Answer:
Approximately [tex]-74.8\; \rm kJ \cdot mol^{-1}[/tex].
Explanation:
Number the three reactions with known enthalpy changes:
[tex]\begin{aligned}& {\rm C\; (s) + O_2\; (g) \to CO_2\; (g)} & \quad \Delta H = -393.5\; \rm kJ\cdot mol^{-1}& \quad (1) \\ & {\rm H_2\; (2) + \frac{1}{2} O_2\; (g) \to H_2O\; (l)} & \quad \Delta H = -285.8\; \rm kJ\cdot mol^{-1} & \quad (2) \\ & {\rm CH_4\; (g) + 2\; O_2\; (g) \to CO_2\; (g) + 2\; H_2O\; (l)} & \quad \Delta H = -890.3\; \rm kJ\cdot mol^{-1} & \quad (3)\end{aligned}[/tex].
The goal is to find a way to combine these three reactions to obtain: [tex]\rm C\; (s) + 2\; H_2\; (g) \to CH_4\; (g)[/tex].
Assume that the three known reactions are combined in this way:
[tex]a \times (1) + b \times (2) + c \times (3)[/tex].
That corresponds to:
[tex]\begin{aligned} & a\; \mathrm{C\; (s)} + \left(a + \frac{1}{2}\, b + c\right) \; \mathrm{O_2\; (g)} + b\; \mathrm{H_2\; (g)} + c\; \mathrm{CH_4\; (g)} \\ & \to (a + c)\; \mathrm{CO_2\; (g)} + (b+ 2\,c )\; \mathrm{H_2O\; (l)}\end{aligned}[/tex].
Compare the coefficients of this reaction with that of the desired reaction:
[tex]\rm C\; (s) + 2\; H_2\; (g) \to CH_4\; (g)[/tex].
Note that some species (e.g., [tex]\rm CH_4\; (g)[/tex]) appeared on the wrong side of the equation. Their desired coefficient should be the opposite of their true coefficient. For example, the coefficient of [tex]\rm CH_4\; (g)[/tex] is supposed to be [tex]1[/tex]. However, because it appeared on the wrong side of the equation, its desired coefficient would be [tex]-1[/tex].
The coefficients of species that are not in the desired equation should be zero.
[tex]\begin{array}{|c|c|c|}\cline{1-3}\text{Species} & \text{Coefficient}& \text{Desired Coefficient} \\ \cline{1-3} \mathrm{C\; (s)}} & a & 1 \\ \cline{1-3} \mathrm{O_2\; (g)} & a + (1/2)\, b + c & 0 \\ \cline{1-3} \mathrm{H_2\; (g)} & b & 2 \\ \cline{1-3}\mathrm{CH_4\; (g)} & c & -1\\ \cline{1-3} \mathrm{CO_2\; (g)} & a + c & 0 \\ \cline{1-3} \mathrm{H_2O\; (l)} & b + 2\, c & 0\\ \cline{1-3}\end{array}[/tex].
Solve for [tex]a[/tex], [tex]b[/tex], and [tex]c[/tex]:
[tex]a = 1[/tex].[tex]b = 2[/tex].[tex]c = -1[/tex]. In other words, the third equation is inverted before being added to the other two equations.In other words, the desired equation is equal to [tex]1 \times (1) + 2 \times (2) - 1 \times (3)[/tex].
By Hess's Law, the enthalpy of the desired equation will be:
[tex]\begin{aligned}& 1\times \Delta H (1) + 2 \times \Delta H (2) - 1\times \Delta H(3) \\ &\approx -393.5 + 2 * (-285.8) - (-890.3) \\ &= -74.8\; \rm kJ \cdot mol^{-1} \end{aligned}[/tex].
Body systems such as the nervous and digestive systems work together and help the body
maintain homeostasis. Which of the following correctly describes one way that the nervous
system and the digestive system work together?
Lungs contract during chewing so that food won't be inhaled.
Blood flow to the stomach and intestines decreases during eating.
The involuntary muscles in the jaw stimulate spinal cord neurons to initiate chewing.
Neurons in the brain stimulate smooth muscles in the intestines to move food through the body.
The strong nuclear force is always smaller than the electrostatic force true or false
Answer:
False
Explanation:
The Strong Nuclear Force is defined as an attractive force between neutrons and protons which is responsible to hold the nucleus together.
Electrostatic force is the repulsive or attractive force between two electrically charged objects.
Strong nuclear force is always greater than electrostatic force but changes with the distance. Strong nuclear attraction keeps the nucleus of an atom together in a small space as well which is stronger than their electrostatic repulsion.
it is said that, the strong nuclear force is the strongest force in the universe.
