PLEASE HELP I NEED HELP ASAP I WILL GIVE BRAINLIEST AS SOON AS POSSIBLE​

Answer:

Hof(X) = - 1474.9 KJ/mol

Explanation:

The reaction equation given to us is:

2 X + 5 O2 (g) --> 4 CO2 (g) + 6 H2O (g) ∆H = -75.0 kJ

Now, the equation for the standard enthalpy of formation of the reaction is written as follows:

ΔH = 4*Hof(CO2(g)) + 6*Hof(H2O(g)) - 2*Hof(X) - 5*Hof(O2(g))

where,

ΔH = - 75 KJ

Hof(CO2(g)) = Standard Heat of Formation of CO2(g) = -393.5 KJ/mol

Hof(H2O(g)) = Standard Heat of Formation of H2O(g) = -241.8 KJ/mol

Hof(X) = Standard Heat of Formation of X = ?

Hof(O2(g)) = Standard Heat of Formation of O2(g) = 0 KJ/mol

Therefore,

-75 KJ = (4)(-393.5 KJ/mol)+ (6)(-241.8 KJ/mol) - (2)(Hof (X)) - (5)(0 KJ/mol)

- 75 KJ + 3024.8 KJ = - (2)(Hof(X))

Hof(X) = -2949.8 KJ/2 mol

Hof(X) = - 1474.9 KJ/mol

Answer:

D

Explanation:

More protons in the nucleus pull the electrons in, making the atomic radius smaller. Therefore, the correct option is option D.

The atomic radius is determined by the nucleus's balance between the attracting force of positively charged protons and the repelling force of electrons.

The most crucial element in calculating the average atomic radius is not Option A. Although atomic mass typically increases with time, increasing nuclear charge has a greater impact on atomic size.

Over time, Option B has no discernible impact on atomic radius. Although the number of valence electrons changes over time, increasing nuclear charge has the biggest impact on atomic size. The valence shell is the outermost electron shell.

The gradual decrease in atomic radius is unaffected by Option C. The most frequent electron pairing occurs within orbitals of the same energy level, and it has little impact on atomic size over a period.

Therefore, the correct option is option D.

To know more about atomic radius, here:

https://brainly.com/question/13963619

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Answer:

today, petroleum is mostly used as a source of energy, being rich in combustible carbon in the production of electricity or running some sorts of heat engines. ... Raw petroleum (also known as crude oil) is used in three major ways: Transportation, Electricity Generation, and Material Production.

Explanation:

hope it helps!!!!!!!!!!!!!!!!!!!!!!!!!!

The answer would be scoria I believe

Answer:

the nucleus of an atom consistens of protons and neutrons

Answer:

A. 39

Explanation:

Mass number= #protons + #neutrons

19+20= 39

Taking into account the definition of mass number, the correct option is the option A: the atomic mass of the atom is 39.

First of all, all atoms are made up of subatomic particles: protons and neutrons, which are part of their nucleus, and electrons, which revolve around them. Protons are positively charged, neutrons are neutrally charged, and electrons are negatively charged (electrons).

On the other hand, the mass number tells us the total number of particles in the nucleus. That is, the mass number is the sum of the number of protons and the number of neutrons in the atomic nucleus:

Mass number = (number of protons) + (number of neutrons)

It is represented by the letter A.

In this case:

So:

Mass number = 19 + 20

Solving:

Mass number= 39

In summary, the correct option is the option A: the atomic mass of the atom is 39.

Learn more:

Answer:

Sometimes the whole alloy in a uniform is a solid solution

Answer:

Ruthenium and Rhodium

Explanation:

Answer:

The correct option is the first option

Explanation:

The equation described in the question is shown below

²³⁹₉₄Pu +¹₀n ⇒ ¹⁰⁰₄₀Zr + blank + 2¹₀n

This equation is a nuclear fission because it involves the splitting of a heavy nucleus, Plutonium (Pu), into smaller nuclei, Zirconium (Zr) and an unknown nuclei.

The law of conservation of matter states that matter can neither be created nor destroyed hence in other to get the missing atom, we must know the total number of subscripts (mass number) and superscripts (atomic number) on both sides.

The total mass number on the reactant side is 239 + 1 = 240

The total atomic number on the reactant side is 94 + 0 = 94

While, The total mass number on the product side is 100 + 2(1) = 102

The total atomic number on the product side is 40 + 2(0) = 40

To determine the missing atom, you subtract the the total atomic number of the product from that on the reactant side; 94 - 40 = 54

The atom with the atomic number 54 is Xenon,

To determine the mass number of the xenon isotope involved, you subtract the the total mass number of the product from that on the reactant side; 240 - 102 = 138.

Hence, the particle that completes the equation is ¹³⁸₅₄Xe, the first option

Answer: A on edge

Explanation:

the person above me explained it well but i wanted to shorten it.

Answer: D

Explanation:

Amorphous

Answer:D

Explanation:

took the apec test

Answer: c

Explanation:

i think the answer is c

Answer:

Lithium Fluoride.

Explanation:I know science.

Answer:

That we know about yes, but physicians still say there are more things out there. (we do not know about these yet tho)

Explanation:

Answer:

1.80 x 10^24 atoms

Explanation:

3moles × 6.022×10^23 atoms/mole

Answer:

As the valance shell have 7 valance electrons .

It belongs to halogen family (group 17).

Answer:

the answer is 4 g/cm cube

Answer:

4g/cm cube is answer of this question

I hope it helped.

Reason. p=m/v

p=20 g/5cm cube

=4g/cm3

Explanation:

General Rules. In general, the electropositive character of the oxide's central atom will determne whether the oxide will be acidic or basic. The more electropositive the central atom the more basic the oxide. The more electronegative the central atom, the more acidic the oxide.

Answer:

B. to determine that electric beams in cathode ray tubes were actually made of particles

Explanation:

Answer:

B. to determine that electric beams in cathode ray tubes were actually made of particles

Explanation:

edg 2020

Answer:the atoms of a solid aluminium can are close together vibrating in a rigid structure if the can is warmed up on a hot plate

Explanation:

Answer:

Ansmure two

ismirgonewart

are you

and de band

what is true beauty and the best

Explanation:

itu diatas jawaban nya

Answer:

Identify the variables and constants in your experiment. In a controlled experi- ment, a is any factor that can change. Constants are all of the factors that are the same in both the experimental group and the control group.

Answer: A) Suleman is watching tv program

Potential energy : energy obtained due to height or position (the force of gravity)

 PE = mhg

g = acceleration due to gravity  (m/s²)

h = height (m)

m = mass (kg)

1. Known

m = 0.5 kg

h = 1 m

g = 9.8 m/s²

then :

[tex]\tt PE=0.5\times 1\times 9.8=4.9~J[/tex]

Kinetic energy is the energy gained by an object's motion

KE = 1/2 mv²

2. To find KE, the required data are the mass and velocity

in this table, you do not display the velocity

Answer:

Try to make it more detailed "Chemistry is the study of all substances" is an amazing start. Can you give some examples of chemistry? Try to make a small paragraph.

Explanation:

Explanation:

Chemistry, the science that deals with the properties, composition, and structure of substances (defined as elements and compounds), the transformations they undergo, and the energy that is released or absorbed during these processes.

This is a more detailed answer...

Answer:

1.85 g per cm^3

The substance is Beryllium(if it is a single element, and not a compound)

Explanation: