Elements of Group 1 and group 2 in the periodic
table contain elements so reactive that they are never found in the free state
<u>Explanation</u>:
The metals in group 1 of periodic table consisting of 'alkali metals' which include lithium, potassium, sodium, rubidium, Francium and caesium. They are highly reactive because they have low ionisation energy and larger radius. The group 2 metals consist of 'alkaline earth metals' which include calcium, strontium, barium, beryllium, radium and magnesium. These alkaline earth metal have +2 oxidation number, hence are highly reactive.
These both group metals are mostly reactive and so are never found in a free state. When they are exposed to air they would immediately react with oxygen. Hence, are stored in oils to avoid oxidation.
Answer:
Pyridine solution has a greater concentration of hydroxide ions.
Explanation:
The pOH of the solution is defined as negative logarithm of hydroxide ion concentration in a solution.
![pOH=-\log [OH^-]](https://tex.z-dn.net/?f=pOH%3D-%5Clog%20%5BOH%5E-%5D)
- Higher the value of pOH lessor will be the hydroxide ion concentration and higher the concentration of hydrogen ions in the solution .
- Lower the value of pOH higher will be the hydroxide ion concentration and lower the concentration of hydrogen ions in the solution.
1) The pOH of the methylamine = 6.8
![6.8=-\log[OH^-]](https://tex.z-dn.net/?f=6.8%3D-%5Clog%5BOH%5E-%5D)
![[OH^-]=1.5848\times 10^{-7} M](https://tex.z-dn.net/?f=%5BOH%5E-%5D%3D1.5848%5Ctimes%2010%5E%7B-7%7D%20M)
2) The pOH of the pyridine = 6.0
![6.0=-\log[OH^-]](https://tex.z-dn.net/?f=6.0%3D-%5Clog%5BOH%5E-%5D)
![[OH^-]=0.000001 M=1.0\times 10^{-6} M](https://tex.z-dn.net/?f=%5BOH%5E-%5D%3D0.000001%20M%3D1.0%5Ctimes%2010%5E%7B-6%7D%20M)
Pyridine solution has a greater concentration of hydroxide ions than the solution of methylamine.
Answer:
No, and yes. As there is a finite amount of matter in the
universe, only so much can be converted to make energy. There will
be a limit, though it is a long, long way from where we are
Explanation:
Gravitational potential energy is the energy stored in an object relative to its position :)
Answer:
50mL of 4M NaCl, 80mL of 40% glucose, 20mL of 1M Tris-HCl (pH 8.5) and 250mL of water.
Explanation:
To make 400mL containing 0.5M NaCl you need to add:
4M / 0.5M = 8 (dilution 1/8). 400mL / 8 = <em>50 mL of 4M NaCl.</em>
Glucose 8% you need to add:
40% / 8% = 5 (dilution 1/5). 400mL / 5 = <em>80 mL of 40% glucose </em>
Buffer 50mM you need to add:
1000mM / 50mM = 20 (dilution 1/20). 400mL / 20 = <em>20mL of 1M Tris-HCl (pH 8.5)</em>
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The resting volume: 400mL - 50mL of 4M NaCl - 80mL of 40% glucose - 20mL of 1M Tris-HCl (pH 8.5) = 250 mL must be completed with water.
Thus, to make the solution you need: <em>50mL of 4M NaCl, 80mL of 40% glucose, 20mL of 1M Tris-HCl (pH 8.5) and 250mL of water.</em>
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I hope it helps!