1.
Kinetika reaksi merupakan cabang ilmu yang mempelajari reaksi kimia secara kuantitatif dan juga mempelajari faktor-faktor yang mempengaruhinya. Kinetika suatu obat menjadi dasar dalam menentukan waktu kadaluarsa dari suatu obat. Pada persamaan mA + nB à pC + qD dapat dijelaskan bahwa ...................
Correct Answer
B. Laju reaksi sebagai laju bertambahnya konsentrasi C dan D
Explanation
The given question asks for an explanation of the statement "Laju reaksi sebagai laju bertambahnya konsentrasi C dan D" (The rate of reaction is the rate at which the concentration of C and D increases). This statement is a correct explanation because in the given reaction equation mA + nB à pC + qD, the rate of reaction is determined by the increase in the concentration of C and D. As the reaction progresses, the concentrations of C and D increase, indicating that the reaction is proceeding forward. Therefore, the correct answer is "Laju reaksi sebagai laju bertambahnya konsentrasi C dan D".
2.
Perhatikan tabel di bawah ini
Andi mereaksikan antara gula dan air sehingga gula menjadi larut, adapun data yang diperoleh sebagai berikut :
No
Sampel
Air panas
Hasil
1
Gula pasir
100 ml
Larut
2
Gula kristal
100 ml
Sedikit larut
Faktor yang mempengaruhi laju reaksi di atas adalah.......
Correct Answer
C. Luas permukaan
Explanation
The data in the table shows that when Andi reacts sugar with water, the type of sugar affects the solubility. Sugar crystals (gula kristal) are only slightly soluble in 100 ml of water, while granulated sugar (gula pasir) is completely soluble in the same amount of water. This suggests that the surface area of the sugar particles influences the rate of reaction. Smaller particles of granulated sugar have a larger surface area compared to larger crystals, allowing for more efficient interaction with water molecules and faster dissolution. Therefore, the factor that affects the rate of reaction in this case is the surface area or luas permukaan.
3.
Pada percobaan dengan reaksi : 2NO + Br2 --> 2NOBr diperoleh data sebagai berikut :
Percobaan
[NO]
[Br2]
Laju reaksi NOBr
1
0,1
0,1
5
2
0,2
0,1
10
3
0,2
0,2
40
Dengan v= k[A]y[B]x maka orde reaksi untuk percobaan di atas adalah ...............
Correct Answer
A. NO berorde 1 dan Br2 berorde 1
Explanation
Based on the given data, the reaction rate of NOBr doubles when the concentration of NO doubles and the concentration of Br2 remains constant. This indicates that the reaction rate is directly proportional to the concentration of NO, suggesting that NO has an order of 1. Similarly, the reaction rate quadruples when the concentration of Br2 doubles and the concentration of NO remains constant. This indicates that the reaction rate is directly proportional to the concentration of Br2, suggesting that Br2 also has an order of 1. Therefore, the order of the reaction for the given experiment is NO berorde 1 dan Br2 berorde 1.
4.
Pada percobaan dengan reaksi : 2NO + Br2 ---> 2NOBr diperoleh data sebagai berikut :
Percobaan
[NO]
[Br2]
Laju reaksi NOBr
1
0,1
0,1
5
2
0,2
0,1
10
3
0,2
0,2
40
dari soal sebelumnya, maka persamaan laju reaksinya dapat ditulis .................
Correct Answer
B. K[NO]1[Br2]2
Explanation
The correct answer is k[NO]1[Br2]2. This is because the rate of the reaction is directly proportional to the concentration of NO raised to the power of 1 and the concentration of Br2 raised to the power of 2. This can be determined by comparing the data in the experiment, where doubling the concentration of Br2 (from 0.1 to 0.2) resulted in a four-fold increase in the rate of the reaction (from 5 to 20).
5.
Dari soal sebelumnya, maka konstanta laju reaksinya adalah ...............
Correct Answer
D. 5 x 103 L/mol.detik
Explanation
The correct answer is 5 x 103 L/mol.detik. This is because the previous question provided the necessary information to calculate the rate constant of the reaction. The rate constant is a measure of how quickly a reaction occurs, and it is determined experimentally. In this case, the rate constant is given in units of L/mol.detik, which represents the volume of reactants consumed or products formed per mole of reactant per second. The value of 5 x 103 L/mol.detik indicates that the reaction is relatively fast.
