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jeyben [28]
3 years ago
12

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]3 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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Chromium(III) oxide reacts with hydrogen sulphide gas to form chromium(III) sulphide and water. How many grams of hydrogen sulph
ahrayia [7]

Answer:

165.726 g.

Explanation:

  • For the balanced equation:

<em>Cr₂O₃ + 3H₂S → Cr₂S₃ + 3H₂O,</em>

It is clear that 1 mol of Cr₂O₃ and 3 mol of H₂S to produce 1 mol of Cr₂S₃ and 3 mol of H₂O.

  • Firstly, we need to calculate the no. of moles of 324.8 g of chromium(III) sulphide:

no. of moles of Cr₂S₃ = mass/molar mass = (324.8 g)/(200.19 g/mol) = 1.62 mol.

  • Now, we can find the "no. of grams" of H₂S are needed:

<u><em>Using cross multiplication:</em></u>

3 mol of H₂S produces → 1 mol of Cr₂S₃, from stichiometry.

??? mol of H₂S produces → 1.62 mol of Cr₂S₃.

∴ The no. of moles of H₂S are needed = (3 mol)(1.62 mol)/(1 mol) = 4.86 mol.

∴ The "no. of grams" of H₂S are needed = (no. of moles of H₂S)(molar mass of H₂S) = (4.86 mol)(34.1 g/mol) = 165.726 g.

7 0
3 years ago
Balance the equation <br><br> __Ni(CIO)3 → _NiCl2+ _02
lora16 [44]
The answer is 1, 1 , 1 because that will balance out the equation and make them equal
3 0
3 years ago
What is the definition of plate tectonics?
zhuklara [117]

The definition from what I know because I remember it from biology I think is "a theory explaining the structure of the earth's crust and some other associated phenomena as resulting from the interaction of a rigid lithospheric plates that move slowly over the underlying mantle." I'll put the quotations for you to copy what I said so it doesn't sound like you got it off me and I hopefully spelt lithospheric right

6 0
3 years ago
Read 2 more answers
The rate constant of a reaction is measured at different temperatures. A plot of the natural log of the rate constant as a funct
Wittaler [7]

Answer:

The activation energy is 7.11 × 10⁴ J/mol.

Explanation:

Let's consider the Arrhenius equation.

lnk=lnA-\frac{Ea}{R} .\frac{1}{T}

where,

k is the rate constant

A is a collision factor

Ea is the activation energy

R is the ideal gas constant

T is the absolute temperature

The plot of ln k vs 1/T is a straight line with lnA as intercept and -Ea/R as slope. Then,

\frac{-Ea}{R} =-8.55 \times 10^{3} K^{-1} \\Ea= 8.55 \times 10^{3} K^{-1} \times 8.314 \frac{J}{K.mol} =7.11 \times 10^{4} J/mol

8 0
3 years ago
What is an isotope? list the isotopes of hydrogen in order from lighter to heavier. which is the most common among them?
malfutka [58]
Isotopes= a group of atoms with the same no. of protons , but different no. of neutrons

Hydrogen isotopes

^1H\implies ^2H\implies ^3H

The name of the second isotope is deuterium and the name of the third isotope is tritium(radioactive).The most abundant isotope is ^1H
6 0
3 years ago
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