Answer: It is important to wet the filter paper in the Buchner funnel first with cold re crystallization solvent before the re crystallization mixture being filtered to minimize gaps around the edges of the filter paper which can prevent mechanical impurities from passing through. This gives better filtration where most impurities can be filtered. Furthermore, it provides good vacuum.
The correct answer is - A) The major constituents of air are gaseous elements.
With the statement ''the major constituents of air are gaseous elements'' we can easily conclude that the air is a mixture. The reason for that is that we have a plural usage of the word element, elements, which mean that there are multiple elements that make up the air.
The air is indeed predominantly a mixture of gaseous elements. The most abundant gas in the air being the nitrogen with 78.9%, oxygen with 20.95%, argon 0.93%, and carbon dioxide 0.04%, with lesser amounts of other gases also be present in it. The water vapor is also present in the air, though it is variable, being around 1% at sea level, but only 0.4% over the entire atmosphere.
Answer : The correct option is, (b) occur when there is more free energy in the reactants than the products.
Explanation :
Endergonic reactions : It i defined as the reaction in which the energy is absorbed during the reaction.
In endergonic reactions, the Gibbs free energy of product is lower than the reactants. That means, ΔG > 0 and the reaction is non-spontaneous.
Exergonic reactions : It i defined as the reaction in which the energy is released during the reaction.
In exergonic reactions, the Gibbs free energy of product is greater than the reactants. That means, ΔG < 0 and the reaction is spontaneous.
Hence, the endergonic reactions is occur when there is more free energy in the reactants than the products.
Answer:
false
true
true
Explanation:
false - changing the hypothesis to meet your needs is not a good researcher
true - when you can further analyze and explain then you have a successful experiment even if it's not what you expected
true - successful experiments do not end there. they can lead to more in depth questions.
Answer:
The interaction reaction of calcium oxide and water leads to the formation of calcium hydroxide, this reaction is exothermic, which indicates that energy is released.
CaO(s) + H2O ⇒ Ca(OH)2
Explanation:
Calcium oxide reacts violently with water, causing it to reach 90 C. It then forms calcium hydroxide, also called slaked lime. It is heated because it releases energy in the form of heat, because the new substance formed (slaked lime) has less internal energy than the original and this is released in the form of heat. As a general rule, acid and base solutions are exothermic.
