Use the reaction and bond information to answer the question. H2 CO2 → CH2O2 Reactant bond energies: H–H is 432 kJ/mol, C=O is 799 kJ/mol Product bond energies: C–H is 413 kJ/mol, C=O is 745 kJ/mol, C–O is 358 kJ/mol, O–H is 467 kJ/mol How much energy must this system absorb before the reaction can begin?.

(a) The heat generated in the process is 28 kJ.

(b) The work done in the process is determined as -28 kJ.

(c) The change in the internal energy is 0.

The heat generated in the process is negative done in the process.

W = -PΔV

W = -P(V₂ - V₁)

W = -P(VB - VA)

W = -11(7 - 12.5)

W = 60.5 L.atm = 60.5 x 101.325 J/L.atm = 6,130.16 J

W = -25(20.5 - 7)

W = -337.5 L.atm = -34,197.18 J

Total work , w = -34,197.18 J +  6,130.16 J = -28 kJ

q = - w

q = 28 kJ

ΔE = q + w

ΔE = 28 kJ - 28 kJ = 0

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.we can read the chemical preparation of the reaction as: "4 g of hydrogen react with 32 g of oxygen to give 36 g of water".   :)

Answer:

H2 PO4 -1 is the correct answer

An acid and a base which differ from each other by a proton are said to form a conjugate pair. Here the conjugate base of H₃PO₄ is H₂PO₄⁻. The correct option is C.

The entity produced when acid gives up a proton has a tendency to regain the proton and hence it behaves as a base. It is called the conjugate base of the parent acid. A base is a substance which acts as a proton acceptor.

Here the conjugate base of H₃PO₄ is formed when a proton is lost from it. So the lose of one proton forms the molecule H₂PO₄⁻ which is the conjugate base. An acid is a proton donor.

When a base accepts a proton it has a tendency to donate the proton and hence behaves as an acid. It is called the conjugate acid of the parent base.

Thus the correct option is C.

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Answer:

B. Can only be concave

Explanation:

Statement A is false because lenses do not reflect light. Lenses do have an optical axis.

Answer:

Explanation:

4NH₃ (g) + 3O₂ (g) ⇒ 2N₂ (g) + 6H₂ O(1)

Δ[tex]H_r={\sum}{ \Delta }H_f(\text{product})-{\sum}{ \Delta }H_f(\text{reactant})[/tex]

ΔH r =(2ΔH f(N 2 )+6ΔH f (H 2 O(l)))−(4ΔH f​ (NH 3 (g))+3ΔH f (O 2 (g)))

ΔH rex =[2×0+6×(−286)]−[4×(−46)+3×0]=−1716+186

ΔH rex =−1532kJ/mol

Thermodynamics is a branch of physical chemistry that studies heat and its effects and interactions. Governed by the four main laws, thermodynamics plays a huge role in physics and chemistry, and is also responsible for the law of conservation of energy, a fundamental rule in science.

Answer:

The speed of light is the speed at which light travels. No, an object cannot move at the speed of light.  

Explanation:

The speed of light is 186,000 miles per second. An object with mass cannot move at the speed of light since it would take an infinite amount of energy to achieve that velocity, since only massless particles can travel at the speed of light. Also, you would have to factor in air friction, meaning even if an object were to reach such high speeds, it would instantly disintegrate.

Answer:

O One system must have higher kinetic energy than the other system.

Explanation:

Higher KE of the system means hotter......the hotter will transfer heat to the cooler by conduction when they are in contact.

Answer:

675g

Explanation:

The equation that relates mass, density and volume is:

Density = mass ÷ volume

By rearranging the equation we can find the mass of the cube.

Mass = density × volume

Mass = 45 × 15

∴ Mass = 675 grams

Answer: B. Grams liquid x mol/g x A Hvap

Stoichiometry used to calculate energy absorbed when a mass of liquid boils is Grams liquid × mol/g × ΔHvap.

It is the amount of heat evolved when mole of liquid is boiled to form vapours. It is a function of pressure according to which the change will happen in the reaction.

