The standard enthalpy of formation of ethane is determined as -192.5 kJ/mol.
Reaction for the formation of ethaneThe reaction for the formation of ethane is given as;
2C + 3H₂ → C₂H₆
Where;
C is carbon (graphite)H is hydrogen C₂H₆ is ethaneStandard enthalpy of formation of ethaneThe standard enthalpy of formation of ethane is calculated as follows;
ΔH = ΔH₁ + ΔH₂ + ΔH₃
where;
ΔH₁ is heat of formation of graphite = -286 kJ/molΔH₂ is heat of formation of hydrogen = -393.5 kJ/molΔH₃ is heat of formation of ethane = 1560 kJ/mol2C + 3H₂ → C₂H₆
ΔH = 2(-286) + 3(-393.5) + 1(1560)
ΔH = -572 - 1180.5 + 1560
ΔH = -192.5 kJ/mol
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PLEASE HELP
Predict the Eº values for all (6) combinations of the following: Cu(s) and Cu(NO3)2(aq) Fe(s) and Fe(NO3)3(aq) Zn(s) and Zn(NO3)2(aq) Pb(s) and Pb(NO3)2(aq)
Answer:
Is this math? Cause as a fourth grader, I can do Algebra, but not this.
Explanation:
how does air pollution cause global warming
Answer:
Air pollution affects the compounds in the air, causing heat to change dramatically over time in the atmosphere.
Calculate the mass in grams for 2.28 moles of N2.
228 g
63.9 g
6.39 g
2.28 g
Answer: 63.9
Explanation:
When was electricity invented?
Answer:In 1752
Explanation:Benjamin franklin in 1752 to prove that lightning was electrical,he flew a kite during a thundorstorm.He tied a metal key onto the string and as he suspected it would ,electrically from the storms clouds flowed down the string ,which was wet and he received an electrical shock.
Electricity was discovered and understood by many scientists. Benjamin Franklin is given the credit for discovering electricity. In the year 1752, Benjamin Franklin conducted an experiment using a kite and key on a rainy day.
If you add 5.9 mL 4.00 mL of pure water to 28.752 mL 6.00 mL of 0.56 M 0.750 M NaCl solution, what is the concentration of sodium chloride in the diluted solution?
pick one volume and concentration as a sample
5.9 ml + 28.752 ml = 34.652
M1V1=M2V2
0.56 x 28.752 = M2 x 34.652
M2=0.464 M
Net ionic equation for Calcium hydroxide reacting with ammonium Chloride?
Answer:
Step 1: Write the balanced chemical equation with the states first:
Ca(OH)₂ (aq) + 2NH₄Cl (aq) → CaCl₂ (aq) + 2NH₃ (g) + 2H₂O (l)
Step2: Write the complete ionic equation, break only the aqueous ones only :
Ca²⁺ + 2OH⁻ + 2NH₄⁺ + 2Cl⁻ → Ca⁺² + 2Cl⁻ + 2NH₃ (g) + 2H₂O (l)
Step 3: cancel the spectator ions ( the ions which stay the same like calciumn and chlorine ions here)
2OH⁻ + 2NH₄⁺ → 2NH₃ (g) + 2H₂O (l)AUDIO
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The ice record shows a period in Earth's history when there was an ice age and the global average temperature was
much colder. During this time, the ice record shows the amount of carbon dioxide in the atmosphere decreased, but the
amount of energy from the sun did not change. How did the the total amount of energy in the Earth system change, how
did this change happen, and how did it contribute to the ice age?
Hand Ir
Sig
The average temperature during the ice age was around 46 degrees Fahrenheit although the polar regions were far colder, around 25 degrees Fahrenheit which is colder than the global average.
What is an average temperature?The monthly mean temperature: It is calculated by adding the daily mean temperatures for each day of the month and dividing the total by the number of days in a month.
The average global temperature during the period known as the Last Glacial Maximum from roughly 23,000 to 19,000 years ago was about 46 degrees Fahrenheit (7.8 degrees Celsius), some 13 degrees Fahrenheit (7 Celsius) colder than 2019, the researchers said.
A team of scientists has nailed down the temperature at the peak of the last ice age, a time known as the ast Glacial Maximum, to about 46 degrees Fahrenheit.
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I WILL GIVE BRAINLIEST FOR THE FIRST RIGHT QUESTION
Construct an argument supported by evidence to describe the connections between the number of people in a society and the amount of plastic waste that they generate.
Scientists use models to
A - Stop the occurrence of tsunamis due to an earthquake
B - Predict the damages due to an earthquake
C - Change the location of a volcanic eruption
D - Increase the duration of a volcanic eruption
What occurs as the atomic number of the elements in period to increases
The answer is moving left to right across a period the nucleus has a greater pull on the outer electrons and the atomic radii decreases.
