Answer:
Hexane should be used first.
Explanation:
Chromatography is a method of separating the constituents of a mixture by taking advantage of their different rates of movement in a solvent over an adsorbent medium. Chromatography is a means of separation and analysis that utilises fractional separation. It is based on the principle that if a fluid containing a number of substances is allowed to pass though an adsorbent medium, the different substances in the fluid may travel at different rates and be separated.
The rate of movement depends on the relative affinities of the constituents for the solvent and adsorbent medium. i.e solutes which are weakly adsorbed by the adsorbent medium are easily redissolved by the ascending solvent and quickly travel up the adsorbent medium. In addition to that , solutes which are very soluble in the solvent move up at a faster rate than those which are not soluble.
In column Chromatography;
A non-polar solvent should be initiated and applied first. This is because , in a column chromatography, a non-polar compound will be removed at first then later polar compound.
Assuming a polar compound is used first, the polar compounds will be removed alongside with all the non-polar compounds.
From the two Compounds given;
We know that :
Hexane is a non-polar compound and Methylene chloride is a polar compound. As such, Hexane should be used first.
Answer:
The air pressure is 9.8 *10^4 pa
The water will rise to a height of 10.0 meter
Explanation:
Step 1: Data given
As a storm from moves in, you notice that a column of mercury in a barometer rises to 736 mm.
Step 2: Calculate the air pressure
The Pressure against the mercury column = h*d*g = 0.736 * 13593 * 9.81 = 9.8 * 10^4 Pa
Step 3: Calculate the height of the water
Let the Pressure the water column for same pressure is h meter : -
9.8 * 10^4 = h*d*g
=>9.8*10^4 = h*1000*9.81
=>h = 10.0 meter
The water will rise to a height of 10.0 meter
The researcher may first weight the beaker with water and then start to heat the water to a constant temperature, for example 30 °C and then start adding salt and stirring. He should add salt slowly until solid salt starts to become visible and the solution starts becoming cloudy. When this happens, he should quickly weigh the beaker. The increase in mass is the mass of salt dissolved at that temperature.
The procedure is then repeated but at an increased temperature until 5-6 temperatures have been tested.
3+
So, compounds of boron contain boron in a positive oxidation state, generally +3. The sum of oxidation numbers of all constituent atoms of a given molecule or ion is equal to zero or the charge of the ion, respectively. ... In most of the stable compounds of boron, its oxidation number is +3
