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Questions in chemistry

[Done] Which is not a property of chlorofluorocarbons? A. They're odorless B. They're highly flammable C. They're non-toxic D. They're very stable E. They're easy to produce

[Done] 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.

[Done] A chemical supply company sells sulfuric acid [tex]$\left( H _2 SO _4\right)$[/tex] in a concentration of 4.00 M. What volume of this solution would you need to make 12.0 mL of a [tex]$0.50 M H _2 SO _4$[/tex] solution? Which equation should you use? [tex]$V_i=\frac{M_f V_f}{M_i}$[/tex] [tex]$V_f-\frac{M_i V_i}{M_f}$[/tex] [tex]$V_f-\frac{M_f V_i}{M_i}$[/tex]

[Done] Group 0 elements are also known as NOBLE gases. Noble gases are... A. semi-reactive B. inert C. highly reactive D. flammable

[Done] A scientist is examining a mixture of nitrogen, hydrogen, and ammonia. The individual pressures that are exerted by nitrogen and hydrogen are [tex]0.26 atm[/tex] and [tex]0.28 atm[/tex], respectively. If the total pressure is [tex]0.90 atm[/tex], what is the partial pressure of ammonia? Use [tex]P_T=P_1+P_2+P_3+\ldots+P_n[/tex]. A. 0.27 atm B. 0.36 atm C. 0.54 atm D. 0.90 atm

[Done] Which statement describes a reaction at 298 K if [tex]$\Delta H=31$ $kJ / mol , \Delta S=0.093 kJ /( mol \cdot K )$[/tex]? A. Gibbs free energy is negative. B. It is not spontaneous. C. It is exothermic. D. It is at equilibrium.

[Done] The chemical symbol for the element calcium is Ca. What would be the symbol representing calcium atoms that Ca [tex]Ca ^{+}[/tex] [tex]Ca ^{-2}[/tex] [tex]Ca ^{+2}[/tex]

[Done] Which of the following is a correct empirical formula if the ratio of compounds is [tex]$2: 1: 3$[/tex]? A. [tex]$Na _2 SO _3$[/tex] B. [tex]$K _2 C _2 O _3$[/tex] C. [tex]$Ca _3( OH )_2$[/tex] D. [tex]$CF _2 Cl _2$[/tex]

[Done] The electrolytic cell shown below is used for the electrolysis of CuCl2 solution. A | | | | | | ----- B CuCl2 (aq) A and B are carbon electrodes. 9.1 Define electrolysis. 9.2 Is the process of electrolysis EXOTHERMIC or ENDOTHERMIC? 9.3 Write down the half reaction that occurs at electrode B. 0.369 g of Cu is deposited on the cathode in 27 minutes. 9.4 Calculate the electrical current used during this process.

[Done] What is crude oil? (ii). State four effects of petrochemicals on the environment.