The enthalpy of combustion for octane (C8H18(l)), a key component of gasoline, is –5074 kJ/mol. The reaction equation is: C8H18(l) + 12.5O2(g) arrwo 8CO2(g) + 9H2O(g).
What is the enthalpy of formation for this reaction?
16CO2(g) + 18H2O(g) arrow 2C8H18(l) + 25O2(g)

Answer:

Its a small dense spherical structure in the nucleus of a cell during interphase.

Answer:

Explanation:

It contains the elements titanium (Ti), zirconium (Zr), hafnium (Hf) and rutherfordium (Rf). This group lies in the d-block of the periodic table. The group itself has not acquired a trivial name; it belongs to the broader grouping of the transition metals.

Answer:

Temperature is a measure of the average kinetic energy of the particles in a substance.

Explanation:

Answer: IV

Explanation:

Atoms with the same number of valence electrons (in this case 2) will have similar chemical properties.

Answer:

Density is defined as how tightly or loosely packed a substance is, or to the number of things or people in a certain area.

Answer:

M g ( s) + 2 H + ( a q) + 2 S O 4 2 − ( a q) -> M g 2 + ( a q) + 2 S O 4 2 − ( a q) + H 2 ( g) The reaction forms magnesium sulfate and hydrogen gas. As the sulfate is still aqueous on either side of the equation, we can leave it out of the ionic equation (it is a spectator ion).

Explanation:

The chemical equation of Magnesium and  sulfuric acid:

Mg  +  H₂SO₄  → MgSO₄ +   H₂

A chemical equation can be described as the equation of a chemical reaction involving substances. An equation consists of reactants contributing, formed products, and an arrow to indicate a chemical reaction.

The balanced equation of a reaction involving an equal number of atoms of substances on either side of the equation is known as a balanced chemical equation.

The law of conservation of mass will be followed by such an equation. By obeying this law, the total mass of the reactants as well as products should be equal in a balanced chemical equation.

Given the reaction of Magnesium metal placed in sulfuric acid. The solution starts to bubble as there is the formation of hydrogen gas.

Mg  +  H₂SO₄  → MgSO₄ +   H₂

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Answer:

i think its replacement

Explanation:

By definition, the correct answer is the second option: the reaction is a replacement.

A simple substitution reaction or simple displacement reaction, called single-displacement reaction, is a reaction in which an element of a compound is substituted by another element involved in the reaction.

The starting materials are always pure elements and an aqueous compound. And a new pure aqueous compound and a different pure element are generated as products.

The general form of a simple substitution reaction is:

AB + C → A +BC

where C and A are pure elements; C replaces A within compound AB to form a new co, placed CB and elementary A.

A single-displacement reaction is characterized by a place of exchange of cations or anions with another to form a new product. A begins as an ion in the solution and appears elementally in the reaction products. In case of reagent C it starts in its elemental form and ends as an ion in an aqueous state forming compound BC.

In this case, it is a single replacement reaction where 1 atom of Zinc metal displaces 2 H⁺ ions from the hydrochloric acid to form hydrogen gas and zinc chloride, a salt.

Finally, the correct answer is the second option: the reaction is a replacement.

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Light bulbs emit photons to produce light. Photons are packets of electromagnetic energy, and when an electric current passes through the filament of a light bulb, it heats up and produces light. Option D is correct.

When an electric current passes through the filament of a light bulb, the filament gets heated up due to the resistance of the material. This heating process causes the filament to become incandescent, meaning it emits light as a result of being heated to a high temperature.

The emitted light consists of photons, which are particles of electromagnetic energy. These photons carry the energy released from the heated filament in the form of electromagnetic waves, resulting in the visible light that illuminates the surrounding area. Protons, electrons, and neutrons are subatomic particles and are not involved in the process of emitting light in a light bulb.

Hence, D. is the correct option.

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--The given question is incomplete, the complete question is

"What do light bulbs emit to produce light? Group of answer choices A) protons B) electrons C) neutrons D) photons."--

Answer:

adding the standard atomic masses (in g/mol) of the constituent atoms.

Answer:

scandium or zinc i think

Explanation:

Answer: All of the above

Explanation:

All of the options are producers, meaning they make their own food from sunlight through the process of photosynthesis.

Answer:

C hope it helps

Explanation:

Answer:

location A creates a volcano

Explanation:

mark as  brainliest

Answer:

covalent bonds

Explanation:

Answer:

The answer option which best describes nuclear fission is: C. A nucleus collides with a neutron and splits, releasing energy.

A nuclear reaction can be defined as a type of reaction in which the nucleus of an atom is transformed by either being joined (fusion) or split (fission) with the nucleus of another atom of a radioactive element and accompanied by a release of energy.

Explanation:

Answer:

4. I think that they started with water that was the same tsmpurature because if they didnt start with the same temp of water then it would be harder to tell which one was better. and could hold the most heat.

5. yes i think it would matter, because if you have more water in one cup it might stay warmer than it would with the cups with less water, and if it was thicker it would hold mor heat because it is not so thin that the heat is just gonna come out it has to come through more for the heat to get out.

Explanation:

sorry if these are to long but thats how i would answer them.

hope it helped

false, the rusting of iron can be prevented by painting, oiling, greasing or varnishing its surface.

Answer:

By contracting, muscles pull on bones and allow the body to move. When you want to bend your elbow, your biceps muscle contracts, and, at the same time, the triceps muscle relaxes. The biceps is the flexor, and the triceps is the extensor of your elbow joint.

Explanation:

yeah, hope it helps a little. :)

This seems to be a Hess' Law problem. Hess' Law states that "states that regardless of the multiple stages or steps of a reaction, the total enthalpy change for the reaction is the sum of all changes." (Libretext)

Compare the step reaction to the final reaction to see the similarity and differences. We may have to flip an equation or multiply it by a constant to obtain the number of moles of the species in the final equation. Just remember, whatever we do to the equation, we have to do to the ΔH as well.

3C  +  4H₂  →  C₃H₈      ΔH= +104 kJ  [1]

      C + O₂ → CO₂        ΔH= -394 kJ  [2]

  2H₂ + O₂ → 2H₂O      ΔH= -572 kJ  [3]

C₃H₈  + 5O₂  → 3CO₂ + 4H₂O  ΔH = ?

_____________________________________________

Compare the Equation

Equation [1]

In [1] the C₃H₈is on the product side. But the final equation has the C₃H₈ on the reactant side. Thus we have to flip the equation. This flips the sign of ΔH.

                C₃H₈   →   3C  +  4H₂     ΔH= - 104 kJ  [1]

Equation [2]

The CO₂ in the final equation is on the product side but is 3 moles. Thus we have to multiply [2] by three. The ΔH is also multiplied by 3.

               3C + 3O₂ → 3CO₂        ΔH= 3 (-394 kJ)    [2]

Equation [3]

The H₂O in the final equation has a coefficient of 4. Thus we have to multiply [3] by 2.

              4H₂ + 2O₂ → 4H₂O      ΔH= 2(-572 kJ)  [3]

Combine the Equations

Combine the newly sorted versions of the equation and simplify to see if it matches the final equation. We also add the ΔH.

⇒  C₃H₈ +  3C + 3O₂ + 4H₂ + 2O₂   →   3C  +  4H₂  + 3CO₂ + 4H₂O

              ΔH= - 104 kJ + 3 (-394 kJ) + 2(-572 kJ)

⇒   C₃H₈ +  + 5 O₂   →  3CO₂ + 4H₂O

              ΔH= - 104 kJ + 3 (-394 kJ) + 2(-572 kJ) = −2430 kJ

Answer:

its classified as a molecule

Answer:

Explanation:

The elements in the long form of periodic table are classified into four blocks. They are s, p, d and f-block elements. The classification is based on the name of orbitals which receive the last electron. The elements in which the valence shell electron enters the s-orbital are called s-block elements.

Explanation:

The charge of a helium atom is zero

It is neutral because

The number of unit negative charges = number of unit positive charges

One unit negative charge = -1.6 x 10^(-19) which is basically the charge of an electron

One unit positive charge = +1.6 x 10^(-19) which is basically the charge of a proton

A helium atom has 2 protons and 2 electrons, so it is neutral

NOTE: an alpha-particle (He2+) is a charged helium atom it has 2 protons and 0 electrons. Charge of an alpha particle = +3.2 x 10^(-19).

Answer:

1. 50 km/hr

2. 5 m/s

3. 180 km/hr 50 m/s

4. 30.56 m/s

5. 11.4 km/hr

Explanation:

#1 500 km/ 10 hours = 50 km/hr

#2 100 m/ 20 s = 5 m/s

#3 540 km/3 hrs = 180 km/hr

180 km/1 hr x (1000 m/ 1 km) x (1 hr/ 60 minutes) x (1 minute/ 60 seconds) = 50 m/s

Answer:

Ionic bond

Explanation:

Answer:

the answer is (B)

the mass before equals the mass after

Taking into account the definition of density,  assuming all other conditions remain the same, increasing mass will cause an object's density to increase.

Density is defined as the property that matter, whether solid, liquid or gas, has to compress into a given space. That is, density is a quantity referred to the amount of mass contained in a given volume.

Density is an intensive property since it does not vary with the amount of substance.

Since density is the relationship between the mass and the volume of a substance, its calculation is defined as the quotient between the mass of a body and the volume it occupies:

[tex]density=\frac{mass}{volume}[/tex]

In the previous expression it can be observed that the density is inversely proportional to the volume: the smaller the volume occupied by a certain mass, the greater the density.

On the other hand, density is directly proportional to mass: the greater the mass, the greater the density.

Finally,  assuming all other conditions remain the same, increasing mass will cause an object's density to increase.

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Answer:

a. Stirring the solution.

Answer:

Mechanical Energy to Thermal Energy

When you strike a match, it moves through the air until it rubs against a surface. The rubbing produces the heat required to light the match. This is a transformation from mechanical energy to thermal (heat) energy.

Explanation:

Answer:

A is the answer.

Explanation: