THE SUBSTANCE MASS AT CHEMISTRY REACTION
PURPOSE
§ To prove “the law of conservation mass “
§ To study reaction Sodium Hydroxide (NaOH) with Cuprum II Sulfate (CuSO4)
§ To study reaction Potassium Iodine (KI) with Lead II Nitrate
THEORY
The master in chemistry at era-18, found the concept and then the concept recognize as basic chemistry of law, one of the that law is “The Conservation Mass Of Law”, its explain about “the substance mass before reaction same with after reaction”. Conservation mass of law is one of the law which explain mass from the shut system will constant although happen some process in that system.
The sign used to explain conservation mass of law is the mass can change type but can't created r destroyed. For a chemistry process in the shut system, mass from reactant must same with product mass.
Conservation Mass of Law explained by Antoine Lavoisier at 1789. Before that, Mikhail Lomonosov (1748) has opinion which same with him and has proved it in experiment.
For example :
Zn(s) + S(s) ZnS (s)
65,4 g 32 g 97,4 g
From that sample, we can know about although a substance realize chemistry change until there new substance, but reaction not happen the mass change.
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. This is also the main idea of the first law of thermodynamics.
As opposed to mass conservation, the principle of matter conservation (in the sense of conservation of particles which are agreed to be "matter") may be considered as an approximate physical law, that is true only in the classical sense, without consideration of special relativity and quantum mechanics. Another difficulty with the idea of conservation of "matter," is that "matter" is not a well-defined word scientifically, and when particles which are considered to be "matter" (such as electrons and positrons) are annihilated to make photons (which are often not considered matter) then conservation of matter does not take place, even in isolated systems.
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 "massless" 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.
The historical concept of both matter and mass conservation is widely used in many fields such as chemistry, mechanics, and fluid dynamics. In modern physics, only mass conservation for closed systems continues to be true exactly.
Instruments and Material
| No | Name Instruments/ Material | Measure/concentration | Total |
| 1 | Erlenmeyer pitcher | 250 ml | 2 |
| 2 | Elastic cork | Match with Erlenmeyer | 2 |
| 3 | Reaction tube | 10x100 mm | 2 |
| 4 | Yarn | | Enough |
| 5 | Measure glass | 10 ml | 2 |
| 6 | Drop pipette | long | 4 |
| 7 | Balance | | 1 |
| 8 | NaOH Liquid | 0,1 M | 10 ml |
| 9 | CuSO4 . 5 H2O Liquid | 0,1 M | 5 ml |
| 10 | KI Liquid | 0,1M | 10 ml |
| 11 | Pb(NO3)2 liquid | 0,1 M | 5 ml |
METHOD
§ Bring in 10 ml of sodium hydroxide 0.1 M to Erlenmeyer pitcher and 5 ml of cuprum II sulfate 0.1 M to small reaction tube (this tube was bundle with yarn). Then into that tube to Erlenmeyer and give cork in mouth of Erlenmeyer glass.
§ Balancing Erlenmeyer pitcher with its fill and write the mass on the work sheet.
§ Slope that picture until both of liquid can mixture. Write what change happen.
§ Consider again Erlenmeyer pitcher with its fill and write the mass.
§ Do that method again with 10 ml of potassium iodide 0.1 M and 5 ml of lead II nitrate 0.1 M.
Observation Data
| | NaOH | CuSO4 | NaOH + CuSO4 |
| Color of substance | Transparent | Transparent blue | Blue, There are sediment |
| Mass before reaction | 155,8 g – 142,3g = 13,5g | ||
| Mass after reaction | 155,8 g – 142,3g = 13,5g | ||
Equation reaction :
2 NaOH(aq) + CuSO4 (aq) Na2SO4(aq) + Cu(OH)2(s)
| | KI | Pb(NO3)2 | KI + Pb(NO3)2 |
| Color of substance | Transparent | Transparent | Yellow, There are sediment |
| Mass before reaction | 182,8 g – 168,1 g = 14,7 g | ||
| Mass after reaction | 182,8 g – 168,1 g = 14,7 g | ||
Equation reactions :
2 KI (aq) + Pb(NO3)2 (aq) 2 KNO3(aq) + PbI2 (s)
DATA ANALYSIS
In this experiment, the purpose is to prove about conservation mass of law. This law explained the substance mass before reaction same with the substance mass after reaction. In this experiment, we do two experiment s. They are :
Reaction between Sodium hydroxide with cuprum II sulfate
Equation reaction is :
2 NaOH(aq) + CuSO4 (aq) → Na2SO4(aq) + Cu(OH)2(s)
This reaction do with slope the Erlenmeyer pitcher was filled sodium hydroxide and in the Erlenmeyer there was reaction tube. In the reaction tube filled with CuSO4. After there is reaction tube in the erlenmeyer, this Erlenmeyer corked with elastic cork. The result from this reaction is blue sediment in there. This sediment is Cuprum hydroxide. The sediment formed because cuprum have relative atom mass more than sodium. Type this sediment are crystal which can out from sediment with sifting method. Before the Erlenmeyer sloped, the substance mass before reaction is 13.5 gram and the substance mass after reaction is 13.5 gram. This happen was prove about that right there is conservation mass of law where the substance mass before reaction same with the substance mass after reaction.
