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3 years ago

Which of the following lists includes only molecules?

Chemistry

1 answer:

siniylev [52]3 years ago

5 0

We are unable to see any list? Can you provide one?

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When used as pure gases for welding ferrous metals, ____ may produce an erratic arc action, promote undercutting, and result in

kvv77 [185]

Answer:

argon and helium

Explanation:

Argon and Helium is belongs to noble gas. Since novel gases are completely filled outer orbital. therefore they are erratic nature. Hence, noble gas are very stable as it neither except electron nor it denote due to it paired of electronic configuration.

Depending on the materials being welded, these atmospheric gases react with welding area and either it reduces the quality of the weld or make the welding more difficult.

Therefore, to protect welding area from atmospheric gases noble gases which are small in size are used.

Thus, argon and helium are used.

4 0

1 year ago

How to set up the rate expressions for the following mechanism?

Anestetic [448]

Answer:

Explanation:

From the given information:

A → B k₁

B → A k₂

B + C → D k₃

The rate law = $\dfrac{d[D]}{dt}=k_3[B][C] --- (1)$

$\dfrac{d[B]}{dt}=k[A] -k_2[B] -k_3[B][C]$

Using steady-state approximation;

$\dfrac{d[B]}{dt}=0$

$k_1[A]-k_2[B]-k_3[B][C] = 0$

$[B] = \dfrac{k_1[A]}{k_2+k_3[C]}$

From equation (1), we have:

$\mathbf{\dfrac{d[D]}{dt}= \dfrac{k_3k_1[A][C]}{k_2+k_3[C]}}$

when the pressure is high;

k₂ << k₃[C]

$\dfrac{d[D]}{dt} = \dfrac{k_3k_1[A][C]}{k_3[C]}= k_1A \ \ \text{first order}$

k₂ >> k₃[C]

$\dfrac{d[D]}{dt} = \dfrac{k_3k_1[A][C]}{k_2}= \dfrac{k_1k_3}{k_2}[A][C] \ \ \text{second order}$

3 0

3 years ago

1. Which of the combinations in the lab activity had indications that a chemical change occured? Defend your argument with evide

ArbitrLikvidat [17]

Answer:The green growing on the penny of copper and the rust forming on the nail of iron are chemical changes. Boiling away salt water, scraping iron filings from a mixture of sand with a magnet, and breaking a rock with a hammer, are physical changes.

Explanation:

4 0

3 years ago

Nal+ pb(SO4) 2 Pbl4 + Na2SO4 explain how to balance the chemical equation and classify its reaction type

Pani-rosa [81]

Explanation:

because there are 4 Iodines on the left, we'll put. 4 in front of NaI to balance it. This would result in 4 Na on the left, so we'll put a 2 in front of Sodium Sulfate to balance the right side. Now we have 4 Na and I on both side, as well as 2 Sulfate on both sides. Pb is already balanced. The equation is now complete.