Multiple Choice Identify the letter of the choice that best completes the statement or answers the question.
__A__ 1. The weight of an object is a. a measure of the gravitational force pulling the object toward the earth. b. equal to the mass of the matter in the object. c. a measure of the space occupied by the object. d. the same at any location on the earth. ___B_ 2. The melting of ice to liquid water is correctly classified as a. a chemical change c. both a chemical and a physical change b. a physical change d. neither a chemical nor a physical change _B___3. As two clear liquid solutions are added together, a red solid forms. This change is most likely a. physical c. neither chemical nor …show more content…
__C__ 24. What is the reason that U-238 is different from U-235? a. three more electrons c. three more neutrons b. three more protons d. there is no difference __B__ 25. How many neutrons are found in the nucleus of a boron-11 (b) atom? a. 11 b. 6 c. 5 d. 4 _A___ 26. Avogadro's number of iron (Fe) atoms would weigh a. 55.9 g b. 27.9 g c. 6.02 × 1023 g d. 6.02 × 10-23 g
_B___ 27. How many atoms are contained in a sample of krypton, Kr, that weighs 8.38 g? a. Avogadro's number c. one b. one-tenth Avogadro's number d. one-tenth _D___ 28. Which of the following has the largest mass? a. 5.0 mol H2O b. 3.5 mol NH3 c. 8.0 mol C d. 6.0 mol C2H2 __A__ 29. How many silicon atoms (Si) are contained in a 12.5 g sample of silicon? a. 2.68 × 1023 b. 5.83 × 10-22 c. 1.35 × 1024 d. 1.71 × 1021
_B__ 30. How many moles of oxygen atoms are in one mole of CO2? a. 1 b. 2 c. 6.02 × 1023 d. 12.04 × 1023
__A__ 31. What is the weight percentage of nitrogen in urea, CN2H4O? a. 46.7 b. 30.4 c. 32.6 d. 16.3
___D_ 32. How many carbon atoms are contained in 5.50 g of ethane, C2H6? a. 2.75 × 10-22 b. 3.29 × 1024 c. 1.10 × 1023 d. 2.21 × 1023
B____ 33. How many grams of iron (Fe) is contained in 15.8 g of Fe(OH)3? a. 12.1