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Unformatted text preview: Version 132 – Exam One: Shear – Shear – (52375) 1 This printout should have 30 questions. Multiplechoice questions may continue on the next column or page – find all choices before answering. 001 10.0 points Can an electron in an atom be in an energy level described by the set of quantum numbers n = 5, ℓ = 3, m ℓ = 2? 1. No, because m ℓ must be equal to ± 1. 2. No, because ℓ must be equal to n 1. 3. No, because m ℓ cannot be negative. 4. No, because n cannot be as large as 5. 5. Yes correct Explanation: Since n is 5, the possible values of ℓ are 0, 1, 2, 3, and 4. Since 3 is a possible value, we then consider if m ℓ could be 2 when ℓ is 3. The possible values of m ℓ are +3, +2, +1, 0, 1, 2, and 3 when ℓ is 3, so this combination of quantum numbers is permitted. 002 10.0 points Which quantum number is most important in determining the type, or shape of atomic orbitals? What would be its value for a 5 p orbital? 1. n, n = 1 2. m ℓ , m ℓ = 2 3. ℓ, ℓ = 5 4. n, n = 5 5. m ℓ , m ℓ = 1 6. ℓ, ℓ = 1 correct Explanation: 003 15.0 points What is the wavelength of an electron travel ing one tenth the speed of light? The speed of light is 2 . 9979 × 10 8 m/s. The mass of an elec tron is 9 . 11 × 10 − 28 g. Planck’s constant is 6 . 626 × 10 − 34 J · s = 6 . 626 × 10 − 34 kg · m 2 / s. 1. 3 . × 10 8 m 2. 1 . 60 × 10 − 19 m 3. 7 . 27 × 10 − 7 m 4. 2 . 42 × 10 − 11 m correct 5. 2 . 42 × 10 − 15 m Explanation: c = 2 . 9979 × 10 8 m/s v e = 0 . 10(2 . 9979 × 10 8 m/s) = 2 . 9979 × 10 7 m/s m e = (9 . 11 × 10 − 28 g) = 9 . 11 × 10 − 31 kg Applying the de Broglie equation, λ = 6 . 626 × 10 − 34 kg · m 2 / s (9 . 11 × 10 − 31 kg)(2 . 9979 × 10 7 m/s) = 2 . 42 × 10 − 11 m 004 12.0 points When the reaction P 4 O 10 + KOH → K 3 PO 4 + H 2 O is balanced, how much KOH is required to react with 3 moles of P 4 O 10 ? 1. 18 mol 2. 27 mol 3. 36 mol correct 4. 9 mol 5. 3 mol Explanation: n P 4 O 10 = 3.0 mol The balanced chemical equation for this reaction is P 4 O 10 + 12 KOH → 4 K 3 PO 4 + 6 H 2 O . Version 132 – Exam One: Shear – Shear – (52375) 2 From the coefficients we see that 12 mol KOH are required for each mole of P 4 O 10 reacted. We use this ratio to calculate the moles of KOH required to react 3 mol P 4 O 10 : ? mol KOH = 3 mol P 4 O 10 × 12 mol KOH 1 mol P 4 O 10 = 36 mol KOH 005 10.0 points Which of the following individual atoms has a paramagnetic electronic structure? 1. He 2. Li correct 3. Be 4. Ne 5. Mg Explanation: 006 10.0 points The number of unpaired electrons in a neutral atom of titanium (Ti) is 1. 2. correct 2. 3. 3. none 4. 1. 5. 4. Explanation: Titanium’s electronic configuration is 1 s 2 2 s 2 2 p 6 3 s 2 3 p 6 4 s 2 3 d 2 All of the orbitals before 3 d are completely filled, so no unpaired electrons exist in them....
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 Spring '09
 RUTH
 Atom, mol KOH

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