The enthalpy ΔH of combustion is - 804 kJ. The change in internal energy ΔE of the reaction process is -801 kJ
The objective of this question is to determine the value of ΔH and ΔE of combustion is for 1 mole of methane.
If we look closely at the question, we will realize that at constant pressure, methane burns and produces heat of 804 kJ into the surroundings.
Since heat is released;
ΔH = -804 kJ
It also does a work of 3kJ, since work is done on the system
W = - 3kJ
According to the first law of thermodynamics;
ΔE = ΔH - W
ΔE = (-804 - (-3 )) kJ
ΔE = -801 kJ
Therefore, we can conclude that the in 1 mole of methane, the enthalpy ΔH of combustion is - 804 kJ. The change in internal energy ΔE of the reaction process is -801 kJ
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Place the events of a fight or flight situation in the correct order.
Question 3 options:
You spring into action
Your heart and lungs prepare to fight or run
You see the bear
Your brain sends signals to you adrenal and pituitary glands
Answer:
you see le bear
you brain sends signals
your heart and lungs receive said signals
spring to action
Which scientific law describes the observation that energy cannot be created or destroyed?
Law of universal gravitation
Law of conservation of energy
Newton's first law of motion
Newton's third law of motion
Answer:
law of conservation of energy
please help me
Select the correct answer.
Who founded the specialized field of anatomy?
A. Herophilus
B. Aristotle
C. Claudius Galen
D. William Harvey
Answer:
the correct answer is A. please mark me brainlist
Explanation:
Answer:
geon, Andreas Vesalius. Vesalius describes what he observes during the public dissection of human corpses. By dissecting human bodies, preparing muscles, tendons, and nerves down to the smallest detail, Vesalius is able to prove more than 200 errors in Galen’s anatomical works.
Explanation:
With his comprehensive scientific studies of human bodies, the young professor of medicine not only revolutionizes anatomy, but consequently, the whole science of medicine.
I know I never completely answered your question, I just wanted to explain it was E. None of the above.
A scientist wants to make a solution of tribasic sodium phosphate, Na3PO4, for a laboratory experiment. How many grams of Na3PO4 will be needed to produce 400. mL of a solution that has a concentration of Na ions of 1.00 M
Answer:
21.86 grams
Explanation:
It is important to note that for every mol of Na3PO4 there is, 3 mols of Na ions are produced.
Na+=1m(0.4l), so mols of Na3PO4= 0.4/3= 0.13333... mols
the molar mass of Na3PO4 is 163.94 grams/mol. 0.1333*163.94=21.86 grams of Na3PO4.
Elements that form diatomic molecules include
a oxygen
b hydrogen
C sodium
d two of the above
Answer:
D, two of the above, oxygen and hydrogen.
Explanation:
To solve this problem we can either use orbital stuff or common knowledge. Oxygen and hydrogen are known to form O2 and H2, while sodium forms metallic bonds between the atoms.
how to experiment titration
Answer:
Add a volume of a solution of known concentration is added to a volume of another solution in order to determine its concentration. Solutions in which a few drops of phenolphthalein have been added turn from colorless to brilliant pink as the solution turns from acidic to basic.
If you want the method:
Method
1) Use a pipette and pipette filler to add 25 cm3 of alkali solution to a clean conical flask.
2) Add a few drops of a suitable indicator and put the conical flask on a white tile.
3) Fill the burette with dilute acid. Flush the tap through to remove any air bubbles. Ensure the burette is vertical.
4) Slowly add the acid from the burette to the conical flask, swirling to mix. (The mixture may at first change colour, and then back again when swirled.)
5) Stop adding the acid when the end-point is reached (when the colour first permanently changes). Note the final volume reading.
6) Repeat steps 1 to 5 until three results are repeatable (in close agreement). Ideally these should lie within 0.10 cm3 of each other.
I hope it helps.
Answer:
To conduct a titration experiment, first fill the burette with an acid or base solution of known concentration. After that, take a burette reading from the top of the miniscus down to the bottom. Then, underneath the burette, place a flask containing an unknown concentration of acid or base. After that, fill the flask halfway with the appropriate indicator and shake it up. Add your titrate to the flask one drop at a time while stirring constantly. Continue to add the titrate until the color change is noticeable. Finally, take one more look at the burette to make sure everything is correct.
Explanation:
Hope it helps:)
Help with this please
Answer:
12
Explanation:
There are 4 sulfur atoms in SO4
4×3=12
This means that it turns into 3×(SO4)
=3SO4
Air is a mixture of (mostly) oxygen (molecular mass 16) and nitrogen (molecular mass 14) gases. At room temperature, which molecules in this room have more kinetic energy (on average)
The molecules of the two gases will have the same kinetic energy at room temperature.
The average kinetic energy of gaseous molecules can be calculated using the formula:
Kinetic Energy = 3/2RT, where R = constant and T = temperature in Kelvin
This means that the kinetic energy of a gaseous molecule is dependent on the temperature of the molecule only.
In other words, the molecular mass of molecules of gases has no bearing on the kinetic energy of each molecule.
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What is the reaction between CCl4 and H2O?
Answer:
At temperatures > 400 °C, CCl4 reacts with H2O over a MgO catalyst to yield HCl and CO2.
Suppose you are performing a titration. At the beginning of the titration, you read the titrant volume as 2.51 mL. After running the titration and reaching the endpoint, you read the titrant volume as 29.95 mL. What volume, in mL, of titrant was required for the titration
The volume of titrant required for the titration would be 27.44 mL
From the illustration, the initial titrant volume was 2.51 mL. This figure represents the initial reading on the burette.
In the same vein, the final volume of the titrant was 29.95 mL. This figure represents the final reading on the burette.
In order to get the volume of titrant used:
Volume of titrant used = final volume - initial volume
= 29.95 - 2.51
= 27.44 mL
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Help pretty please :)
A containing vessel holds a gaseous mixture of nitrogen and butane. Thepressure in the vessel at 126.9 Cis 3.0 atm. At 0 C, the butane completelycondenses and the pressure drops to 1.0 atm. Calculate the mole fraction of nitrogenin the original gaseous mixture.
A vessel that contains a mixture of nitrogen and butane has a pressure of 3.0 atm at 126.9 °C and a pressure of 1.0 atm at 0 °C. The mole fraction of nitrogen in the mixture is 0.33.
A vessel contains a gaseous mixture of nitrogen and butane. At 126.9 °C (400.1 K) the pressure is due to the mixture is 3.0 atm.
We can calculate the total number of moles using the ideal gas equation.
[tex]P \times V = n \times R \times T\\\\n = \frac{P \times V}{R \times T} = \frac{3.0 atm \times V}{0.082 atm.L/mol.K \times 400.1 K} = 0.091 mol/L \times V[/tex]
At 0 °C (273.15 K), the pressure due to the gaseous nitrogen is 1.0 atm.
We can calculate the moles of nitrogen using the ideal gas equation.
[tex]P \times V = n \times R \times T\\\\n = \frac{P \times V}{R \times T} = \frac{1.0 atm \times V}{0.082 atm.L/mol.K \times 400.1 K} = 0.030 mol/L \times V[/tex]
The mole fraction of nitrogen in the mixture is:
[tex]X(N_2) = \frac{0.030 mol/L \times V}{0.091 mol/L \times V} = 0.33[/tex]
A vessel that contains a mixture of nitrogen and butane has a pressure of 3.0 atm at 126.9 °C and a pressure of 1.0 atm at 0 °C. The mole fraction of nitrogen in the mixture is 0.33.
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A carrot originally has a mass of 0.39g and after being left in a salt solution overnight it gained 0.3g. Calculate the percentage mass increase of the carrot.
Answer:
77%
Explanation:
The formula for finding percent change is change/original.
So, you have to do 0.3/0.39
You have to divide this to get 0.769 which can be rounded 0.77
0.77 as a percentage is 77%
So, the percentage mass increase of the carrot is 77%
A city carrier resigns and trains as an office receptionist this is a person’s metabolism is likely to
Consider an ice cube and a hot radiator. Which has the higher thermal energy?
the ice cube
the radiator
The thermal energy of a material increases with temperature. Therefore, the radiator has the higher thermal energy.
What is thermal energy?When the temperature rises, a type of energy called thermal energy is produced. The amount of thermal energy usually directly inversely proportional to the object's change in temperature. Thermal energy takes the form of heat.
The thermal energy of a material increases with temperature. The quicker motions of the substance's atoms and molecules are what cause thermal energy to grow as temperature rises.
In some cases, a substance's molecules will separate from one another and leave because the temperature is just so high. Unexpectedly, thermal energy also affects the states of matter. The radiator has the higher thermal energy.
Therefore, the radiator has the higher thermal energy.
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What would be the atomic number of this atom?
Answer:
1 would be the answer
protons = atomic # I think
Answer:
hydrogen
Explanation:
hydrogen has the atomic number of 1 which means that hydrogen has one proton and is neutral so it has one electron as well.
Help with this please :) will mark Brainlyist if right
Answer:
3
Explanation:
Compare the average motion of the particles in the 3 containers of water
Answer:
c>b=a
Explanation:
It is important to note that mass does not affect the average motion/energy per molecule, but temperature does. the higher the temperature the faster the particles are. A has the same temperature as B, so they have the same amount of motion. C is warmer than A and B, so the average motion of the particles in beaker C is the largest
What is the balanced form of the chemical equation shown below?
C6H1206(s) + O2(g) → H20(1) + CO2(g)
-
+
A. C6H1206(s) + O2(g) → H2O(1) + CO2(9)
B. C6H1206(s) + 602(9) — 6H20() + 6C02(9)
C. CH2O(s) + O2(g) → H20(1) + CO2(9)
D. CH1206(s) + O2(g) – 12H20(1) + 6C02(9)
Answer:
B. C6H1206(s) + 602(9) → 6H20(l) + 6C02(9)
Explanation:
You can see that it's balanced;
C6H1206(s) + 602(g) → 6H20(l) + 6C02(g)
C ⇒ 6 C ⇒ 6
H ⇒ 12 H ⇒ 6 x 2 = 12
O ⇒ 6 + (6 x 2) = 18 O ⇒ 6 + (6 x 2) = 18
If 22.5 L of nitrogen at 748 mm Hg are compressed to 725 mm Hg at constant temperature. What is the new volume?
