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Questions in chemistry

[Answered] Which balances the equation [tex]Mg + O _2 \rightarrow MgO[/tex]? [tex]Mg +2 O _2 \rightarrow 4 MgO[/tex] [tex]2 Mg +2 O _2 \rightarrow 2 MgO[/tex] [tex]2 Mg + O _2 \rightarrow 2 MgO[/tex] [tex]2 Mg +2 O _2 \rightarrow 4 MgO[/tex]

[Answered] Fill in the name and empirical formula of each ionic compound that could be formed from the ions in this table: | cation | anion | empirical formula | name of compound | |---|---|---|---| | [tex]Ca ^{2+}[/tex] | [tex]CH _3 CO _2^{-}[/tex] | | | | [tex]K ^{+}[/tex] | [tex]BrO _3^{-}[/tex] | | | | [tex]Na ^{+}[/tex] | [tex]BrO _4^{-}[/tex] | | |

[Answered] Solid A + water [$\longrightarrow$] saturated solution At $60^{\circ} C$ 24g + 100g [$\rightarrow$] 124g At $60^{\circ} C$ 100g of water saturate 124g solid 80 g of water saturate? [$=\frac{80g \times 124g}{100g}$]

[Answered] Which compound contains only a nonpolar covalent molecule? $O _2$ HCl $H _2 O$ $NO _3$

[Answered] - reaction A: Your answer is incorrect. - reaction B: Your answer is incorrect. - reaction C: Your answer Is Incorrect. Use the observations about each chemical reaction in the table below to decide the sign (positive or negative) of the reaction enthalpy [tex]$\Delta H$[/tex] and reaction entropy [tex]$\Delta S$[/tex]. Note: if you have not been given enough information to decide a sign, select the "unknown" option. | reaction | observations | conclusions | |---|---|---| | A | The reverse of this reaction is always spontaneous but proceeds slower at temperatures below [tex]$140 .^{\circ} C$[/tex]. | [tex]$\Delta H$[/tex] is negative [tex]$\Delta S$[/tex] is | | B | This reaction is spontaneous only below [tex]$45 .^{\circ} C$[/tex]. | [tex]$\Delta H$[/tex] is [tex]$\Delta S$[/tex] is | | C | This reaction is slower below [tex]$-3 .^{\circ} C$[/tex] than above. | [tex]$\Delta H$[/tex] is [tex]$\Delta S$[/tex] is |

[Answered] Which of the following factors will slow down the rate of reaction? A. Volume reduction B. Increased surface area C. Use as an enzyme D. Decreased temperature

[Answered] " $Na _2 SO _3$ " represents sodium sulfite. What does the 4 mean in the formula $4 Na _2 SO _3$ ? A. There are four atoms of sodium. B. There are four atoms of sodium sulfite. C. There are four molecules of sodium sulfite. D. There are four elements in sodium sulfite.

[Answered] What is the atomic mass of oxygen-18?

[Answered] Which reaction is an example of a balanced endothermic reaction? Answer Options: Select one of four $N_2(g)+O_2(g)-\text { heat } \rightarrow 2 NO(g)$ $N_2(g)+O_2(g)+\text { heat } \rightarrow 2 N(g)$ $N_2(g)+O_2(g)+\text { heat } \rightarrow 2 NO(g)$ $N_2(g)+O_2(g) \rightarrow 2 NO(g)$

[Answered] What's missing from this chemical reaction that shows the combustion of propane? [tex]C _3 H _8+ O _2 \rightarrow H _2 O + CO _2[/tex] Answer Options: A. Methane as a secondary product B. The release of heat with the products C. An intermediary transition to butane D. The absorption of heat by the reactants