1.) A.) Because the compounds that require high temperatures to melt. This is due to the ties that occur in the compound for example an ionic bond. Ionic compounds formed from positive and negative ions arranged alternately to form a giant molecule. The attraction between positive ions and negative ions in these compounds is quite large, and one charged ions with ions of opposite. Consequently the resulting boiling point higher. So it is with covalent compounds messkipun not as high boiling point compounds ions. Right but if dibandingkn with elements, of course, will lower the boiling point. Besides a solid compound will not be able memcair at room temperature.
b) Yes, the chemical changes that occur in the reaction above is endothermic. Endoterem reactions require high temperatures to produce the product.
c.) No, because if senyaberubah faseny will remain a compound, kecxuali if it is separated. For instance X that it contains elements of the melt has a lower boiling point then he will evaporate first. And stay pure element X.
2.) Not associated with the law of conservation of mass. Because the law is a law of conservation of mass states of a closed system is constant despite the wide range of processes in the system (mass of substances in closed systems before and after the reaction is the same (fixed / constant). While the above chemical reaction occurs in the open . Deviations law of conservation of mass can occur in open systems with processes involving energy changes are very significant. It should be noted that in a closed system, because energy is not out of the system, the mass of the system will not change.
3.) CO2 gas that is formed can be reduced by the absorption process, ie the process of separation of components of gas mixtures with melarutkannnya the liquid solvent.
4.) How can Mendeleev predicted the atomic weight is wrong?
4.) How can Mendeleev predicted the atomic weight is wrong?
Considers Mendeleev periodic law can not tolerate any exceptions as any deviation from the sequence of elements by atomic weight. For example, in the case of the elements tellurium and iodine, he predicted that the atomic weights of these two elements are not appropriate because the available values suggest the opposite order to what is determined by chemical properties. More specifically, tellurium showed a higher atomic weight in accordance with the values measured and then the order of elements based on this feature will put the tellurium in the same chemical group as fluorium, klorium, and bromium, where it is not included in the periodicity used the chemical. Apparently, the reversal of the order according to Mendeleev's true but the reason is used inappropriately. It actually has an atomic weight close to the accuracy, but the order of elements is better placed based on the number of atoms of each element. Schematic sequence elements enhanced by the work of Moseley in 1912, and the accuracy of the main complication lies in the mixture of isotopes occurring in the chemical elements are most important.
Mendeleev predictions are not always true because:
1) The length of period is not the same and why is not explained.
2) Some elements are not arranged according to their atomic mass increases, for example: Te (128) before I (127).
3) Difference in mass of successive elements is not always 2, but ranged between 1 and 4 that it is difficult to predict the mass of elements that have not known exactly.
4) valence elements are difficult to forecast more than one of the faction.
5) anomalies (deviations) elements of hydrogen from the other elements are not described.
5.) Precipitate formed on adding more than the addition of AgNO3 HgCl2. The reaction between the metal with the protein can cause breakdown of protein side chains in proteins yangmenyebabkan become inactive. In addition, these metals can decide disulfide bonds and bonds in the salt bridge. Protein yangterdenaturasi seen from the white precipitate formed. Ag +-charged metal one whose value is smaller than Hg2 + so it is more reactive and the bond between the NH 2 group with the C ± ± l gam in the terbent very strong to break ties in sulida and bonding in the salt bridge (Ophart2003).
HgCl2 + 2AgNO3 --> Hg(NO3)2 + 2AgCl