6.
Perhatikan soal sebelumnya, jika konsentrasi NO 0,3 M dan konsentrasi Br2 0,5 M maka laju reaksinya adalah ..........
Correct Answer
C. 3,75 x 102 M/s
Explanation
The rate of a chemical reaction can be determined using the rate law equation, which is expressed as rate = k[A]^m[B]^n, where k is the rate constant, [A] and [B] are the concentrations of the reactants, and m and n are the reaction orders with respect to A and B, respectively. In this case, since the reaction involves only NO and Br2, the rate law can be simplified to rate = k[NO]^1[Br2]^1. Given that the concentration of NO is 0.3 M and the concentration of Br2 is 0.5 M, we can substitute these values into the rate law equation to find the rate of the reaction. The rate is calculated to be 3.75 x 102 M/s.
7.
Stabilitas obat dapat dijaga sampai obat tersebut memberikan efek terapi. Contoh upaya menjaga stabilitas obat yaitu .......
Correct Answer
B. Amoksisilin merupakan antibiotik yang mudah terhidrolisis, agar stabil maka dibuat sediaan tablet
Explanation
Amoksisilin is an antibiotic that is easily hydrolyzed, meaning it breaks down when exposed to water. To maintain its stability, it is formulated into tablet form. Tablets provide a protective barrier for the drug, preventing it from coming into contact with water and undergoing hydrolysis. This ensures that the drug remains stable and effective until it is consumed and can provide its therapeutic effects.
8.
Suatu sediaan sirup dengan kadar 125 mg/ml. Volume larutan adalah 60 mL. Setelah 1 minggu (7 hari) ternyata konsentrasinya tinggal 118 mg/ mL. Reaksi penguraian berjalan pada orde 1, Maka waktu paruhnya adalah .......
Correct Answer
D. 84,26 hari
Explanation
The given question provides information about a syrup solution with a concentration of 125 mg/ml and a volume of 60 mL. After 7 days, the concentration decreases to 118 mg/ml. The question states that the decomposition reaction is of first order. The half-life of a first-order reaction can be calculated using the formula t1/2 = 0.693/k, where k is the rate constant. In this case, the rate constant can be determined by dividing the natural logarithm of the initial concentration by the difference between the natural logarithm of the initial concentration and the natural logarithm of the final concentration. Using this information, the calculated half-life is 84.26 days.
9.
Suatu sediaan sirup dengan kadar 125 mg/ml. Volume larutan adalah 60 mL. Setelah 1 minggu (7 hari) ternyata konsentrasinya tinggal 118 mg/ mL. Reaksi penguraian berjalan pada orde 1, Maka usia simpan obat adalah .......
Correct Answer
B. 12,77 hari
Explanation
The given question provides information about a syrup preparation with a concentration of 125 mg/ml and a volume of 60 mL. After 7 days, the concentration decreases to 118 mg/ml. The question states that the decomposition reaction follows a first-order kinetics. To calculate the shelf life of the drug, we can use the formula for the half-life of a first-order reaction: t1/2 = (0.693/k), where k is the rate constant. In this case, the rate constant can be determined by taking the natural logarithm of the ratio of the initial concentration to the final concentration, divided by the time elapsed. By substituting the given values into the formula, we can calculate the shelf life to be approximately 12.77 days.
10.
Setiap kenaikan suhu 20°C mengakibatkan reaksi berlangsung 2 kali lebih cepat. Jika pada suhu 35°C reaksi berlangsung selama 40 menit. Berapa lama reaksi tersebut akan berlangsung pada suhu 75°C ? dimana t2 = t1. (1/n) ΔT/x
Correct Answer
B. 10 menit
Explanation
According to the given information, every increase of 20°C causes the reaction to occur 2 times faster. So, if the reaction takes 40 minutes at 35°C, it means that the reaction would take 80 minutes at 15°C (20°C lower than 35°C). Therefore, the reaction would take 40 minutes at 55°C (20°C higher than 35°C). Since the question asks for the time at 75°C, which is 20°C higher than 55°C, the reaction would take half the time, which is 10 minutes.