Answer:
35Cl ⇒ 34.968853 amu has an abundance of 30.05%
Explanation:
The molar mass of chlorine, (which is the average of all its naturally stable isotope masses), is 36.36575 amu.
There are 2 naturally stable isotopes, this means together they have an abundance of 100%
The isotopes are:
35Cl ⇒ 34.968853 amu has an abundance of X %
37Cl ⇒ 36.965903 amu has an abundance of Y %
X + Y = 100% OR X = 100% - Y
36.36575 = 34.968853X + 36.965903Y
36.36575 = 34.968853(1-Y) + 36.936.96590365903Y
36.36575 = 34.968853 -34.968853Y + 36.965903Y
1.396897 = 1.99705Y
Y = 0.699 = 69.95%
X = 100-69.9 = 30.05%
To control, we can plug in the following equation:
34.968853 * 0.3005 + 36.965903 * 0.6995 = 36.3658
This means
37Cl ⇒ 36.965903 amu has an abundance of 69.95 %
35Cl ⇒ 34.968853 amu has an abundance of 30.05%
The energy change if 84.0 g of CaO react with excess water is 98KJ of heat is released.
calculation
heat = number of moles x delta H
delta H = - 65.2 Kj/mol
first find the number of moles of CaO reacted
moles = mass/molar mass
the molar mass of CaO = 40 + 16= 56 g/mol
mass = 84 g
moles therefore = 84 g/56 g/mol =1.5 moles
Heat is therefore = 1.5 moles x -65.2 = - 97.8 Kj = -98 Kj
since sign is negative the energy is released
The elements in the periodice table are not listed in alphabetical order, because the arragement in rows (periods) and columns (groups or familes), in increasing order of atomic number (number of protons of the atoms) permits to explain similarities among the elements, trend in some properties, and even predict properties of unknown elements.
For example, the elements of the first group (family), called alkaline metals, all have 1 valence electron, have similar physical properties (ductibility, malleability, luster, thermal and electricity conductivity), react in similar way with water, show a trend in the atomic radii and in the ionization energy.
You can tell similar stories for other groups like, alkalyne earth metals, halogens and noble gases.
You can also tell trends in electroneativities, and atomic radii, for a row of elements, as per the order they are in the row.
So, the current array resulted very helpul for chemists to explain and predict the behavior and properties of the elements.
Answer:
The Bayer process is the principal industrial means of refining bauxite to produce alumina (aluminium oxide) and was developed by Carl Josef Bayer. Bauxite, the most important ore of aluminium, contains only 30–60% aluminium oxide (Al2O3), the rest being a mixture of silica, various iron oxides, and titanium dioxide.
