What best describes the enthalpy of formation of a substance?
A. The energy needed to cause the substance to change phases
B. The energy change that happens when a substance forms from its
elements
C. The energy absorbed or released in a chemical reaction
D. The total thermal energy of all the molecules in the substance

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!The answer is D!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Answer:

salt sodium chloride (NaCl)

Answer:

[A]²

Explanation:

Since the formation is independent of D, D is 0 order.

Since a quadruples when it is doubled it can be written as

2A^X= 4

To find the unknown power we can assume A= 1 to make the math simple. So When a = 2 (Because you doubled it) raised to X power it will equal 4

so the unknown power is 2

Making the rate law

[a]²[b]⁰

or simply just

[A]²

Answer:

Gastritis can be caused by irritation due to excessive alcohol use, chronic vomiting, stress, or the use of certain medications such as aspirin or other anti-inflammatory drugs. It may also be caused by any of the following:

If gastritis is left untreated, it can lead to a severe loss of blood and may increase the risk of developing stomach cancer.

Answer:

Atomic orbital

Explanation:

Electrons are found around the atomic nucleus in three-dimensional regions.

The energy levels they are in can be named according to a numbering order such as 1, 2, 3, 4, ..., increasing in proportion to the distance to the nucleus. Each of these energy levels can be divided into sublevels s, p, d, f which are also called orbitals.

Answer:

2 Cr(s) + 3 Fe(NO3)2(aq) = 3 Fe(s) + 2 Cr(NO3)3(aq)

Explanation:

I balanced this chemical equation so that both sides are equal, meaning that the mass of reactants is equal to mass of products.

Answer:

52,000 kJ

Explanation:

The combustion reaction is the following:

2 C₂H₆(g) + 7 O₂(g) → 4CO₂(g) + 6H₂O(l)  ΔHm= –3120 kJ

From the chemical reaction and the value of ΔH we can see that 2 moles of ethane gas (C₂H₆(g)) release 3120 kJ of heat energy. So, we have the conversion factor: 3120 kJ/2 moles C₂H₆.

To calculate how many kJ are released from the combustion of 1 kg of ethane, we have to first convert the mass to moles by using the molecular weight (MW) of ethane (C₂H₆):

MW(C₂H₆) = (12 g/mol x 2 C) + (1 g/mol x 6 H) = 30 g/mol

mass = 1 kg x 1000 g/1 kg = 1000 g

moles of C₂H₆= mass/MW = 1000 g/(30 g/mol) = 33.3 mol C₂H₆

Finally, we multiply the conversion factor by the number of moles of C₂H₆ in 1 kg:

heat energy released = 33.3 mol C₂H₆ x 3120 kJ/2 moles C₂H₆ = 52,000 kJ

Therefore, 51,000 kJ are released when 1 kg of ethane is burned.

Answer:

400.58

Explanation:

Standard pressure is 1atm/760 mm Hg

760-359.42= 400.58

Answer:

The correct answer is (C) 0.2 mole MgCl2

Explanation:

Answer:

answer is here bit.^{}ly/3gVQKw3

Answer:

sure

Explanation:

Answer: Uhmmmm what dude i dont know what to say how the heck so i solve this?

Explanation:

Answer:

About 0.01

Explanation:

1 grams of H2O = 0.0010

0.0010 x 10 = 0.01

Answer:

mettaliods

Explanation:

It has the both property of metal and non metal so it is called mettaliod.

Answer:

metalloids

Explanation:

they are solid at roomtempreture and alloys with metals.

examples boron,silicon,arsenic,tellurium

Answer:

64.5g

Explanation:

First you add the mass of reactant 1 and reactant 2, then you simply subtract the amount of gas released from your answer, and that would be the total mass of ALL the products formed.

My work:

13.6g + 72.9 = 86.5g

86.5g - 22g = 64.5g

Answer:

4400, and 0

Explanation:

since they traveled 2200 in one direction, to return home they must travel that distance again, so they travel 4400

displacement is the distance from the start point, so since they are back home at the end of the trip, they did not get displaced at all

if you have any questions, leave them in the comments and i will try to answer them, if this helped, pls give brainliest

Answer:

My answer to the question is 4400 and 0

I'm pretty sure it's B :)

Answer:

During photosynthesis, plants absorb carbon dioxide and sunlight to create fuel, glucose and other sugars for building plant structures. This process forms the foundation of the fast carbon cycle.In all four processes, the carbon dioxide released in the reaction usually ends up in the atmosphere.

Answer:

During photosynthesis, plants also absorb carbon dioxide and sunlight to create fuel, glucose, and other sugars for building plant structures. This process forms the foundation of the fast carbon cycle.

Explanation:

hope this helps

pls mark me brainliest

The question is: Calculate the molar fractions of the components of a solution made up of: 250 g of water, 50 g of acetic acid and 25 g of sodium chloride.

Answer: The mole fraction of water, acetic acid and sodium chloride is 0.916, 0.054, and 0.028.

Explanation:

As number of moles is the mass of substance divided by its molar mass.

Therefore, moles of given species are calculated as follows.

The number of moles of water (molar mass = 18 g/mol):

[tex]Moles = \frac{mass}{molar mass}\\= \frac{250 g}{18 g/mol}\\= 13.88 mol[/tex]

The number of moles of acetic acid (molar mass = 60.052 g/mol):

[tex]Moles = \frac{mass}{molar mass}\\= \frac{50 g}{60.052 g/mol}\\= 0.832 mol[/tex]

The number of moles of sodium chloride (molar mass = 58.44 g/mol):

[tex]Moles = \frac{mass}{molar mass}\\= \frac{25 g}{58.44 g/mol}\\= 0.427 mol[/tex]

Therefore, mole fraction of each component is calculated as follows.

Mole fraction of water:

[tex]Mole fraction = \frac{moles of water}{Total moles}\\= \frac{13.88}{13.88 + 0.832 + 0.427}\\= \frac{13.88}{15.139}\\= 0.916[/tex]

Mole fraction of acetic acid:

[tex]Mole fraction = \frac{moles of water}{Total moles}\\= \frac{0.832}{13.88 + 0.832 + 0.427}\\= \frac{0.832}{15.139}\\= 0.054[/tex]

Mole fraction of NaCl:

[tex]Mole fraction = \frac{moles of water}{Total moles}\\= \frac{0.427}{13.88 + 0.832 + 0.427}\\= \frac{0.427}{15.139}\\= 0.028[/tex]

Thus, we can conclude that mole fraction of water, acetic acid and sodium chloride is 0.916, 0.054, and 0.028.

Answer:

hggggggggggggggggggggggggggggggggggggsssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss

Explanation:

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Answer:

electron is the right answer

Answer:

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Answer:

Hello There!!

Explanation:

The answer is b. lonic.

hope this helps,have a great day!!

~Pinky~

Answer:

Explanation:

Answer:

i think that it is C. both

Explanation:

Answer:

the last one

explanation is the white colour

Answer:

The oxygen will occupied 84.7 L.

Explanation:

Ideal gases are a simplification of real gases that is done to study them more easily. It is considered to be formed by point particles, do not interact with each other and move randomly. It is also considered that the molecules of an ideal gas, in themselves, do not occupy any volume.

The pressure, P, the temperature, T, and the volume, V, of an ideal gas, are related by a simple formula called the ideal gas law:  

P*V = n*R*T

where P is the gas pressure, V is the volume that occupies, T is its temperature, R is the ideal gas constant, and n is the number of moles of the gas. The universal constant of ideal gases R has the same value for all gaseous substances.

In this case:

Replacing:

768 mmHg* V= 3.5 mol* 62.36 [tex]\frac{mmHg*L}{mol*K}[/tex] *298 K

Solving:

[tex]V=\frac{3.5 mol*62.36\frac{mmHg*L}{mol*K}*298 K }{768 mmHg}[/tex]

V= 84.7 L

The oxygen will occupied 84.7 L.