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level: 1/3/2021

Questions and Answers List

level questions: 1/3/2021

Question	Answer
In the hydrogen spectrum, what is the wavelength of light associated with the n = 3 to n = 1 electron transition? A) 3.97 * 10^–25 nm B) 8.21 10^2 nm C) 9.75 10^6 cm D) 1.94 * 10^–18 m E) 1.03 *10^–7 m	E PTS: 1 DIF: Moderate REF: 7.4 KEY: Chemistry \| general chemistry \| atomic theory \| light \| Bohr theory \| atomic line
Which of the following arrangements is in order of increasing size? A) Ga3+ > Ca2+ > K+ > Cl– > S2– B) S2– > Cl– > K+ > Ca2+ > Ga3+ C) Ga3+ > S2– > Ca2+ > Cl– > K+ D) Ga3+ > Ca2+ > S2– > Cl– > K+ E) Ga3+ > Ca2+ > S2– > K+ > Cl–	A PTS: 1 DIF: Moderate REF: 8.4 KEY: Chemistry \| general chemistry \| bonding \| ionic bonding \| ionic radii
97. Which of these statements is a consequence (follows from) the Law of Definite Proportion? A) All samples of chlorine contain 35Cl and 37Cl in the same (definite) ratio. B) The mass of oxygen that is combined with a fixed mass of nitrogen in each of the binary nitrogen oxides can be expressed as a ratio of small whole numbers. C) The atomic masses of all of the elements in the periodic table have fixed values. D) The % lead by mass in the compound galena is the same for all pure samples obtained from any source. E) None of these is correct	D PTS: 1 DIF: Easy REF: 2.2 KEY: Chemistry \| general chemistry \| early atomic theory \| atomic theory of matter \| Dalton's atomic theory
Given that Ka for HOCl is 3.5 * 10^–8 and the Ka for HF is 7.2 * 10^–4 (both at 25°C), which of the following is true concerning K for the above reaction at 25°C? A) K is greater than 1. B) K is less than 1. C) K is equal to 1. D) Cannot be determined with the above information. E) None of these (A-D).	B PTS: 1 DIF: Moderate REF: 14.2 KEY: Chemistry \| general chemistry \| chemical equilibrium \| equilibrium constant \|
Consider a solution consisting of the following two buffer systems: H2CO3 HCO3– + H+ pKa = 6.4 H2PO4– HPO42– + H+ pKa = 7.2 At pH 6.4, which one of the following is true of the relative amounts of acid and conjugate base present? A) [H2CO3] > [HCO3–] and [H2PO4–] > [HPO42–] B) [H2CO3] = [HCO3–] and [H2PO4–] > [HPO42–] C) [H2CO3] = [HCO3–] and [HPO42–] > [H2PO4–] D) [HCO3–] > [H2CO3] and [HPO42–] > [H2PO4–] E) [H2CO3] > [HCO3–] and [HPO42–] > [H2PO4–]	B PTS: 1 DIF: Moderate REF: 15.2 KEY: Chemistry \| general chemistry \| acids and bases \| solutions of a weak acid or base with another solute \| buffer \| Henderson-Hasselbalch equation