The value of enthalpy(ΔHº) for the final reaction (2C(s) + H₂(g) → C₂H₂(g) ) is -1932.8KJ.
Enthalpy change: what is it?A system's enthalpy is its heat capacity. A reaction's enthalpy change is roughly equivalent to how much energy is lost or gained throughout the reaction. If the enthalpy of the system decreases over the reaction, the reaction is preferred.
C(s) + O₂(g) → CO₂(g) ΔHº = -94.6 kJ --- (1)
H₂(g) + O₂(g) → H₂O(l) ΔHº = -286.0 kJ ---(2)
2C₂H₂(g) + 5O₂(g) → 4CO₂(g) + 2H₂O (l) ΔHº = -2598.8 kJ ---(3)
The value of ΔHº for the final reaction,
2C(s) + H₂(g) → C₂H₂(g)
ΔH₄° = 2× ΔH₂º + ΔH₃º - ΔH₁º
ΔH₄° = 2× -286.0 + ( -2598.8) - (- 94.6)
ΔH₄° = 2× -286.0 -2598.8 + 94.6
ΔH₄° = 666 - 2598.8
ΔH₄° = -1932.8KJ.
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when might the BAC of a dead body be misleading or unhelpful
Answer: Blood alcohol levels at autopsy are valid up to 48 hours after death when simple principles are observed in the collection and storage of samples. Alcohol levels in samples of blood taken from the intact heart are as significant as levels of blood from the femoral veins.
Explanation:
Answer:
If the victim was submerged in water
Explanation:
Which fuels are non-renewable
Answer:
fossil fuels
Explanation:
Well I had some topics on this stuff last quarter in science and from what I can remember it should be fossil fuels I think that fossil fuels are technically renewable but they are considered non-renewable since they are either in small supplies, are hard to obtain or take a long time to form.
A graduated cylinder contains 50.0 ml of water. A 23.5 g piece of unknown metal is carefully dropped into the cylinder. When
the metal is completely covered with water, the water rises to the 53.4 ml mark. What is the density of the unknown piece of
metal in g/ml?
To find the density of the unknown piece of metal, we can use the formula:
Density = mass / volume.
How to find the density ?The volume of the metal can be calculated by deducting the starting water volume (50.0 ml) from the final water volume (53.4 ml) after the metal is introduced. We know the mass of the unknown metal is 23.5 g.Volume of metal = 53.4 ml - 50.0 ml = 3.4 ml.Now we can substitute the values into the density formula: Density = 23.5 g / 3.4 ml = 6.9 g/ml.Therefore, the density of the unknown piece of metal is 6.9 g/ml.To know more about density , check out :
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Which type of sedimentary rock forms from weathered sediment?
Answer:
Clastic or detrital sedimentary rocks are made from pieces of bedrock, sediment, derived primarily by mechanical weathering.
Explanation:
PLEASE HELP! 80 POINTS
Create a VESPR drawing for
NH3
CH20
N3
SO2CI2
BrF5
Answer:
hope it helps you
URGENT PLEASE HELP
1) The following balanced chemical equations are for based on the combustions of various fuels. Calculate the heats of combustion for each reaction
a. C2H5OH(l) + 3O2(g) à 2CO2(g) + 3H2O(g)
b. 2C4H10(g) + 13O2(g) à 8CO2(g) + 10H2O(g)
c. C3H8(g) + 5O2(g) à 3CO2(g) + 4H2O(g)
2) Express the heats of combustion from the above reactions as energy changes per mole of fuel combusted. State the reason why energy changes are often expressed per mole of reactant.
3) An Electric Generator burns gasoline to produce electricity. The balanced equation is below:
2C8H18(l) + 25O2(g) à 16CO2(g) + 18H2O(g)
a. Calculate the energy change for the burning of gasoline.
b. If the generator produces 2000kJ of electrical energy for every mole of gasoline combusted calculate the efficiency of the generator.
