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3 years ago

Which of the following happens during a chemical reaction?

Chemistry

2 answers:

Lana71 [14]3 years ago

5 0

C. atoms of reactants rearrange to form new substances

meriva3 years ago

5 0

Answer: Option (c) is the correct answer.

Explanation:

A chemical reaction is defined as the reaction that leads to formation of new substances through exchange of electrons.

For example, $2Al + 3CuCl_{2} \rightarrow 2AlCl_{3} + 3Cu$

Here, aluminium on displacing copper from copper chloride leads to the formation of a new compound, that is, aluminium chloride.

Hence, it shows that atoms of reactant molecules rearrange themselves to form new substances.

Thus, we can conclude that during a chemical reaction atoms of reactants rearrange to form new substances .

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According to de Broglie, which of these objects does not have a wavelength?

polet [3.4K]

Answer: Option D is correct.

Explanation: Equation given by de Broglie is:

$\lambda =\frac{h}{mv}$

where, $\lambda$ = wavelength of the particle

h = Planck's constant

m = mass of the particle

v = velocity of the particle

In option A, football will have some mass and is moving with a velocity of 25 m/s, hence it will have some wavelength.

In Option B, unladen swallow also have some mass and is moving with a velocity of 38 km/hr, hence it will also have some wavelength.

In Option C, a person has some mass and is running with a velocity of 7 m/hr, hence it will also have some wavelength.

As, the momentum of these particles are large, therefore the wavelength will be of small magnitude and hence, is not observable.

From the above, it is clearly visible that all the options are having some wavelength, so option D is correct.

7 0

2 years ago

If you have access to stock solutions of 1.00 M H3PO4, 1.00 M of HCl, and 1.00 M NaOH solution, (and distilled water of course),

garri49 [273]

Answer:

0.10L of 1.00M of H₃PO₄ and 0.1613L of 1.00M NaOH

Explanation:

The pKa's of phosphoric acid are:

H₃PO₄/H₂PO₄⁻ = 2.1

H₂PO₄⁻/HPO₄²⁻ = 7.2

HPO₄²⁻/PO₄³⁻ = 12.0

To make a buffer with pH 9.40 we need to convert all H₃PO₄ to H₂PO₄⁻ and an amount of H₂PO₄⁻ to HPO₄²⁻

To have a 50mM solution of phosphoures we need:

2L * (0.050mol / L) = 0.10 moles of H₃PO₄

0.10 mol * (1L / mol) = 0.10L of 1.00M of H3PO4

To convert the H₃PO₄ to H₂PO₄⁻ and to HPO₄²⁻ must be added NaOH, thus:

H₃PO₄ + NaOH → H₂PO₄⁻ + H₂O + Na⁺

H₂PO₄⁻ + NaOH → HPO₄²⁻ + H₂O + Na⁺

Using H-H equation we can find the amount of NaOH added:

pH = pKa + log [A⁻] / [HA] (1)

Where [A-] is conjugate base, HPO₄²⁻ and [HA] is weak acid, H₂PO₄⁻

pH = 7.40

pKa = 7.20

[A-] + [HA] = 0.10moles (2)

Replacing (2) in (1):

7.40 = 7.20 + log 0.10mol - [HA] / [HA]

0.2 = log 0.10mol - [HA] / [HA]

1.5849 = 0.10mol - [HA] / [HA]

1.5849 [HA] = 0.10mol - [HA]

2.5849[HA] = 0.10mol

[HA] = 0.0387 moles = H₂PO₄⁻ moles

That means moles of HPO₄²⁻ are 0.10mol - 0.0387moles = 0.0613 moles

The moles of NaOH needed to convert all H₃PO₄ in H₂PO₄⁻ are 0.10 moles

And moles needed to obtain 0.0613 moles of HPO₄²⁻ are 0.0613 moles

Total moles of NaOH are 0.1613moles * (1L / 1mol) = 0.1613L of 1.00M NaOH

Then, you need to dilute both solutions to 2.00L with distilled water.

4 0

2 years ago

The sum of the potential energy and the kinetic energy of an object is its thermal energy. True or false?

liq [111]

Answer:

false

Explanation:

4 0

2 years ago

Read 2 more answers

QUESTION 2

Aleksandr [31]

Answer:

you can see the answer at the pic

4 0

2 years ago

Identify three nonmetal atoms that, when bonded covalently, have an argon electron configuration.

Advocard [28]

Answer:

Phosphorus

Sulphur

And chlorine are non metals when bonded covalently gain electronic configuration of argon

Like PCl3

SO2 and HCl

Explanation:

8 0

2 years ago