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4 years ago

Why was it important to polish the copper strips and wire, the coin, and the nail in the electroplating experiment?

Chemistry

1 answer:

Ierofanga [76]4 years ago

7 0

Answer:

You need to have a clean surface for contact between the solution and the material.

Explanation:

The presence of impurity on the surface of the material, and lack of surface uniformity (smoothness) can reduce the effective contact between material and solution and can interfere with the electroplating process's success.

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In an aqueous solution of a certain acid the acid is 0.10% dissociated and the pH is 4.06. Calculate the acid dissociation const

Kruka [31]

Answer : The acid dissociation constant Ka of the acid is, $8.7\times 10^{-5}$

Explanation :

First we have to calculate the concentration of hydrogen ion.

$pH=-\log [H^+]$

Given: pH = 4.06

$4.06=-\log [H^+]$

$[H^+]=8.71\times 10^{-5}M$

The dissociation of acid reaction is:

$HA\rightarrow H^++A^-$

Initial conc. c 0 0

At eqm. c-cα cα cα

Given:

Degree of dissociation = α = 0.10 % = 0.001

$[H^+]=c\alpha$

$8.71\times 10^{-5}=c\times 0.001$

$c=0.0871M$

The expression of dissociation constant of acid is:

$K_a=\frac{[H^+][A^-]}{[HA]}$

$K_a=\frac{(c\times \alpha)\times (c\times \alpha)}{(c-c\alpha)}$

Now put all the given values in this expression, we get:

$K_a=\frac{(0.0871\times 0.001)\times (0.0871\times 0.001)}{(0.0871-0.0871\times 0.001)}$

$K_a=8.7\times 10^{-5}$

Thus, the acid dissociation constant Ka of the acid is, $8.7\times 10^{-5}$

7 0

3 years ago

Help me how to draw this graphhh??ASAPPPP

Aleksandr [31]

Refer to the attachment

7 0

3 years ago

Can anyone help me with the calculations for the Frequency, Wavelength, Energy Chart?

sergeinik [125]

Use the following equations to fill the chart.

E = hf
where
h = 6.63 x 10⁻³⁴ J/s, Planck's constant
f = frequency Hz
E = quanta of energy, J

c = fλ
where
c = 3 x 10⁸ m/s, the velocity of light
λ = wavelength, m

If energy is given in J/mmol, divide by Avogadro's number, N = 6.02 x 10²³, to convert it to J.

The completed table is shown below.

3 0

4 years ago

Both natural products and synthetic products come from natural resources. Explain why this statement is true.

xz_007 [3.2K]

Explanation:

All resources used in making all products can be traced to their natural origin. What differentiates a natural product from a synthetic one is the level of processing that goes into making synthetic products.

For example, a synthetic product such as plastic is actually derived from natural product.
Instead of using the sap of rubber plants for making this product, scientists engineered a way to produce plastics from petroleum products which are derived from crude oil.
Most synthetic products are merely products of alternate source of manufacturing which are well engineered.

5 0

3 years ago

Solids, liquids, and gases are three common states of matter. in which of these physical states would a water molecule likely ha

melamori03 [73]

The States of Matter are classified into solid, liquid, and gas. Among these physical states, if we are going to refer to the water molecules, the one that would possess the greatest energy is gas. If you would take the energy of gas, this would become liquid. The answer is option C.

8 0

3 years ago