Answer:
Explanation:
1) The following balanced chemical equations are for based on the combustions of various fuels. Calculate the heats of combustion for each reaction a. C₂H₂OH + ...
A scientist did a test to compare two substances: substance Q and substance R. At room temperature, both substances are liquid. When the scientist transferred the same amount of energy out of both substances, only one substance changed phase while the other did not. Which substance changed phase, and how did it change?
Responses
a
Substance Q changed phase because the attraction of the molecules was able to overcome their slower movement. Its molecules now move in place.
Substance Q changed phase because the attraction of the molecules was able to overcome their slower movement. Its molecules now move in place.
b
Substance Q changed phase because the strong attraction between molecules made their movement slower. Its molecules now move in place.
Substance Q changed phase because the strong attraction between molecules made their movement slower. Its molecules now move in place.
c
Substance R changed phase because the weak attraction between molecules let them move faster. Its molecules now move around each other.
Substance R changed phase because the weak attraction between molecules let them move faster. Its molecules now move around each other.
d
Substance R changed phase because the attraction was able to overcome the slower molecules. Its molecules now move away from each other.
Substance R changed phase because the attraction was able to overcome the slower molecules. Its molecules now move away from each other.
Substance R changed phase because the weak attraction between molecules let them move faster. Option C
What is phase change?We know that a change of phase has to do with the movement of a material from a given state of matter to the other. Net us note that when there is a change of state, we are going to notice that the force of attraction in the molecule would also change.
Since we know that the substance that we have are liquid at room temperature, we know that the supply of some energy may cause to be bale to change its phase.
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Why atoms form compounds
Answer:
Because the atoms are trying to reach the most stable ( lowest energy ) state they can.
ammonia chemically reacts with oxygen gas to produce nitric oxide and water. what mass of oxygen gas is consumed by the reaction of 8.4 g of ammonia?
the mass of nitric oxide produced by the reaction of 8.4 g of oxygen gas is 4.32 g. ammonia chemically reacts with oxygen gas to produce nitric oxide and water.
What oxygen is used for?Common uses of oxygen include production of steel, plastics and textiles, brazing, welding and cutting of steels and other metals, rocket propellant, oxygen therapy, and life support systems in aircraft, submarines, spaceflight and diving.
Why is oxygen important?Oxygen helps organisms grow, reproduce, and turn food into energy. Humans get the oxygen they need by breathing through their nose and mouth into their lungs. Oxygen gives our cells the ability to break down food in order to get the energy we need to survive.
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For this assignment, you will make a scale model—a “core sample”—showing the layers of the Earth: crust, lithosphere, asthenosphere, mantle, outer core, and inner core.
Iron has a density of 7.31 g/cm3.what is the mass of 2.25 cm3 of sodium?
7.9 g/cm3 is the density of iron. There are three possibilities: 1.3 × 103 g 2.3 × 10-2 g 4.3 × 102 g 2.1 × 104 g 1.4 g.
What is the density of iron?Iron has a density of 7.874g/cm3.
At atmospheric pressure, different substances have their typical densities.
The mass per unit volume is the definition of density. Mathematically speaking, its intense attribute is defined as mass divided by volume:
ρ = m/V
The total mass (m) of a material divided by the total volume (V) . it occupies is how a substance is defined as having a density (). The kilogram per cubic meter (kg/m3) is the metric unit used by the SI. The pounds mass per cubic foot (lbm/ft3) measurement is used in Standard English.
Compressibility (also known as the coefficient of compressibility is a measure of the relative volume change of a fluid or solid as a response to a pressure (or mean stress) change.
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If 467.08 grams of Oz are reacted, how many grams of C6H5CH3 will also be reacted?
In order to react with 467.08 grams of O2, 4034.95 g of toluene (C6H5CH3) is required.
