Answer:
Explanation:
m / z = 20 , 21 , 22
m / 1 = 20 , 21 , 22
m = 20 , 21 , 22 .
ratio of isotopes = 112 : 0.21 : 11.1
Average atomic mass = (112 x 20 + .21 x 21 + 11.1 x 22) / (112 + .21 + 11.1 )
= (2240 + 4.41 + 244.2) / 123.31
= 2488.61 / 123.31
= 20.18
Answer:

Explanation:
Hello,
In this case, since the mineral torbernite has one copper atom, two uranium atoms, twenty oxygen atoms (2x2+4x2+8), two phosphorous atoms and sixteen hydrogen atoms (12x2) and therefore forty one in total, by using the Avogadro's number one is able to compute the total number of atoms in one formula unit or one mole:

Best regards.
<u>Answer:</u> The result of the given calculation is 
<u>Explanation:</u>
Scientific notation is defined as the notation in which a number is expressed in the decimal form. This means that the number is always written in the power of 10 form.
We are given an expression:

The operation carried out in the above expression is division operation. The units are also treated in the same way.
The solution for the above expression is:

The value in scientific notation is 
Hence, the result of the given calculation is 
Percent error=(experimentally determined boiling point-actual boiling point)
=(124.1 - 125.7) = 1.6 °C

Quantity Number of significant figures
0.070020 meter 5
10,800 meters 5
0.010 square meter 2
5.00 cubic meters 1
507 thumbtacks 3
(5.3 x 10⁴) + (1.3 x 10⁴) =6.6 x 10⁴
(7.2 x 10⁻⁴) ÷ (1.8 x 10³)=4 x 10⁻⁷
10⁴ x 10⁻³ x 10⁶=10⁷
(9.12 x 10⁻¹) - (4.7 x 10⁻²)=(9.12 x 10⁻²) - (4.7 x 10⁻²)
=(91.2-4.7) x 10⁻²
=85.5 x 10⁻²
<span>58.6934 +/- 0.0002 u</span>