Answer:
The correct answer is the epipelagic zone
A chemist titrates 60.0 mL of a 0.1935 M benzoic acid (HC (H5CO2) solution with 0.2088 M KOH solution at 25 °C. Calculate the pH at equivalence. The pKg of benzoic acid is 4.20.
Answer:
pH at the equivalence point is 8.6
Explanation:
A titulation between a weak acid and a strong base, gives a basic pH at the equivalence point. In the equivalence point, we need to know the volume of base we added, so:
mmoles acid = mmoles of base
60 mL . 0.1935M = 0.2088 M . volume
(60 mL . 0.1935M) /0.2088 M = 55.6 mL of KOH
The neutralization is:
HBz + KOH ⇄ KBz + H₂O
In the equilibrum:
HBz + OH⁻ ⇄ Bz⁻ + H₂O
mmoles of acid are: 11.61 and mmoles of base are: 11.61
So in the equilibrium we have, 11.61 mmoles of benzoate.
[Bz⁻] = 11.61 mmoles / (volume acid + volume base)
[Bz⁻] = 11.61 mmoles / 60 mL + 55.6 mL = 0.100 M
The conjugate strong base reacts:
Bz⁻ + H₂O ⇄ HBz + OH⁻ Kb
0.1 - x x x
(We don't have pKb, but we can calculate it from pKa)
14 - 4.2 = 9.80 → pKb → 10⁻⁹'⁸ = 1.58×10⁻¹⁰ → Kb
Kb = [HBz] . [OH⁻] / [Bz⁻]
Kb = x² / (0.1 - x)
As Kb is so small, we can avoid the quadratic equation
Kb = x² / 0.1 → Kb . 0.1 = x²
√ 1.58×10⁻¹¹ = [OH⁻] = 3.98 ×10⁻⁶ M
From this value, we calculate pOH and afterwards, pH (14 - pOH)
- log [OH⁻] = pOH → - log 3.98 ×10⁻⁶ = 5.4
pH = 8.6
Determine the molar mass of iron(II) chloride hexahydrate. Provide an answer to two decimal places.
Answer:
FeCl₂ · 6H₂O = 234.75 g/mol
Explanation:
Iron (II) = Fe²⁺
Number between () indicates the oxidation state
Chloride = Cl⁻
Iron (II) chloride = FeCl₂
If we say hexahydrate, it means that our salt is hydrated by 6 molecules of water.
FeCl₂ · 6H₂O = Iron(II) chloride hexahydrate
Molar mass is = 55.85 g/mol + 35.45 g/mol . 2 + 6 . 18g/mol = 234.75 g/mol
We have just summed molar mass of Fe, plus Cl (x2), plus 6 H₂O
What is the oxidation number for N in the compound NH3? (Recall that H usually has an oxidation number of +1.)
0 -3
0-1
Ο Ο
O +3
Answer:
the oxidation number is -3
Taking into account the definition of oxidation number, the oxidation number for N in the compound NH₃ is -3.
Definition of oxidation numberThe oxidation number is the charge that an atom has; is an integer that represents the number of electrons an atom puts into play when it forms a given compound.
In other words, the oxidation number of an element is a value that indicates the number of electrons that element gains or loses when it combines with another.
Oxidation number determinationTo determine the oxidation state it is necessary to know that The oxidation number of hydrogen in a compound is +1, except in metal hydrides, where is –1.
On the other side, the sum of the oxidation numbers of the existing elements in a chemical formula must add up to zero.
Then, considering the oxidation numbers of each element, multiplying it by the number of existing elements in the chemical formula and adding it and equaling it to zero, the value of the missing oxidation number can be obtained.
Oxidation number of nitrogenIn this case, the oxidation numbers of nitrogen is calculated as:
NH₃: oxidation numbers of nitrogen + 3×(+1)= 0
Solving:
oxidation numbers of nitrogen + 3= 0
oxidation numbers of nitrogen = -3
Finally, the oxidation number for N in the compound NH₃ is -3.
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What mass of sucrose, C12H22O11, should you dissolve in 100.0 g of water to obtain a solution in which the mole fraction of C12H22O11 is 0.124?
