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3 years ago

What is true about energy in an ordinary chemical reaction? Energy is

Chemistry

2 answers:

Mila [183]3 years ago

5 0

Answer: third choice, not created or destroyed.

Explanation:

1) During a chemical reaction energy is not either created or destroyed. It is only transferred and the total amount of energy remains constant.

2) That is the first law of thermodynamics, which means that it is a universal true and is verified in any process either chemical or physical.

3) Of course we constantly experience that some form of energy that we observe "dissapears". Well it does not. It is just transformed into other form of energy.

4) In the case of the chemical reactions, whe usually observe that in the form of heat: for example when H₂ reacts with O₂ to form H₂O a considerable amount of heat evolves. That is because potential chemical energy in the bonds of the reactants (O₂ and H₂) is released, this is, some potential chemica energy is transformed into heat and part of the chemical potential energy is in the product bonds.

That is why you can write the expression:

ΔH rxn = ∑ΔH products - ∑ΔH reactants, or

∑ΔH products = ΔH rxn + ∑ ΔH reactants.

Which you must interpret as that the energy of the reactants ends up as energy on the products or heat released by the reaction.

RSB [31]3 years ago

3 0

Energy is not created or destroyed due to the law of Conservation of Energy. Hope this helps!

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If the prescribed dosage of milk of magnesia Mg(OH)2 is 3.5 moles, how many grams

OlgaM077 [116]

Answer:

Explanation:

1 mole is equal to 58.31968 grams.

so 3.5 moles equal to answer choice B

3 0

3 years ago

Before entering the cyclotron, the particles are accelerated by a potential difference V. Find the speed v with which the partic

vesna_86 [32]

Answer:

Speed, $v=\sqrt{\dfrac{2qV}{m}}$

Explanation:

The device which is used to accelerate charged particles to higher energies is called a cyclotron. It is based on the principle that the particle when placed in a magnetic field will possess a magnetic force. Just because of this Lorentz force it moves in a circular path.

Let m, q and V are the mass, charge and potential difference at which the particle is accelerated.

The work done by the particles is equal to the kinetic energy stored in it such that,

$qV=\dfrac{1}{2}mv^2$

v is the speed with which the particles enter the cyclotron

So,

$v=\sqrt{\dfrac{2qV}{m}}$

So, the speed with which the particles enter the cyclotron is $v=\sqrt{\dfrac{2qV}{m}}$ . Hence, this is the required solution.

7 0

3 years ago

I need help in thiss

Papessa [141]

I know CL is chlorine and NA is sodium.

8 0

2 years ago

Please fill this formula

Maurinko [17]

1.) Na
2.) Cl ( at the second blank)
sodium metal+hydrochloric acid

3 0

2 years ago

The equilibrium concentrations of the reactants and products are [HA]=0.280 M, [H+]=4.00×10−4 M, and [A−]=4.00×10−4 M. Calculate

Tems11 [23]

Answer:

6.24

Explanation:

The following data were obtained from the question:

Concentration of HA, [HA] = 0.280 M,

Concentration of H+, [H+] = 4×10¯⁴ M

Concentration of A-, [A−] = 4×10¯⁴ M

pKa =.?

Next, we shall write the balanced equation for the reaction. This is given below:

HA <===> H+ + A-

Next, we shall determine the equilibrium constant Ka for the reaction. This can be obtained as follow:

Equilibrium constant for a reaction is simply the ratio of concentration of the product raised to their coefficient to the concentration of the reactant raised to their coefficient.

The equilibrium constant for the above equation is given below:

Ka = [H+] [A−] /[HA]

Concentration of HA, [HA] = 0.280 M,

Concentration of H+, [H+] = 4×10¯⁴ M

Concentration of A-, [A−] = 4×10¯⁴ M

Equilibrium constant (Ka) =

Ka = (4×10¯⁴ × 4×10¯⁴) / 0.280

Ka = 1.6×10¯⁷/ 0.280

Ka = 5.71×10¯⁷

Therefore, the equilibrium constant for the reaction is 5.71×10¯⁷

Finally, we shall determine the pka for the reaction as follow:

Equilibrium constant, Ka = 5.71×10¯⁷

pKa =?

pKa = – Log Ka

pKa = – Log 5.71×10¯⁷

pKa = 6.24

Therefore, the pka for the reaction is 6.24.

6 0

3 years ago