CHEM 211 Chapter 1 Review

Which measurement is expressed to 4 significant figures? A. 0.423 kg B. 24.049 cm C. 1300 K D. 82,306 m E. 62.40 g

E. 62.40 g because final zeros or trailing zeros in the decimal portion are significant

Which of the following is an extensive property of oxygen? A. Boiling point B. Temperature C. Average kinetic energy of molecules D. Density E. Mass

E. Mass because it is a physical quantity whose value is proportional to the size of the system; it depends on the amount of the substance

Water vapor is less dense than ice because...... A. molecules in the gas phase are in constant motion. B. molecules in the gas phase have more potential energy than in solids. C. molecules in the gas phase have more kinetic energy than in solids. D. gaseous molecules have less mass. E. molecules in the gas phase have more space between them than in solids.

E. because the particles in the gas phase have large distances between them and move randomly throughout the container.

A large pizza has a diameter of 15 inches. Express this diameter in centimeters. A. 38 cm B. 24 cm C. 18 cm D. 9.3 cm E. 5.9 cm

A. 30 cm because multiply the inches by 2.54

The difference between a student's experimental measurement of the density of sodium chloride and the known density of this compound reflects the __________ of the student's result. A. Accuracy B. Precision C. Random Error D. Systematic Error E. Indeterminate Error

A. Accuracy because accuracy is the closeness of a measurement to the actual value.

Choose the Correct Statement: A. Physical changes may be reversed by changing the temperature. B. Physical changes alter the composition of the substances involved. C. Physical properties are not valid characteristics for identifying a substance. D. Physical properties are mostly extensive in nature. E. Physical changes are usually accompanied by chemical changes.

A. Because temperture and pressure of surroundings, many substances can exist in each three states

State whether the following are a solid, liquid, or gas: A. helium in a balloon B. Mercury in a thermometer C. Soup in a bowl

A. gas B. liquid C. liquid

State whether the density of the object increases, decreases, or remains the same: A. a sample of chlorine gas is compressed B. A lead weight is carried up a high mountain C. A sample of water is frozen D. An iron bar is cooled E. A diamond is submerged in water

A. increases B. remains the same C. decreases D. increases E. remains the same Density is the measurement of the denseness with which the mass is packed; compression: increase; temperature: changes density

Acetone, which is used as a solvent and as a reactant in the manufacture of Plexiglas®, boils at 56.1°C. What is the boiling point in degrees Fahrenheit? A. 159°F B. 133°F C. 101°F D. 69.0°F E. 43.4°F

B. 133°F because times (133 x 1.8) + 32 = 133

The speed needed to escape the pull of Earth's gravity is 11.3 km/s. What is this speed in mi/h? A. 65,500 mi/h B. 25,300 mi/h C. 18,200 mi/h D. 1,090 mi/h E. 5.02 × 10^−3 mi/h

B. 25,300 mi/h because times by 3600 (60 minutes X 60 seconds) = 40680 km/h times that by (1 km =) .6214 miles = 25,300 mi/h

Isopropyl alcohol, commonly known as rubbing alcohol, boils at 82.4°C. What is the boiling point in kelvins? A. 387.6 K B. 355.6 K C. 323.6 K D. 190.8 K E. −190.8 K

B. 355.6 K because 82.4 times 273.5 = 355.6

Which are chemical changes? A. boiling canned soup B. toasting a slice of bread C. chopping a log D. burning a log

B: Toast because the change in appearance shows irreversible chemical change; D: Log because the wood and air become different substances with different compositions

The distance between carbon atoms in ethylene is 134 picometers. Which of the following expresses that distance in meters? A. 1.34 × 10^−13 m B. 1.34 × 10^−12 m C. 1.34 × 10^−10 m D. 1.34 × 10^−7 m E. 1.34 × 10^−6 m

C. 1.34 x 10^-10m because divide picometers by 1e +12

The mass of a sample is 550 milligrams. Which of the following expresses that mass in kilograms? A. 5.5 × 10^8 kg B. 5.5 × 10^5 kg C. 5.5 × 10^−4 kg D. 5.5 × 10^−6 kg E. 5.5 × 10^−1 kg

C. 5.5 x 10^-4 kg because divide milligrams by 1e +6

Select the best statement: A. Chemical changes provide the only valid basis for identification of a substance. B. Chemical changes are easily reversed by altering the temperature of the system. C. Chemical changes always produce substances different from the starting materials. D. Chemical changes are associated primarily with extensive properties. E. Chemical changes are accompanied by changes in the total mass of the substances involved.

C. because a chemical change/reaction has different substances before and after.

A scientist made careful measurements of the pressure and temperature of many different gases. Based on these measurements, he concluded that "the pressure of a fixed amount of gas, measured at constant volume, is directly proportional to its absolute temperature." This statement is best described as a...... A. theory. B. hypothesis. C. law. D. experiment. E. definition.

C. law because law is a summary, often in mathematical form, of a universal observation.

Which of the following is a physical change? A. Milk turning sour B. Battery cables corroding C. Sugar turning brown when heated D. Liquid water being cooled and forming ice E. An egg being hard-boiled

D. liquid water being cooled and forming ice because it has no change in composition/ no reaction with another substance

Select the answer that expresses the result of this calculation with the correct number of significant figures. (13.602 x 1.90 x 3.06)/(4.2 x 1.4097) A. 13.3568 B. 13.357 C. 13.36 D. 13.4 E. 13

E. 13 because you use the lowest amount of sig figs when multiplying and dividing

Select the answer with the correct number of decimal places for the following sum: 13.914 cm + 243.1 cm + 12.00460 cm = A. 269.01860 cm B. 269.0186 cm C. 269.019 cm D. 269.02 cm E. 269.0 cm

E. 269.0 cm because the answer must have the least amount of decimal places from decimals in the problem