Homework 8-solutions - dewitt(aad777 Homework 8 sutclie(52380 This print-out should have 21 questions Multiple-choice questions may continue on the next

Homework 8-solutions - dewitt(aad777 Homework 8...

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dewitt (aad777) – Homework 8 – sutcliffe – (52380) 1 This print-out should have 21 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 10.0 points Name H 3 PO 2 . 1. phosphoric acid 2. perphosphorous acid 3. perphosphoric acid 4. hypophosphorous acid correct 5. hypophosphoric acid 6. hydrophosphoric acid 7. phosphorous acid Explanation: H 3 PO 4 is phosphoric acid. H 3 PO 2 has two fewer oxygens and would therefore be named hypo phosphor ous acid. 002 10.0 points The term strong in strong electrolyte means 1. All of these 2. that the compound is very concentrated. 3. that the compound is very soluble. 4. that the compound ionizes or dissociates completely or almost completely in solution. correct Explanation: To be an electrolyte, the compound must not only be soluble in water, but must also dis- sociate into ions. To be a strong electrolyte, the dissociation should be nearly complete. 003 10.0 points Which one of the following is a water-soluble,weak electrolyte? 1. H 2 CO 3 correct 2. H 2 SO 4 3. NH 4 ClO 4. Ca(OH) 2 5. KBr Explanation: All of the choices are electrolytes, but only carbonic acid (H 2 CO 3 , a weak acid) does not ionize completely, so it is a weak electrolyte. 004 10.0 points How much solute is needed to make 1.45 L of a 3.53 M solution of Ba(NO 3 ) 2 ? Correct answer: 1337 . 46 g. Explanation: [Ba(NO 3 ) 2 ] = 3.53 M V soln = 1.45 L m Ba(NO 3 ) 2 = ? M = mol solute L soln mol solute = 3 . 53 M × 1 . 45 L = 5 . 1185 mol n = g solute × 1 mol solute molar mass solute m solute = # of moles × molar mass solute 1 mol solute = 5 . 1185 mol Ba(NO 3 ) 2 × 261.3 g 1 mol = 1337 . 46 g Ba(NO 3 ) 2 005 10.0 points We wish to dilute some 18 . 4 M H 2 SO 4 solution to make 600 mL of a 0 . 1 M H 2 SO 4 solution. How much of the 18 . 4 M solution should we start with? 1.2.70 mL2.3.26 mLcorrect
dewitt (aad777) – Homework 8 – sutcliffe – (52380) 2 3. 1.80 mL 4. 4.00 mL 5. 4.60 mL Explanation: M 1 V 1 = M 2 V 2 V 2 = M 2 V 2 M 1 = (0 . 1 M) (600 mL) 18 . 4 M = 3 . 26087 mL 006 10.0 points What are the products of the reaction be-tween bromic acid and potassium hydroxide? 6. KBrO 3 + H 2 O correct 7. KBrO 2 + H 2 O Explanation: 007 10.0 points What, if anything, is precipitated when aque- ous solutions of Ba(OH) 2 and MgSO 4 are mixed? 1. only Mg(OH) 2 2. both BaSO 4 and Mg(OH) 2 correct 3. only BaSO 4 4. Nothing precipitates. Explanation: This is a metathesis reaction with the prod- ucts barium sulfate (BaSO4) and magnesium hydroxide (Mg(OH) 2 ). Both of these prod- ucts are insoluble and will form precipitates. 008 10.0 points Write the formula unit equation for this reac- tion occurring in water: Ammonium fluoride

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