Assignment 1

Written Assignment 1: Introduction and Measurement

Answer all assigned questions and problems, and show all work.

1. Do the following statements describe chemical or physical properties? (10 points)

a. Oxygen gas supports combustion.

*Chemical-oxygen gas combustion is chemical change

b. Fertilizers help to increase agricultural production.

*Chemical-fertilizer adds chemical to increase growth

c. Water boils below 100°C on top of a mountain.

*Physical-water boils below 100C is a measurement

d. Lead is denser than aluminum.

*Physical-denser is a measurement

e. Uranium is a radioactive element.

*Chemical-uranium is chemical properties

(Reference: Chang 1.11)

2. Classify each of the following as an element, a compound, a homogeneous mixture, or a heterogeneous mixture: (7 points)

a. water from a well *homogeneous mixture

b. argon gas *element

c. sucrose *compound

d. air *homogeneous mixture

e. dirt *heterogeneous mixture

f. a rusty iron nail * heterogeneous mixture

g. ozone *element

3. Express the answers to the following calculations in scientific notation: (12 points)

a. 145.75 + (2.3 × 10 –1) = 145.98 = 1.4598 x 10^2

b. 79,500 ÷ (2.5 × 102) = 3.18 = 3.18 x 10^2

c. (7.0 × 10–3) – (8.0 × 10–4) = .0062 = 6.2 x 10^-3

d. (1.0 × 104) × (9.9 × 106) = (1 x 9.9) ^4+6 = 9.9 x 10^10

(Reference: Chang 1.31)

4. What is the number of significant figures in each of the following measurements? (8 points)

a. 4867 mi *4 all digits nonzero and so significant

b. 56 mL *2 all digits nonzero and so significant

c. 60,104 ton *5 the two zeros in between nonzero digits so all significant

d. 2900 g *ambiguous case can be 4 significant figure (2.900x10^3), 3 (2.90x10^3), or 2 (2.9x10^3)

e. 40.2 g/cm3 *3 zero in between nonzero digits so all significant

f. 0.0000003 cm *1 leading zeros not...