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2 years ago

12

What is this and explain why please:)

2 answers:

Yuliya22 [10]2 years ago

8 0

Answer:

C Atomic number

Explanation:

The question is typo it should be 19 is the____ of pottasium. The atomic number is the number on top

Alex777 [14]2 years ago

6 0

I don’t think would have like that to

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What do scientists call a smart guess?

Alexus [3.1K]

An educated guess is called estimation

4 0

2 years ago

Read 2 more answers

If an atom has 11 protons and 13 neutrons what is it’s atomic number

Travka [436]

Answer:

the atomic number is 11 and element is Sodium (Na)

Explanation:

Number of Protons = Number of Electrons = 11

Number of Neutrons = 13

Here, the Number of Protons and Number of Electrons is 11

So,

the atomic number is <em><u>11</u></em> and element is <em><u>Sodium </u></em><em><u>(</u></em><em><u>Na) </u></em>

5 0

2 years ago

When particles that attract each other are allowed to come to together, energy is ______

Rufina [12.5K]

Answer:

Released

Explanation:

When particles that attract each other come together, energy is usually released. The combination of the two particles is expected to result in a lower energy system. This lower energy system will be more stable than the different individual particles.

Hence, as this lower energy system is formed, the excess energy originally possessed by the particles is evolved hence energy is released when particles that attract each other are allowed to come together.

5 0

2 years ago

A small cylinder of helium gas used for filling balloons has a volume of 2.20 L and a pressure of 14300 kPa at 25 ∘C. Part A How

Korvikt [17]

Answer:

You can fill 212 balloons.

Explanation:

First we <u>calculate the helium moles in the small cylinder</u>, using <em>PV=nRT:</em>

P = 14300 kPa ⇒ 14300 * 0.009869 = 141.13 atm

V = 2.20 L

n = ?

R = 0.082 atm·L·mol⁻¹·K⁻¹

T = 25 °C ⇒ 25 + 273.16 = 298.16 K

141.13 atm * 2.20 L = n * 0.082 atm·L·mol⁻¹·K⁻¹ * 298.16 K

n = 12.70 mol

Then we <u>calculate the number of moles that can fit in a single balloon</u>:

1.22 atm * 1.20 L = n * 0.082 atm·L·mol⁻¹·K⁻¹ * 298.16 K

n = 0.0599 mol

Finally we <u>divide the total number of available moles by the number of moles in a single balloon</u>:

12.70 mol / 0.0599 mol = 212.09

So the answer is that you can fill 212 balloons.

7 0

2 years ago

An atom has a diameter of 2.50 Å and the nucleus of that atom has a diameter of 9.00×10−5 Å . Determine the fraction of the volu

chubhunter [2.5K]

Answer:

The fraction of the volume of the atom that is taken up by the nucleus is $4.6656\times 10^{-14}$ .

The density of a proton is $6.278\times 10^{14} g/cm^3$ .

Explanation:

Diameter of the atom ,d = 2.50 Å

Radius of the atom ,r = 0.5 d=0.5 × 2.50 Å = 1.25Å

Volume of the sphere= $\frac{4}{3}\pi r^3$

Volume of atom = V

$V=\frac{4}{3}\pi r^3$ ..[1]

Diameter of the nucleus ,d' = $9.00\times 10^{-5}\AA$

Radius of the nucleus ,r' = 0.5 d'= $0.5\times 9.00\times 10^{-5}\AA=4.5\times 10^{-5}\AA$

Volume of nucleus = V'

$V=\frac{4}{3}\pi r'^3$ ..[2]

Dividing [2] by [1]

$\frac{V'}{V}=\frac{\frac{4}{3}\pi r'^3}{\frac{4}{3}\pi r^3}$

$=\frac{r'^3}{r^3}=\frac{(4.5\times 10^{-5}\AA)^3}{(1.25 \AA)^3}$

$\frac{V'}{V}=4.6656\times 10^{-14}$

The fraction of the volume of the atom that is taken up by the nucleus is $4.6656\times 10^{-14}$ .

Diameter of the proton ,d = $1.72\times 10^{-15} m = 1.72\times 10^{-13} cm$

1 m = 100 cm

Radius of the proton,r = 0.5 d= $0.5\times 1.72\times 10^{-13} cm=8.6\times 10^{-14} cm$

Volume of the sphere= $\frac{4}{3}\pi r^3$

Volume of atom = V

$V=\frac{4}{3}\times 3.14\times (8.6\times 10^{-14} cm)^3=2.664\times 10^{-39}cm^3$

Mass of proton, m = 1.0073 amu = $1.0073\times 1.66054\times 10^{-24} g$

$1 amu = 1.66054\times 10^{-24} g$

Density of the proton : d

$d=\frac{m}{V}=\frac{1.0073\times 1.66054\times 10^{-24} g}{2.664\times 10^{-39}cm^3}=6.278\times 10^{14} g/cm^3$

The density of a proton is $6.278\times 10^{14} g/cm^3$ .

5 0

3 years ago