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.
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The chemical reaction for the dissolving of calcium fluoride is the following:
CaF₂(s) ⇄ Ca⁺²(aq) + 2F⁻(aq)
In this reaction, and according to Le Chatelier's principle, the action that would shift this reaction away from solid calcium fluoride and towards the dissolved ions is the removing of fluoride ions.
Le Chatelier's principle states that in an equilibrium reaction, the system would shift in the opposite direction of the changes. If we remove fluoride ions from the system, it will shift towards the formation of more fluoride ions by dissolving more Calcium Fluoride to achieve equilibrium again.
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Answer: The approximate molecular mass of the polypeptide is 856 g/mol
Explanation:
To calculate the concentration of solute, we use the equation for osmotic pressure, which is:
Or,
where,
= osmotic pressure of the solution = 4.19 torr
i = Van't hoff factor = 1 (for non-electrolytes)
Mass of solute (polypeptide) = 0.327 g
Volume of solution = 1.70 L
R = Gas constant = 
T = temperature of the solution = ![26^oC=[273+26]K=299K](https://tex.z-dn.net/?f=26%5EoC%3D%5B273%2B26%5DK%3D299K)
Putting values in above equation, we get:
Hence, the molar mass of the polypeptide is 856 g/mol
Answer:
0.01M = [H⁺]; 1x10⁻¹²M = [OH⁻]; Ratio is: 1x10¹⁰
Explanation:
pH is defined as -log [H⁺]
For a pH of 2 we can solve [H⁺] as follows:
pH = -log [H⁺]
2 = -log [H⁺]
10^-2 = [H⁺]
<h3>0.01M = [H⁺]</h3>
Using Keq of water:
Keq = 1x10⁻¹⁴ = [H⁺] [OH⁻]
1x10⁻¹⁴ / 0.01M = [OH⁻]
<h3>1x10⁻¹²M = [OH⁻]</h3><h3 />
The ratio is:
[H⁺] / [OH⁻] = 0.01 / 1x10⁻¹² =
<h3>1x10¹⁰</h3>
