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Questions in chemistry

[Answered] Calculate the enthalpy change (kJ) when 40.0 g of [tex]$Na_2 O_2$[/tex] reacts with excess water? Report your answer with the correct number of significant figures. Do not include units in your answer.

[Answered] Translate the following statements into chemical equations and then balance them: a. Hydrogen combines with nitrogen to form ammonia. b. Hydrogen sulphide burns in air to give water and sulphur dioxide. c. Zinc reacts with dilute sulphuric acid to give zinc sulphate and hydrogen. d. Potassium metal reacts with water to give potassium hydroxide and hydrogen.

[Answered] Under which conditions would the solubility of a gas be greatest? A. high pressure and high temperature B. high pressure and low temperature C. low pressure and high temperature D. low pressure and low temperature

[Answered] What is the formula for the ammonium ion? [tex]NH _4{}^{+}[/tex]

[Answered] Given the following reaction, what will cause no impact on the equilibrium if the forward reaction is endothermic? [tex]2 PbS(s)+3 O_2(g)+C(s) \rightleftharpoons 2 Pb(s)+CO_2(g)+2 SO_2(g)[/tex] A. adding C B. adding Pb C. applying pressure D. applying heat

[Answered] {\begin{tabular}{|c|c|} \hline liquid & density \ \hline glycerol & $1.3 g \cdot mL ^{-1}$ \ \hline dimethyl sulfoxide & $1.1 g \cdot mL ^{-1}$ \ \hline acetone & $0.79 g \cdot mL ^{-1}$ \ \hline methyl acetate & $0.93 g \cdot mL ^{-1}$ \ \hline ethanolamine & $1.0 g \cdot mL ^{-1}$ \ \hline \end{tabular}} Next, the chemist measures the volume of the unknown liquid as $1574 . cm ^3$ and the mass of the unknown liquid as {\begin{tabular}{|l|l|} \hline Calculate the density of the liquid. Round your answer to 3 significant digits. & $\square$ $g \cdot mL ^{-1}$ \ \hline Given the data above, is it possible to identify the liquid? & yes no \ \hline If it is possible to identify the liquid, do so. & glycerol dimethyl sulfoxide acetone methyl acetate ethanolamine \ \hline \end{tabular}}

[Answered] Write the empirical formula of at least four binary ionic compounds that could be formed from the following ions: [tex]$Ca^{2+}, Pb^{4+}, I^{-}, O^{2-}$[/tex]

[Answered] Given the following equilibrium system, what will occur if the system is subjected to an increase in temperature? [tex]CuCl_4^{2-}(a q) green \rightleftharpoons Cu^{2+}+(a q) blue+4 Cl^{1-}(a q)+ energy[/tex] A. Keq will decrease B. The solution will turn more blue C. The solution will shift right D. Nothing will change

[Answered] A physical chemist measures the temperature [tex]$T$[/tex] inside a vacuum chamber. Here is the result: [tex]$T=-19 .{ }^{\circ} C$[/tex] Convert [tex]$T$[/tex] to SI units. Round your answer to 3 significant figures.

[Answered] What is the name for the $H _3 O ^{+}$ ion? A. hydrogen trioxide B. trihydroxide C. hydronium