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Questions in chemistry

[Done] A 1-gram sample of a compound is added to 100 grams of [tex]H_2O(l)[/tex], and the resulting mixture is then thoroughly stirred. Some of the compound is then separated from the mixture by filtration. Based on Table F, the compound could be: 1. AgCl 2. CaCl₂ 3. NaCl 4. NiCl₂

[Done] Which statement describes a reversible reaction at equilibrium? 1. The activation energy of the forward reaction must equal the activation energy of the reverse reaction. 2. The rate of the forward reaction must equal the rate of the reverse reaction. 3. The concentration of the reactants must equal the concentration of the products. 4. The potential energy of the reactants must equal the potential energy of the products.

[Done] Which change results in the formation of different substances? A. burning of propane B. melting of NaCl (s) C. deposition of CO2(g) D. solidification of water

[Done] What type of formula represents the simplest whole number ratio of atoms of the elements in a compound? 1. Molecular formula 2. Condensed formula 3. Empirical formula 4. Structural formula

[Done] Which quantity can be calculated for a solid compound, given only the formula of the compound and the Periodic Table of the Elements? 1. The density of the compound 2. The heat of fusion of the compound 3. The melting point of each element in the compound 4. The percent composition by mass of each element in the compound

[Done] When an excited electron in an atom moves to the ground state, the electron: 1. absorbs energy as it moves to a higher energy state 2. absorbs energy as it moves to a lower energy state 3. emits energy as it moves to a higher energy state 4. emits energy as it moves to a lower energy state

[Done] Given the balanced equation representing a reaction: \[ \text{Al}_2(\text{SO}_4)_3 + 6\text{NaOH} \rightarrow 2\text{Al(OH)}_3 + 3\text{Na}_2\text{SO}_4 \] The mole ratio of NaOH to Al(OH)3 is: 1. 1:1 2. 3:1 3. 1:3 4. 3:7

[Done] When lithium reacts with bromine to form the compound LiBr, each lithium atom 1. gains one electron and becomes a negatively charged ion 2. gains three electrons and becomes a negatively charged ion 3. loses one electron and becomes a positively charged ion 4. loses three electrons and becomes a positively charged ion

[Done] Which compound is an electrolyte? 1. CH₃CHO 2. CH₃OCH₃ 3. CH₃COOH 4. CH₃CH₂CH₃

[Done] Given the balanced equation representing the reaction: \[ \text{N}_2 + \text{energy} \rightarrow \text{N} + \text{N} \] Which statement describes this reaction? A. Bonds are broken, and the reaction is endothermic. B. Bonds are broken, and the reaction is exothermic. C. Bonds are formed, and the reaction is endothermic. D. Bonds are formed, and the reaction is exothermic.