What is Atomic Number ?The atomic number or nuclear charge number (symbol Z) of a chemical element is the charge number of an atomic nucleus.
Atomic Number (generally ) = Number of Protons
The atomic number can be used to uniquely identify ordinary chemical elements.
In an ordinary uncharged atom, the atomic number is also equal to the number of electrons.
The atomic number increases moving left to right across a period and subsequently so does the effective nuclear charge.
Therefore, moving left to right across a period the nucleus has a greater pull on the outer electrons and the atomic radii decreases.
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An element P with electron configuration 2,
8, 2 combined with another element Q with
electron configuration 2, 8, 7. The chemincal
bond between P and Q is
A. covalent B. coordinate
C. metallic D. electrovalent
Answer:
Electrovalent.
Explanation:
[tex]\text{The element P is }~ _{12}Mg\\\\\text{The element Q is }~ _{17}Cl\\\\\text{The chemical bond between P and Q is ionic or electrovalent bond.}\\\\Mg^{2+} + 2\text{Cl}^{-} \rightleftharpoons MgCl_2[/tex]
A buffer solution made from a generic acid (HA with Ka =4.82 x 10-5 )is 0.110 M in HA and 0.110 M in NaA. How many moles of NaOH can 200 mL of this buffer neutralize before the pH rises by 0.50?
0.634 mol of NaOH can 200 mL of this buffer neutralize before the pH rises by 0.50.
What is a buffer solution?A buffer is a solution that can resist pH change upon the addition of an acidic or basic components.
Solution:
A buffer consists of 0.11 M HA and 0.11 M NaA.
Ka =[tex]4.82 X 10^-^5[/tex]
pKa = -log ([tex]4.82 X 10^-^5[/tex])
pKa = 11.83
Using Henderson equation to calculate pH of the buffer solution.
pH =PKa -log [tex]\frac{Conjugate \;base}{Acid}[/tex]
pH = 11.83 - [tex]\frac{0.11 M}{0.11 M}[/tex]
pH = 10.83
pOH = 14 - 10.83
pOH = 3.17
Calculating the moles of NaOH added by the addition of 200 mL
Molarity = [tex]\frac{Moles \;of \;NaOH}{0.2 L}[/tex]
3.17 X 0.2 = Moles of NaOH
Moles of NaOH = 0.634 mol
Hence, 0.634 mol of NaOH can 200 mL of this buffer neutralize.
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You are standing outside in a rural area at night, looking up to the sky and observe many stars. If you were to look up to the sky in the city on that exact same night, what would you observe? (2 points)
Group of answer choices
That only the street lights shine in the sky
That there appears to be little to no stars in the sky
That there appears to be many stars in the sky
Answer:
That there appears to be many stars in the sky
Explanation: hope this helps! <33333
I will mark as brainliest if correct
Which of the following is described by the equation H2O(l) --> H2O(s) + heat?
A. Melting
B. Condensing
C. Freezing
D. Evaporating
Answer:
[A] Melting
Explanation:
From the giving it means:
H2O(s) - Solid {Ice}
H2O(l) - Liquid {water}
So the equation is:
Liquid ⇒ Solid + Heat
Water ⇒ Ice + Heat
Hence, if you add ice and heat it equal to melting.
Therefore the correct answer is [A] Melting.
Kavinsky
Answer: C. Freezing
Explanation:
CH3-CH=CH3-CH what is the name of this structure?
Answer:
if you meant CH3-CH=CH-CH3, the IUPAC name is 2-butene.
Na-23 has 11 protons.How many neutrons does it have?
this is how you find it:
23-11=12
the 12 is the amount of neutrons
A force of 20 N
acts upon a 5 kg
block. Calculate
the acceleration
of the object.
Answer:
0.25m/s²
Explanation:
here
weight(w)-20 N
mass(m)-5 kg
acceleration (g) -?
we know
w=mg
g=m/w
=5/20
=0.25 m/s²
Answer:
acceleration=0.04g/s
Explanation:
force=Ma
20N=5kgXa
5kg=5000g
20N=5000Xa
20N=5000a
divide both sides by 5000
acceleration=0.04g/s
13 a plant will start to wilt/sprout without sunlight
Answer:
wilt
Explanation:
Without sunlight, photosynthesis cannot occur, and photosynthesis makes chlorophyll, the plant's food. Therefore, a plant without sunlight will "starve," and begin wilting.
Answer:
it will true
Explanation:
WILL GIVE BRAINLIEST!
A certain reaction is endothermic in the forward direction. The reaction has less moles of gas on the product side. Which of the following stresses would increase the yield of the products (shift right)?
•Decreasing the temperature
•Decreasing the reactant concentration
•Increasing the volume
•Increasing the pressure
answer is either A or D
Answer:
A
Explanation:
Increasing the the temperature would favour the endothermic reaction which is the forward direction however increasing the pressure would make the reaction try to counteract this change by favouring the reaction that would create more products so the equilibrium will shift left instead of right.
