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Questions in chemistry

[Terjawab] Select the correct answer. How would adding the catalyst nitrogen monoxide (NO) affect this reaction? [tex]2 SO_2(g)+O_2(g) \rightarrow 2 SO_3(g)[/tex] A. NO increases the rate at which [tex]SO _3[/tex] molecules are formed. B. NO reacts with [tex]SO _3[/tex] to produce more [tex]SO _2[/tex] molecules. C. NO decreases collisions between the [tex]SO _2[/tex] and [tex]O _2[/tex] molecules. D. NO increases the concentration of the [tex]SO _2[/tex] and [tex]O _2[/tex] molecules. E. NO increases the activation energy of the [tex]SO _2[/tex] and [tex]O _2[/tex] molecules.

[Terjawab] Which of the following is NOT a common source of particulate matter? A. volcanic dust B. salt particulates C. CFC's D. pollen

[Terjawab] Which pair of ions can form an ionic bond with each other and why? A. [tex]Cu ^{+}[/tex] and [tex]Ag ^{+}[/tex]; They are both metal ions. B. [tex]S ^{2-}[/tex] and [tex]O ^{2-}[/tex]; They have like charges. C. [tex]Br ^{-}[/tex] and [tex]At ^{-}[/tex]; They are both halogen ions. D. [tex]Li ^{+}[/tex] and [tex]Br ^{-}[/tex]; They have unlike charges.

[Terjawab] The elements beryllium, calcium, and strontium are all in group 2. What is the correct relationship of these elements regarding their ionization energy? A. [tex]$Ca \ \textless \ Be \ \textless \ Sr$[/tex] B. [tex]$Sr \ \textless \ Be \ \textless \ Ca$[/tex] C. [tex]$Be \ \textless \ Ca \ \textless \ Sr$[/tex] D. [tex]$Sr \ \textless \ Ca \ \textless \ Be$[/tex] E. [tex]$Ca \ \textless \ Sr \ \textless \ Be$[/tex]

[Terjawab] What causes pressure changes of reactants to affect the reaction rate? A. The boiling point of the gas is changed. B. The speed of the molecules is changed. C. The temperature of the molecules is changed. D. The frequency of collisions is changed.

[Terjawab] Choose the chemical equation that is correctly balanced. A. [tex]2 Ca ( s )+ Cl _2(g) \rightarrow CaCl _2(s)[/tex] B. [tex]4 Mg ( s )+ O _2(g) \rightarrow 2 MgO ( s )[/tex] C. [tex]Li ( s )+ Cl _2(g) \rightarrow 2 LiCl ( s )[/tex] D. [tex]C ( s )+ O _2(g) \rightarrow CO _2(g)[/tex]

[Terjawab] Which best describes an element? A. a pure substance B. a type of a mixture C. a pure compound D. an impure substance

[Terjawab] Find the mass of [tex]$AlCl _3$[/tex] that is produced when 25.0 grams of [tex]$Al _2 O _3$[/tex] react with excess HCl according to the following equation: [tex]$Al_2 O_3(s)+6 HCl(a q) \rightarrow 2 AlCl_3(a q)+3 H_2 O(l)$[/tex] A. 65.4 g B. 72.9 g C. 155 g D. 16.3 g E. 32.6 g

[Terjawab] What are "representative elements"? A. Elements in the same row of the periodic table B. Elements in the tall columns of the periodic table C. Elements in the short columns of the periodic table D. Elements that share the same properties on the periodic table

[Terjawab] Which of the following is the correct Lewis structure for nitrogen gas, [tex]$N _2$[/tex]?