Reaction between Potassium Iodine with Lead II Nitrate
This reactions do same method with first experiment but sodium hydroxide substitution with potassium iodide and lead II sulfate substitution lead II nitrate. Before into liquid to instrument, this chain instrument balanced before, the balance result is 168.1 gram. Result this reaction is yellow sediment. This sediment is lead iodine. Before reaction, mass of instrument chain with KI and Pb(NO3)2 is 182.8 gram. So, the substance mass before reaction is 182.8 g – 168.1 g = 14.7 gram. And after sloped the Erlenmeyer, substance mass after reaction is 14.7 gram. This result same with substance mass before reaction. Because of that, we can see about that’s right conservation mass of law where substance mass before reaction same with substance mass after reaction.
Calculation and Question
Reaction I
Data : V NaOH = 10 ml
V CuSO4 = 5 ml
M NaOH = 0,1 M
M CuSO4 = 0,1 M
Mr NaOH = 40
Mr CuSO4 = 159,5
Mr Cu(OH)2 = 97,5
Mr Na2SO4= 142
Question : Prove there is conservation mass of law!
Answer :
2 NaOH(aq) + CuSO4 (aq) Na2SO4(aq) + Cu(OH)2(s)
M : 0,001 0,0005
B : 0,001 0,0005 0,0005 0,0005
S : - - 0,0005 0,0005
Ø Mass before reaction : mass NaOH + mass CuSO4
= (0,001 . 40) + (0,0005 . 159,5)
= 0,04 + 0,0798
= 0,1198 gram
Ø Mass after reaction = mass Na2SO4 + mass Cu(OH)2
= (0,0005 . 142) + (0,0005 . 97,5)
= 0,071 + 0,0488
= 0,1198 gram
Ø It’s prove that there’s the conservation mass of law, where the mass before reaction = mass after reaction, is 0,1198 gram.
Reaction II
Data : M KI = 0,1 M
M Pb(NO3)2 = 0,1 M
V KI = 10 ml = 10 . 10-3 L
V Pb(NO3)2 = 5 ml = 5 . 10-3 L
Mr KI = 166
Mr Pb(NO3)2 = 331
Mr PbI2 = 461
Mr KNO3 = 101
Question : prove there is conservation mass of law
Answer :
2 KI (aq) + Pb(NO3)2 (aq) 2 KNO3(aq) + PbI2 (s)
M : 0,001 0,0005 -------- ---------
B : 0,001 0,0005 0,001 0,0005
S : ----- ------- 0,001 0,0005
Ø Mass before reaction : mass KI + mass Pb(NO3)2
= (0,001 . 166) + (0,0005 . 331)
= 0,166 + 0,165
= 0,3315 gram
Ø Mass after reaction = mass KNO3 + MASS PbI2
= (0,0005 . 461) + (0,001 . 101)
= 0,2305 + 0,101
= 0,3315 gram
Ø It’s prove that there’s the conservation mass of law, where the mass before reaction is same with mass after reaction, the mass is 0,3315 gram
Conclude
§ Conservation mass of law proved in this experiment where the substance mass before reaction same with the substance mass after reaction.
§ Reaction between NaOH with CuSO4 result Cu(OH)2 sendiment
Equation reaction :
2NaOH(aq) + CuSO4 (aq) Na2SO4(aq) + Cu(OH)2(s)
§ Reaction between KI with Pb(NO3)2 result PbI2 sendiment
Equation reaction :
2KI (aq) + Pb(NO3)2 (aq) 2 KNO3(aq) + PbI2 (s)
§ The chemistry change happened in two reaction, are colour change and sendiment in there.
References
- Brady, James E. (1999). Kimia Universitas Asas dan Struktur.
- Chang, Raymond (2005). Kimia Dasar Konsep – Konsep Inti, 3rd ed.
- Gunawan (1988). Kimia Larutan.
- Petrucci, Raiph (1992). Kimia Dasar Prinsip dan Terapan Modern, 2nd ed.
- S, Syukri (1994). Kimia Dasar 1.
- Selangka, Sulaeman (1997). Buku Instan Sains Kimia.
