CHM166 Chapter 1 - Matter, Energy, and Measurement

Chemistry

CHM166

Chapter 1: Introduction: Matter, Energy, and Measurement

Homework Assignment

All work and calculations must be shown

Question 1:

Identify each of the following as measurements of length, area, volume, mass, density, time, or temperature:

a. 25 ps

b. 347.2 mg

c. 77 K

d. 100,000 km2

e. 16 nm2

f. -78 °C

g. 2.56 g/cm3

h. 28 cm3

Question 2:

The three targets from a rifle range shown below were produced by: (A) the instructor firing a new rifle; (B) the instructor firing his personal rifle; and (C) a student who has fired his target rifle only a few times.

a. Comment on the accuracy and precision for each of these three sets of results

b. For the A and C results in the future to look like those in B, what needs to happen (i.e. does accuracy and/or precision need to be improved.)

Question 3:

Classify each of the following as a pure substance or a mixture. If a mixture, indicate whether it is homogenous or heterogenous:

a. Air

b. Tomato juice

c. Iodine crystals

d. Sand

Question 4:

Give the chemical symbol or name for each of the following elements, as appropriate:

a. Carbon

b. Nitrogen

c. Titanium

d. Zinc

e. Iron

f. P

g. Ca

h. He

i. Pb

j. Ag

Question 5:

Two beakers contain clear, colorless liquids. When the contents of the beakers are mixed a white solid is formed.

a. Is this an example of a chemical or physical change?

b. What would be the most convenient way to separate the newly formed white solid form the liquid mixture – filtration, distillation, or chromatography?

Question 6:

For each of the following processes, does the potential energy of the objects(s) increase or decrease?

a. The distance between two oppositely charged particles is increased.

b. Water is pumped from ground level to the reservoir of a water tow 30 m above the ground.

c. The bond in a chlorine molecule, Cl2, is broken to form two chlorine atoms.

Question 7:

Use the appropriate metric prefixes to write the following measurements without use of exponents:

a. 2.3 X 10-10 L

b. 4.7 X 10-6 g

c. 1.85 X 10-12 m

d. 16.7 X 106 s

e. 15.7 X 103 g

f. 1.34 X 10-3m

g. 1.74 X 102 cm

Question 8:

a. The temperature on a warm summer day is 87 °F. What is the temperature in °C?

b. Many scientific studies are conducted at 25 °C. What is this temperature in kelvins and in °F?

c. Suppose a recipe calls for an oven temperature of 400 °F. Convert this temperature to degrees Celsius and kelvins.

d. Liquid nitrogen boils at 77 K. Convert this temperature to °F and °C.

Question 9:

a. After the label fell of a bottle containing a clear liquid believed to be benzene, a chemist measured the density of the liquid to verify its identity. A 25.0 mL portion of the liquid had a mass of 21.97 g. A chemistry handbook list the density of benzene at 15 °C as 0.8787 g/mL. Is the calculated value in agreement with the literature value?

b. An experiment requires 15.0 g of cyclohexane, whose density at 25 °C is 0.7781 g/mL. What volume of cyclohexane should be used?

c. A spherical ball of lead has a radius of 10.0 cm. What is the mass of the sphere if the lead has a density of 11.34 g/cm3? (The volume a sphere can be calculated using the following equation: , where r is the radius of the sphere.)

Question 10:

Indicate the number of significant figures in each of the following measured quantities:

a. 3.774 km

b. 205 m2

c. 1.700 cm

d. 350.00 km

e. 307.080 g

f. 1.3 X 103 m/s

Question 11:

Carry out the following operations and express the answers with the appropriate number of significant figures.

a.

b.

c.

d.

 

Question 12:

Using your knowledge of metric units, English units, write down the conversion factors needed to convert:

a. μm to mm

b. ms to ns

c. mi to km

d. ft3 to L

Question 13:

Carry out the following conversions:

a. 0.105 in to mm

b. 8.75 μm/s to km/hr

c. 1.955 m3 to yd3

d. 8.75 lb/ft3 to g/mL

Question 14:

The concentration of carbon monoxide in an urban apartment is 48 μg/m3. What is the mass, in grams, of carbon monoxide present in a room measuring 14.5 ft X 14.8 ft X 20.5 ft?