
At a certain temperature, a chemist finds that a reaction vessel containing a mixture of mercury(II) oxide, mercury, and oxygen at equilibrium has the following composition:
compound amount
HgO 24.0g
Hg 23.6g
O2 22.7g
Calculate the value of the equilibrium constant for this reaction. Round your answer to significant digits.
Answer:
[tex]Kc=0.71=7.1x10^{-1}[/tex]
Explanation:
Hello,
In this case, since the equilibrium constant is written including gaseous and aqueous species only, for this reaction, it is:
[tex]Kc=[O_2][/tex]
Thus, since the volume is missing, we are going to assume 1 L, but you can change it based on the one you are given, thus, the concentration of oxygen at equilibrium is:
[tex][O_2]=\frac{22.7g*\frac{1mol}{32g} }{1L} =0.709M[/tex]
It means, that the equilibrium constant, with two significant figures is:
[tex]Kc=0.71=7.1x10^{-1}[/tex]
Best regards.
Determine the volume of an object that has a mass of 441 g and a density of 21 g/cm3.
Answer: 21cm^3
Explanation:
Volume Formula:
Mass / Density = Volume
441g/21g/cm^3 = 21cm^3
