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Questions in chemistry

[Answered] Now that we have put a coefficient of 2 in front of $NaNO_3$ and a coefficient of 1 in front of $PbCl_2$, what coefficient should go in front of NaCl to balance both the Cl atoms and the Na atoms? $Pb(NO_3)_2+? NaCl \rightarrow 1 PbCl_2+2 NaNO_3$ Express your answer numerically as an integer.

[Answered] What is the rate constant of a reaction if rate $=1 \times 10^{-2}(mol / L ) / s ,[ A ]$ is 2 M , [B] is $3 M, m=2$, and $n=1$ ? $k=\frac{\text { rate }}{|A|^r|B|^r}$ A. $8.3 \times 10^{-4}$ B. $1.7 \times 10^5$ C. $2.5 \times 10^{-3}$ D. $60 \times 10^4$

[Answered] Use Table B in your Student Guide to answer the questions about ion concentrations. A solution with a [tex]$pH =13$[/tex] has approximately how many moles of [tex]$OH ^{-}$[/tex] ions per liter? How many moles of [tex]$H ^{+}$[/tex] would this same solution have per liter? (Use the decimal form of your answer.) A different solution with an [tex]$H +$[/tex] concentration of [tex]$1.0 \times 10^{-4}$[/tex] would have a [tex]$pH =$[/tex]?

[Answered] Present the periodic table.

[Answered] A flammable gas that is leaking out of a compressed gas cylinder will burn or possibly explode if it finds... A. an ignition source. B. an open window. C. a nebulizer. D. Both B and C are correct.

[Answered] A chemical reaction is represented by the following unbalanced chemical equation: [tex]$Na _2( aq )+ HCl ( aq ) \rightarrow NaCl ( aq )+ H _2 S( g )$[/tex] Which statement best describes why it is necessary to balance all chemical equations? A. Chemical reactions do not destroy matter, so the same number of atoms must be present before and after the reaction. B. Chemical reactions make new substances, so the new elements must be accounted for. C. The total number of atoms in a chemical reaction are relative, so you can add as many as you want. D. The total number of atoms in a chemical reaction can change as the reaction proceeds, so they must be identified first.

[Answered] How many protons, neutrons, and electrons are in this ion? ${ }_{31}^{71} Ga^{3+}$ A. $31 p^+, 40 n^0, 28 e^-$ B. $31 p^+, 40 n^0, 31 e^-$ C. $31 p^+, 71 n^0, 31 e^-$ D. $40 p^+, 31 n^0, 40 e^-$

[Answered] Calculate the wavenumber of a beam of infrared radiation with a wavelength of $5.00 \mu m$.

[Answered] Select the correct answer. What would cause the equilibrium to shift left in this reaction? [tex]$CO+3 H_2 \rightleftharpoons CH_4+H_2 O$[/tex] A. adding heat to the product mixture B. a faster rate of forward reaction C. increased collisions between CO and [tex]$H _2$[/tex] D. the escape of water from the mixture E. placing the mixture in a cold water bath

[Answered] Which would lower the reaction rate? A. Increasing the concentration of reactants B. Raising the value of k C. Decreasing the temperature of the system D. Increasing the temperature of the system