Given is that a particular mass of liquid is boiling.

We have supposed that heat of vapourisation for the same liquid is ΔHvap mol/g. Now if ΔHvap is the heat for 1 mole per gram of the liquid then if the mass of liquid is given,

Energy absorbed can be calculated as = Grams liquid × mol/g × ΔHvap

We should know that when a liquid boils it transforms into gaseous state and the process is called as Vapourisation.

Therefore, Stoichiometry used to calculate energy absorbed when a mass of liquid boils is Grams liquid × mol/g × ΔHvap.

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Explanation:

 On the basis of electrical conductivity, materials are classified as conductors, semi-conductors and non-conductors. Conductors : Substances through which electricity can easily pass through are known as conductors. For example, copper, silver, mercury etc are good conductors of electricity

Answer:

Explanation:

The organic product formed in the reaction shown in the image would be bromoethane.

Alkanes, such as ethane undergoes a substitution reaction with halogens such as bromine to produce haloethanes.

For example, the equation of the reaction between ethane and bromine water is as below:

[tex]C_2H_6 + Br_2 --- > C_2H_5Br + HBr[/tex]

The products formed are bromoethane and hydrobromic acid.

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Answer: Products have a higher total potential energy than the reactants.

Explanation:

During endothermic reactions, energy is absorbed, meaning that the products will have more potential energy.

Answer:

You will typically get another chance to retake the exam

Answer:

well you either have a chance to retake the test if your teacher or just not let you take it at all. you have to pass 4 regents test including chemistry in order to get a regent diploma. so you can either retake or it you just failed it.

Answer:

It represents the number of atoms of that particular element present in the compound. In C₂H₄O₂ there are 2 Carbon atoms, 4 Hydrogen atoms and 2 Oxygen atoms.

Answer: Scientists make designs based on engineering knowledge and

then make it available for public use.

Answer:

See below

Explanation:

Boiling point of water is 100 C

 this substance is higher boiling point and the molecules are likely with higher e-static forces

The unknown substance has a higher boiling point than water, and it has stronger electrostatic forces between its molecules than water. Therefore, option B is correct.

Boiling point is a measure of the temperature at which a substance changes from a liquid to a gas phase. Substances with higher boiling points generally have stronger intermolecular forces, such as hydrogen bonding or stronger dipole-dipole interactions.

Since the boiling point of the unknown substance is higher than that of water (which boils at 100°C), it suggests that the unknown substance likely has stronger electrostatic forces between its molecules compared to water.

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The combined reaction is exothermic , with the heat of reaction as -206.7 kJ

A reaction in which energy is liberated when reactants react to form products , The energy level of the reactant is more than that of the products.

The energy is liberated in the form of heat.

In the question it is given that

The energy changes in two partial reactions are 225.3 kJ and -432.0 kJ

The combined reaction is exothermic.

For the reaction to be exothermic the value of the heat of the reaction must be negative.

Summing the two energy changes will give us the heat of the combined reaction.

225.3 - 432.0

= -206.7 kJ

The combined reaction is exothermic , with the heat of reaction as -206.7 kJ.

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Answer:

synthesis reaction

Explanation:

please mark me as brainlest

From the mechanism shown, the major product of the reaction is (S)-(+)-2-octanol.

An SN2 reaction is one in which there is an inversion of configuration and the attack of the nucleophile occurs from behind the substrate.

As shown in the mechanism attached here, the major product of this reaction is (S)-(+)-2-octanol.

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Answer:

C

Explanation:

Recall that, at equilibrium, the concentration of the reactants and products stop changing because both the forward and reverse reaction rates are equal.

Therefore, Choice C is correct.

Choice A is incorrect because there is no indication that the upper line describes the products and the lower line describes the reactants.

Choice B is incorrect because the statement, while true, is not reflected by the graph. (The two lines after equilibrium are not at the same y-value.)

Choice D is incorrect because the forward reaction rate generally decreases as time increases due to the decrease in reactant concentration(s).

Answer:

2C2H6 + 7O2 ==> 4CO2 + 6H2O

When dealing with gases, it is possible to use liters and mols interchangeably.

