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3 years ago

How does the appearance of a substance change when it changes phase?

Chemistry

1 answer:

kicyunya [14]3 years ago

6 0

Answer:

Melting: the substance changes back from the solid to the liquid. Condensation: the substance changes from a gas to a liquid. Vaporization: the substance changes from a liquid to a gas. Sublimation: the substance changes directly from a solid to a gas without going through the liquid phase.

Explanation:

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For the following electron-transfer reaction:

creativ13 [48]

Answer:

1. The oxidation half-reaction is: Mn(s) ⇄ Mn²⁺(aq) + 2e⁻

2. The reduction half-reaction is: Ag⁺(aq) + 1e⁻ ⇄ Ag(s)

Explanation:

Main reaction: 2Ag⁺(aq) + Mn(s) ⇄ 2Ag(s) + Mn²⁺(aq)

In the oxidation half reaction, the oxidation number increases:

Mn changes from 0, in the ground state to Mn²⁺.

The reduction half reaction occurs where the element decrease the oxidation number, because it is gaining electrons.

Silver changes from Ag⁺ to Ag.

1. The oxidation half-reaction is: Mn(s) ⇄ Mn²⁺(aq) + 2e⁻

2. The reduction half-reaction is: Ag⁺(aq) + 1e⁻ ⇄ Ag(s)

To balance the hole reaction, we need to multiply by 2, the second half reaction:

Mn(s) ⇄ Mn²⁺(aq) + 2e⁻

(Ag⁺(aq) + 1e⁻ ⇄ Ag(s)) . 2

2Ag⁺(aq) + 2e⁻ ⇄ 2Ag(s)

Now we sum, and we can cancel the electrons:

2Ag⁺(aq) + Mn(s) + 2e⁻ ⇄ 2Ag(s) + Mn²⁺(aq) + 2e⁻

4 0

3 years ago

How many miles of lead are equal to 9.51 x 10^3 g Pb?

Lemur [1.5K]

Molar mass Pb = 207.2 g/mol

1 mole Pb ------------- 207.2
? mole Pb ------------ 9.51 x 10³

moles = 9.51 x 10³ * 1 / 207.2

moles = 9.51 x 10³ / 207.2

= 45.89 moles

hope this helps!

7 0

3 years ago

A sample of water at 100°C is converted to steam after absorbing 820 kJ of heat. How grams of H2O are contained in the sample? A

Varvara68 [4.7K]

Since water is already at 100<span>°C all the energy is used to evaporate it.
Now we can calculate how many </span>mols of water are evaporated with 820kJ.
$N= \frac{820}{41} =20 mol$
We calculated that we got 20 mols of water evaporated. Now, all we have to do is find how many grams is a mol of water. Molar mass of water is <span>20.16 g/mol.
</span>The final answer is:
$m=20*20.16=403.2g$

7 0

3 years ago

Use the drop-down menus to label each of the following changes P for physical change and C for the chemical change. The substanc

dlinn [17]

Answer:

Chemical, Physical, Chemical, Chemical, Physical!!

Explanation:

I just did it correctly.

6 0

2 years ago

Read 2 more answers

Fill in the blank Cells break down sugar and release ___________ into the plant.

katrin2010 [14]

Answer:

oxygen

Explanation:

8 0

2 years ago