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Questions in chemistry

📝 Answered - Compare the total mass of the reactants to the total mass of the products. What choice demonstrates the Law of Conservation of Mass? [tex]$12 g C + 22 g O_2 \rightarrow 44 g CO_2$[/tex] [tex]$4 g H_2 + 61 g Cl_2 \rightarrow 75 g HCl$[/tex] [tex]$23 g Na + 12 g H_2O \rightarrow 40 g NaOH + 1 g H_2$[/tex] [tex]$10 g H_2 + 46 g N_2 \rightarrow 56 g NH_3$[/tex]

📝 Answered - Fill in the gaps to balance the equation. Use the smallest set of whole numbers to balance the equation and include coefficients of "1" when appropriate. [tex]$\square$ $Na _3 N+$ $\square$ $SrF _2 \rightarrow$ $\square$ $NaF +$ $\square$ $Sr _3 N_2$[/tex] Complete the table to determine how many atoms of each element are present in the reactants and products. | Element | Reactant | Products | | :------ | :------- | :------- | | Na | $\square$ | | | N | $\square$ | $\square$ | | Sr | $\square$ | $\square$ | | F | $\square$ | $\square$ |

📝 Answered - Consider the chemical equations shown here. [tex]$\begin{array}{l} CH_4(g)+2 O_2(g) \rightarrow CO_2(g)+2 H_2 O(g) \Delta H_1=-802 kJ \\ 2 H_2 O(g) \rightarrow 2 H_2 O(l) \Delta H_2=-88 kJ \end{array}$[/tex] Which equation shows how to calculate [tex]$\Delta H_{ rxn }$[/tex] for the equation below? [tex]$CH_4(g)+2 O_2(g) \rightarrow CO_2(g)+2 H_2 O(l)$[/tex]

📝 Answered - Fill in the gaps to balance the equation. Use the smallest set of whole numbers to balance the equation and include coefficients of "1" when appropriate. [tex]$\square$ Mg _3 P _2+ $\square$ Ag _2 S \rightarrow $\square$ MgS + $\square$ Ag _3 P[/tex] Complete the table to determine how many atoms of each element are present in the reactants and products. | Element | Reactant | Products | |---|---|---| | Mg | $\square$ | $\square$ | | P | $\square$ | $\square$ | | Ag | $\square$ | $\square$ | | S | $\square$ | $\square$ |

📝 Answered - Consider the chemical equations shown here. [tex]$\begin{array}{l}< CH_4(g)+2 O_2(g) \rightarrow CO_2(g)+2 H_2 O(g) \Delta H_1=-802 kJ \\ 2 H_2 O(g) \rightarrow 2 H_2 O(l) \Delta H_2=-88 kJ \end{array}$[/tex] Which equation shows how to calculate [tex]$\Delta H_{ rxn }[/tex] for the equation below? [tex]$CH_4(g)+2 O_2(g) \rightarrow CO_2(g)+2 H_2 O(l)$[/tex] What is [tex]$\Delta H_{ rxn }[/tex] for the overall reaction?

📝 Answered - What choice demonstrates the Law of Conservation of Mass? A. [tex]$26 g CaO +8 g H _2 O \rightarrow 31 g Ca ( OH )_2$[/tex] B. [tex]$2 g H _2+16 g O _2 \rightarrow 19 g H _2 O$[/tex] C. [tex]$74 g Fe ^{+} 32 g O _2 \rightarrow 105 g Fe _2 O _3$[/tex] D. [tex]$50 g Mg +33 g O _2 \rightarrow 83 g MgO$[/tex]

📝 Answered - Which is the electron configuration for nobelium (No)? A. [ Rn ] 7 s^2 5 f^{14} B. [ Rn ] 7 s^2 5 f^7 C. [ Ne ] 3 s^2 3 p^7 D. [ Xe ] 6 s^2 5 d^1

📝 Answered - Consider the chemical equations shown here. [tex] \begin{array}{l} NO(g)+O_3(g) \rightarrow NO_2(g)+O_2(g) \Delta H_1=-198.9 kJ \\ \frac{3}{2} O_2(g) \rightarrow O_3(g) \Delta H_2=142.3 kJ \\ O(g) \rightarrow \frac{1}{2} O_2(g) \Delta H_3=-247.5 kJ \end{array} [/tex] What is [tex]$\Delta H_{\text {rxn }}$[/tex] for the reaction shown below? [tex]$NO(g)+O(g) \rightarrow NO_2(g)$[/tex]

📝 Answered - What law says the total amount of substance at the beginning of a reaction must be equal to the amount of substance at the end of the reaction? A. Law of Conservation of Heat B. Law of Conservation of Moles C. Law of Conservation of Mass D. Law of Conservation of Energy

📝 Answered - $Zn(s) + HCl(aq) \rightarrow ZnCl_2(aq) + H_2(g)$ A piece of zinc is dropped into $0.1 cm^3$ of $0.1 mol \cdot dm ^{-3} HCl$ and the following data were obtained at 4 second intervals. | Time (s) | Mass of zinc (g) | | -------- | ---------------- | | 0 | 0.016 | | 4 | 0.012 | | 8 | 0.010 | | 12 | 0.009 | | 16 | 0.008 | | 20 | 0.008 | 5.1 Calculate the average rate of the reaction for the first 12 s in $mol ^{-1}$. 5.2 Explain why the mass of the zinc remained constant after 16 s. 5.3 Explain how the rate of the reaction changes as time passes. Answer only INCREASES, DECREASES, or REMAINS THE SAME. 5.4 A graph that shows the amount of $H _2$ gas that was produced against time for this reaction is shown below: