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4 years ago

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Plasma spray-coating processes are often used to provide surface protection for materials exposed to hostile environments, which

induce degradation through factors such as wear, corrosion, or outright thermal failure. True or false?

1 answer:

Kisachek [45]4 years ago

6 0

The answer is True.

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The voltage for the following cell is +0.731 V. Find Kb for the organic base RNH2. Use EscE 0.241V.

tino4ka555 [31]

Complete Question

The complete question is shown on the first uploaded image

Answer:

The value is $K_b = 1.89 *10^{-6}$

Explanation:

From the question we are told that

The voltage of the cell is $V = 0.731 \ V$

Generally $K_b$ is mathematically represented as

$K_b = \frac{K_w }{ K_a }$

Where $K_w$ is the equilibrium constant for this auto-ionization of water with a value $K_w = 1.0 *10^{-14}$

Generally the $E_{cell}$ is mathematically represented as

$E_{cell} = V - E_{SCE}$

=> $E_{cell} = 0.731 - 0.241$

=> $E_{cell} = 0.49 V$

This $E_{cell}$ is mathematically represented as

$E_{cell} = \frac{0.0592}{n} * log K_a$

Where n is the number of moles which in this question is n = 1

So

$0.490 = \frac{0.0592}{1} * log K_a$

=> $K_a = 5.30*10^{-9}$

So

$K_b = \frac{ K_w}{ K_a}$

=> $K_b = \frac{1.0 *10^{-14}}{ 5.30*10^{-9}}$

=> $K_b = 1.89 *10^{-6}$

5 0

3 years ago

How many grams do 6.534e+24 molecules of phosphoric acid weigh?

fredd [130]

Answer:

1,063 grams H₃PO₄

Explanation:

To find the mass of phosphoric acid (H₃PO₄), you should (1) convert molecules to moles (via Avogadro's number) and then (2) convert moles to grams (via molar mass from periodic table).

Molar Mass (H₃PO₄): 3(1.008 g/mol) + 30.974 g/mol + 4(15.998 g/mol)

Molar Mas (H₃PO₄): 97.99 g/mol

6.534 x 10²⁴ molecules H₃PO₄ 1 mole 97.99 g
--------------------------------------------- x ------------------------------------- x --------------
6.022 x 10²³ molecules 1 mole

= 1,063 grams H₃PO₄

3 0

2 years ago

Choose all the answers that apply.

vodka [1.7K]

Answer:

9 protons

Explanation:

By looking at the periodic table, you will see that Fluorine has 9 protons. Since the number of electrons equal the number of protons, Fluorine has 9 electrons as well. Meanwhile, it's mass number of 19, minus 10 neutrons, gives you 9 protons or electrons. Hence, the atom would be Fluorine.

hope u make me brainlesst ʘ‿ʘ

4 0

3 years ago

Read 2 more answers

How many grams of al(oh)3 (molar mass = 78.0 g/mol) can be produced from the reaction of 48.6 ml of .15 m koh with excess al2(so

Fudgin [204]

Taking into account the reaction stoichiometry, 0.18954 grams of Al(OH)₃ are formed from the reaction of 48.6 mL (0.0486 L) of 0.15 M KOH with excess Al₂(SO₄)₃.

<h3>Reaction stoichiometry</h3>

In first place, the balanced reaction is:

Al₂(SO₄)₃ + 6 KOH → 2 Al(OH)₃ + 3 K₂SO₄

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

Al₂(SO₄)₃: 1 mole
KOH: 6 moles
Al(OH)₃: 2 moles
K₂SO₄: 3 moles

The molar mass of the compounds is:

Al₂(SO₄)₃: 342 g/mole
KOH: 56.1 g/mole
Al(OH)₃: 78 g/mole
K₂SO₄: 174.2 g/mole

Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:

Al₂(SO₄)₃: 1 mole ×342 g/mole= 342 grams
KOH: 6 moles ×56.1 g/mole= 336.6 grams
Al(OH)₃: 2 moles ×78 g/mole= 156 grams
K₂SO₄: 3 moles ×174.2 g/mole= 522.6 grams

<h3>Definition of molarity</h3>

Molarity is a measure of the concentration of a solute in a solution and indicates the number of moles of solute that are dissolved in a given volume:

Molarity= number of moles÷ volume

<h3>Mass of Al(OH)₃ formed</h3>

In firts place, you know that 48.6 mL (0.0486 L) of 0.15 M KOH react with excess Al₂(SO₄)₃.

Replacing in the definition, you can calculate the amount of moles of KOH that react:

0.15 M= number of moles÷ 0.0486 L

Solving:

0.15 M× 0.0486 L= number of moles

<u><em>0.00729 moles= number of moles</em></u>

Then, 0.00729 moles of KOH react with excess Al₂(SO₄)₃. So, following rule of three can be applied: if by reaction stoichiometry 6 moles of KOH form 156 grams of Al(OH)₃, 0.00729 moles of KOH form how much mass of Na₂SO₄?

$mass of Al(OH)_{3} =\frac{0.00729 moles of KOHx156 grams of Al(OH)_{3}}{6 moles of KOH}$

<u><em>mass of Al(OH)₃= 0.18954 grams</em></u>

Then, 0.18954 grams of Al(OH)₃ are formed from the reaction of 48.6 mL (0.0486 L) of 0.15 M KOH with excess Al₂(SO₄)₃.

Learn more about

the reaction stoichiometry:

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molarity:

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4 0

2 years ago

How many liters of a 2.0 M solution of HCl do you need to have 8.0 moles of HCI?

kakasveta [241]

Answer:

1M HCl: add 1mol/12M = 83 ml conc. HCl to 1L of water or 8.3ml to 100ml.

2M HCl: add 2mol/12M = 167 ml conc. HCl to 1L of water or 16.7ml to 100ml.

4 0

3 years ago