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3 years ago

A match has about 21 milligrams of red phosphorus coating the tip. How many atoms of phosphorus is this?

Chemistry

1 answer:

MAXImum [283]3 years ago

3 0

Answer:

4.083 * 10^20 atoms.

Explanation:

One Mole of phosphorus contains 6.022 * 10^23 atoms (Avogadros number)'

Since 1 mole of Phosphorus has a mass of 30.974 grams, 21 milligrams has

6.022 * 10^23 * 0.021 / 30.974

= 0.004083 * 10^23

= 4.083 * 10^20

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Que es la electronegatividad

yanalaym [24]

Answer:

Es la capacidad, el poder de un átomo en una molécula para atraer a los electrones hacia sí.

Explanation:

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3 years ago

What is the molariity of a 50.0 mL aqueous solution containing 10.0 grams of table salt, NaCl?

tia_tia [17]

Answer:

3 mol/L

Explanation:

You should know or have the equation to solve for Molarity which is;

M = n/v (M: Molarity) (n: moles of solute) (v: Liters of solute)

You can start off differently but I would start by converting the mL to L. This is your "v" value.

50.0 mL/ 1000 mL = 0.05 L

Now, you have to convert grams to moles in order to solve for molarity (M).

1.) On the periodic table find the molecular weights of Na and Cl.

Na= 22.99 g/mol Cl= 35.45g/mol

2.) Add them together to have their combined molecular weights.

22.99 + 35.45= 58.44 g/mol

3.) Now, you're going to use the "picket fence method" or whichever your teacher taught you to convert from grams to moles. This will be your "n" value. (I cannot show it on here without it looking weird, so my sincere apologies.)

10.0 g/ 58.44 g = 0.17111 mol

4.)You are now going to plug in your answers into the equation for Molarity.

M= 0.17111 mol / 0.05 L = 3.4222

5.) I am sure your professor might be a stickler so for sig figs sake when you multiply or divide use the smallest amount of sig figs you see which is 1. Round 3.4222 to 3 mol/L

Sorry this explanation is long let me know if you need a better more written out sample.

3 0

3 years ago

. percent iron in a mixture that is 52.2% Fe2O3

AVprozaik [17]

Answer:

36.51%.

Explanation:

First find the percentage of iron in pure Fe2O3 using the atomic masses of the elements:

= (2 * 55.845) * 100 / (2*55.845+ 3*15.999)

= 69.94 %.

So the percentage of iron in the mixture

= 52.2 * 0.6994

= 36.51 (answer).

8 0

3 years ago

The speed of sound depends on these two things:

IrinaVladis [17]

The speed of sound depends on these two things: The type of medium and the temperature of the medium; option a.

<h3>What is the speed of sound?</h3>

The speed of sound is the distance covered in meters over a given period of time.

Speed = distance/time

The speed of sound depends on the following:

temperature - the speed of sound increases with temperature
medium - the speed of sound increases with increase in density of the medium.

In conclusion, the speed of sound increases with temperature.

Learn more about speed of sound at: brainly.com/question/95976

#SPJ1

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2 years ago

5.5x10² – 6.50x10'<br> Express the calculation in correct significant digits

OLga [1]

Answer:

$6.15x10^2$

Explanation:

Hello!

In this case, when performing mathematical operations with numbers in scientific notation, the first step is to write them in standard notation:

550 - 65.0

Thus, the result without any significant figures-based analysis is:

615.0

However, since 550 is significant to the ones and 65.0 to the tenths, we need to round the result to the bigger significance, in this case to the ones; therefore the appropriate result would be:

615

That in scientific notation would be:

$6.15x10^2$

Best regards!

5 0

3 years ago