So 4.00 L C2H6 x (7 mols O2/2 mols C2H6) = 4.00 x 7/2 = ? L O2

Explanation:

Answer:

3150.5g

Explanation:

1 mole of nitric acid weighs 63.01g

so i did 63.01g times 50.0g which equals 3150.5g

g= Grams

Hope This Helped

Answer:

0.79 moles

Explanation:

Formula :

Number of moles = Weight of substance / molecular mass

=============================================================

Here :

⇒ Weight of HNO₃ = 50 g

⇒ Molecular mass = 63 g

============================================================

Solving :

⇒ Number of moles = 50/63

⇒ Number of moles = 0.79 moles

The pH of the buffer solution after the addition of sulfuric acid is determined as 4.43.

The initial moles of acid and base conjugate is determined as follows;

n = CV

na₁ = (150 x 1.1341)/1000

na₁ = 0.17 mol

nb₁ = (100 x 0.831)/1000

nb₁ = 0.083 mol

H₂SO4  ⇄ 2H²⁺  + SO₄²⁻

na₂ = (10 x 0.01)/1000

na₂ = 0.0001 mol

nb = 0.083 - 2(0.0001) = 0.0829 mol

na = 0.17 + 2(0.0001) = 0.1702 mol

[tex]Ka = \frac{[CH_3COO][H^+]}{[CH_3COOH]} \\\\1.8\times 10^{-5} = \frac{0.0829(H^+)}{0.1702} \\\\H^+ = \frac{(1.8 \times 10^{-5})(0.1702)}{0.0829} \\\\H^+ = 3.696 \times 10^{-5}\\\\pH = -Log [H^+]\\\\pH = -Log (3.696 \times 10^{-5})\\\\pH = 4.43[/tex]

Thus, the pH of the buffer solution after the addition of sulfuric acid is determined as 4.43.

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Taking into account the definition of dilution, 227.5 mL of the 0.20 M solution is needed to prepare 455 mL of the diluted NaOH.

Dilution is the process of reducing the concentration of solute in solution, which is accomplished by simply adding more solvent to the solution at the same amount of solute.

In a dilution the amount of solute does not change, but as more solvent is added, the concentration of the solute decreases, as the volume (and weight) of the solution increases.

A dilution is mathematically expressed as:

Ci×Vi = Cf×Vf

where

In this case, you know:

Replacing in the definition of dilution:

0.20 M× Vi= 0.10 M× 455 mL

Solving:

(0.10 M× 455 mL)÷ 0.20 M= Vi

227.5 mL= Vi

In summary, 227.5 mL of the 0.20 M solution is needed to prepare 455 mL of the diluted NaOH.

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Answer:

1.) 2 molecules

2.) 4 H atoms, 2 S atoms, 2 O atoms

3.) 8 total atoms

Explanation:

1.) 2 H₂SO

--------> The molecule is all of the elements bonded together (H₂SO). Because there is a coefficient of 2 in front of the molecule, this means that there are 2 molecules present.

2.) 2 H₂S₁O₁

---------> The number of atoms of each element is determined by the subscripts and the coefficients. In one molecule, there is one oxygen, one sulfur, and 2 hydrogen atoms (denoted by subscripts). Because there are two molecules, these values are doubled.

3.)

--------> The total number of atoms is calculated by adding the number of atoms of each element. If between 2 molecules there are 4 hydrogens, 2 sulfurs, and 2 oxygens, combined there would be a total of 8 atoms.

Answer:

M=93.5g/mol

Explanation:

I did this in class and it was a review. :)

Answer:

31°C

Explanation:

Using the ratio, we can find the temperature of the gas at 705mm.

 725mm : 32°C

 705mm : x

[ x is the temperature we have to find ]

Cross multiply the ratios.

 725x = 705 × 32

 725x = 22560

 x = [tex]\frac{22560}{725}[/tex] = 31°C

Answer:

carbonhydrates, fats and ptoteins

Answer:3 carbohydrates, fats, and proteins

Explanation: