Answer:
-252.5 kJ/mol = ΔH H2O(g)
Explanation:
ΔH Fe2O3 = -825.5kJ/mol
ΔH H2 = 0kJ/mol
ΔH Fe = 0kJ/mol
Based on Hess's law, ΔH of a reaction is the sum of ΔH of products - ΔH of reactants. For the reaction:
Fe2O3(s) + 3 H2(g) →2Fe(s) + 3 H2O(g)
ΔHr = 67.9kJ/mol = 3*ΔH H2O + 2*ΔHFe - (ΔH Fe2O3 + 3*Δ H2)
67.9kJ/mol = 3*ΔH H2O + 2*0kJ/mol - (ΔH -825.5kJ/mol + 3*Δ H2)
67.9 = 3*ΔH H2O(g) + 825.5kJ/mol
-757.6kJ/mol = 3*ΔH H2O(g)
-252.5 kJ/mol = ΔH H2O(g)Calculate the volume (in mL) of 6.0 M NaOH solution required to prepare 1.0 L of 0.09000 N NaOH solu
Answer:
the volume in mL is 15
Explanation:
The computation of the volume in mL is shown below:
As we know that
N = nM
where
N denotes the normality
n denotes the number of equivalents
M denotes the molarity
Also
For NaOH , N = M
Now
M× V_1 = N × V_2
V_1 = N × V_2 ÷ M
= 0.09000 N × 1.0 L ÷ 6.0 M
= 15 mL
hence, the volume in mL is 15
Compare the ionization energies of each pair of atoms. Enter the symbol for the atom with the larger ionization energy.
(If both atoms would be expected to have the same ionization energy, enter the word same.)
Pairs Symbol of atom with the larger ionization energy
Cl and I
Na and K
F and Br
Answer: 1. I
2. Na
3. F
Explanation:
Ionization energy is the energy required to remove the most loosely bound electron from an isolated gaseous atom.
In a group, the ionization energy decreases as we move down a group as the size increases. The electrons get added to the next shell. Thus the valence electron moves far from the nucleus and thus less energy is required to remove the valence electron.
1. Cl and I: Cl will have larger ionization energy as I lies lower in the group.
2. Na and K : Na will have larger ionization energy as K lies lower in the group
3. F and Br : F will have larger ionization energy as Br lies lower in the group.
Methanol has a melting point of -97 degrees celsius and a boiling point of 65 degrees celsius. What phase is methanol in at 80 degrees celsius? (Solid, Gas, or Liquid?)
Which describes how technology has changed society?
A. There is less food available to people.
B. People live longer than they used to
O C. It is more difficult to move goods
O d. It is hard for people to communicate
Answer:
B. People live longer than they used to
Explanation:
None of the other answers are correct.
this type of air pressure is associated with warm air rising
Areas where the air is warmed often have lower pressure because the warm air rises. These areas are called low pressure systems. Places where the air pressure is high, are called high pressure systems. A low pressure system has lower pressure at its center than the areas around it.
1. How many grams are in 1.4 moles of Mg(NO3)2?
Explanation:
molar mass of the compound = 24 + 2× 14+ 16×6
= 24 + 28 + 96
= 148g/mol
no of moles = given mass / molar mass of the compound
1.4 = given mass/ 148
1.4×148=given mass
207.2 g
8. A train travels at a at a speed of 30 miles per hour if 1 mile = 1.6 kilometers, how fast is the train traveling in kilometers per minute?
A. 0.8 km/min
B. 1.0 km/min
C. 0,4 km/min
D. 0,6 km/min
Answer:
Explanation:
A: 0.8 KM/Min
1.6 x 30 = 48
48/60 = 0.8
A reaction has activation energy of 85kjper mol. What is the effect on the rate of raising the temperature from 20degree to 30 degree
Answer: The rate increases 3 times on raising the temperature from 20degree to 30 degree
Explanation:
According to Arrhenius equation with change in temperature, the formula is as follows.
[tex]ln \frac{k_{2}}{k_{1}} = \frac{-E_{a}}{R}[\frac{1}{T_{2}} - \frac{1}{T_{1}}][/tex]
where [tex]k_2[/tex] = rate constant at temp [tex]T_2[/tex]
[tex]k_1[/tex] = rate constant at temp [tex]T_1[/tex]
[tex]E_a[/tex]= activation energy
R= gas constant
[tex]T_1[/tex]= temperature = [tex]20^0C=(20+273)K=293K[/tex]
[tex]T_2[/tex]= temperature = [tex]30^0C=(30+273)K=303K[/tex]
[tex]ln \frac{k_{2}}{k_{1}} = \frac{-85\times 1000J/mol}{8.314J/Kmol}[\frac{1}{303} - \frac{1}{293}][/tex]
[tex]ln \frac{k_{2}}{k_{1}}=1.15[/tex]
[tex]\frac{k_{2}}{k_{1}}=3[/tex]
Thus rate increases 3 times on raising the temperature from 20degree to 30 degree
Rain, snow, hail, and sleet are examples of
a
bad weather.
b condensation.
C precipitation.
d evaporation
Answer:
C. Precipitation
It made me put more on my answer.
If 1.8 moles of sodium are present, how many moles of zinc are produced?
Answer:
0.9moles of Zn are produced
Explanation:
Based on the reaction:
ZnO + 2Na → Na2O + Zn
1 mole of ZnO reacts with 2 moles of Na to produce 1 mole of Na2O and 1 mole of Zn
For 2 moles of sodium present, 1 mole of Zn is produced (The conversion factor is 2mol Na = 1mol Zn
If 1.8 moles of sodium are present:
1.8mol Na * (1mol Zn / 2mol Na) =
0.9moles of Zn are produceda sample of oxygen has its absolute temperature halved while the pressure of the has remained constant. if the initial volume is 400ml, what is the final volume?
Answer: 200mL
Explanation:
If a rigid can of volume 10.0 L starts at a temperature of 27 oC and 800.0 torr and is heated to 327 oC, what is the new pressure in torr?
Answer: The final pressure is 1600 torr.
Explanation:
To calculate the final pressure of the system, we use the equation given by Gay Lussac' Law. This law states that pressure of the gas is directly proportional to the temperature of the gas at constant volume.
Mathematically,
[tex]\frac{P_1}{T_1}=\frac{P_2}{T_2}[/tex]
where,
[tex]P_1\text{ and }T_1[/tex] are the initial pressure and temperature of the gas.
[tex]P_2\text{ and }T_2[/tex] are the final pressure and temperature of the gas.
We are given:
[tex]P_1=800.0torr\\T_1=27^oC=(27+273)K=300K\\P_2=?\\T_2=327^0C=(327+273)K=600K[/tex]
Putting values in above equation, we get:
[tex]\frac{800.0torr}{300K}=\frac{P_2}{600K}\\\\P_2=1600torr[/tex]
Thus the final pressure is 1600 torr.
Use the expression we obtained in class to write the molar absorption coefficient of a particular transition in terms of the transition dipole moment of the transition. If the transition dipole moment is tripled in value, how would the molar absorption coefficient change
Answer:
Initially the function is symmetric with respect to the axis of the one dimensional box. In the final state it is also symmetrical, however you can envision a snapshot of the system as the light field is interacting with the wave-function wherein a node begins to develop as is shown in the middle and the wave function is evolving from the initial to final state. Now consider that the electron density during process is the square of the wave function:
Electron density during transition
As can be seen in the initial and final states the electron density is symmetrically distributed with respect to the axis of the box. However with the field on, the electron density is not symmetrically distributed and a transitory dipole moment can be present. To relate back to real molecules think of each of those orbitals as a linear combination of atomic orbitals. One important factor is the symmetry. But there may be one other factor that will be just as important as symmetry. If you treat orbital 1 as a linear combination over n orbitals and orbital 2 as a linear combinations of orbitals as well, there will be a spatial over lap between the orbital in the ground state and the orbital in the excited state. If there is no spatial overlap between the ground state and excited state orbitals there will be no transition dipole moment. However, if the electrons are in the same place spatially, a large transition dipole moment will result.
