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Questions in chemistry

📝 Answered - Fill in the missing information: | symbol | atom or ion? (check all that apply) | number of protons | number of electrons | |---|---|---|---| |$\square$ |$\square$ neutral atom $\square$ cation $\square$ anion | 49 | 47 | | Kr |$\square$ neutral atom $\square$ cation $\square$ anion | $\square$ | $\square$ | | $P ^{2-}$ |$\square$ neutral atom $\square$ cation $\square$ anion | $\square$ | $\square$ |

📝 Answered - Fill in the missing information: | symbol | | atom or ion? check all that apply | | number of protons | number of electrons | | :----- | :-: | :-------------------------------- | :-: | :---------------- | :---------------- | | 2+ Mg | | cation | | | | | C | | neutral atom | | | | | | | neutral atom | | 51 | 54 |

📝 Answered - Complete the table below. For example, in the first row decide whether [tex]$Sc ^{3+}$[/tex] is a cation or anion. In the second row, write the symbol for the ion that an atom of potassium is mostly likely to form and then decide what type of ion it is. | element | most likely ion | |---|---| | | symbol of ion | type of ion | | scandium | [tex]$Sc ^{3+}$[/tex] | | | potassium | | cation | | oxygen | | cation | | barium | | cation | | chlorine | | cation anion

📝 Answered - $33.6 \text{ g}$ of $N_2$ and 24 g of $H_2$ are placed in a $5 \text{ dm}^3$ sealed container and react according to the following balanced equation until dynamic equilibrium is reached. $N_2(g)+3 H_2(g) \rightleftharpoons 2 NH_3(g)$ 6.1 Explain the term "dynamic chemical equilibrium" At 573 K when equilibrium is reached, there is $5.6 \text{ g}$ of $N_2$ gas left inside the container. 6.2 Calculate the concentration of both reactants when the reaction reached equilibrium for the first time. 6.3 Calculate the equilibrium constant $(K_c)$ when this reaction reached equilibrium. 6.4 How would the yield of $NH_3$ change if a smaller container than the $5 \text{ dm}^3$ is used? Write only INCREASES, DECREASES or REMAINS THE SAME. The temperature of this reaction increases from 573 K to 700 K. At this new temperature the equilibrium constant for this reaction decreases. 6.5 Is the forward reaction endothermic or exothermic? 6.6 Explain your answer to QUESTION 6.5.

📝 Answered - Which element will have the smallest atomic radius? nitrogen (N) arsenic (As) antimony (Sb) phosphorus (P)

📝 Answered - Which element will have the largest atomic radius? potassium (K) germanium (Ge) calcium (Ca) gallium (Ga)

📝 Answered - A chemist needs to know the mass of a sample of [tex]$MgCl _2$[/tex] to 5 significant digits. He puts the sample on a digital scale. This is what the scale shows: 0 0 4 0 7 If this measurement is precise enough for the chemist, round it to 5 significant digits. Otherwise, press the "No solution" button.

📝 Answered - Count the significant digits in each of these measurements: | measurement | number of significant digits | | :---------------------- | :----------------------------- | | [tex]$4.3 \times 10^{-3} mL$[/tex] | $\square$ | | [tex]$72700 . kg$[/tex] | $\square$ | | 0.005100 J | $\square$ | | [tex]$-6.0 \times 10^{-1} kJ / mol$[/tex] | $\square$ |

📝 Answered - Count the significant digits in each of these measurements: | measurement | number of significant digits | | ----------- | ----------------------------- | | [tex]$4.3 \times 10^{-3} mL$[/tex] | | | [tex]$72700 . kg$[/tex] | | | 0.005100 J | | | [tex]$-6.0 \times 10^{-1} kJ / mol$[/tex] | |

📝 Answered - A chemical reaction is described by the following equation: [tex]Mg(OH)_2(aq)+2 HCl_{(aq)} \rightarrow MgCl_2(aq)+2 H_2 O_{(l)}[/tex] What type of reaction is this? Which of the statements below best describes this reaction? A. One compound breaks down into two or more substances. B. Two or more substances combine to form one compound. C. A hydrocarbon combines with oxygen to form carbon dioxide and water. D. One of the elements in a compound is replaced. E. Two compounds swap "partner" elements with each other.