Hence, the given statement is false.
Answer:
False
Explanation:
Strong nuclear forces are much higher than the electrostatic repulsive force. In case if these strong nuclear forces would have not been there, then the nucleus would have disintegrated. This is so because only gravity cannot keep hold on these particles. The nuclear force varies with the size of nucleus. As the size of nucleus increases, the electrostatic repulsion becomes greater
Hence, the given statement is false
If the mole fraction of sulfuric acid H2SO4 is 0.432 what is the percent by mass of H2SO4.
Answer:
19.47%
Explanation:
The percentage by mass of [tex]H_2SO_4[/tex] would be 19.47%.
The percentage by mass of a substance in solution is calculated as:
[tex]\frac{mass of substance}{mass of substance + water} * 100%[/tex]
Given that the mole fraction of [tex]H_2SO_4[/tex] = 0.432
The total number of mole fraction of a solution = 1
Hence, mole fraction of water = 1 - 0.432 = 0.568
Mass of water = molar mass x mole
= 98.079 x 0.432 = 42.37 g
Mass of [tex]H_2SO_4[/tex] = molar mass x mole
= 18.02 x 0.568 = 10.24 g
Hence,
%mass of [tex]H_2SO_4[/tex] = [tex]\frac{10.24}{10.24 + 42.37} * 100[/tex]
= 19.47%
Which of these is a conversion from chemical energy to mechanical energy?
A. A dark light bulb starting to glow
B. A ball rolling down a hill
C. A person lifting a weight
D. A potato being heated in an oven
Answer:
C . A person lifting a weight
Consider this reaction:
N2 (g) + 3H2 (9) = 2 NH3 (9). If Q ea, which statement is true?
O A.
The reaction will move forward.
B.
The reaction will move in reverse.
C.
The concentration of the product should decrease.
D.
The concentrations of the reactants should increase.
E.
The reaction is in equilibrium.
Answer:
Explanation:
its E
trust me i got a 100
Answer:
E. The Reaction Is In Equilibrium.
Explanation:
Plato Answer
Which of the following is a chemical reaction?
1- Dropping a sliced orange into a vat of Sodium Dydroxide
2-Cutting a piece of paper into two pieces
3-Filling a balloon with air
4-Freezing liquid Mercury
Answer:
1- Dropping a sliced orange into a vat of Sodium Dydroxide
Explanation:
The other answers (2-4) are only physical changes that don't change any chemical compositions.
Explain the different principles that allow roller coasters to rip and roar around the tracks. In your response, include how energy is transferred back and forth between kinetic and potential.
Answer:
In the roller coasters the potential energy that is given is the gravitational potential energy, which this energy increases its value as the object moves away from the earth, that is to say, the more height the roller coaster acquires the more gravitational potential energy it will have, and Said train where people usually get on the roller coaster will descend or descend with greater acceleration.
This gravitational potential energy once the mountain begins to descend or descend is converted into kinetic energy
Explanation:
This that we wrote above is considering that the roller coaster does not have curved routes but rectilinear, in the case that it had curved routes, a force would be added in addition to those written that is the centripetal force, it is the same force that appears in the centrifuges or dryers of clothes or the same washing machine. This force, the centripetal force is the force that draws a moving object, in a curvilinear path, towards the center of the curvature.
Frosted glass and wax paper are ____.
A) transparent
B) translucent
C) clear
D) opaque
Answer:
B) translucent
Explanation:
Light only partially passes through them.
How does activation energy affect the progress of a reaction?
O A. The reaction will not occur unless the activation energy is met.
B. The activation energy decreases the energy needed for a reaction
to progress.
C. The activation energy increases how quickly the reaction will
progress.
D. The activation energy determines equilibrium concentrations of
products.
Answer:
The reaction will not occur unless the activation energy is met.
Explanation
Answer:
A. The reaction will not occur unless the activation energy is met.
Explanation:
a.p.e.x
how many atoms are in 50 grams of calcium
The number of atoms in an elemental atom can be estimated by Avogadro's number or the number of equivalents. In 50 grams of calcium, there are 7.53 × 10²³ atoms.
What is Avogadro's number?Avogadro's numbers are used to estimate the number of smaller entities like the number of atoms and molecules in a compound for a substance. It determines the atom in a given mass of the atom. Avogadro's number (Nₐ) is equal to 6.022 × 10²³.
Given,
Mass of calcium = 50 gm
The molar mass of calcium = 40 gm/mol
The moles are calculated from mass and molar mass as:
Moles = mass ÷ molar mass
n = 50 ÷ 40
= 1.25 mol
It is known that a mole of a substance contains Nₐ atoms.
1 mol = 6.022 × 10²³ atoms
Then, 1.25 mol = 1.25 × 6.022 × 10²³
= 7.53 × 10²³
Therefore, there are 7.53 × 10²³ atoms in 50 grams of calcium.
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Which of the following is a chemical property of liquid water?
Its density is 1.00 g/cm3.
It reacts with sodium metal to form sodium hydroxide and hydrogen gas
It flows.
It freezes to form ice.
It boils at 100°C.
Answer:
B) it reacts with sodium metal to form sodium hydroxide and hydrogen gas
Explanation:
B is the only option that show a chemical property, density, freezing, and boiling points are physical properties.
The volume of an air bubble at the bottom of a lake is 1.35 mL. If the pressure at the bottom of the lake is 125 kPa and the air pressure at the top of the lake is 105 kPa, what will the volume of the bubble be when it rises to the surface?
Answer:
1.61 mL
Explanation:
Step 1:
Data obtained from the question. This includes the following:
Initial volume (V1) = 1.35 mL
Initial pressure (P1) = 125 kPa
Final pressure (P2) = 105 kPa
Final volume (V2) =..?
Step 2:
Determination of the volume of the air bubble at the surface of the lake.
This can be obtained by use the Boyle's law equation as follow:
P1V1 = P2V2
125 x 1.35 = 105 x V2
Divide both side by 105
V2 = (125 x 1.35)/105
V2 = 1.61 mL
Therefore, the volume of the air bubble at the surface of the lake is 1.61 mL
A 350. mL air sample collected at 35 degrees C has a pressure of 556 mm Hg.
What pressure will the air exert if it is allowed to expand to 425 mL at 57 degrees
C? Show your work in the space below.
Answer:
485 torr
Explanation:
Explanation:
We can solve this equation using the combined gas law:
P1V1/T1=P2V2/T2
Remember, always use the absolute (Kelvin) temperature when working with gas equations.
The temperature conversions are
T1=C+273=35o+273=308K
T2=57C+273=330K
Since we're trying to find the final pressure, let's rearrange this equation to solve for
P2:
P2=P1V1T2/T1V2
Our known values:
P1= 550 torr
V1=350mL
T1=308K
V2=425"mL
T2=330K
Let's plug these into the equation to find the final pressure:
The final pressure after it is subjected to these changes is thus 485torr
can somebody help me name these organic compound plz
Answer:
A. 3–Ethyl–2–methylpentane.
B. 3–Ethyl–1,5,5–trimethylcyclohexene.
Explanation:
To name the compound, we must observe the following:
1. Locate the longest continuous carbon chain. This gives the parent name.
2. Identify the substituent groups attached.
3. Locate the position of the substituent groups by giving them the lowest possible low count alphabetically.
4. Combine the above to name the compound.
Now let us name the above compounds
For compound (A)
1.The longest chain is carbon 5 i.e pentane.
2. The substitute attached are:
Ethyl => CH2CH3
Methyl => CH3
3. Ethyl comes before methyl alphabetically. But considering the structure of the compound, ethyl assume same position from either side of the compound. Therefore, we'll consider the lowest possible count for methyl. Therefore, their position is given below:
Ethyl => CH2CH3 => carbon 3.
Methyl => CH3 => carbon 2.
4. The name of the compound is:
3–Ethyl–2–methylpentane.
Compound B.
This is a cyclic structure.
1. The parent name is cyclohexene.
2. The substitute groups attached are:
Ethyl => CH2CH3
Methyl => CH3
3. Since the compound is unsaturated, the functional group is the double bond. Hence, we shall start our counting from the double bond and also considering alphabetical order of the substituent.
Please note methyl (CH3) appears three times.
Ethyl => CH2CH3 => carbon 3
Methyl => CH3 => carbon 1, 5 and 5.
4. The name of the compound is:
3–Ethyl–1,5,5–trimethylcyclohexene
0.450 moles of K2SO4 are dissolved in 195.0 mL of water. Calculate the molarity of the solution.
Answer:
2.31M
Explanation:
The following data were obtained from the question:
Mole of K2SO4 = 0.450 mole
Volume of water = 195.0 mL = 195/1000 = 0.195L
Molarity =...?
Molarity is defined as the mole of solute per unit litre of the solution. This can be expressed as:
Molarity = mole /Volume
With the above formula we can calculate the molarity of the K2SO4 solution as follow:
Molarity = mole /Volume
Molarity = 0.450/0.195
Molarity = 2.31M
The mole concept will most likely be used in
calculating the average height of a mountain range.
measuring how many liters of gasoline are poured into a tank.
determining how many ozone molecules are lost in the atmosphere.
finding the mass of a piece of steak in a butcher shop.
Answer:
determining how many ozone molecules are lost in the atmosphere
Pls Mark as Brainliest!!! if this helps...
The mole concept The mole concept can be used to determine the number of ozone molecules are lost in the atmosphere.
The mole concept was introduced by Avogadro. The mole is the SI unit of amount of substance. According to Avogadro, one mole of a substance contains 6.02 × 10^23 atoms, ions, molecules etc.
The mole concept is important in many chemical calculations. The mole concept can be used to determine the number of ozone molecules are lost in the atmosphere. (option C)
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A 52-gram sample of water that has an initial temperature of 10.0 °C absorbs 4,130 joules. If the specific heat of water is 4.184 J/(g °C), what is the final temperature of the water? (4 points) Group of answer choices 11 °C 19 °C 29 °C 51 °C
Answer:
28.98°C
Explanation:
Mass = 52g
Initial temperature (T1) = 10°C
Final temperature (T2) = ?
Heat energy (Q) = 4130J
Specific heat capacity of water = 4.184J/g°C
Heat energy (Q) = mc∇T
Q = heat energy
M = mass of the substance
C = specific heat capacity of the substance
∇T = change in temperature (T2 - T1)
Q = mc∇T
4130 = 52 * 4.184 * (T2 - 10)
4130 = 217.568 * ( T2 - 10)
4130 = 217.568T2 - 2175.68
217.568T2 = 4130 + 2175.68
217.57T2 = 6305.68
T2 = 6305.68 / 217.57
T2 = 28.98°C
Final temperature is 28.98°C
A fox spots a rabbit in a field. The fox begins to chase the rabbit, and the rabbit runs away. Which statement best describes the rabbit's behavior in response to the stimulus of being chased?
Select one:
The rabbit's behavior is a response caused by an internal stimulus.
The rabbit's behavior is a tropism.
The rabbit's behavior is a fight-or-flight response.
The rabbit's behavior is a response caused by hunger.
Answer:
C. The rabbit's behavior is a fight-or-flight response
Explanation:
The rabbit has a fight or flight response which means that when there is danger, the rabbit will either fight it or run away. In this case it ran away
The response of the rabbit in response to the fox chasing has been the fight and flight response. Thus, option C is correct.
What is a stimulus?A stimulus can be given as the physical or the chemical messenger that mediates the formation of the functional change in the body. The reaction to the stimulus has been the spontaneous reaction that can form the sudden response forming reaction.
The fox chasing the rabbit has been mediating the formation of the stimulus. The chasing act as the stimulus to the rabbit forming the rabbit to create the response or reaction of running. The reaction that forms with the stimulus of fear and frightening has been the fight and flight response.
The stimulus that has been formed arouses the fear of getting caught and works as the fight and flight response. Thus, option C is correct.
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Where does your body get the energy needed to transform into kinetic energy to move around all day
Answer:
food, mostly consists of what you eat.
Explanation:
The body get the energy needed to transform into kinetic energy from food.
Food:Every body part (muscles, brain, heart, and liver) need energy to work. This energy comes from the food we eat. Our bodies digest the food we eat by mixing it with fluids (acids and enzymes) in the stomach.
The main sources of energy are: carbohydrates, lipids, and proteins.
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11. Calculate the energy required to produce 12.00 mol of CI207 on the basis of the
following balanced equation.
2012(g) + 702(g) + 130 kcal yields 201207(9)
Answer: 780 kcal are required to produce 12.00 mol of [tex]Cl_2O_7[/tex]
Explanation:
Endothermic reactions are defined as the reactions in which energy of the product is greater than the energy of the reactants. The total energy is absorbed in the form of heat and written along with reactants.
The balanced chemical reaction is:
[tex]2Cl_2(g)+7O_2(g)+130kcal\rightarrow 2Cl_2O_7(g)[/tex]
According to stoichiometry :
2 moles of [tex]Cl_2O_7[/tex] are produced by absorption of energy = 130 kcal
Thus 12.00 moles of [tex]Cl_2O_7[/tex] are produced by absorption of energy = [tex]\frac{130}{2}\times 12.00=780kcal[/tex]
Thus 780 kcal are required to produce 12.00 mol of [tex]Cl_2O_7[/tex]
What type of bond is formed during dehydration synthesis?
O A
carbon bonds between amino acids
B.
carbon bonds between carbohydrates
C. hydrogen bonds between lipids
O D. peptide bonds between amino acids
A carbon bond between the amino acids is formed in a dehydration reaction. So the correct option is A.
What is a dehydration reaction?
