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Questions in chemistry

[Terjawab] What mass of NaCl formed when 0.25 g Na react completely with $0.39 g Cl _2$? A. -0.14 g NaCl B. 0.14 g NaCl C. 0.59 g NaCl D. 0.64 g NaCl

[Terjawab] Your answer is wrong. In addition to checking your math, check that you used the right data and DID NOT round any intermediate calculations. The reduction of iron(III) oxide ( $Fe _2 O _3$ ) to pure iron during the first step of steelmaking, $2 Fe_2 O_3(s) \rightarrow 4 Fe(s)+3 O_2(g)$ is driven by the high-temperature combustion of coke, a purified form of coal: $C(s)+O_2(g) \rightarrow CO_2(g)$ Suppose at the temperature of a blast furnace the Gibbs free energies of formation $\Delta G_f$ of $CO _2$ and $Fe _2 O _3$ are $-415 . kJ / mol$ and $-840 . kJ / mol$, respectively. Calculate the minimum mass of coke needed to produce $440 . t$ of pure iron. (One metric ton, symbol t, equals 1000 kg. ) Round your answer to 2 significant digits.

[Terjawab] Which is a correct set of values of [tex]$m$[/tex] for one of the subshells of [tex]$n=2$[/tex]? A. [tex]$-1,0,1$[/tex] B. [tex]$-1,-2,0,1,2$[/tex] C. [tex]$-1,-2,-3,0,1,2,3$[/tex] D. [tex]$-1,-2,-3,-4,0,1,2,3,4$[/tex]

[Terjawab] What mass of [tex]$Cl _2$[/tex] reacted when 0.243 g Mg reacted completely to form [tex]$0.953 g MgCl _2$[/tex]?

[Terjawab] Using the "NAS" idea, how many electrons are "available" for the compound HOCl? $N=18$ 24 14 32 18

[Terjawab] For each row in the table below, decide whether the pair of elements will form a molecular compound held together by covalent chemical bonds. If the elements will form a molecular compound, check the box and enter the chemical formula and name of the compound. (If the elements will form more than one molecular compound, use the compound with the fewest total number of atoms.) You may assume all chemical bonds are single bonds, not double or triple bonds. | element #1 | element #2 | element pair will form a molecular compound | molecular compound | |---|---|---|---| | | | | chemical formula | name | | magnesium | nitrogen | | | | nitrogen | fluorine | | | | hydrogen | bromine | | |

[Terjawab] The electronic configuration of three elements $X$, $Y$, and $Z$ are $X - 2,8,7$; $Y - 2, 8, 2$; and $Z = 2,8$. Which of the following statements is correct? A. $Y$ and $Z$ are metals B. $Y$ and $X$ are non-metals C. $X$ is a non-metal and $Y$ is a metal D. $Y$ is a non-metal and $Z$ is a metal

[Terjawab] 1. Describe pH Scale: Write what is meant by the term 'pH' and what are the variations on the scale. Use examples, if possible. 2. List uses of pH Scale: Provide two or more uses of the pH scale.

[Terjawab] Select the best answer for the question. 20. On the pH scale, which value is considered neutral? A. 5 B. 7 C. 2 D. 11

[Terjawab] A chemist fills a reaction vessel with 0.536 g aluminum hydroxide $[Al(OH)_3]$ solid, 0.337 M aluminum $[Al^{3+}]$ aqueous solution, and 0.196 M hydroxic $[OH^-]$ aqueous solution at a temperature of $25.0^{\circ} C$. Under these conditions, calculate the reaction free energy $\Delta G$ for the following chemical reaction: $Al(OH)_3(s) \rightleftharpoons Al^{3+}(aq)+3 OH^{-}(aq)$ Use the thermodynamic information in the ALEKS Data tab. Round your answer to the nearest kilojoule.