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Questions in chemistry

[Terjawab] $\begin{array}{c} Al \left( NO _3\right)_3( aq ) \text { and } Na _3 PO _4( aq ) \\ Al \left( NO _3\right)_3( aq )+ Na _3 PO _4( aq ) \rightarrow AlPO _4(s) \\ \text { Molecular Equation } \\ Al ^3+( aq )+3 NO _3( aq )+3 Na ^3+( aq )+ PO _4{ }^{3-}( aq ) \\ \text { Complete Ionic Equation } \\ Al ^{3+}( aq )+ PO _4{ }^3 \\ \text { Net Ionic Equation } \\ \text { Spectator Ions }\end{array}$

[Terjawab] Consider the intermediate chemical reactions: [tex] \begin{array}{ll} Ca(s)+CO_2(g)+\frac{1}{2} O_2(g) \rightarrow CaCO_3(s) & \Delta H_1=-812.8 kJ \\ 2 Ca(s)+O_2(g) \rightarrow 2 CaO(s) & \Delta H_2=-1.269 .8 kJ \end{array} [/tex] The final overall chemical equation is [tex]$CaO ( s )+ CO _2(g) \rightarrow CaCO _3(s)$[/tex]. When the enthalpy of this overall chemical equation is calculated, the enthalpy of the second intermediate equation A. is halved and has its sign changed. B. is halved. C. has its sign changed. D. is unchanged.

[Terjawab] Calculate the standard entropy change for the following reaction: [tex]$N _2 O _4(g) \rightarrow 2 NO _{2(g)}$[/tex] Given that: Substance (Formula) | Molar entropies | [tex]$S ^{\circ}$[/tex] in J/K ---|---|--- [tex]$N _2 O _4$[/tex] | 304.2 | [tex]$NO _2$[/tex] | 240.0 |

[Terjawab] Lexi is balancing equations. She is finding one equation to be very difficult to balance. Which explains how to balance the equation [tex]ZnSO _4+ LbCO _2+ ZnCO _3+ Li _2 SO _4[/tex]? A. One reactant and one product needs the coefficient 2. B. The products both need a 3 coefficient. C. The reactants both need a 2 coefficient. D. Atoms in the equation are mostly in balance.

[Terjawab] What is the mass of $CO_2$ in atomic mass units? A. 22 amu B. 12 amu C. 28 amu D. 44 amu

[Terjawab] Select the correct answer. Polonium-210 decays once before it becomes a stable atom. What is that stable atom? [tex] {}_{84}^{210} Po \rightarrow \ldots+{ }_2^4 He [/tex] A. [tex] {}_{82}^{206} Pb [/tex] B. [tex] {}_{84}^{210} Po ^{-} [/tex] C. [tex] {}_{86}^{214} Rn [/tex] D. [tex] {}_{86}^{222} Rn [/tex] E. [tex] {}_{82}^{214} Pb [/tex]

[Terjawab] (a) If M is a metal, then the litmus will turn ...... (b) If M is a non-metal, then the litmus will turn ...... (c) If M is a reactive metal, then ...... will be evolved when M reacts with dilute sulphuric acid. (d) If M is a metal, it will form ...... oxide, which will form ...... solution with water. (e) If M is a non-metal, it will not conduct electricity in the form of ......

[Terjawab] Consider the following intermediate chemical equations: [tex]$\begin{array}{l} 2 Na(s)+Cl 2(g) \rightarrow 2 NaCl(s) \ 2 Na_2 O(s) \rightarrow 4 Na(s)+O_2(g) \end{array}$[/tex] In the final chemical equation, NaCl and [tex]$O _2$[/tex] are the products that are formed through the reaction between [tex]$Na _2 O$[/tex] and [tex]$Cl _2$[/tex]. Before you can add these intermediate chemical equations, you need to alter them by A. multiplying the second equation by 2. B. multiplying the first equation by 2. C. multiplying the first equation by (1/2). D. multiplying the second equation by ([tex]$1 / 4$[/tex]).

[Terjawab] Which fire extinguisher should only be used in a well-ventilated area? A. Class B B. Class C C. Class D D. Class A

[Terjawab] Use your understanding of the ideal gas law to identify the correct relationships among the variables. Pressure is inversely related to volume Temperature is inversely related to moles Volume is inversely related to pressure Moles are inversely related to temperature Identify the ideal gas law equation.