A reaction where two smaller molecules are combined in a chemical manner by the removal of an element from each of these molecules is called a dehydration reaction. Organic compounds are classified on the basis of structure. They are classified as aliphatic and aromatic compounds. Different kinds of chemical reactions are involved in the formation of new compounds when there is a change in bonding between the atoms.
There are some chemical reactions that form a molecule and some only show a displacement or substitution of atoms. There are synthesis or combination reactions that involve a combination of two substances to form one molecule.
On the other hand, there are decomposition reactions in which one substance decomposes to form more than one substance. There are displacement reactions which can be single or double displacement. They involve the displacement of one or more components of compounds among each other. Addition, substitution, rearrangement, elimination, and oxidation-reduction reactions are some of the common organic reactions.
Therefore, the correct option is A.
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Why do we use nuclear energy from power plants?
Answer:
Nuclear energy originates from the splitting of uranium atoms – a process called fission. This generates heat to produce steam, which is used by a turbine generator to generate electricity. Because nuclear power plants do not burn fuel, they do not produce greenhouse gas emissions.
Explanation:
Enjoy!
In which two ways can the timber industry help prevent loss of forest cover and animal habitats?
Answer:
Cut trees at a sustainable rate
and
Plant one tree for every tree that is cut.
hope i helped, if i could get brainliest that would be great
A plant was placed in the corner of a room away from a window. What might you observe about the plant after five days?
Select one:
The plant is leaning toward the window.
The plant is not affected by the light in the window.
The plant is standing straight up from the pot.
The plant is leaning away from the window.A plant was placed in the corner of a room away from a window. What might you observe about the plant after five days? Select one: The plant is leaning toward the window. The plant is not affected by the light in the window. The plant is standing straight up from the pot. The plant is leaning away from the window.
Answer:
1. A. The plant leans toward window.
Explanation:
Plants need light to perform photosynthesis and live. Therefore, this means the plant will always lean toward light in order to survive.
- Hope that helps! Please let me know if you need further explanation.
Answer
Last one I think
Explanation:
Which of the following is the energy that comes from changes in an atom’s nucleus?
a. thermal energy
b. nuclear energy
c. light energy
d. electrical
How does the pressure of a container change as the volume is changed?
Answer: If the volume is decreased, the pressure would increase because the gas molecules have less space to move around. Same goes for the opposite; if the volume increased, the pressure would decrease because the molecules have more space to move and aren't packed as tightly .
Hope this helps!!!
A gas occupies a volume of 2.45 L at a pressure of 1.03 atm. What volume will the
gas occupy if the pressure changes to 0.980 atm and the temperature remains
unchanged? Show your work in the space below. *
Answer:
2.58 L
Explanation:
Please see the step-by-step solution in the picture attached below.
Hope this answer can help you. Have a nice day!
At constant temperature, if the pressure of the gas decreases to the given value, the volume increases to 2.58L.
What is Boyle's law?Boyle's law simply states that "the volume of any given quantity of gas is inversely proportional to its pressure as long as temperature remains constant.
Boyle's law is expressed as;
P₁V₁ = P₂V₂
Where P₁ is Initial Pressure, V₁ is Initial volume, P₂ is Final Pressure and V₂ is Final volume.
Given the data in the question
Initial volume V₁ = 2.45LInitial pressure P₁ = 1.03atmFinal pressure P₂ = 0.980 atmFinal volume V₂ = ?P₁V₁ = P₂V₂
V₂ = P₁V₁ / P₂
V₂ = ( 1.03atm × 2.45L ) / 0.980atm
V₂ = 2.5235Latm / 0.980atm
V₂ = 2.58L
Therefore, at constant temperature, if the pressure of the gas decreases to the given value, the volume increases to 2.58L.
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Compare and contrast the dynamics of energy transfer between the Eocene Period and the Cryogenian Period. In which period would you say that Earth's system is experiencing a net gain in energy and in which period would you say that Earth's system is experiencing a net loss in energy
Answer:
The Eocene Period is experiencing net gain in energy while Cryogenian Period is experiencing a net loss in energy.
Explanation:
In Eocene Period, the population of mammals such as horses , whales and bats etc were high due to the presence of high amount of food and good atmospheric condition such as high temperature while the population of animals were low in Cryogenian Period due to the presence of very low temperature which experiencing loss of energy. Most of area of the earth consist of icy desert.
What is the similarity between speed and vilocity
Do metals or nonmetals have the greatest tendency to lose electrons and become positive ions?
Answer:
The metals have the tedency to lose electrons and become positive ions
Explanation:
In order to attain noble gases electronic configuration, metals of group I A lose one electron and II A lose 2 electrons with ionization energy.