Hope this helps.
A 49.2 g sample of barium hydroxide is dissolved in water and the solution is diluted to give a final volume of 629.84 mL. What is the final molarity of the solution?
Answer:
.455 M
Explanation:
Ba (OH)^2 has mole weight of (from periodic table) = 171.341 gm/mole
49.2 gm / 171.341 gm/mole = .287 mole
.287 M / .62984 L = .455 M
Convert 5.50 mol of MgO to g.
Answer:
5.50 moles of magnesium oxide is 221.6742 grams
Explanation:
to do this you multiply the number of moles by the molar mass
Calculate the volume(mo) of 0.50 M NaCl stock solution need to make 100mL of a diluted solution with a concentration of 0.03
Answer:
.006L or 6 mL
Explanation:
The magnetite has a mass of
42.0 g and a volume of 8.1 cm3.
What is the density of the
magnetite sample?
Answer:
5.185 gcm⁻³
Explanation:
The formula to find density is:
Density = [tex]\frac{mass}{volume}[/tex]
Density = [tex]\frac{42}{8.1}[/tex]
Density of magnetite sample = 5.185 gcm⁻³
Answer: 5.185
Explanation: the formula to find the density is
Density = mass/volume
Density = 42/8.1
Density of magnetite sample = 5.185 g/cm3
The space race was between
a.
the United States and China.
b.
Great Britain and the Soviet Union.
c.
the Soviet Union and China.
d.
the United States and the Soviet Union.
Answer:
the United States and the Soviet Union.
Explanation:
Basically we were in toe to toe with the russians for space explorations like who's gonna get to space first or moon or do such explorations
aluminum + sulfur aluminum sulfide
10.8 g 19.2 g (REACTANT/PRODUCT)??
Answer:
Al + S -> Al2S3
Al and S are the reactants, Al2S3 is the product
Explanation:
Calculate the pH of the following solutions at 298 K.
a) 0.25 mol dm-3 HCl.
b) 0.15 mol dm-3 H2SO4.
c) 0.15 mol dm-3 benzoic acid. Ka(benzoic acid) = 6.4 x 10-5 mol dm-3.
d) 0.10 mol dm-3 KOH. Kw(298 K) = 1.0 x 10-14 mol2 dm-6.
The term pH has to do with the hydrogen ion concentration of a solution.
What is pH?The term pH has to do with the hydrogen ion concentration of a solution. Let us now proceed the pH of the solutions;
a) pH of HCl = -log(0.25) = 0.62
b) pH of H2SO4 = -log(0.15) = 0.82
c) We have to set up an ICE table here;
C6H5COOH + H2O ⇄ C6H5COO- + H^+
I 0.15 0 0
C -x +x +x
E 0.15 -x x x
Ka = [C6H5COO-] [ H^+]/[C6H5COOH]
6.4 x 10^-5 = x^2/0.15 - x
6.4 x 10^-5(0.15 - x) = x^2
9.6 * 10^-6 - 6.4 x 10^-5x = x^2
x^2 + 6.4 x 10^-5x - 9.6 * 10^-6 = 0
x=0.003 M
Hence;
[C6H5COO-] = [ H^+] = x = 0.003 M
pH = - log[0.003 M] = 2.5
d) [OH-] [H^+] = 1.0 x 10-14 mol2 dm-6
[H^+] = 1.0 x 10-14 mol2 dm-6/ 0.10 mol dm-3
[H^+] = 1 * 10^-13 M
pH= - log[1 * 10^-13 M] = 13
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The concentration of a solution refers to the amount of solute that has been dissolved in a given amount of solute. consider the solution seen. here select all the ways that this solution could be made more concentrated.
A.) increase the amount of solute
B.) decrease the amount of solute
C.) decrease the amount of solvent
D.) increase the amounts of solute and solvent
How can glass be a liquid if it's so hard?
Answer: below
Explanation:
Glass can be heated up and turn into a liquid, its a hard procces, due to the extreme heat, machines are used today.
Answer:
answer
[tex]\huge\tt{\underline{\colorbox{maroon}{✨ANSWER}}}[/tex]
Explanation:
Because glass is hard, it must be a supercooled liquid. Glass, however, is actually neither a liquid—supercooled or otherwise—nor a solid. It is an amorphous solid—a state somewhere between those two states of matter
What is the BEST explanation for how stirring the salt into the glass of water increases the rate of solution?
A) Stirring increases the surface area of the solute
B) The solute particles do not stay on the bottom of the glass
C)Stirring increases random motion and contact between solute and solvent
D) Stirring decreases the kinetic energy of the solution and aids in dissolving
6.45g of lithium reacts with 9.2g of oxygen gas to produce lithium oxide.How many grams of Li20 are formed? Hint: write the balanced chemical equation first.