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Questions in chemistry

[Done] The polymer used in making synthetic hair wigs is made up of: (A) C₂H₃CH=CH₂ (B) CH₂=CH-CH=CH₂ (C) CH₂=CHO (D) CH₂=CHCOOCH₃

[Done] For a first order reaction, [tex] t_{99.99\%} = y \times t_{90\%} [/tex] Find the value of [tex] y [/tex].

[Done] An electric device delivers a current of [tex]$15.0 A$[/tex] for 30 seconds. How many electrons flow through it?

[Done] Using the activity series provided, which reactants will form products? $Na>Mg>Al>Mn>Zn>Cr>Fe>Cd>Co>Ni>Sn>Pb>H>Sb>Bi>Cu>Ag$ $Ag + NaNO _3 \rightarrow$ $Fe + Al _2 O _3 \rightarrow$ $Ni + NaCl \rightarrow$ $Fe + Cu \left( NO _3\right)_2 \rightarrow$

[Done] Consider the following chemical equation in equilibrium: [tex]$H_2 SO_4(aq) \Leftrightarrow 2 H^{+}+SO_4^{2-}$[/tex] What will happen to the chemical equilibrium if HCl is added to the system? A. The chemical equilibrium will be lost permanently. B. The chemical equilibrium will not be affected. C. The chemical equilibrium will shift to the left

[Done] Use the reaction [tex]I _2(s) \rightleftharpoons I _2(g), \Delta H=62.4 kJ / mol , \Delta S=0.145[/tex] [tex]kJ /( mol \cdot K )[/tex], for this question. At what temperature is the reaction at equilibrium? A. 62 K B. 0.002 K C. 157 K D. 430 K

[Done] Sodium carbonate is a basic salt because it is a salt of: A. strong acid and strong base B. weak acid and weak base C. strong acid and weak base D. weak acid and strong base

[Done] Consider the chemical equation in equilibrium: [tex]2 H_2(g)+O_2(g) \Leftrightarrow 2 H_2 O(g)[/tex] What will happen if the pressure of the system is increased? A. The reaction will not change. B. The reaction will stop completely.

[Done] Based on the information in the table, which elements are most likely in the same periods of the periodic table? | Element | Atomic mass (amu) | Total electrons | Valence electrons | Year isolated | | -------------- | ----------------- | --------------- | ----------------- | ------------- | | Aluminum (AI) | 27 | 13 | 3 | 1825 | | Boron (B) | 11 | 5 | 3 | 1808 | | Carbon (C) | 12 | 6 | 4 | 1803 | | Gallium (Ga) | 70 | 31 | 3 | 1875 | | Germanium (Ge) | 73 | 32 | 4 | 1886 | A. Boron and carbon are likely together in one period because they have very close atomic masses, while gallium and germanium are likely together in another period because they have very close atomic masses. B. Aluminum, boron, and carbon are likely together in one period because they were first isolated in the first half of the 1800s, while gallium and germanium are likely together in another period because they were first isolated in the second half. C. Boron and carbon are likely together in one period because they each end in "-on," while aluminum, gallium, and germanium are likely together in another period because they each end in "-ium." D. Aluminum, boron, and gallium are likely together in one group because they have the same number of valence

[Done] Considering the activity series given for nonmetals, what is the result of the below reaction? Use the activity series provided. [tex]F > Cl > Br > I[/tex] [tex]Br_2+NaF \rightarrow[/tex] A. no reaction B. [tex]Na + FBr _2[/tex] C. [tex]NaBr + F _2[/tex] D. [tex]Na _2 F+ Br _2[/tex]