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aalyn [17]
3 years ago
13

What is the atomic number of this element?

Chemistry
1 answer:
Illusion [34]3 years ago
5 0

Answer:

27

Explanation:

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The diameter of the He He atom is approximately 0.10 nm nm . Calculate the density of the He atom in g/cm 3 g/cm3 (assuming that
Sladkaya [172]

Answer:

Density of the He atom = 12.69 g/cm³

Explanation:

From the information given:

Since 1 mole of an atom = 6.022x 10²³ atoms)

1 atom of He = 1  \ atom \times  (\dfrac{1  \ mole}{  6.022 \times  10^{23}  \ atoms}) \times ( \dfrac{4.003 \ grams}{  1  \ mole})

=6.647 \times  10^{-24} \  grams

The volume can be determined as  folows:

since the diameter of the He atom is approximately 0.10 nm

the radius of the He = \dfrac{0.10}{2} = 0.05 nm

Converting it into cm, we have:

0.05 nm \times  \dfrac{10^{-9} \  meters}{ 1  nm} \times \dfrac{ 1 cm }{10^{-2} \ meters}

=5 \times  10^{-9}  \ cm

Assuming that it is a sphere, the volume of a sphere is

= \dfrac{4}{3}\pi r^3

= \dfrac{4}{3}\pi  \times (5\times 10^{-9})^3

= 5.236 \times 10^{-25} \ cm^3

Finally, the density can be calcuated by using the formula :

Density = \dfrac{mass}{volume}

D =  \dfrac{6.647 \times  10^{-24} \  grams }{ 5.236 \times 10^{-25} \  cm^3}

D = 12.69 g/cm³

Density of the He atom = 12.69 g/cm³

4 0
3 years ago
Read 2 more answers
How much heat energy is needed to heat 300g of water from 10 degrees Celsius to 50 degrees Celsius
elixir [45]

Answer:

There is 50.2 kJ heat need to heat 300 gram of water from 10° to 50°C

Explanation:

<u>Step 1: </u>Data given

mass of water = 300 grams

initial temperature = 10°C

final temperature = 50°C

Temperature rise = 50 °C - 10 °C = 40 °C

Specific heat capacity of water = 4.184 J/g °C

<u>Step 2:</u> Calculate the heat

Q = m*c*ΔT

Q = 300 grams * 4.184 J/g °C * (50°C - 10 °C)

Q = 50208 Joule = 50.2 kJ

There is 50.2 kJ heat need to heat 300 gram of water from 10° to 50°C

8 0
3 years ago
1. An example of a polyatomic ion is:<br>a) SO²-4<br>b) Ca?<br>c) O2<br>d) NaCl​
zlopas [31]

Answer:

A is the answer. Ca(calcium) is an element, O2 is a diatomic element, and NaCl is a compound composed of Na(sodium) and Cl(chlorine)

Explanation:

hopefully that helps!!!

8 0
3 years ago
Convert 10 liter into m3.
stellarik [79]
0.01 cubic meters
Hope this helps
3 0
3 years ago
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Phase changes!a. Write out the Clapeyron equation and explain what it describes.b. Write out the Clausius-Clapeyron equation and
djverab [1.8K]

Answer:

Solutions in the attachment.

Explanation:

4 0
3 years ago
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