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3 years ago

Which of the following is NOT true about one mole?

1 answer:

7 0

The option in “the mass of 1me of carbon equals the mass of 1 mole of boron atoms” is false since

Mass=molesx molar mass

And the molar masses of these two elements are different so their masses aren’t equal

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Phosphorus pentachloride decomposes to phosphorus trichloride at high temperatures according to the equation:

weqwewe [10]

Answer:

D) [PCl5]=0.00765M,[PCl3]=0.117M,and [Cl2]=0.0.117M

Explanation:

Based on the reaction:

PCl₅(g) ⇄ PCl₃(g) + Cl₂(g)

And knowing:

Kc = [PCl₃] [Cl₂] / [PCl₅] = 1.80

When you add PCl₅ into a flask, this gas will react producing PCl₃ and Cl₂ until [PCl₃] [Cl₂] / [PCl₅] = 1.80

This could be written as:

[PCl₃] = X

[Cl₂] = X

[PCl₅] = 0.125M - X

<em>Where X represents the moles of PCl₅ that react, </em><em>reaction coordinate.</em>

Replacing in Kc expression:

[PCl₃] [Cl₂] / [PCl₅] = 1.80

[X [X] / [0.125 - X] = 1.80

X² = 0.225 - 1.80X

0 = -X² -1.80X + 0.225

Solving for X:

X = -1.9M → False solution, there is no negative concentrations

X = 0.11735M → Right solution.

Replacing, concentrations in equilibrium are:

[PCl₃] = X

[Cl₂] = X

[PCl₅] = 0.125M - X

[PCl₃] = 0.117M

[Cl₂] = 0.117M

[PCl₅] = 0.00765M

And right option is:

7 0

3 years ago

If i increase the [h+] of a solution by 10x, how much will the ph change? and in what direction will ph change?

igomit [66]

For example...
You have solution with [H+] = 0,01M
>>>> pH = -log[H+] = -log0,01 = 2

And you increase the [H+] by 10x ---> 0,01×10 = 0,1M
>>>> pH = -log0,1 = 1

○ pH decrease by 2x
○ pH is more acidic

4 0

3 years ago

T/F___ At the eutectic composition, an alloy can solidify at a constant temperature.___ For effective dispersion strengthening,

azamat

Answer:

TRUE
FALSE
TRUE
FALSE
FALSE
TRUE

Explanation:

At the eutectic composition, an alloy can solidify at a constant temperature : TRUE . this is because at eutectic composition the type of reaction that takes place there is invariant reaction in its thermal equilibrium
For effective dispersion strengthening, the dispersed phase should be needle-like, as opposed to round : FALSE. because the rounded shape will not cause a crack.
Intermetallic compounds are usually hard and brittle : TRUE. because Intermetallic compounds prevents dislocation movements and this makes them brittle and hard
For the effective dispersion and strengthening, the dispersed phase should be continuous : FALSE. this is because the dispersed precipitate must be small and not continuous
Stoichiometric intermetallic compounds exist over a range of compositions : FALSE
Faster solidification results in smaller interlamellar spacing : TRUE

4 0

3 years ago

Rust is a compound with the formula F e 2 O 3 . Which elements combine to form rust?

DanielleElmas [232]

Remembering the periodic table, Fe is iron and O is oxygen. The elements that combine to create rust are iron and oxygen, with the chemical compound being (Iron)2(Oxygen)3.

5 0

3 years ago

Read 2 more answers

The atomic number of nitrogen is 7. How many protons, neutrons, and electrons make up an atom of Nitrogen-15?

earnstyle [38]

<h2><u>Answer:</u></h2>

A nonpartisan iota of Nitrogen has a mass of 18. There are 7 protons in the core of this iota. What number of neutrons, complete electrons, and valence electrons are available

Nitrogen 15 has a nuclear mass of 15. The mass number is # protons in addition to # of neutrons, so for N-15 mass is 15 and the protons are dependably 7 so there must be 15-7=8 neutrons. N-15 has 7 electrons since it has 7 protons and p = e.

6 0

3 years ago