What type of reaction does the generalized equation AB-->A+B represent?

Select the correct electron configurations from the list below. You can refer to the periodic table for atomic numbers. Check al

vesna_86 [32]

What’s the list?.......

4 0

3 years ago

Which phase change has more kinetic energy:boiling or melting?

Romashka-Z-Leto [24]

the phase change of boiling has more kinetic energy.

boiling is a liquid ---> gas

melting is solid ---> liquid

in a liquid, there is medium kinetic energy but when a liquid is boiled it turns into a gas and gains more kinetic energy, so there is more movement and the particles move freely as there is high KE.

in a solid, there is low kinetic energy as the particles vibrate in fixed positions. a solid gains kinetic energy when it becomes a liquid (melting) and there is medium kinetic energy.

there is a higher amount of kinetic energy when a substance is boiled.

therefore, the answer is boiling.

5 0

4 years ago

How many seconds does it take to deposit 0.94 g of Ni on a decorative drawer handle when 14.9 A is passed through a Ni(NO3)2 sol

Goshia [24]

Answer:

Time take to deposit Ni is 259.02 sec.

Explanation:

Given:

Current $I = 14.9$ A

Faraday constant $= 96485$ $\frac{C}{mole}$

Molar mass of Ni $= 58.69$ $\frac{g}{mole}$

Mass of Ni $= 0.94$ g

First find the no. moles in Ni solution,

Moles of Ni $= \frac{0.94}{58.69}$

$= 0.02$ mol

From the below reaction,

$Ni^{2+} + 2e$ ⇆ $Ni_{(s)}$

Above reaction shows "1 mol of $Ni^{2+}$ requires 2 mol of electron to form 1 mol of $Ni_{(s)}$ "

So for finding charge flow in this reaction we write,

$=$ $0.02 \times \frac{2 }{1 } \times 96485 \frac{C}{mol}$

Charge flow $= 3859.4$ C

For finding time of reaction,

$I = \frac{q}{t}$

Where $q =$ charge flow

$t = \frac{q}{I}$

$t = \frac{3859.4}{14.9}$

$t = 259.02$ sec

Therefore, time take to deposit Ni is 259.02 sec.

3 0

3 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

3 years ago

What determines the strength of the attraction between molecules?

alexandr402 [8]

To determine strength of attractive forces between the molecules the size of the molecules, their polarity (dipole moment), and their shape. ... If two molecules have about the same size and similar shape, the dipole-dipole intermolecular attractive force increases with increasing polarity.

5 0

3 years ago

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