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2 years ago

You weigh a 24K gold chain and find that it weighs 400 grams. Determine home many moles of gold atoms you have

Chemistry

1 answer:

makkiz [27]2 years ago

4 0

Answer:

2.03 moles of Gold

Explanation:

Gold is one of the most precious metal metal used in many applications and mainly as a jewellery. In terms of purity it is categorized in Karats. 24 Karat is considered the purest Gold (i.e. 100 % Gold) while other Karats (14, 18, 22 e.t.c) are alloys with other metals and gyms.

Data Given:

Mass of Gold = 400 g

A.Mass of Gold = 196.97 g.mol⁻¹

Calculate Moles of Gold as,

Moles = Mass ÷ M.Mass

Putting values,

Moles = 400 g ÷ 196.97 g.mol⁻¹

Moles = 2.03 moles of Gold

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Caleb has a 860-kilogram car sitting in his back yard, gathering rust.

emmasim [6.3K]

<h3>Answer:</h3>

A. 860 kg

<h3>Explanation:</h3>

To answer the question we need to understand that;

Mass refers to the amount of matter in an object.
Weight, on the other hand, refers to the gravitational pull of an object to a given surface.
Mass is measured using a spring balance.

We also need to know that;

The mass of an object remains constant every where irrespective of the gravitational acceleration.

Therefore, an object on the surface of the earth would have the same mass as on the surface of the moon.
In this case; the mass of the car remains the same on the outer space as on the back yard.

3 0

3 years ago

Read 2 more answers

A 0.2722 g sample of a pure carbonate, X n CO 3 ( s ) , was dissolved in 50.0 mL of 0.1200 M HCl ( aq ) . The excess HCl ( aq )

Alex73 [517]

Answer:

0.00369 moles of HCl react with carbonate.

Explanation:

Number of moles of HCl present initially = $\frac{0.1200}{1000}\times 50.0$ moles = 0.00600 moles

Neutralization reaction (back titration): $NaOH+HCl\rightarrow NaCl+H_{2}O$

According to above equation, 1 mol of NaOH reacts with 1 mol of 1 mol of HCl.

So, excess number of moles of HCl present = number of NaOH added for back titration = $\frac{0.0980}{1000}\times 23.60$ moles = 0.00231 moles

So, mole of HCl reacts with carbonate = (Number of moles of HCl present initially) - (excess number of moles of HCl present) = (0.00600 - 0.00231) moles = 0.00369 moles

Hence, 0.00369 moles of HCl react with carbonate.

3 0

3 years ago

Which element cannot be the central atom of a lewis structure?.

zalisa [80]

Answer:

Hydrogen

Explanation:

Hydrogen can never be central atom despite its low electronegativity

5 0

1 year ago

_______ is the measure of how much water vapor is in the air

pickupchik [31]

Answer:

Humidity is the measure of how much water vapor is in the air.

6 0

3 years ago

WILL MARK BRANILEST

ahrayia [7]

Answer:

FeCl3 is the limiting reactant

O2 is in excess

Theoretical yield Cl2 = 9.84 grams

The % yield is 96.5 %

Explanation:

Step 1: Data given

Mass of FeCl3 = 15.0 grams

Moles O2 = 4.0 moles

Mass of Cl2 produced = 9.5 grams

Step 2: The balanced equation

4FeCl3 + 3O2 → 2Fe2O3 + 6Cl2

Step 3: Calculate moles FeCl3

Moles FeCl3 = mass FeCl3 / molar mass FeCl3

Moles FeCl3 = 15.0 grams / 162.2 g/mol

Moles FeCl3 = 0.0925 moles

Step 4: Calculate limiting reactant

FeCl3 is the limiting reactant. Because we have way more (more than ratio 3:4) moles O2 than FeCl3. It will completely be consumed (0.0925 moles). O2 is in excess. There will react = 0.069375 moles O2

There will remain 4.0 - 0.069375 = 3.930625 moles

Step 5: Calculate moles Cl2

For 4 moles FeCl3 we need 3 moles O2 to produce 2 moles Fe2O3 and 6 moles Cl2

For 0.0925 moles FeCl3 moles we'll have 6/4 * 0.0925 = 0.13875 moles Cl2.

Step 6: Calculate mass Cl2

Mass Cl2 = moles * molar mass

Mass Cl2 = 0.13875 moles * 70.9 g/mol

Mass Cl2 = 9.84 grams

Step 7: Calculate % yield

% yield = (actual yield / theoretical yield) * 100%

% yield = (9.5 grams / 9.84 grams ) * 100%

% yield = 96.5 %

The % yield is 96.5 %

4 0

3 years ago