Answer:
1.a
2. b
Explanation:
Distillation is a process whereby a mixture of liquids having different vapor pressures is separated into its components. At first one might think that this would be quite simple: if you have a solution consisting of liquid A that boils at 50°C and liquid B with a boiling point of 90°C, all that would be necessary would be to heat the mixture to some temperature between these two values; this would boil off all the A (whose vapor could then be condensed back into pure liquid A), leaving pure liquid B in the pot. But that overlooks that fact that these liquids will have substantial vapor pressures at all temperatures, not only at their boiling points.
source: https://chem.libretexts.org/Bookshelves/General_Chemistry/Book%3A_Chem1_(Lower)/08%3A_Solutions/8.09%3A_Distillation
Answer:
endothermic reaction
Explanation:
It simply means that you are witnessing<u> an endothermic reaction</u>.
An endothermic reaction is one that absorbs heat energy from its surrounding, thereby leaving the reaction vessel with a lower temperature as compared to before the reaction.
It is as opposed to exothermic reactions which are reactions that give off energy in the form of heat to the surrounding, thereby leaving a reaction vessel warmer than before the reaction.
<em>In this case, the formation of ice crystals outside the test tube means that heat energy has been absorbed by the reaction which leaves the vessel a temperature cold enough to activate the formation of ice. </em>
The bottom of group 1. Francium (or Fr) is the element with the greatest metallic properties.
Francium is not a naturally-occurring element, however. It is man-made. There is an isotope of francium that exists naturally, but it's half life is so short that it decays almost instantly into a different element.
The naturally-occurring element with the highest metallic properties is cesium (or Cs), located right above francium.
Metallic characteristics decrease as you move from left to right on the periodic table.
The Iron atom lost two electrons to become the Fe2+ ion. This is referred to as oxidation.
Answer:
The statement is considered to be true
Explanation:
The statement is true because when elements chemically combine, there are interactions between their valence electrons, causing the two elements to be bonded together to form what is known as a compound.
Compounds can only be formed from interactions between two or more elements. examples include:
Hydrogen + Oxygen = H2O (water)
Sodium + Chlorine = NaCl
Note that if atoms of the same element combine, what is formed is a molecule, not a compound. Some atoms usually do this to attain stability. examples include = O2 H2 and N2. They are oxygen molecule, hydrogen molecule, and nitrogen molecule respectively.
Compounds are only formed when different elements combine to attain electronic stability.
