Mid Semester Test
1.pure substance x is solid at room temperature. if the
substance is heated to 230 C is melted gradually. if the cooled to room
temperature, the liquid can not be frozen.
a. is it possible x of an element or a compound. explain it!
b. Does it chemical change occured? if so can it be said
undergo an endotherm changing, based on the information provided?
c.can it be said that the liquid is an element, based on the
information provided
2. When a candle that weighs 10 g is burned in oxigen,
carbon dioxide and water vapor formed by combustion the weight more than 10 g.
was this case match with the law of conservation of mass. Explain it!
3. When carbon burns in oxigen under limited number, it will
form teo gaseous compounds. Suggest the way to diffrerentiate the two compounds
with one another
4. after mendeev compiled the periodic table, he concluded
that the atomic weights of certain elements was wrong ruling, and this
conclusion was apparently correct. How mendeelev was able to predict the
several atomic weights were wrong? whyhis predictions are not always right.
Explainit!
5. When an a queous solution of merkuri chloride is addded
an aqueous solution of silver nitrate, a white solid forms. Identify the white
solid and write the balanced equation for the reavtion thatoccurs
Answers to Mid Semester
1.a. Compounds, because the compound is a substance that emerged from some
elements through chemical reactions and compounds also can be decomposed again
into its constituent elements by chemical reactions. Compounds can exist in
several phases. Most compounds can be solids. Molecular compounds can also be a
liquid or gas. All compounds will break down into smaller compounds or
individual atoms if heated to a certain temperature (called the decomposition
temperature). Compounds have different properties with its constituent
elements. DAPT compounds only broken down into its constituent elements by
chemical reactions. At the same conditions, the compound may have a shape
different from its constituent elements. Physical and chemical properties of
compounds is different from its constituent elements. For example the reaction
between hydrogen gas and oxygen gas to form liquid water compounds.
b. yes, because the chemical reaction is a natural process that always results antarubahan chemical compounds. [1] The compounds or compounds involved early in the reaction is referred to as reactants. Chemical reactions are usually characterized by a chemical change, and will result in one or more products which typically have characteristics different from the reactants. Endothermic reaction, because the reaction is accompanied by heat transfer from the environment to the system (heat absorbed by the system from its environment); characterized by a decrease in ambient temperature around the system.
c. sodium absorption ratio, because the liquid is not a form element, but the compound, penegertian of the element itself is not a single substance which is described again dapt into other substances are more modest,
2. no, because by law or legal lavoiser kekelan masssa which says that the mass of substances in closed systems before and after the reaction is the same.
3.berdasarkan matter, if the carbon in the fuel with oxygen gas it will produce a second compound, possibly the first of CO2 gas and gas that produced one more possibility of H2O, how to distinguish, as a result of combustion in the form of a compound that is then how to distinguish the based on the chemical properties of each element and compound
4. 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 periodic believes that the law can be used to predict the existence of several new elements and properties of compounds, as well as to correct the atomic weights of some elements are already known. However, historian and author overemphasized chemical predictions in its legal aspect. Mendeleev ability to accommodate elements that are known to have contributed positively in the periodic system.
5. HgCl2 + 2AgNO3 => Hg (NO3) 2 + 2AgCl
AgCl precipitate formed on the gray-white colored
Answers to Mid Semester
BalasHapus1.a. Compounds, because the compound is a substance that emerged from some elements through chemical reactions and compounds also can be decomposed again into its constituent elements by chemical reactions. Compounds can exist in several phases. Most compounds can be solids. Molecular compounds can also be a liquid or gas. All compounds will break down into smaller compounds or individual atoms if heated to a certain temperature (called the decomposition temperature). Compounds have different properties with its constituent elements. DAPT compounds only broken down into its constituent elements by chemical reactions. At the same conditions, the compound may have a shape different from its constituent elements. Physical and chemical properties of compounds is different from its constituent elements. For example the reaction between hydrogen gas and oxygen gas to form liquid water compounds.
b. yes, because the chemical reaction is a natural process that always results antarubahan chemical compounds. [1] The compounds or compounds involved early in the reaction is referred to as reactants. Chemical reactions are usually characterized by a chemical change, and will result in one or more products which typically have characteristics different from the reactants. Endothermic reaction, because the reaction is accompanied by heat transfer from the environment to the system (heat absorbed by the system from its environment); characterized by a decrease in ambient temperature around the system.
c. sodium absorption ratio, because the liquid is not a form element, but the compound, penegertian of the element itself is not a single substance which is described again dapt into other substances are more modest,
2. no, because by law or legal lavoiser kekelan masssa which says that the mass of substances in closed systems ebelum and after the reaction is the same.
3.berdasarkan matter, if the carbon in the fuel with oxygen gas it will produce a second compound, possibly the first of CO2 gas and gas that produced one more possibility of H2O, how to distinguish, as a result of combustion in the form of a compound that is then how to distinguish the based on the chemical properties of each element and compound
4. 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 periodic believes that the law can be used to predict the existence of several new elements and properties of compounds, as well as to correct the atomic weights of some elements are already known. However, historian and author overemphasized chemical predictions in its legal aspect. Mendeleev ability to accommodate elements that are known to have contributed positively in the periodic system.
5. HgCl2 + 2AgNO3 => Hg (NO3) 2 + 2AgCl
AgCl precipitate formed on the gray-white colored