What are some uses for toluene?Toluene is a white liquid hydrocarbon found in petroleum and coal tar that is employed like a solvent and in the synthesis of organic compounds. Toluene is a naturally occurring substance found in crude oil and is used for oil refining as well as the production of glues, lacquers, paints, and explosives. Toluene can be discovered in household products like paint, paintbrush cleaner, nail polish, glue, inks, and stain removers.
For the balanced equation
2C6H5CH3 + 3O2 → 7CO2 + 4H2O
We required three steps
1.) Convert mass of O2 to mol of O2
mole = mass / molar mass
2.) Find mole of C6H5CH3 by multiply mol O2 by the mol ratio between O2 and C6H5CH3 in balanced equation.
3.) Find mass C6H5CH3 by multiply mol C6H5CH3 by its molar mass (92.14 g/mol)
= 467.08 gm /15.999 gm × 3/ 2 ×92.14 gm
= 4034.95 gm. of C6H5CH3
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If hydrogen diffuses at the rate of 10 cm³ per second from a given apparatus under given conditions of temperature and pressure, calculate under same conditions: a) the volume of oxygen (O₂) which diffuses in 20 seconds
Answer:
Volume of O₂ = 200cm³
Explanation:
Rate of diffusion of gas is directly and inversely proportional to the volume and time taken for the gas to diffuse completely.
Volume
R = -----------
time
let R₁ represent the rate at which the given volume of hydrogen gases diffuses and R₂ represent the rate at which the the volume of the oxygen gas diffused.
V₁, V₂, T₁ and T₂ follows the same process
If the two gases diffuses at the same rate, then;-
R₁ = R₂
V₁ V₂
---------- = ------------
T₁ T₂
V₂
10 = ----------------
20
V₂ = 20•10
V₂ = 200cm³
Therefore, the volume of oxygen that could diffuse in 20 seconds is 200cm³
Use the ideal gas law to find the volume that 4.30 mol of oxygen gas occupies at 99.7 kPa and 35.0 °C.
help please
According to the ideal gas law, 4.30 molecule of o2 occupies 0.11 m³ at 99.7 kPa with 35.0 °C.
What is a straightforward definition of ideal gas law?The relationship between a gas's pressure P, volumes V, and t in the range between low pressures and extremely high temperatures, when the gas's water moves virtually independently of one another, is known as the ideal gas, also known as the perfect gas law.
PV = nRTp = pressure in PaV
= volume in m³n = number of molesR
= molar gas constant (8.31 JK⁻¹mol⁻¹)T
= temperature in Kpressure ⇒ 99.7 × 10³ Pa
temperature ⇒ 35.0 + 273 = 308
KpV = nRT
= 99.7×10³×V= 4.30×8.31×308V
=(4.30×8.31×308)/(99.7×10³3 )V
= 0.11 m³
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sap can be turned into syrup by
Answer: by boiling it
Explanation:
By boiling the sap to remove water, also to concentrate the sugar that makes maple syrup.
Scientists found the remains of dinosaur fossils in a remote section in the west, located
within ten miles of a meteor crash site. Which statement can be made about the
dinosaur and the meteor?
O a. The dinosaur could have died from a flood.
O b. The dinosaur and the meteor are not related.
O c. The dinosaur could have died from freezing to death.
O d. The dinosaur could have died due to an meteor crash.
Answer:
D The dinosaur could have died due to an meteor crash.
Explanation:
Answer:
D
Explanation:
The dinosaurs fossils were found ten miles away from the meteor crash site. Correct me if I'm wrong
Which of these is an example of a physical property?
A. Iron combines with oxygen to rust.
B. Potassium reacts in water to form a base.
C. Sodium metal is soft and malleable.
D. Sodium ignites when placed in water.
why is it important for a consumer to know the properties of a textile fibre
A thorough understanding of clothing and textiles will enable one to evaluate standards and product brands intelligently. It will also help one develop the capacity to recognize fabric quality, which will help one understand the best applications for the various qualities.
Understanding why some fabrics are more durable and so more suited for particular uses comes from studying textiles. It permits one to comprehend the rationale behind why particular materials generate cool-looking clothing in addition to creating the sense of coolness when used as décor. A thorough understanding of clothing and textiles will enable one to evaluate standards and product brands intelligently.
It will also help one develop the capacity to recognize fabric quality, which will help one understand the best applications for the various qualities. Although clothes don't necessarily make a person, they certainly help to develop a positive personality and a sense of self-assurance. Housewives should therefore be familiar with clothing and textiles to obtain the best out of it.
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Bauxite ore contains aluminum oxide, which is decomposed using electricity to
produce aluminum metal and oxygen. What mass of aluminum metal can be
produced from 125 g of aluminum oxide?
Answer:
66.48 g.
Explanation:
Bauxite ore contains aluminium oxide which is decomposed using electricity to produce aluminium metal and oxygen gas
Please help me I really need help
Answer:
wow okay um so first you go home, get in bed, never open that computer again
Explanation:
Using ethylene (HC-CHz) as your only source of carbon atoms, outline a synthesis for 3- hexanone,
The organic compound 3-hexanone can be prepared from ethylene using the second method given in the options.
What is 3-hexanone?3-hexanone is an organic compound classified to the ketones. Ketones are compounds with C=O group. 3-hexnone has the carbonyl group in the third carbon in the chain.
3- hexanone can be synthesized alkene sources by first converting them to alkynes. This process is oxidation. Ethylene can be oxidized to ethyne by treating with HBr and NaNH2 followed by hydrolysis.
The obtained higher alkyne or hexyne undergone acid hydrolysis in presence of sulphuric acid giving 3-hexanone.
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Please help me fill in the blanks
Answer: ew i hate science but ive done that same thing before i dont remember the answers though
Explanation:
46 g of glycerin were dissolved in 100 g of water. What is the freezing point of this solution?
Additional information:
М(С3Н5(ОН)3) = 92 g/mol;
Тf(Н2О) = 273.15 К;
Кf = 1.86 kg⋅К/mol.
Based on the formula to determine the freezing point depression of the solvent, the freezing point of the solution is 263.85 K.
What is the freezing point of a substance?
The freezing point of a substance is the temperature at which the liquid changes to solid without any further decrease in temperature occurring during the process.
The addition of solute substances in liquids usually lowers the freezing point of the liquid solvent.
The formula to determine the freezing point depression of solvent is given below:
ΔT = i * Kf * mwhere'
ΔT is the change in freezing point,i is the van't Hoff factor,Kf is the freezing point depression constant, andm is the molality of the solution.The molality of the given solution = moles of solute/kg of solvent
moles of solute = 46/92
mass of solvent = 100 g or 0.1 kg
Molality of solution = (46/92) / 0.1
Molality of solution = 5
for glycerine, i = 1
ΔT = ΔT = 1 * 1.86 * 5
ΔT = 9.3
The freezing point of the solution = 273.15 - 9.3
The freezing point of the solution = 263.85 K
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What is the domain of the following function?
A) x < 15
B) x ≤ 4
C) x > 2
D) All Real Numbers
The domain of the function that has been shown are all real numbers. Option D
What is the domain of a function?Let us note that when we are talking about the domain of the function, we mean the areas that the function is able to have a value. We are also trying to define the areas where the actual value of the function can be determined.
It is normal that all the mathematical functions that we have must have a domain and a range. The domain of the function would depend on the kind of function that it is and that determines what its domain would be.
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Neera and Tom dissolved different masses of salt in 500 cm³ of water.
They measured the temperature at which each salt solution boiled.
salt
solution
(They wrote down the variables that might affect the investigation.
temperature of the
mass of salt
laboratory
dissolved in water
boiling point of
salt solution
thermometer
volume of water
starting temperature
of the water
type of salt used
The variables that might affect the investigation while dissolving different masses of salt are temperature and mass of the salt.
In the provided investigation, what are the independent and dependent variables?A variable that changed during the inquiry is regarded as an independent variable and is called "mass of salt dissolved in water." While the investigation's dependent variable, "boiling point of salt solution," is a variable that was monitored.
What are variables in a laboratory?There are numerous things that can be changed to see how they affect other things. Variables are the changeable quantities. Any element, character trait, or condition that can exist in a variety of forms or concentrations is a variable. Independent, dependent, and controlled variables are the three types of variables that often make up an experiment.
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Neera and Tom dissolved different masses of salt in 500 cm3 of water.
They measured the temperature at which each salt solution boiled.
(a) They wrote down the variables that might affect the investigation.
temperature of the laboratorymass of salt dissolved in waterstarting temperature of the waterboiling point of salt solutionvolume of watertype of salt used(i) What is the independent variable (the variable they changed) in
their investigation?
(ii) What is the dependent variable (the variable they measured) in
their investigation?
(iii) Which variable above would affect the experiment the least?
CHEMISTRY FORM THREE Exercise 2.1 1) Not all metals share the typical metal properties.name a metal that is: a. hard and strong b. malleable at room temperature
a) The strongest metal on the planet is tungsten.
When it comes to tensile strength, tungsten tops all other metals. One of the strongest metals known to man, tungsten has an ultimate strength of 1510 Megapascals.
In addition to having the greatest melting point of any unalloyed metal, tungsten boasts greater strength. Tungsten is frequently employed in electrical and military applications due to its strength.
Tin is a malleable, silvery-white metal that is highly flammable at ambient temperature.
Metal malleability is a complex subject. There is no objective test available to measure this feature, as we previously stated. We most frequently test it for hardness.
The most malleable and ductile metals are gold and silver. Pure gold and silver are too soft to be used to create items that will keep their shape.
Metals may be molded into different shapes, such as thin sheets or foils, without breaking or shattering because they are malleable. They are also ductile, making it simple to draw them into wires.
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Osmosis.
10 % solution of sodium chloride is on the first side of the semipermeable membrane separating the vessel and 2 % solution of sodium chloride is on its other side. Describe the process taking place there.
Answer:
Osmosis is taking place in the vessel, where a 10% solution of sodium chloride is on one side of the semipermeable membrane and a 2% solution of sodium chloride is on the other side. Osmosis is a special case of diffusion, where water moves from an area of higher concentration to one of lower concentration. In this case, water will move from the 10% solution to the 2% solution, as it has a higher solute concentration. This process is known as osmoregulation and it involves maintaining salt and water balance across membranes within the body’s fluids. The key to remember about osmosis is that water flows from the solution with the lower solute concentration into the solution with higher solute concentration. As such, in this case, water will flow from the 2% solution to the 10% solution.
Explanation:
Write a skeleton molecular equation for the following chemical reaction: Sulfuric acid reacts with solid sulfur to form sulfur dioxide gas and water. You should have two equations, one word equation and one chemical equation.
Word equation: sulfuric acid + sulfur -> sulfur dioxide + water
Chemical equation: H2SO4 + S -> SO2 + H2O
Answer:
Word equation: Sulfuric acid + Sulfur → Sulfur Dioxide + Water
Chemical equation: H2SO4 + S → SO2 + H2O
Explanation:
Which block of elements is non-reducing?
Answer: S-block elements
Explanation: Elements of S-block are prepared through the electrolysis process not by the reduction of their compounds with the other group elements of their compounds. For example in Carbon dioxide carbon is non reducing because oxidation state of `C "in" CO_(2)` is `+4`, which is maximum So it does not undergo oxidation, and hence, it is not a reducing agent.
order these elements by decreasing electron affinity:
Na, Al, S, K, F
Answer:
increasing to decreasing:
F--- S--- Al--- Na--- K
not sure...