09/12 Worksheet for Exam 1

11) Consider the following selected postulates of Dalton's atomic theory: (i) Each element is composed of extremely small particles called atoms. (ii) Atoms are indivisible. (iii) Atoms of a given element are identical. (iv) Atoms of different elements are different and have different properties. Which of the postulates is(are) no longer considered valid?

A) (i) and (ii) B) (ii) only *C) (ii) and (iii)* D) (iii) only E) (iii) and (iv)

18) Calcium forms an ion with a charge of ________.

A) 1- B) 2- C) 1+ *D) 2+* E) 0

The correct answer (reported to the proper number of significant figures) to the following is ________. (2.05631)(6.9391136) / 12.59326 = ________

A) 1.1330639 *B) 1.13306* C) 1.133064 D) 1.1361 E) none of the above

13) An atom of the most common isotope of gold, Au, has ________ protons, ________ neutrons, and ________ electrons

A) 197, 79, 118 B) 118, 79, 39 C) 79, 197, 197 D) 79, 118, 118 *E) 79, 118, 79*

15) Which one of the following molecular formulas is also an empirical formula?

A) C6H6O2 *B) C2H6SO* C) H2O2 D) H2P4O6 E) C6H6

10) The symbol for the element sodium is ________.

A) Me B) Hg C) Sn *D) Na* E) Pb

14) Isotopes are atoms that have the same ________ but differing ________.

A) atomic masses, charges B) mass numbers, atomic numbers *C) atomic numbers, mass numbers* D) charges, atomic masses E) mass numbers, charges

5) In the following list, only ________ is not an example of a chemical reaction.

A) burning a plastic water bottle B) the production of hydrogen gas from water C) the tarnishing of a copper penny *D) chopping a log into sawdust* E) charging a cellular phone

1 ) A combination of sand, salt, and water is an example of a ________.

A) homogeneous mixture *B) heterogeneous mixture* C) compound D) pure substance E) solid

4) Which one of the following is an intensive property?

A) mass *B) temperature* C) heat content D) volume E) amount

12) Of the following, the smallest and lightest subatomic particle is the ________.

A) neutron B) proton *C) electron* D) nucleus E) alpha particle

3) For which of the following can the composition vary?

A) pure substance B) element *C) both homogeneous and heterogeneous mixtures* D) homogeneous mixture E) heterogeneous mixture

16) An empirical formula always indicates ________.

A) which atoms are attached to which in a molecule B) how many of each atom are in a molecule *C) the simplest whole-number ratio of different atoms in a compound* D) the isotope of each element in a compound E) the geometry of a molecule

17) Which species has 54 electrons?

B )128 52 Te2-

6) Osmium has a density of 22.6 g/cm3. What volume (in cm3) would be occupied by a 21.8 g sample of osmium?

*A) 0.965* B) 1.04 C) 493 D) 2.03 × 10-3 E) 2.03 × 103

7) In which one of the following numbers are all of the zeros significant?

*A) 100.090090* B) 0.143290 C) 0.05843 D) 0.1000 E) 00.0030020

9) How many Significant Figures does the number 0.005000 have?

*A) 4* B) 5 C) 1 D) 2 E) 3

2) Which one of the following is often easily separated into its components by simple techniques such as filtering or decanting?

*A) heterogeneous mixture* B) compounds C) homogeneous mixture D) elements E) solutions