Explanation:
Question 2
Which of the following correctly describes what a mutation is?
A). A change in the DNA code of an organism
B). A change to a gene of an organism
C). A change to the nucleotide sequence
D).All the above
Answer:
d
Explanation:
a mutation is the variation of a norm, a mutation can alter any organism in any way
Determine the moles of carbon dioxide in 2.9 X 10¹² molecules.Round to 2 significant figures.
Determine the empirical formula for dioxin (C12H4C14O2)
The empirical formula for dioxin (C₁₂H₄Cl₄O₂) is (C₆H₂Cl₂O).
We can determine the components of a chemical compound by looking at its formula. We can determine the precise number of atoms in a compound's molecule using its molecular formula. The ratio of these components is provided by the empirical formula. It is the compound's molecular formula scaled down to its lowest integer ratio.
Empirical formula for dioxin (C₁₂H₄Cl₄O₂) is (C₆H₂Cl₂O).
To determine the emperical formula:
Step1: Determine the masses.
Step 2: Multiply the grams by the atomic mass to get the number of moles.
Step 3: Subtract the least number of moles from the total number of moles of each element.
Learn more about the Emperical formula with the help of the given link:
https://brainly.com/question/21743699
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28.
Hormones:
A. are released into the interstitium.
B. require target cell receptors to illicit a target cell response.
C. are always proteins.
Only A & B are correct
Answer: I believe that B) require target cell receptors to illicit a target cell response, is the right answer.
Explanation:
c5h12 with one tertiary carbon
Answer:
See attached image.
Explanation:
Hello there!
In this case, according to the isomeric structure of hydrocarbons, it is possible to draw a five-carbon hydrocarbon with a tertiary carbon by keeping in mind these tertiary carbons are characterized by the presence of three bonds with carbon atoms.
In such a way, as shown on the attached image, the second carbon from left to right is tertiary because of the aforementioned, and also, the compound has five carbon atoms and twelve hydrogen atoms.
Best regards!
An orgo lab student named Bob wanted to synthesize an isoamyl acetate ester because it smells like bananas and he really likes to sniff it. He heated 7.50 grams of isoamyl alcohol (3-methyl-1-butanol) with 22.5 grams of acetic acid (ethanoic acid) and 4.50 grams of sulfuric acidto prepare his favorite ester. Based on these numbers, how many grams of isoamyl acetateshould he theoretically obtain
Answer:
The answer is "11.07 g".
Explanation:
Isoamyl alcohol is a reagent restriction
Isoamyl alcohol Moles:
[tex]= \frac{7.5}{88.15} \\\\ =0.085[/tex]
Moles only with the shape of isoamyl acetate are equivalent to numbers.
Isoamyl acetate grams:
[tex]= 0.085 \times 130.19\\\\ = 11.07 \ g[/tex]
3.
Balance the following reactions.
i)
Mg +
HCI →
MgCl2 +
H2
ii)
Mg(OH)2 +_
HCI →
MgCl2 +
H20
AgNO3 +
K3PO4 →
Ag3PO4 +
KNO3
iv)
H2SO4 +
Pb(OH)4 →
Pb(SO4)2 +
H2O
v)
Ca (OH)2 +
H3PO4 →
Ca3(PO4)2 +
H20
Answer: i) [tex]Mg+2HCl\rightarrow MgCl_2+H_2[/tex]
ii) [tex]Mg(OH)_2+2HCl\rightarrow MgCl_2+2H_2O[/tex]
iii) [tex]3AgNO_3+K_3PO_4\rightarrow Ag_3PO_4+3KNO_3[/tex]
iv) [tex]2H_2SO_4+Pb(OH)_4\rightarrow Pb(SO_4)_2+4H_2O[/tex]
v) [tex]3Ca(OH)_2+2H_3PO_4\rightarrow Ca_3(PO_4)_2+6H_2O[/tex]
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
The balanced chemical reactions will be:
i) [tex]Mg+2HCl\rightarrow MgCl_2+H_2[/tex]
ii) [tex]Mg(OH)_2+2HCl\rightarrow MgCl_2+2H_2O[/tex]
iii) [tex]3AgNO_3+K_3PO_4\rightarrow Ag_3PO_4+3KNO_3[/tex]
iv) [tex]2H_2SO_4+Pb(OH)_4\rightarrow Pb(SO_4)_2+4H_2O[/tex]
v) [tex]3Ca(OH)_2+2H_3PO_4\rightarrow Ca_3(PO_4)_2+6H_2O[/tex]
What do you do while drawing a conclusion?
O A. Find a connection between variables
O B. Make a hypothesis
O C. Record observations
D. Make up new data if you need to
Answer:
A. Find a connection between variables
Explanation:
In the scientific method, the first step is to make an observation. To observe means to carefully monitor phenomena with a view to draw general patterns from specific occurrences.
The second step is to draw up a hypothesis; this is a tentative explanation for the observation.
The next step is to perform an experiment to determine the effect of change in one more variables on another variable. The experiment will confirm or disprove the hypothesis.
The last step is to draw a conclusion. In drawing up a conclusion, a scientist finally establishes the relationship between two variables and finds the connection between them.
g What are the relative rates of diffusion of the three naturally occurring isotopes of krypton, 80Kr80Kr , 82Kr82Kr, and 83Kr83Kr. What are the relative rates of diffusion of the three naturally occurring isotopes of krypton, , , and . The relative rates of diffusion are: 82Kr(1.02)>82Kr(1.02)>83Kr(1.01)>80Kr(1.00)83Kr(1.01)>80Kr(1.00) The relative rates of diffusion are: 80Kr(1.02)>80Kr(1.02)>82Kr(1.01)>83Kr(1.00)82Kr(1.01)>83Kr(1.00) The relative rates of diffusion are: 82Kr(1.02)>82Kr(1.02)>80Kr(1.01)>83Kr(1.00)80Kr(1.01)>83Kr(1.00) The relative rates of diffusion are: 83Kr(1.02)>83Kr(1.02)>82Kr(1.01)>80Kr(1.00)82Kr(1.01)>80Kr(1.00)
Solution :
According to the Graham's law of diffusion, we know that, the rate of the diffusion varies inversely to the molar mass of the gas, i.e.
Rate of diffusion, [tex]$r_d = \frac{a}{\sqrt M}$[/tex]
where, the 'M' is the molar mass of the gas.
Now in the case of the isotopes of the Krypton,
Atomic mass of [tex]$^{80}Kr$[/tex] = 80 AMU
Atomic mass of [tex]$^{82}Kr$[/tex] = 82 AMU
Atomic mass of [tex]$^{83}Kr$[/tex] = 83 AMU
So the ratio of the rate of diffusion of the three isotopes are :
[tex]$M_{d,^{80}Kr}:M_{d,^{82}Kr}:M_{d,^{83}Kr}$[/tex]
[tex]$=\frac{1}{\sqrt{80}}:\frac{1}{\sqrt{82}}:\frac{1}{\sqrt{83}}$[/tex]
[tex]$=0.1118:0.1104:0.10976$[/tex]
Dividing the above three with the smallest number among the three i.e. 0.10976, we get the relative rates of diffusion.
∴ [tex]$M_{d,^{80}Kr}:M_{d,^{82}Kr}:M_{d,^{83}Kr}$[/tex]
= 1.02 : 1.01 : 1
Hence the relative rate of diffusion are :
[tex]$^{80}Kr(1.02)>^{82}Kr(1.01)>^{83}Kr(1.00)$[/tex]
If carbon is in an animal is it:
A. Abiotic matter
B. Biotic matter
C. Energy storage molecules
D. Carbon dioxide
I WILL MARK BRAINLIEST IF YOU HELP!
Do not guess or give me a file or I will report you!!
Answer:
It is A
Explanation:
Abiotic matter
Which statement describes a reason scientists predict that carbon dioxide emissions will increase over the next few decades? Choose the correct answer.
The use of geothermal energy is increasing.
Fossil fuels are being replaced with renewable energy sources.
Increased carbon dioxide in the atmosphere can lead to a loss of biodiversity.
Many countries are undergoing an increase in technology and standard of living.
Answer:
Many countries are undergoing an increase in technology and standard of living.
Explanation:
The statement describes a reason scientists predict that carbon dioxide emissions will increase over the next few decades is many countries are undergoing an increase in technology and standard of living. Therefore, option D is correct.
What increases carbon dioxide emissions?The main contributor to the rising carbon dioxide concentrations in the atmosphere is human activity, specifically the burning of fossil fuels like coal, oil, and gas, as well as deforestation.
Coal and oil emissions are expected to be higher than they were in 2021, with oil accounting for the majority of the increase in overall emissions.
The delayed recovery of international aviation following COVID-19 pandemic limitations accounts for a major portion of the increase in emissions from burning oil.
Greenhouse gases have far-ranging environmental and health effects. They make climate change by trapping heat, and they also impart to respiratory disease from smog and air pollution.
Thus, option D is correct.
To learn more about the carbon dioxide emissions, follow the link;
https://brainly.com/question/14275614
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Describe two signs that show that a chemical reaction happens when magnesium
burns in air.
Answer:
When magnesium burns in air, the oxygen in the air reacts with magnesium metal to produce magnesium oxide.
Magnesium burns in oxygen present in the air to produce magnesium.
HNO3 + Sn + H2O → H2SnO3 + NO
By algebraic method pls
Answer:
3Sn + 4HNO3 + H2O → 3H2SnO3 + 4NO
how many oxygen molecules in 2.3x10-⁸g of molecular oxygen
Answer:
6.321 × 10^22
Explanation:
Mass of Oxygen =
3.36
g
Molar mass of oxygen (
O
2
) = 16 x 2 =
32
g
m
o
l
−
Total molecules in oxygen = Mass in grams/Molar mass x
N
A
=
3.36
32
x
6.02
x
10
23
=
6.321
x
10
22
Note:
N
A
(Avagadro's number) =
6.02
x
10
23
Hope it helps...
pls help! What is N for CLO3- ?
Answer:
There is no molecule or ion as ClO3. The correct formula of chlorate ion is ClO3-.
Any type of material or substance that has mass and volume is called
Answer:
Matter
Explanation:
In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume.
The hybridization of orbitals on the central atom in a molecule is sp. The electron-domain geometry around this central atom is ________. The hybridization of orbitals on the central atom in a molecule is sp. The electron-domain geometry around this central atom is ________. trigonal bipyramidal octahedral trigonal planar tetrahedral linear
Answer:The electron-domain geometry around this central atom is linear
Explanation:
The hybridization is sp which means the number of electron pairs involved are 2. The electron domain geometry will have two sigma bonds and thus geometry will be linear.
The electron domain geometry will be Trigonal bipyramidal when hybridization is [tex]sp^3d[/tex]
The electron domain geometry will be octahedral when hybridization is [tex]sp^3d^2[/tex]
The electron domain geometry will be Trigonal planar when hybridization is [tex]sp^2[/tex]
The electron domain geometry will be tetrahedral when hybridization is [tex]sp^3[/tex]