Answer:
the enthalpy change of this is 5.02mol
what is the percent (mass/volume) if 22 g of kcl is added to 75 ml of water to make 83 ml of solution
Considering the definition of volume percentage, the mass/volume percent in this solution is 26.5%.
Definition of mass/volume percentMass/volume percent is a measure of concentration that indicates the number of grams of solute in each 100 mL of solution.
In other words, the volume percent of a component in the solution is defined as the ratio of the mass of solute that is present in a solution, relative to the volume of the solution, as a whole.
The volume percentage of a solution is determined by the following expression:
[tex]mass/volume percent=\frac{mass of solute}{volume of solution}100[/tex]
Mass/volume percent in the solutionIn this case, you know:
mass of solute= 22 gvolume of solution= 83 mLReplacing in the definition of mass/volume percent:
[tex]mass/volume percent=\frac{22 g}{83 mL}100[/tex]
Solving:
mass/volume percent= 26.5 %
Finally, the mass/volume percent in this solution is 26.5%.
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What is not a part of the digestive system
A. Large intestine
B. Small intestine
C.Trachea
D. Esophagus
Answer:
Trachea is not the part of digestive system
Explanation:
Trachea is the part of the respiratory system
How many grams of oxygen gas are required to react completely with 2.8 g of solid sodium
in a synthesis reaction?
Explanation:
0.9 grams of oxygen gas we need.
Suppose that a 10-mL sample of a solution is to be tested for I− ion by addition of 1 drop (0.2 mL) of 0.13 M Pb(NO3)2.
What is the minimum number of grams of I− that must be present in order for PbI2(s) ( Ksp=8.49×10−9 ) to form?
The minimum number of grams of I that must be present is ; 0.01836 * 10⁻³ mol
Given data :
Volume of solution to be tested for I-ion = 10 mL
Volume of Pb(NO₃)₂ = 0.2 mL
molarity of Pb(NO₃)₂ = 0.13 M
Determine the number of I that must be presentFirst step : calculate conc of PB²⁺ ions in the solution
conc of PB²⁺ ions = ( molarity of Pb(NO₃)₂ * volume of Pb(NO₃)₂ ) / ( total volume )
= ( 0.13 * 0.2 ) / ( 10 + 0.2 )
= ( 0.026 ) / ( 10.2 ) = 0.002549 M
Next step : determine the molarity of I
using the dissociation reaction of PbI₂
PbI₂(s) ---> Pb²⁺ (aq) + 2I (aq)
also; Ksp = [ Pb²⁺ ] [ I ]² ---- ( 1 )
From the question the given value of Ksp = 8.49 * 10⁻⁹
Therefore equation ( 1 ) becomes
8.49 * 10⁻⁹ = ( 0.002549 ) * [ I ]²
[ I ] = √ ( 8.49 * 10⁻⁹ ) / ( 0.002549 )
= 0.0018 M
Final step : Determine the minimum number of grams of I
moles of I = molarity of I * total volume
= 0.0018 M * 10.2 mL
= 0.01836 * 10⁻³ mol
Hence we can conclude that The minimum number of grams of I that must be present is ; 0.01836 * 10⁻³ mol
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To what temperature must a sample of helium gas be cooled from 139ºC to reduce its volume from 3.1 L to 0.71 L at constant pressure?
Answer:
To what temperature must a sample of helium gas be cooled from 22.2 degrees C to reduce its volume from 1.00L to 100cm3 ?
Explanation:
Why is an enzyme in a chemical reaction like a lock and key?
A. The active site and the substrate fit perfectly together, and when they do, they unlock the chemical reaction.
B. The non-reactive site and the substrate fit perfectly together, and when they do, they unlock the chemical reaction.
C. None of these
D. The nucleoid and Golgi Apparatus fit perfectly together, and when they do, they unlock the chemical reaction.
E. The active site and the cell membrane fit perfectly together, and when they do, they unlock the chemical reaction.
Answer:
A
Explanation:
the enzyme is substrate specifix coz of this trait
Planck's constant, h, is 6.626 x 10-34 Js. The speed of light in a vacuum, c, is 3.00 x 108 m/s. Calculate the energy of ultraviolet light with a frequency of 9.58 x 1014 Hz. A) 1.45x1048 J B) 3.92x107 J C) 6.35x10-19 J D) 6.92x10-49 J
Given the Planck's constant and the speed of light, the energy of the ultraviolet light with a frequency of 9.58×10¹⁴ Hz is 6.35×10¯¹⁹ J (Option C)
Data obtained from the question Planck's constant (h) = 6.626×10¯³⁴ JsSpeed of light (v) = 3×10⁸ m/sFrequency (f) = 9.58×10¹⁴ HzEnergy (E) =? How to determine the energyThe energy of the ultraviolet light can be obtained as follow:
E = hf
E = 6.626×10¯³⁴ × 9.58×10¹⁴
E = 6.35×10¯¹⁹ J
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Which of the following aqueous solutions would have the lowest freezing point?