Answer:
the sucrose mass is 264.g
Explanation:
The computation of the sucrose mass is shown below;
The Molar mass of [tex]C_{12}H_{22}O_{11}[/tex] is 342.3 g/mol
And, the molar mass of [tex]H_2O[/tex] is 18g/mol
The mass of [tex]C_{12}H_{22}O_{11}[/tex] be Y
Now
The moles of [tex]C_{12}H_{22}O_{11}[/tex] is
= Mass of [tex]C_{12}H_{22}O_{11}[/tex] ÷ molar mass of [tex]C_{12}H_{22}O_{11}[/tex]
= Y ÷ 342.3 mol
And,
The moles of [tex]H_2O[/tex] is
= Mass of [tex]H_2O[/tex] ÷ molar mass of [tex]H_2O[/tex]
= 100.0 ÷ 18
= 5.56mol
Now
The molar fraction of [tex]C_{12}H_{22}O_{11}[/tex] is
= Moles of [tex]C_{12}H_{22}O_{11}[/tex] ÷ (moles of[tex]C_{12}H_{22}O_{11}[/tex] + moles of [tex]H_2O[/tex]) = 0.124
= (Y ÷ 342.3) ÷ [(Y ÷ 342.3) + 5.56] = 0.124
Y ÷ 342.3 = 0.124 × [(Y ÷ 342.3 + 5.56]
Y = 0.124 × Y + (0.124 × 5.56 × 342.3)
Y = 269.4 g
hence, the sucrose mass is 264.g
A sample of rubidium contains two different isotopes. 72.15% of the sample
if Rubidium-85 while 27.85% is Rubidium-87. What is the average atomic
mass of the sample?
Answer:
Average atomic mass = 85.557 amu.
Explanation:
Given data:
Percent abundance of Rb-85 = 72.15%
Percent abundance of Rb-87 = 27.85%
Average atomic mass = ?
Solution:
Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) / 100
Average atomic mass = (72.15×85)+(27.85×87) /100
Average atomic mass = 6132.75 + 2422.95 / 100
Average atomic mass = 8555.7 / 100
Average atomic mass = 85.557 amu.
How many TOTAL ELECTRONS are in the compound CO2?
o (2 dots at the top and 2 on the bottom) = c = o (2 dots on the top and 2 dots on the bottom)
16
14
12
8 ml
What is the correct name for PBr3?
phosphorus bromine
Phosphorus tribromide
monophosphorus tribromide
Answer:
22 electrons are in the compound CO2. And the correct answer is Phosphorus tribromide.
Explanation:
whats the awnser? i cant find it and i need it asap! anyone i will crown you the brainleist!
How many electron dots should As have?
Answer:
5
Explanation:
CAN SOMEONE PLEASE HELP ME ANSWER THIS QUESTION
Answer:
Carbon Dioxide
Explanation:
Plants inhale Carbon Dioxide and exhale Oxygen
What is the major cause of the greenhouse effect?
soot from coal plants in the water
carbon dioxide in the water
carbon dioxide in the atmosphere
soot from coal plants in the atmosphere
Answer:
carbon dioxide in the atmosphere
Explanation:
Carbon dioxide in the atmosphere is the major cause of greenhouse effect.
Greenhouse effect is the main cause of global warming.
This effect is produced as a result of some certain gases called greenhouse gases. These gases are carbon dioxide, water vapor, methane etc. They prevent short wave radiations from leaving the earth. This causes the increase in temperature of the surface.what is triavalent monovilant divalent ?
Answer:
I HOPE IT HELPED THANKS
A chemical equation is shown: C2H4 + O2 → CO2 + H2O According to the law of conservation of mass, how many atoms of oxygen exist in the products of this reaction? (3 points) 2 4 6 8
Answer:
6 oxygens on the product side
Explanation:
1) balance the equation:
C2H4 + 3O2 → 2CO2 + 2H2O
2) calculate the number of oxygens on the product side
2CO2=4
2H2O=2
According to the law of conservation of mass, there are 6 atoms of oxygen in the product of this reaction.
What is law of conservation of mass?According to law of conservation of mass, it is evident that mass is neither created nor destroyed rather it is restored at the end of a chemical reaction .
Law of conservation of mass and energy are related as mass and energy are directly proportional which is indicated by the equation E=mc².Concept of conservation of mass is widely used in field of chemistry, fluid dynamics.
Law needs to be modified in accordance with laws of quantum mechanics under the principle of mass and energy equivalence.This law was proposed by Antoine Lavoisier in the year 1789.
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Which statement about stars is correct?
