Common Benchmark Exam 1

Common Benchmark Exam 1 Name: Date:

Chemistry Benchmark Exam #1

Multiple Choice

Identify the choice that best completes the statement or answers the question. 1. Who conducted experiments to determine the quantity of charge carried by an electron? A) Dalton B) Millikan C) Thomson D) Rutherford

2. What quantity is represented by the metric system prefix deci-? A) 0.1 B) 100 C) 0.01 D) 1000

3. The diameter of a carbon atom is 0.000 000 000 154 m. What is this number expressed in scientific notation? A) 1.54 10 - 12 m B) 1.54 10 12 m C) 1.54 10 10 m D) 1.54 10 - 10 m

4. Why did J. J. Thomson reason that electrons must be a part of the atoms of all elements? A) An electron is 2000 times lighter than a hydrogen atom. B) Cathode rays are negatively-charged particles. C) Charge-to-mass ratio of electrons was the same, regardless of the gas used. D) Cathode rays can be deflected by magnets.

5. Which of the following isotopes has the same number of neutrons as phosphorus-31? A) S B) Si C) P D) Si

1 Common Benchmark Exam 1 Name: Date:

6. Using the chart below answer the following question: Liquid Description Density Boiling Point (g/mL) ( oC) H Nonflammable colorless compound 1.62 59.5 I Flammable colorless compound 0.71 34.6 J Yellow mixture with strong odor 0.73 160.4 K Viscous pale-yellow oil 0.93 300.00

If you were to pour samples of the fluids (all insoluble in water) listed in the table into flasks filled with water, which has a density of 0.998 g/mL, which liquid would form a layer at the top of the flask?

I. H II. J III. K A) I only B) II only C) I and III D) II and III E) None of the above

7. Which of the following quantum leaps would be associated with the greatest energy of emitted light? A) n = 4 to n = 5 B) n = 5 to n = 1 C) n = 5 to n = 4 D) n = 2 to n = 5

8. The range in size of most atomic radii is approximately ____. A) 5 10 - 11m to 2 10 - 10 m B) 2 to 5 cm C) 2 to 5 nm D) 5 10 - 21m to 2 10 - 20 m

9. In the measurement 0.503 L, which digit is the estimated digit? A) 5 B) the 0 to the left of the decimal point C) the 0 immediately to the left of the 3 D) 3

10. A fictitious element X is composed of 10 percent of the isotope 55X 20 percent of the isotope 56X, and 70 percent of the isotope 57X. Estimate the atomic mass of element X. A) 56.5 amu B) 55.4 amu C) 56.6 amu D) 55.5 amu

11. What is the next atomic orbital in the series 1s, 2s, 2p, 3s, 3p? A) 3f B) 4s C) 2d D) 3d

12. Emission of light from an atom occurs when an electron ____. A) drops from a higher to a lower energy level B) jumps from a lower to a higher energy level C) moves within its atomic orbital D) Falls into the nucleus

13. The shape (not the size) of an electron cloud is determined by the electron's ____. A) principal quantum number B) Speed C) energy sublevel D) Position

14. The correct number of electrons in an neutral atom of Iridium is: A) 269 B) 192 C) 115 D) 77

15. Which electron configuration of the 4f energy sublevel is the most stable? A) 4f B) 4f C) 4f D) 4f

16. Which of the following was originally a tenet of Dalton's atomic theory, but had to be revised about a century ago? A) Atoms of the same element are identical. B) Compounds are made by combining atoms. C) Atoms are tiny indivisible particles. D) Atoms of different elements can combine with one another in simple whole number ratios.

17. As changes in energy levels of electrons increase, the frequencies of atomic line spectra they emit ____. A) Increase B) Decrease C) cannot be determined D) remain the same

18. The correct electron configuration for chlorine is: A) 1s 2s 2p33s 3p3 B) 1s 2s 2p 3s3 C) 1s 2s 2p 3s 3p D) 1s 2s 2p 3p3

19. What is the maximum number of electrons in the second principal energy level? A) 32 B) 8 C) 18 D) 2

20. In Bohr's model of the atom, where are the electrons and protons located? A) The electrons move around the protons, which are at the center of the atom. B) The electrons occupy fixed positions around the protons, which are at the center of the atom. C) The electrons and protons are located throughout the atom, but they are not free to move. D) The electrons and protons move throughout the atom.

21. Using the periodic table, determine the number of neutrons in O. A) 4 B) 24 C) 8 D) 16

22. A cubic meter is about the same as the volume occupied by a ____. A) basketball arena B) washing machine C) kilogram of water D) cup of milk

23. Express the product of 2.2 mm and 5.00 mm using the correct number of significant digits. A) 10 mm2 B) 11 mm2 C) 11.0 mm2 D) 11.00 mm2 E) None of these

24. Using the periodic table, the number of neutrons in nitrogen-14 is: A) 1 B) 14 C) 21 D) 7

25. Scientists A and B, from different labs, got the same results when the mixed two gases under very cold conditions. They published their results in a well-known journal. A year later, scientist C performed the same experiment but got different results. What should be done now? A) Nothing; the data were already published B) Nothing; scientist C could not be correct because sicentists A and B found the same results. C) More tests will need to be completed and the experiment further investigated. D) The new data should be published, but the experiment should not b e attempted again.

26. In relation to the expected theoretical mass of a compound of 3.12 x 10 2, the data in the table below are

Experimental Mass Experiment 1 3.00 x 10 2 Experiment 2 2.99 x 10 2 Experiment 3 3.00 x 10 2 Experiment 4 2.98 x 10 2 Experiment 5 2.98 x 10 2 A) Accurate B) Precise C) Both accurate and precise D) Neither accurate or precise

27. As a consequence of the discovery of the nucleus by Rutherford, which model of the atom is thought to be true? A) The nucleus is made of protons, electrons, and neutrons. B) Electrons are distributed around the nucleus and occupy almost all the volume of the atom. C) The nucleus is made of electrons and protons. D) Protons, electrons, and neutrons are evenly distributed throughout the volume of the atom.

28. How do the energy differences between the higher energy levels of an atom compare with the energy differences between the lower energy levels of the atom? A) They are smaller in magnitude than those between lower energy levels. B) There is no significant difference in the magnitudes of these differences. C) No answer can be determined from the information given. D) They are greater in magnitude than those between lower energy levels.

29. Chlorine boils at 239 K. What is the boiling point of chlorine expressed in degrees Celsius? A) B) 93 C C) –61 C D) 34 C

A) –34 C B) –93 C C) –61 C D) 34 C

30. Which of the following was NOT among Democritus’s ideas? A) Atoms are indestructible. B) Atoms retain their identity in a chemical reaction. C) Matter consists of tiny particles called atoms. D) Atoms are indivisible.

31. How does the speed of visible light compare with the speed of gamma rays, when both speeds are measured in a vacuum? A) No answer can be determined from the information given. B) The speed of gamma rays is greater. C) The speed of visible light is greater. D) The speeds are the same.

32. Why do chemists use relative masses of atoms compared to a reference isotope rather than the actual masses of the atoms? A) The actual masses of atoms are very small and difficult to work with. B) The actual masses of protons, electrons, and neutrons are not known. C) The actual mass of an electron is very large compared to the actual mass of a proton. D) The number of subatomic particles in atoms of different elements varies.

33. A train travels at a speed of 30 miles per hour. If 1 mile = 1.6 kilometers, how fast is the train traveling in kilometers per minute (km/min)? A) 1.0 km/min B) 0.4 km/min C) 0.6 km/min D) 0.8 km/min

34. Dimensional analysis involves which of the following processes? A) B) C) D) E)

A) Solving a formula B) Estimating the magnitude of the answer C) Splitting the problem into steps D) Multiplying a known measurement by a conversion factor E) None of these

35. How can the position of a particle be determined? A) by determining its charge B) by analyzing its interactions with another particle C) by measuring its velocity D) by measuring its mass

Essay Question Write a well organized essay that includes an introduction, several paragraphs addressing the task below, and a conclusion.

Theme: Measurements in Science

Task: Explain the difference between precision and accuracy.

Suppose you made threee different mass measurements of a sugar sample you knew to have a mass of 1.00 g.

♦ Discuss how you would know whether or not the measurements were accurate. ♦ Discuss how you would know whether or not they were precise. ♦ Explain how the three measurements could be precise, but not accurate.