What the frequency of this X-ray

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Reference no: EM132848125

Assignment - General Chemistry Questions

Q1. Which of the following is NOT a conjugate acid-base pair?

a) HF/NaF.

b) H₂PO₄^-/HPO₄^-2.

c) H₂C₂O₄/C₂O₄^-2.

d) CH₃NH₂/CH₃NH₃⁺.

Q2. The ionic strength of a 0.020 M CaCl₂ solution is

a) 0.010 M.

b) 0.020 M.

c) 0.040 M.

d) 0.060 M.

Q3. Which of the following solutions, when mixed with 40.0 mLs of 0.050 M CH₃COOH solution, makes a buffer solution?

a) 40.0 mls of 0.050 M NaOH.

b) 40.0 mLs of 0.10 M NaOH.

c) 20.0 mls of 0.050 M NaOH.

d) 20.0 mLs of 0.10 M NaOH.

Q4. Which of the following statements regarding random errors is FALSE?

a) Random error can be reduced by averaging multiple measurements.

b) Random error can be both positive and negative and varies in magnitude.

c) Random error can be estimated from statistical analysis of replicate measurements.

d) Random error can be eliminated from an analysis by using extreme caution.

Q5. The solubility of BaF₂ in water is 7.5x10^-3. The K_sp for BaF₂ is

a) 1.7x10^-6.

b) 4.2x10^-7.

c) 8.4x10^-7.

d) 5.6x10^-5.

Q6. The oxidizing agent in the following redox reaction is

H⁺ + Cr₂O₇^-2 + Ni → Ni⁺² + Cr⁺³ + H₂O

a) Cr₂O₇^-2.

b) Ni.

c) Ni⁺².

d) H⁺.

Q7. A salt bridge connects the two solutions in a voltaic cell. Which of the following statements about a salt bridge is FALSE?

a) A salt bridge helps maintain charge balance in both half-cells through movement of ions.

b) A salt bridge completes the circuit in a voltaic cell.

c) A salt bridge transfers electrons between the anode and the cathode.

d) A salt bridge contains ions that can be exchanged with the solutions in the half-cells.

Q8. Which of the following half reactions will take place at the anode of a voltaic cell?

a) HNO₂ → NO₃^-.

b) BrO₃^- → Br₂.

c) MnO₄^- → MnO₂.

d) Fe⁺³ → Fe⁺².

Q9. When the following redox reaction is balanced, the coefficient in front of I^- is

I^- + NO₃^- → NO + I₂

a) 2.

b) 3.

c) 6.

d) 8.

Q10. A table of half-reactions and their standard electrode potentials is given:

Half-reactions	E^o(volts)
Al⁺³ + 3e^- → Al	-1.66
Au⁺³ + 3e^- → Au	+1.50
Mn⁺² + 2e^- → Mn	-1.18
Ag⁺ + e^- → Ag	+0.80

The strongest reducing agent in this group is

a) Al.

b) Au.

c) Mn.

d) Ag.

Q11. The form of the electromagnetic spectrum listed with the smallest wavelength is

a) infrared.

b) visible.

c) ultraviolet.

d) X-rays.

Q12. Ka for HF is 7.1x10^-4. The pH of a 0.3 M HF solution is

a) 0.52.

b) 1.42.

c) 1.84.

d) 3.15.

Q13. The energy of a photon with a frequency of 5.26x10⁵ cycles/sec is

a) 1.26x10^-39 Joules.

b) 3.49x10^-28 Joules.

c) 4.10x10^-19 Joules.

d) 7.93x10³⁸ Joules.

Q14. Atoms emit energy as light when the electrons

a) jump from lower energy levels to higher energy levels.

b) condense from a gas to a liquid.

c) jump from a higher energy level to lower energy levels.

d) move about the atom within a circular orbit.

Q15. An X-ray has a wavelength of 2.85x10^-10 meters. The frequency of this X-ray is

a) 9.50x10^-19 cycles/sec.

b) 7.16x10^-16 cycles/sec.

c) 8.55x10^-2 cycles.sec.

d) 1.05x10¹⁸ cycles/sec.

Q16. A transition metal complex appears colorless. The reason is that it

a) contains only spin allowed transitions.

b) contains a metal ion with a d¹⁰ configuration.

c) contains charge transfer transitions.

d) contains laPorte forbidden transitions.

Q17. The d-d transitions necessary for the appearance of color in a compound are observed in an aqueous solution of

a) Co(NO₃)₂.

b) Zn(NO₃)₂.

c) Al(NO₃)₃.

d) MnO₄^-.

Q18. A solution is prepared by mixing 100.0 mLs of 0.001 M Ca(NO₃)₂ and 100.0 mls of 0.001 M NaF. The K_sp for CaF₂ is 4.0x10^-11. What happens when these solutions are mixed?

a) A precipitate of CaF₂ forms.

b) No reaction occurs.

c) CaF₂ forms, but does not precipitate.

d) Q_sp is greater than K_sp.

Q19. A buffer solution is prepared containing 0.7 M HF and 0.9 M NaF. The K_a for HF is 7.2x10^-4. The pH of the solution after the addition of 0.1 moles of HCl to 1 liter of the buffer solution is

a) 3.25.

b) 3.14.

c) 3.02.

d) 3.36.

Q20. An electrochemical cell is constructed using the substances given:

Pb⁺² + 2 e^- → Pb E^o = -0.12 volts

Cu⁺² + 2 e^- → Cu E^o = +0.34 volts

The free energy change (?G) for the reaction that would occur when these reactions are coupled is

a) +0.46 volts.

b) -44390 Joules/mole.

c) -96,500 Joules/mole.

d) -88780 Joules/mole.

Reference no: EM132848125

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