A. Star formation begins in a nebula.
B. White dwarfs become main-sequence stars when they gain mass.
C. Supergiants are stars that can absorb black holes.
D. Main-sequence stars are formed by comets.
Answer:
A. star formation begins in a nebula.
Explanation:
An exothermic reaction
.
In an endothermic reaction, the energy of the products is
the energy of the reactants.
Activation energy is
the potential energy of the products.
An exothermic reaction Produces energy
In an endothermic reaction, the energy of the products is more than the energy of the reactants. and Activation energy is always greater than the potential energy of the products
An endothermic reaction is a reaction which requires an external source of energy before the reaction will take place ( i.e. endothermic reaction absorbs energy in the form of heat from its surrounding ) while an exothermic reaction releases energy in the form of heat into the environment.
Activation energy is amount of energy required to start a reaction since an endothermic reaction absorbs energy from its environment to kick off its reaction, its activation energy is always higher than the potential energy of its products.
Hence we can conclude that An exothermic reaction Produces energy In an endothermic reaction, the energy of the products is more than the energy of the reactants. and Activation energy is always greater than the potential energy of the products.
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Answer:
An exothermic reaction
✔ produces energy
.
In an endothermic reaction, the energy of the products is
✔ more than
the energy of the reactants.
Activation energy is
✔ always greater than
the potential energy of the products.
Explanation:
2023 edge
The wavelength of transmission is 9.7mm. What is the energy of this transition
Answer:
E = 2.05×10⁻²³ J
Explanation:
Given data:
Wavelength of transmission = 9.7 mm (9.7/1000 = 0.0097 m)
Energy of transition = ?
Solution:
9.7 mm (9.7/1000 = 0.0097 m)
9.7×10⁻³ m
Formula:
E = hc/λ
By putting values,
E = 6.63 ×10⁻³⁴ Js × 3×10⁸ m/s / 9.7×10⁻³ m
E = 19.89×10⁻²⁶ J.m / 9.7×10⁻³ m
E = 2.05×10⁻²³ J
the element chlorine is a member of which chemical family?
Answer:
is it from bleacH?
Explanation:
hazardous
Answer:
halogen family
Explanation:
Please help me answer this
NEED HELP WILL MARK U AS BRAINLIEST .
Answer:
C.
Explanation:
Corrosive means having the tendency to erode or eat away at something. Strong acids and bases are both corrosive.
A. True
B. False
Answer:
true
Explanation:
What is the
difference in
the number of
neutrons
between an
atom of
Oxygen and
Boron?
Answer:
its 2
Explanation:
boron has 6 neutrons and oxygen has 8 neutrons on avg.
the difference is 2 neutrons
At a high elevation, there is little chance of... a) flooding b)lack of oxygen c) getting dizzy
Answer:
A. flooding
Explanation:
At high elevations air becomes thinner so a person may not be receiving enough oxygen which can cause dizziness. Flooding typically happens at sea level.
What coefficients would balance the following equation?
__C2H6 + __O2 → __CO2 + __H2O
CAN SOMEONE PLEASE HELP ME I WILL GIVE BRAINLIEST
Answer:
9812
Explanation:
i think
Answer:
if im correct its b but im not 100 percent sure
Explanation:
Whatss the answer giving brainliest:)
Answer:
A.
Explanation:
I just know.
Answer:
a.
Explanation:
if a horse gallops 1 meter per second, how far can it travel in 1 minute?
pls help
Answer:
60 meters
Explanation:
What happens to valence electrons when a covalent bond forms?
Explanation:
Covalent bonding occurs when pairs of electrons are shared by atoms. Atoms will covalently bond with other atoms in order to gain more stability, which is gained by forming a full electron shell. By sharing their outer most (valence) electrons, atoms can fill up their outer electron shell and gain stability
Oxygen
Hydrogen
Nitrogen
Carbon
A.
B.
c.
D
Which model represents the chemical formula NO2, nitrogen dioxide?
A)
A
B)
B.
o
C С.
D D
Answer:
the answer is C
Explanation:
there is 1 purple and 2 blues
The model which represents chemical formula of nitrogen dioxide is C.
What is chemical formula ?Chemical formula is a way of representing information about the proportions of elements which are present in a compound or molecule.It is generally written with the symbols of chemical elements. It also makes use of brackets and subscripts.
Number of atoms of each element is written as a subscript .Chemical formula makes use of no words . It is not the same as structural formula .Chemical formula in the simplest form is called as the empirical formula.