Before
P1 : 748 mmHg
V1 : 22.5 L
After
P2 : 725 mmHg
V2 : ?
748 mmHg / 22.5 L = 725 mmHg / V2
Cross Multiply...
748 mmHgV2 = 16312.5 mmHgL
748 mmHgV2 / 748 mmHg = 16312.5 mmHgL / 748 mmHg
V2 = 21.808155 L
V2 = 21.8 L (sig figs)
Balancing Chemical Equations
Based on the chemical equation, use the drop down menu to choose the coefficients that will balance the chemical
equation
(vbo,- (v]),
Will make Brainlyest plzzzz help!!!
Answer:
3O2→ 2O3
Explanation:
by multiplying 2 by 3 we get 6 on both sides
Question 10
What is this structure name?
CH3 – CH2 - CH
CH – CH – CH2 - CH2
CH; CH – CH, -CH,
СН
CH3
cosh(-cosh(-CH
Simplify the expression using the symmetry of hyperbolic functions
cosh(cosh(CH))
Simplify the expression using the symmetry of hyperbolic functions
the answer is cosh(cosh(CH))
ethylene glycol, an antifreeze boils at 197 ⁰C. Convert 197 ⁰C to:
⁰F =
K =
[tex]\boxed{\sf °F=\dfrac{9}{5}°C+32}[/tex]
[tex]\\ \sf\longmapsto °F=\dfrac{9}{5}(197)+32[/tex]
[tex]\\ \sf\longmapsto °F=\dfrac{1773}{5}+32[/tex]
[tex]\\ \sf\longmapsto °F=354.6+32[/tex]
[tex]\\ \sf\longmapsto °F=386.6°F[/tex]
[tex]\rule{200pt}{5pt}[/tex]
[tex]\boxed{\sf K=°C+273}[/tex]
[tex]\\ \sf\longmapsto K=197+273[/tex]
[tex]\\ \sf\longmapsto K=470K[/tex]
Identify the major ionic species present in an aqueous solution of C6H12O6 (glucose).
A. 6 C-
, 12 H+
, 6 O–
B. 6 C+
, 12 H+
, 6 O2–
C. 6 CH2+, 6 O2–
D. C6
+
, 12 H+
, 6 O2–
E. no ions are present
Glucose is a molecular substance therefore, there are no ionic species in glucose.
Ionic substances dissolve in water to yield ions. Molecular substances do not produce ions in solution. The conductivity of ionic solutions owes to the presence of ions in solutions. Molecular solutions do not conduct electricity due to the absence of ions.
Glucose is a molecular substance hence they are are no ions present hence glucose does not conduct electricity.
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what is another extraction that uses gravity filtration and describe it
Answer -ˋˏ ༻༺ ˎˊ-
A common use for gravity filtration is for separating anhydrous magnesium sulfate (MgSO4) from an organic solution that it has dried (Figure 1.68b). Anhydrous magnesium sulfate is powdery, and with swirling in an organic solvent creates a fine dispersal of particles like a snow globe.
The collision theory state that?
Answer:
Collision theory states that molecules must collide to react. For most reactions, however, only a small fraction of collisions produce a reaction.
leopard has canine teeth because
Explanation:
Leopards have 32 teeth, 4 of which are long, pointed canine teeth. Canine teeth are used to kill prey. Other teeth are for cutting flesh and grinding bone
An unknown hydrocarbon compound was analyzed for hydrogen by elemental analysis and results show that it contains 15.88 % H. What is the empirical formula
Answer:
C4H9
Explanation:
If H = 15.88%
Then C = 100.00 – 15.88 = 84.12
Divide each % value by respective atomic mass
H = 15.88/1 = 15.88
C = 84.12/12 = 7.01
Divide through by smaller value
H = 15.88/7.01 = 2.26
C = 7.01/7.01 = 1
Remove fraction , multiply by 4
H = 9
C = 4
Empirical formula = C4H9
The hydrocarbon could be ( C4H9)2 = C8H18 = octane.
What is the percent composition of Be(OH)2?
Answer:
Ba 80.148%. H 1.77% O 18.657%
A 32.1 mole sample of gas has a temperature of 21 Celsius and a pressure of 2280.0 torr. What is the volume of the gas?
The volume of the gas is 27 ml
The calculation can be done as follows
The first step is to convert the pressure to atm
convert 2280 tors to atm
760 tors= 1 atm
= 2280/780
= 3 atm
The formula is
PV= nRT
The next step is to write out the parameters
Pressure= 3 atm
Temperature= 21 °C
no of moles= 32.1 mole
volume= ?
(r)constant= 8.314
3 × v= 32.1×8.314×21
3v= 81.080
V= 81.080/3
V= 27 ml
Hence the volume of the gas is 27 ml
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