Is energy absorbed or given off when an electron and a hole of a semi-conductor crystal

Calculate the average atomic mass of element, X. A sample of X is 65.20% X-17, 13.50% X-18, and 21.30% X-19.

k0ka [10]

Answer:

The average atomic mass of element X is 17.561 u.

Explanation:

Average atomic mass of an element is defined as the sum of masses of each isotope each multiplied by their natural fractional abundance.

Formula used to calculate average atomic mass follows:

$\text{Average atomic mass }=\sum_{i=1}^n\text{(Atomic mass of an isotopes)}_i\times \text{(Fractional abundance})_i$ .....(1)

We are given:

Mass of isotope X-17 = 17 u

Percentage abundance of isotope X-17 = 65.20 %

Fractional abundance of isotope 1 = 0.6520

Mass of isotope X-18 = 18 u

Percentage abundance of isotope X-18 = 13.50 %

Fractional abundance of isotope X-18 = 0.1350

Mass of isotope X-19 = 19 u

Percentage abundance of isotope X-19 =21.30%

Fractional abundance of isotope X-19 = 0.2130

Putting values in equation 1, we get:

$\text{Average atomic mass of Z}=\sum[(17 u\times0.6520 )+(18 u\times 0.1350)+(19 u\times 0.2130)]$

$\text{Average atomic mass of Z}=17.561 u$

6 0

3 years ago

A motorcycle cover a distance of 1.8 km in 5 minute. calculate its average velocity?

OlgaM077 [116]

Answer:

$solution \\ distance \: travelled = 1.8 \: km \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 1.8 \times 1000m \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 1800 \: m \\ time \: taken = 5 \: minute \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 5 \times 60 \: seconds \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 300 \: seconds \\ average \: velocity = \frac{distance \: travelled}{time \: taken} \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = \frac{1800}{ 300} \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 6 \: {ms}^{ - 1}$

hope this helps..

8 0

3 years ago

Read 2 more answers

The Hubble space telescope has been maintained by which of these?

ra1l [238]

The answer to your question is NASA's Hubble Space Telescope is the first major infrared-optical-ultraviolettelescope to be placed into orbit around the Earth.And it Located high above Earth's obscuring atmosphere, the telescope has provided the clearest views of the universe yet obtained in optical astronomy. Its in the International Space Station
Hope this helps

6 0

3 years ago

An object is falling downward at a rate of 25 m/s. Two seconds later, what is its acceleration?

zhenek [66]

acceleration times time falling

25*2

50 m*s^-1

6 0

3 years ago

What are the two categories of waves

fredd [130]

answer: transverse and longitudinal

6 0

3 years ago