All categories

3 years ago

20. The mass of one mole of lead (Pb) atoms is 207.2 g. Use a proportion to calculate the n

Chemistry

1 answer:

AnnZ [28]3 years ago

8 0

Answer:

a) atoms Pb = 4.3595 E22 amu

b) g = ( 6.022 E23 amu ) × ( Mw )

Explanation:

m Pb = 207.2 g / mol Pb

sample:

∴ m = 15.00 g

a) atoms Pb = ?

1 mol ≡ 6.022 E23 amu

⇒ atoms Pb = (15.00g Pb)(mol Pb/207.2 g)(6.022 E23 amu/mol)

⇒ atoms Pb = 4.3595 E22 amu

b) relationship:

∴ 1 mol (n) ≡ 6.022 E23 amu......(1)

∴ mass (g) ≡ (Mw)×(n)

⇒ n = g / Mw..........(2)

∴ Mw: molecular weight

(1) = (2):

⇒ g / Mw ≡ 6.022 E23 amu

⇒ g ≡ ( 6.022 E23 amu ) × ( Mw )

You might be interested in

Identify the molecular shape of each Lewis structure.

saw5 [17]

Panel One

Trigonal Planar: This is in the shape of a triangle. It is an equilateral triangle with three equal atoms/ions at each corner of the triangle. The most well known example is a molecule with Boron at the center and the corner molecules some like Florine or iodine.

Trigonal Planar is the second Lewis Diagram from the right.

The uploaded picture is the second from the left.

==========

Tetrahedral (Second Lewis Diagram from the left) is something like a pyramid except that that the base is triangular as are each of the faces. The carbon is in the center and the chlorines (in this example) are each in a corner. If this made of just carbon (like diamond or anthracite coal) then you are talking about something that is extremely hard. It's the first upload on the left.

=====================

The Trigonal pyramid is the first Lewis Diagram on the left. It usually has an unattached pair of electrons. Nitrogen or Phosphorous are ususally the samples in the center. The nitrogen with its unused paired electrons are at the peak of blue sphere in the diagram that is uploaded second from the right.

======================

The Bent one is first lewis diagram on the right. It bends because of the unbalance (and double bonds) away from the nitrogen. Water looks something like that. Water is an example of Bent.

The upload is first on the right. These diagrams help you visulize what the various molecules look like

Summary of Lewis Diagrams.

From Left to right on the diagrams you gave me.

Trigonal Pyramidal

Tetrahedral

Trigonal Planar

Bent

Summary of uploaded diagrams.

From Left to right

Tetrahedral

Trigonal Planar

Trigonal Pyramidal

Bent

Problem Two

The very quick answer is E. Water is a bent molecule. It is flat. It has a very definite (+) end and a very definite (-) end. The marriage of a plus end with a minus is a very long lasting relationship. It is not the strongest bond in the world, but it is strong enough to create all the properties that the stem of the question has listed. [High melting and boiling points and high surface tension.

A is a repulsive condition. Likes repulse. Wrong answer.

B is wrong. We are talking about water itself, not water with something in it.

C is Wrong. Water molecules are distinct. They are a bit on the hermit side. They do not connect directly with each other.

D Wrong. There is no interchange of electrons between molecules.

5 0

3 years ago

Read 2 more answers

How many grams of chlorine gas can be produced when 50.0 grams of aluminum chloride decompose? 2AlCl3→ 2Al + 3Cl2

lianna [129]

Answer:

Explanation:

Approx.

425

⋅

Explanation:

(

)

(

)

→

(

)

You have given a stoichiometrically balanced equation, so bravo.

The equation explicitly tells us that

⋅

of aluminum metal reacts with

35.45

⋅

gas to give

266.7

⋅

aluminum trichloride

hope this helps

6 0

3 years ago

A student is asked to standardize a solution of potassium hydroxide. He weighs out 1.08 g potassium hydrogen phthalate (KHC8H4O4

natka813 [3]

Answer:

A. 0.143 M

B. 0.0523 M

Explanation:

Let's consider the neutralization reaction between potassium hydroxide and potassium hydrogen phthalate (KHP).

KOH + KHC₈H₄O₄ → H₂O + K₂C₈H₄O₄

The molar mass of KHP is 204.22 g/mol. The moles corresponding to 1.08 g are:

1.08 g × (1 mol/204.22 g) = 5.28 × 10⁻³ mol

The molar ratio of KOH to KHC₈H₄O₄ is 1:1. The reacting moles of KOH are 5.28 × 10⁻³ moles.

5.28 × 10⁻³ moles of KOH occupy a volume of 36.8 mL. The molarity of the KOH solution is:

M = 5.28 × 10⁻³ mol / 0.0368 L = 0.143 M

Let's consider the neutralization of potassium hydroxide and perchloric acid.

KOH + HClO₄ → KClO₄ + H₂O

When the molar ratio of acid (A) to base (B) is 1:1, we can use the following expression.

$M_{A} \times V_{A} = M_{B} \times V_{B}\\M_{A} = \frac{M_{B} \times V_{B}}{V_{A}} \\M_{A} = \frac{0.143 M \times 10.1mL}{27.6mL}\\M_{A} =0.0523 M$

8 0

3 years ago

As a cooking method, braising is valued for its A. ability to retain flavor. B. quickness and convenience. C. ability to create

SSSSS [86.1K]

Answer: Option (A) is the correct answer.

Explanation:

Braising means first of all fry a dish slightly and then cook it slowly in a closed vessel or dish. The vessel is close so that the liquid present inside it does not evaporates.

Also, Braising is done to mix the flavors of different liquids or spices appropriately.

Thus, we can conclude that as a cooking method, braising is valued for its ability to retain flavor.

5 0

3 years ago

Read 2 more answers

Why is using only clean glassware important?

stealth61 [152]

Good laboratory technique demands clean glassware because the most carefully executed piece of work may give an erroneous result if dirty glassware is used. In all instances, glassware must be physically and chemically clean and in many cases, it must be bacteriologic-ally clean or sterile.

6 0

3 years ago

Read 2 more answers