Chemistry & STEAM Fundamentals II Density / Precision & Accuracy Quiz Dr. Ron Rusay

1. A pool is filled with 100 L of pure water. An aluminum block is dropped in and the volume rises to 105 L. What is the volume of the block? A. 5 L B. 105 L C. It depends on the block’s shape D. Not enough information is given.

2. A pool is filled with 100 L of pure water. A wooden block is dropped in. It floats and the volume rises to 102 L. What is the volume of the block? A. 2 L B. 102 L C. It depends on the block’s shape D. Not enough information is given.

3. Two different blocks, both with a mass of 5 kg have different volumes. How is it possible? A. One is more dense B. They are made of the same material C. They are made of different material D. More than one of these E. None of the above

4. What is the density of the block? A L/kg B. 1.6 L/kg C kg/L D. 1.6 kg/L

5. What is the mass of the block if it has a density of 0.86? A. 5.0 kg B. 91 kg C kg D. 6. kg

QUESTION #6 Which would provide more grams of NaCl, sample one with a mass of 2,350 mg, or sample two, a solid with a volume of 2.00 cm 3 ? (The density of solid salt is 2.16 g/cm 3.) Select the most massive sample and its mass in grams. A. Sample two; 1.08 grams B. Sample two; 4.32 grams C. Sample one; 2.35 grams D. Sample one; grams

QUESTION #7 The volume of any material can be obtained from its density and mass. If the mass of a sample of acid from a battery were 5.00 grams and its density was 1.2 g/mL, what would the correct reported volume in mL with the proper number of significant digits? A.6.0 mL B.6.00 mL C.4.2 mL D.4.17 mL

Melody weighed an object, then submerged it in pure water, and measured the water it displaced. Her respective measurements were 6.5 g and 5.0 mL. Her volume was 1. 2% less than her research group’s average and her mass was 0. 5% less than the average. What might the object be? A. Quebracho Wood; D (ρ) =1,235 kg/m 3 B. Diamond; D (ρ) = 3.53 g/cm 3 C. Lead; D (ρ) = 11.3 kg/L D. Cannot determine, because Melody’s value was less precise than the group’s. E. Cannot determine, because Melody’s value was less accurate than the group’s. QUESTION #8

Precision & Accuracy QUESTION #9: True (A)/ False (B) The image with the green darts has both the best accuracy and best precision of the three. (The bulls eye is the target.)

The melting point of pure benzoic acid is 122°C. The average melting point and deviation for the respective experimental results of four different student’s data are shown below. Which is the most precise, but not the most accurate student result? A) Student A (119+/-0.6 o C)B) Student B (115+/- 2.5 o C) C) Student C (122+/-3.7 o C)D) Student D (121+/-0.7 o C) QUESTION #10

The melting point of pure benzoic acid is 122°C. The average melting point and deviation for the respective experimental results of four different student’s data are shown below. Which is the most accurate, but not the most precise student result? A) Student A (119+/-0.6 o C)B) Student B (115+/- 2.5 o C) C) Student C (122+/-3.7 o C)D) Student D (121+/-0.7 o C) QUESTION #11

The melting point of pure benzoic acid is 122°C. The average melting point and deviation for the respective experimental results of four different student’s data are shown below. Which is the best overall result considering both accuracy and precision? A) Student A (119+/-0.6 o C)B) Student B (115+/- 2.5 o C) C) Student C (122+/-3.7 o C)D) Student D (121+/-0.7 o C) QUESTION #12