concentration? 1 _ 1010 M -10 M 10 M Correct! 1 _ 10-10 M Question 2 According to the following reaction, which molecule is acting as an acid? H2O + H2SO4 _ H3O+ + HSO4- H3O+ none of the above H2O Correct! H2SO4 HSO4- Question 3 According to the following reaction, which molecule is acting as a base? H3O+ + HSO4- _ H2O + H2SO4 H3O+ Correct! HSO4- none of the above H2SO4 H2O Question 4 Can an acid and a base react to form an acid? Yes and No. The reaction can only occur if the substances reacting are true acids and bases. Correct! Yes. An acid and a base can react to form an acid if the acid is a strong acid and the base is a weak base. No. Acids always react with bases to form salts. Yes and No. The reaction can only occur if the reactants are organic/carboxylic acids and organic bases. Question 5 A weak acid is added to a concentrated solution of hydrochloric acid. Does the solution become more or less acidic? Correct! Less acidic, since the solution becomes more dilute with a less concentrated solution of hydronium ions being added to the solution. More acidic, since there are more hydronium ions being added to the solution. No change in acidity, since the concentration of the hydrochloric acid is too high to be changed by the weak solution. Less acidic since the concentration of hydroxide ions will increase. Question 6 For the following reaction, identify whether the compound in bold is behaving as an acid or a base. H3PO4 + H2O _ H2PO4- + (H3O+) both base neither Correct! acid Question 7 1.12 / 1.12 pts According to the following reaction, which molecule is acting as a base? OH- + NH4+ _ H2O + NH3 none of the above Correct! OH- H2O NH4+ NH3 Question 8 For the following reaction, identify whether the compound in bold is behaving as an acid or a base. H3PO4 + H2O _ (H2PO4- )+ H3O+ both neither Correct! base acid Question 9 The hydroxide ion, HO-, is a ________. Correct! polyatomic ion proton donator very strong acid unique form of water Question 10 Which of the following statements about buffers is untrue? A salt from the reaction of a strong acid and a strong base can be used to make a buffer. Addition of small amounts of base to a buffer changes the pH. Correct! The pH of a buffer solution cannot change. None of the above are true. Addition of small amounts of acid to a buffer changes the pH. Question 11 An acid and a base react to form a salt, which consists of positive and negative ions. Which forms the positive ions: the acid or the base? Which forms the negative ions? all of the above Correct! The acid forms the negative ion, the base forms the positive ion. Because different substances can act as an acid or a base, it depends on the substance you begin with. The acid forms the positive ion, the base forms the negative ion. Question 12 According to the following reaction, which molecule is acting as a base? H2O + H2SO4 _ H3O+ + HSO4- HSO4- Correct! H2O H3O+ none of the above H2SO4 Question 13 Water is formed from the reaction of an acid and a base. Why is it not classified as a salt? The attraction between the two ions in water molecules are too strong. By definition, a salt must be able to dissolve in water, so water itself cannot be called a salt. Not all acid base reactions produce a salt, as in the case with the formation of water. Correct! A salt is an ionic compound, whereas water is a covalent compound. Question 14 According to the following reaction, which molecule is acting as an acid? H3O+ + HSO4- _ H2O + H2SO4 none of the above Correct! H3O+ H2O HSO4- H2SO4 Question 15 What best describes what happens when an acid such as HCl is mixed with water? A hydroxide ion from the water is transferred to the HCl molecule to form a proton and hydronium ion. Correct! The proton chemically bonded to the chlorine is transferred to a water molecule and forms a chloride ion and a hydronium ion. HCl is not an acid. none of the above A proton from the chlorine nucleus is ejected and captured by a water molecule to form a negatively charged HCl and a new hydronium ion. Question 16 According to the following reaction, which molecule is acting as an acid? H2O + NH3 _ OH- + NH4+ NH3 Correct! H2O none of the above NH4+ OH- Question 17 According to the following reaction, which molecule is acting as an acid? OH- + NH4+ _ H2O + NH3 Correct! NH4+ H2O none of the above NH3 OH- Question 18 Which of the following statements is not true about a neutralization reaction? None of the above are true. One molecule of acid neutralizes one molecule of base. Correct! Water is always formed in a neutralization reaction. A neutralization is the reaction of a hydroxide ion with a proton. All of the above are true. Question 19 Which of the following solutions is the most acidic? Correct! a solution with a pH = 5 a solution with a pH = 12 All of the solutions are basic. a solution with a pH = 13 a solution with a pH = 14 Question 20 How do you make a proton out of a hydrogen atom? let the hydrogen atoms undergo fusion remove an electron from a helium nucleus let the hydrogen atoms combine to form a hydrogen molecule and eject an electron Correct! remove an electron from a hydrogen atom Question 21 As the pH increases, the hydroxide ion concentration ________. goes down starts to affect the H+ concentration Correct! gets larger stays constant starts to decrease because it is reacting with the excess hydronium ions Question 22 What is the main characteristic of a strong base? It readily accepts an acidic proton. It is corrosive. Correct! It is completely dissociated in water. It will damage your skin. Question 23 A strong acid tends ________. Correct! all of the above to form negatively charged ions when dissolved in water to be strongly polar to form positively charged ions when dissolved in water Question 24 The hydronium ion, H3O+, is a ________. very strong base Correct! polyatomic ion unique form of water proton acceptor Question 25 For the following reaction, identify whether the compound in bold is behaving as an acid or a base. H3PO4 + (H2O) _ H2PO4- + H3O+ acid Correct! base neither both