0.1 M sodium chloride
0.1 M calcium phosphate
0.2 M potassium sulfide
0.3 M aluminum nitrate
0.3 M barium chloride
Answer:
0.1 M Calcium phosphate
Explanation:
Which is also
0.1mCal2
In the following acid-base reaction,
HPO42- is the
H2PO4- (aq) + NH3(aq) → HPO42- (aq) + NH4+(aq)
А
B
С
acid
conjugate
acid
conjugate
base
Taking into account the Brønsted-Lowry acid-base theory, HPO₄⁻² is conjugate base of H₂PO₄⁻.
Brønsted-Lowry acid-base theoryThe Brønsted-Lowry acid-base theory (or the Brønsted-Lowry theory) identifies acids and bases based on whether the species accepts or donates protons or H⁺.
According to this theory, acids are proton donors while bases are proton acceptors.
So, reactions between acids and bases are H⁺ proton transfer reactions, causing the acid to form its conjugate base and the base to form its conjugated acid by exchanging a proton.
In other words, a conjugate base is an ion or molecule resulting from the acid that loses the proton, while a conjugate acid is an ion or molecule resulting from the base that gains the proton:
acid + base ⇄ conjugate base + conjugate acid
This caseIn this case, you know:
H₂PO₄⁻ + NH₃ → HPO₄⁻² + NH₄⁺
H₂PO₄⁻ behaves like acid because donates an H⁺ proton while NH₃ behaves like base because accepts an H⁺ proton from the acid.
So, NH₄⁺ is the conjugate acid of the NH₃ and HPO₄⁻² is conjugate base of H₂PO₄⁻.
In summary, HPO₄⁻² is conjugate base of H₂PO₄⁻.
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how many days it take to a year
Hey there!
January = 31 ☑️
February = 28 (sometimes 29 on a leap year) ☑️
March = 31 ☑️
April = 30 ☑️
May = 31 ☑️
June = 30 ☑️
July = 31 ☑️
August = 31 ☑️
September = 30 ☑️
October = 31 ☑️
November = 30 ☑️
December = 31 ☑️
Therefore, your answer is: 365
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Calculate the pH of a hydrochloride acid solution, HCl, whose hydronium ion (H3O)+ concentration is 8.29 X 10-4 M.
Note: answer should have three significant figures
Answer:
Explanation:
Calculate the pH of a hydrochloride acid solution, HCl, whose hydronium ion (H3O)+ concentration is 8.29 X 10-4 M.
Note: answer should have three significant figures
Why do some animals migrate in and out of the coniferous forest? (select two) Food Cover Precipitation Temperature
Answer:Tep/Shel/
Explanation:
Answer:
it's food and procipitation
Explanation:
2 Which of these rates of travel is slowest
a.5 kilometres per second
b.20 kilometres per minute
c.60 kilometres per hour
Answer:
60 kilometres per hour is the slowest rate of travel
Explanation:
we convert
20 kilometer per minute into kilometer per second
it comes out 1/3 kilometer per sec
Answer:
c
Explanation:
a- 5/1km per second
b-1/3km per second
c. 1/60km per second
the larger the denominator the smaller the fraction
Choose all that apply for neap tides
Moon and sun are at right angles to the earth
Moon, sun, and earth are all in alignment
Smaller than normal range of highs and low tides
Gravity of the sun and moon work against each other
Answer:
1. Moon and sun are at right angles to the earth
2. Smaller than normal range of highs and low tides
3. Gravity of the sun and moon work against each other
Match each form of energy with its definition
Chemical energy
Kinetic energy
Potential energy
mechanical energy
energy of motion ----
the energy of the bonds between atoms-----
the sum of an object's kinetic and potential energies----
stored energy based on position or arrangement-------
Answer:
energy of motion is kinetic
energy of Bond between atom chemical energy
stored energy based on position or arrangement-potential
the sum of an object's kinetic and potential energies----mechinical
Balance the equation
Unwanted elements are removed from metals by a process called
a. mining
b. fission
c.refining
d. recycling
Answer:
C. Refining
Explanation:
Refining process removes elements from a substance
Why is oxygen reduced in the reaction of hydrogen with oxygen to make water
Answer:
A. Oxygen pushes electrons towards the hydrogens.
Explanation:
The oxygen is reduced because it undergoes a partial gain of electrons. The oxygen atom in water has greater electron density near it than they did in the O₂ molecule.
What is Reduction Reaction ?
Reduction is a chemical reactions in which the number of electrons associated with an atom or a group of atoms is increased.
The electrons taken up by the substance reduced are supplied by another substance, which is thereby oxidized.
The hydrogen is oxidized because it added oxygen to form water.
Conversely the oxygen is reduced because it added hydrogen to form water.
Therefore, The oxygen is reduced because it undergoes a partial gain of electrons. The oxygen atom in water has greater electron density near it than they did in the O₂ molecule.
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Use the bond energy to calculate an approximate value of ΔH for the following reaction. Which is the more stable form of FNO2?
The Lewis structures in which there are no formal charges is the most stable. Hence, structure (b) is the more stable form of FNO2.
Lewis structureThe question is incomplete but I will try to answer you as much as I can. Now the equation is missing hence we can't numerically caculate the enthalpy chnage of the reaction from bond energies. However, we can do this using the formula; Σbond energy of reactants - bond energy of products.
Concerning the Lewis structures of FNO2, the most stable structure is structure (b) as shown in the image attached where the atoms have no formal charges.
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Amory turns the light on in her house. Looking at the lights, she begins to wonder how the charges are moving through the bulb. Which statement best describes how the charges move through the bulb ?
The statement 'when charges pass through the bulb, light is produced' best describes how the charges move through the bulb.
What is an electrical charge?An electrical charge is a type of positive or negative charge of the particles that move in a conductor.
At the atomic level, protons are positively charged particles, electrons are negative, and neutrons do not have a charge.
The electrical charges depend on the charge's initial time, the final time, and the net outward current.
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the ability of atoms to attract electrons from surrounding atoms is called
Answer:
Electronegativity
Explanation:
The ability of an atom to attract itself an electron pair shared with another atom in a chemical bond.
Which property of water makes it effective in protecting firefighters?
Answer:
water has a high specific heat
Explanation:
this should work as an answer
1. How many joules of heat are necessary to melt 500 g of ice at its freezing point?
Please show work!
Answer:
40 kcal
Explanation:
Heat required to melt
1 g
of ice at
0°C
is approximately
80 cal
. This is also called latent heat of fusion of ice.
For
500 g
of ice
Q
=
500
g
×
80
cal
g
=
40000 cal = 40 kcal
What properties of water are related to Oxidation?
Answer:
water has several important physical properties. Most of the physical properties of water are quite atypical e.g molar mass is 18.0151grams per mol and melting point is 0.00 degree
What is the chemical name of the covalent compound SF6?
Answer:
The name of it is Sulfur Hexafluoride
Explanation:
Bonus fact: It is over 5 times heavier than air so when inhaling it, it makes your voice go very deep. The opposite of helium some would say
the square below has anarea of 49ft2 what is the perimeter of the square
Answer:
28ft
Explanation:
if it's a square then each side is equal
the square root of 49 is 7
each side is 7 ft
7 ft times 4 sides is 28ft
how many CO grans are produced from 1.80 mol of sulfur dioxide2
Answer:
A mol (approximately)represents the number 6.02 X 10^^23. Mols become useful when we learn that, for any element on the periodic table, 6.02 X 10^^23 atoms of that element have a mass equal to the atomic mass in grams. So, on the periodic table carbon has an atomic mass of 12.011. That means: 12.011 grams of carbon is made up of 6.02 X 10^^23 atoms.
The above question is tricky.
If the question considers 1 molecule of SO2 as a particle, then the answer is 1.80 * 6.02 X 10^^23
If the question considers the S as one particle, and the O2 as 2 more particles, then the answer is: 3 * 1.8 * 6.02 X 10^^23.
Explanation:
hope it helps U
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You compare the gas generated from a reaction using two antacid tablets with the gas generated from a reaction using four antacid tablets (consider the antacid as the limiting reagent).
At constant pressure and temperature, how do the volumes of the gases compare?
The two reactions produce the same amount of gas.
The gas generated by four antacid tablets has a smaller volume.
The gas generated by two antacid tablets has a smaller volume.
Answer: The gas generated by two antacid tablets has a smaller volume.
Explanation:
Since the antiacid is the limiting reagent, we know that the more tablets there are, the more gas there will be.
This means that there will be more gas generated by the four antiacid tablets when compared to the two antiacid tablets, which gives us that the gas generated by the two antiacid tablets has a smaller volume.
state one possible mistake in a simple distillation setup and explain the significance of the mistake.
Answer:
liquid is heated. As the liquid is heated, the molecules within it gain the energy to escape the liquid phase and transition into the gas phase in the form of bubbles.
Explanation:
Sodium hydroxide (0.400 mol) is allowed to react with an excess of sulfuric acid. How many moles of
sodium sulfate could be recovered from the products?
NaOH + H2SO4 → Na2SO4 + H20
Answer:
2 moles
Explanation:
In this reaction, the stoichiometry (mole ratio) is 1 mole of sulfuric acid reacting with 2 moles of sodium hydroxide (1:2 ratio)