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Questions in chemistry

[Terjawab] What prediction can you make about future levels of carbon dioxide $(CO_2)$ in the atmosphere? | Year | Carbon Dioxide, $CO_2$ (ppm) | |---|---| | 1960 | 317 | | 1970 | 326 | | 1980 | 339 | | 1990 | 354 | | 2000 | 371 | | 2010 | 390 |

[Terjawab] Which of the following is an acid? A. LiOH (Lithium hydroxide) B. NH3 (Ammonia) C. H₂SO₄ (Sulfuric acid) D. KOH (Potassium hydroxide)

[Terjawab] A CSTR of volume 1 L (constant density liquid phase) is operated at steady state and constant temperature. The following irreversible reaction occurs: A → C The feed always contains reactant A at the concentration C_A0 = 1 mol/L. The rate depends only on A, and this dependence is expressible by an nth order rate form. Exit concentrations of un-reacted reactant A were measured in two runs. In each run, steady state was achieved at different volumetric flow rates q listed below. | Run | q (L/min) | C_A (mol/L) | |---|---|---| | Run 1 | q_1 = 0.707 | C_A = 0.5 | | Run 2 | q_2 = 0.112 | C_A = 0.2 | (d) Find the order of reaction rounded off to 1 decimal place. V = \frac{f_A F_{A0}}{-r_A} Run 1: 1 = \frac{(0.5)(1)(0.707)}{k_A(0.5)^n} Run 2: 1 = \frac{(0.5)(1)(0.112)}{k_A(0.2)^n} Equating (1) and (2) and solving for n gives n = 1.498.

[Terjawab] Consider the following statements: Statement I: One atomic mass unit is defined as 1/12 of the mass of one carbon-12 atom. Statement II: Carbon-12 isotope is the most abundant isotope of carbon and has been chosen as standard. In the light of the above statements, choose the most appropriate answer from the options given below: A. Statement I is correct but Statement II is incorrect. B. Statement I is incorrect but Statement II is correct. C. Both Statement I and Statement II are correct. D. Both Statement I and Statement II are incorrect.

[Terjawab] If the activation energy required for a chemical reaction were reduced, what would happen to the rate of the reaction? A. The rate would increase. B. The rate would decrease. C. The rate would remain the same. D. The rate would be zero.

[Terjawab] In a group assignment, students are required to fill 10 beakers with [tex]$0.720 M CaCl _2$[/tex]. If the molar mass of [tex]$CaCl _2$[/tex] is 110.98 g/mol and each beaker must have [tex]$250 . mt$[/tex] of solution, what mass of [tex]$CaCl _2$[/tex] would be used? Use molarity [tex]$=\frac{\text { moles of solute }}{\text { Iters of solution }}$[/tex].

[Terjawab] Select all the correct answers. A sample of an unknown compound has a percent composition of $52.14 \%$ carbon, $13.13 \%$ hydrogen, and $34.73 \%$ oxygen. Which compounds could the sample be? $CH _3 CH _3 CH _2 O _2$ $C _2 H _5 OH$ $C _4 H _{10} O _2$ $C _4 H _{12} O _2$

[Terjawab] Consider the chemical equation in equilibrium: [tex]$A(g)+2 B(g) \Leftrightarrow C(g)+D(g)+\text { heat }$[/tex] What will happen to the equilibrium of this reaction if the temperature is increased? A. It will shift to the left because heat is released. B. It will shift to the left because heat is absorbed. C. It will shift to the right because heat is released.

[Terjawab] Which type of chemical reaction occurs in $C _6 H _{12}+9 O _2 \rightarrow 6 CO _2+6 H _2 O$? A. synthesis B. combustion C. single replacement D. double replacement

[Terjawab] Commonly called laughing gas, what are the molecular and empirical formulas of this substance? A. C2O2, CO2 B. C4O, CO C. CO2, CO₂ D. C402, C20 E. C₂O, CO2