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Questions in chemistry

[Terjawab] Consider the reactivity data for 4 unknown elements and their ions. | | I (ion) | J (ion) | K (ion) | L (ion) | | :--------- | :------------ | :------------ | :------------ | :------------ | | Element I | x | Color change | Color change | Color change | | Element J | Color change | x | x | x | | Element K | Color change | x | x | Color change | | Element L | x | x | x | x | What is the relative reactivity of the elements from least to most reactive? A. Element I < Element K < Element J < Element L B. Element I and L are the same. Element J and K are the same. J and K are less than I and L. C. Element L < Element J < Element K < Element I

[Terjawab] Part A $NH _2 OH ( g ) \rightarrow NH _3(g)+ N _2(g)+ H _2 O ( g )$ Express your answer as a chemical equation. Identify all of the phases in your answer.

[Terjawab] Which statement best describes the relationship between activation energy and rate of reaction? A. Increasing the activation energy can increase the rate of a reaction. B. Reducing the activation energy can increase the rate of a reaction. C. Increasing the reaction energy does not alter the rate of reaction. D. Reducing the activation energy can decrease the rate of a reaction.

[Terjawab] Calculate the current that must be passed into a solution of aluminum salt for 1 hr 30 minutes in order to deposit 1.5 g of Aluminum. $(Al = 27)$

[Terjawab] Use the table to compare the solubilities of substances. Check all of the boxes that apply. A. Aspirin is less soluble than table salt, but more soluble than carbon dioxide. B. A saltwater solution can be made by dissolving 20 g NaCl in 50 mL water. C. A saturated solution of table sugar is more concentrated than a saturated solution of table salt. D. Increasing the temperature will increase the solubility of all the solutes in the table | Solute | Solubility (g/100 g water) | | :--------------------------------- | :----------------------------- | | Table sugar, [tex]$C _{12} H _{22} O _{11}$[/tex] | 200 | | Table salt, NaCl | 36 | | Aspirin, [tex]$C _9 H _8 O _4$[/tex] | 0.33 | | Carbon dioxide, [tex]$CO _2$[/tex] | 0.17 | *1 g water = 1 mL water

[Terjawab] X is a solution containing 6.0g/dm³ of HCl. Y contains 12g/dm³ of Na2CO3.XH2O. A student treated 25cm³ of Y with x using methyl orange as an indicator, and the average titer value was 12.9cm³. a) Write a balanced equation for the reaction. b) Calculate: i) the concentrated anhydrous Na2CO3 in solution Y ii) the value of x iii) the percentage of water of crystallization in solution y c) What type of salt is NA2CO3.XH2O?

[Terjawab] Write the empirical formula of at least four binary ionic compounds that could be formed from the following ions: [tex]$Mg^{2+}, Ni^{4+}, Cl^{-}, S^{2-}$[/tex]

[Terjawab] A physical chemist measures the temperature [tex]$T$[/tex] inside a vacuum chamber. Here is the result: [tex]$T=-13.8^{\circ} C$[/tex] Convert [tex]$T$[/tex] to SI units. Round your answer to 4 significant figures.

[Terjawab] Select the best answer for the question. Sulfur dioxide emitted from power plants eventually causes acid rain in the atmosphere. Which term best describes acid rain? A. Greenhouse gas B. Primary and secondary pollutant C. Primary pollutant D. Secondary pollutant

[Terjawab] Use [tex]$pH=-\log [H+]$[/tex] to find [tex]$[H+]$[/tex] Milk has a pH of 6.6. What is the hydrogen concentration [tex]$[H+]$[/tex] (in moles per liter) of milk? A. [tex]$-\log 6.6$[/tex] B. [tex]$log 6.6$[/tex] C. [tex]$10^{-6.6}$[/tex] D. [tex]$10^{6.6}$[/tex]