A. Objective
To prove the law of mass conservation
B. Basic theory
The Englishman Robert Boyle (1627-1691) is generally credited with being the first person to study chemistry as a separate intellectual discipline and the first to carry out rigorous chemical experiments. Through a careful series of researches into the nature and behavior of gases, Boyle provided evidence for the atomic make up of matter in addition. Boyle was the first to clearly define an element as a substance that cannot be chemically broken down further and to suggest that a substantial number of different elements might exist. Progress in chemistry was slow in the 100 years following Boyle, and it was not until the work of Joseph Priestley (1733-1804) and Antoine Lavoisier (1743-1794) that the next great leap was made. Priestley prepared and isolated the gas oxygen in 1774 by heating mercury (II)oxide, HgO, according to the equation we would now write as Lavoisier then showed soon there after that oxygen is the key substance involved in combustion. Furthermore, Lavoisier demonstrated by careful measurements that when combustion is carried out in a closed container, the mass of the combustion products exactly equals to the mass of the starting reactants. For example, when hydrogen gas burns and combines with oxygen to tiled water, the mass of the water formed is equal to the mass of the hydrogen and oxygen consumed. Called the law of mass conservation, this principle is a cornerstone of chemical science. The law of conservation of mass/matter, also known as principle of mass/matter conservation is that the mass of a closed system (in the sense of a completely isolated system) will remain constant over time. The mass of an isolated system cannot be changed as a result of processes acting inside the system. A similar statement is that mass cannot be created/destroyed, although it may be rearranged in space, and changed into different types of particles. This implies that for any chemical process in a closed system, the mass of the reactants must equal the mass of the products.
C. Chemicals &Apparatus
1. Apparatus
Y-pipe
Beaker glass
Balancing
Balloon
2. Chemicals
2ml of K2Cr2O7 solution
2 ml of BaCl2 solution
2ml of HCl solution
half spoon full of Zn powder
Ineu Gustiani 0902108 IPSE-FPMIPA Fundamental of Chemistry laboratory report
To prove the law of mass conservation
B. Basic theory
The Englishman Robert Boyle (1627-1691) is generally credited with being the first person to study chemistry as a separate intellectual discipline and the first to carry out rigorous chemical experiments. Through a careful series of researches into the nature and behavior of gases, Boyle provided evidence for the atomic make up of matter in addition. Boyle was the first to clearly define an element as a substance that cannot be chemically broken down further and to suggest that a substantial number of different elements might exist. Progress in chemistry was slow in the 100 years following Boyle, and it was not until the work of Joseph Priestley (1733-1804) and Antoine Lavoisier (1743-1794) that the next great leap was made. Priestley prepared and isolated the gas oxygen in 1774 by heating mercury (II)oxide, HgO, according to the equation we would now write as Lavoisier then showed soon there after that oxygen is the key substance involved in combustion. Furthermore, Lavoisier demonstrated by careful measurements that when combustion is carried out in a closed container, the mass of the combustion products exactly equals to the mass of the starting reactants. For example, when hydrogen gas burns and combines with oxygen to tiled water, the mass of the water formed is equal to the mass of the hydrogen and oxygen consumed. Called the law of mass conservation, this principle is a cornerstone of chemical science. The law of conservation of mass/matter, also known as principle of mass/matter conservation is that the mass of a closed system (in the sense of a completely isolated system) will remain constant over time. The mass of an isolated system cannot be changed as a result of processes acting inside the system. A similar statement is that mass cannot be created/destroyed, although it may be rearranged in space, and changed into different types of particles. This implies that for any chemical process in a closed system, the mass of the reactants must equal the mass of the products.
C. Chemicals &Apparatus
1. Apparatus
Y-pipe
Beaker glass
Balancing
Balloon
2. Chemicals
2ml of K2Cr2O7 solution
2 ml of BaCl2 solution
2ml of HCl solution
half spoon full of Zn powder
D. Procedure
1. Reaction between K2Cr2O7 solution with BaCl2 solutiom
a. Insert 2ml of K2Cr2O7 solution to the one side of Y pipe
b. Then insert 2ml of BaCl2 solution to another side of Ypipe
c. Measure the weight of Ypipe and those two solutions
d. Turn the Y pipe until one of two solution move to another solution
e. Observe the reaction
f. Repeat the measurement of weight
2. Reaction between Zn solid and concentrated HCl solution
a. Insert half spoon full of Zn powder to the one side of Y-pipe.
b. Then insert 2ml of HCl solution to another side of Y-pipe
c. Close the Y-pipe with a balloon.
d. Measure the weight of Y-pipe with the insert and the balloon.
e. Turn the Y-pipe until HCl solution move to the solid
f. Observe the reaction.
g. Repeat the measurement of weight.
E. Observation Result
1. Reaction between K2Cr207
a. The appearance color of BaCl2 solution is pure white and the color of K2Cr207 solution is transparent orange.
b. When both of those solution are poured into another side of one Y-pipe and measured, the weight is 87,297 grams
c. When one of two solution moves to another solution, the color changes become thick orange.
d. When its weight is measured again, the weight becomes 87,294 grams
W beaker glass+Y-pipe (W) = 84.626 g
W beaker glass+Y-pipe+initial solution (Wsi) = 87.297 g
W beaker glass+Y-pipe+final solution (Wsf) = 87.294
Winitial solution (Wi) = Wsi – W = 87.297 g – 84.626 g = 2.671 g
Wfinal solution (Wf) = Wsf – W = 87.294 g – 84.626 g = 2.668 g
ΔW = Wi-Wf = 2.671 g – 2.668 g = 0.003 g
2. Reaction between Zn solid and concentrated HCl solution
a. the weight of Y-pipe + Zn powder + HCl solution + beaker glass + balloon (Wi) is 87.36 grams
b. when HCl solution moves into Zn solid, there is some precipitate and bubble exist
c. After that, the weight is measured again, and the result of weight (Wf) is 87.33 grams.
ΔW = Wi- Wf = 87.36 g – 87. 33 g = 0. 03 g
F. Conclusion
Based on experiment result, there is different amount of mass between reactants and products, there is about 0,003 g are lost from the initial mass. This is not accordance with the law of conservation mass which states that the principle that in any closed system subjected to no external forces, the mass is constant irrespective of its changes in form; the principle that matter cannot be created or destroyed.
The factor which influence the accordance maybe, there is wrong measurement or the system is not isolated at all. So, it causes some amount of mass are lost.
Mass is also not generally conserved in "open" systems (even if only open to heat and work), when various forms of energy are allowed into, or out of, the system (see for example, binding energy). However, the law of mass conservation for closed (isolated) systems, as viewed over time from any single inertial frame, continues to be true in modern physics. The reason for this is that relativistic equations show that even "mass less" particles such as photons still add mass and energy to closed systems, allowing mass (though not matter) to be conserved in all processes where energy does not escape the system. In relativity, different observers may disagree as to the particular value of the mass of a given system, but each observer will agree that this value does not change over time, so long as the system is closed.
G. References
- Kotz&Purcell.Chemistry&Chemical Reactivity.1990.United States of
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