Drawbacks of chemical formula are that they do not provide information about the position of atoms and not also on the structure. Owing to these reasons, chemical formula is not that informative as that of structural formula.
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A 7.417 gram sample of an organic compound containing C, H and O is analyzed by combustion analysis and 10.52 grams of CO2 and 6.460 grams of H2O are produced. In a separate experiment, the molar mass is found to be 62.07 g/mol. Determine the empirical formula and the molecular formula of the organic compound.
Answer:
Empirical formula: CH₃O
Molecular formula: C₂H₆O₂
Explanation:
All carbon is converted in CO2 and all hydrogen in H2O. Thus, we can find mass of each element and, by subtracting, the mass of Oxygen:
Mass C:
10.52g CO2 * (1mol / 44g) = 0.239 moles CO2 = Moles C * (12.01g / mol) =
2.87g C
Mass H:
6.460g H2O * (1mol / 18g) = 0.359 moles H2O * 2 = 0.718 moles H * (1g / mol) =
0.718g H
Mass O:
7.417g Sample - 2.87g C - 0.718g H =
3.829g O
Now, we can determine empirical formula defined as the simples whole number ratio of atoms present in a compound with moles of each atom:
Moles C: 0.239 moles C
Moles H: 0.718 moles H
Moles O: 3.829g * (1mol / 16g) = 0.239 moles O
The ratio of moles of each atom divided in moles of oxygen:
C: 0.239 mol / 0.239 mol = 1
H: 0.718 mol / 0.239 mol = 3
C: 0.239 mol / 0.239 mol = 1
Empirical formula: CH₃OThe molar mass of CH3O is:
12.01g/mol + 1g/mol*3 + 16g/mol =
31.01g/mol
That means molecular formula is twice empirical formula because its molecular mass is 31.01g/mol * 2 = 62.02g/mol ≈ 62.07g/mol
Molecular formula: C₂H₆O₂I need a hand with this one:
Having this equation:
Na2SO4 +BaCl2 = BaSO4+NaCl
If 10.09 grams of Na2SO4 were added to a 50mL barium solution and reacted completely, what was the BaCl2 molarity of the solution?
Yes, I already know its a displacement reaction
Thx
Answer:
[BaCl₂] = 1.42M
Explanation:
Given: Na₂SO₄(aq) + BaCl₂(aq) => 2NaCl(aq) + BaSO₄(s)
The balanced equation shows a 1:1 reaction between Na₂SO₄(aq) & BaCl₂(aq) and means the moles of sodium sulfate used equals the moles of baium chloride used. The concentration is the theoretical mole value calculated divided by 0.050 Liters.
Na₂SO₄(aq) + BaCl₂(aq) => 2NaCl(aq) + BaSO₄(s)
Moles of Na₂SO₄(aq) = moles of BaCl₂(aq) = 10.09g/142.04g/mol = 0.071mole
∴ Molar Concentration of BaCl₂(aq) = moles BaCl₂/Volume of Soln in Liters
= 0.071mole/0.050Liters = 1.42M in BaCl₂.
Diazomethane has the following composition by mass: 28.57% C, 4.80% H, and 66.64% N. The molar mass of diazomethane is 42.04 g/mol. Find the molecular formula of diazomethane.
Answer:
CH2N2
Explanation:
To find the molecular formula, we must first find the empirical formula as follows:
28.57% C - 28.57g of Carbon
4.80% H - 4.80g of Hydrogen
66.64% N - 66.64g of Nitrogen
Next, we convert this mass values to mole by dividing by their respective atomic mass.
C = 28.57/12 = 2.38mol
H = 4.80/1 = 4.80mol
N = 66.64/14 = 4.76mol
Next, we divide each mole value by the smallest mole value (2.38mol)
C = 2.38mol ÷ 2.38 = 1
H = 4.80mol ÷ 2.38 = 2.01
N = 4.76mol ÷ 2.38 = 2
The empirical ratio of C, H and N is therefore 1:2:2. Hence, the empirical formula is CH2N2
To calculate the molecular formula;
(CH2N2)n = 42.04 g/mol
{12 + 1(2) + 14(2)}n = 42.04
{12 + 2 + 28}n = 42.04
{42}n = 42.04
n = 42.04/42
n = 1.00009
Since n = 1, molecular formula is CH2N2
