Answer : 9773 kJ
Explanation:
Exothermic reactions are defined as the reactions in which energy of the product is lesser than the energy of the reactants. The total energy is released in the form of heat and 
for the reaction comes out to be negative.
To calculate the moles :
Given : Change in enthalpy on combustion of 1 mole of methanol = -1278 kJ
According to stoichiometry :
1 mole of methanol produce energy = 1278 kJ
Thus 7.647 moles of methanol produce energy =
Thus 9773 kJ of energy is produced from burning 245.0 g of methanol in excess oxygen
Answer:
I think the answer is D...
Answer:
neither accurate nor precise
Explanation:
Accuracy is the ability to give the same result on different measurements made under the same conditions or to give the desired result accurately, therefore, as observed in the image, the results are not accurate, since they are all different.
They are not precise either, since the precision is the degree of agreement between the independent results of a measurement, obtained under stipulated conditions, be it repeatability, reproducibility or intermediate.
Answer:
Explanation:
You should allow the solvent to drop to the level of the adsorvent, so it would never run dry.
When you let your sample to run dry it will never finish to flow from the adsorbent depending of it polarity.
Water should not be used because it can dissolve the adsorbent.
You could use another technique to identify the compound, as an infrared or a ultraviolet detector. You can also, if you know the compounds, identify it for the retention time, for example, if you need to detect two compounds, one more polar than the other, and use a polar adsorbent and a non-polar solvent, the first compound to exit the column will be the less polar one, because it will have a bigger interaction with the solvent than the stationary phase (adsorbent) and will go faster, the second will be the more polar one, because it will have a bigger interaction with the stationary phase.
<span>That the mass is far lesser
and distributed mistakenly, as compared to what the orbits of stars declare it
should be. Stars orbit more rapidly than the mass would predict, particularly
out toward the galactic edge. This means that there is more mass than has been
measured, and that it is spread out in a huge cloud around the galaxy. This is
one of the reasons why scientists believe that dark matter exists.</span>
