General Chemistry Ch. 1 - Bowie State University

T/F: The numerical value of any temperature expressed in Celsius is always different from the numerical value of the same temperature in Fahrenheit.

False

T/F: The ripening of fruit, once picked, is an example of physical change.

False

T/F: An important aim in much chemical work is to use macroscopic measurements Turein order to gain an understanding of the microscopic world.

True

T/F: The number 6.0448, rounded to 3 decimal places, becomes 6.045.

True

T/F: When a wooden match burns in air, chemical potential energy is converted to kinetic energy.

True

T/F: When applying the scientific method, a model or theory should be based on experimental data.

True

chemical change

a substance is changed into one or more different substances. chemical composition and physical properties of the new substance will be different from the original substance

Write the following numbers and results in standard notation, with appropriate significant figures. a. 7.85 × 10^-3 b. 7.85 × 10^4 c. 5.920 × 10^3 d. 7.85 × 10^12 ÷ 1010 e. 7.00 × 10^-5 f.. circumference of a circle, 2πr, where r = 8.7 cm 6.626 x 10^-34 x 6.02214x10^23 x 2.9979 x 10^8 _______________________________________________________ 5.23 x 10^-6

a. 0.00785 b. 78500 c. 5920. d. 785 e. 0.0000700 f. 55 cm g. 22900

when rounding and the digit removed is 5. what do you do?

-the preceding number increased by if if it is even it remains the same

An evacuated 276 mL glass bulb weighs 129.6375 g. Filled with an unknown gas, the bulb weighs 130.0318 g. Calculate the gas density in g/L, and express it with an appropriate number of significant figures.

1.43 g/L

The result of (3.8621 × 1.5630) - 5.98 is properly written as A) 0.06 B) 0.056 C) 0.0565 D) 0.05646 E) 0.056462

A) 0.06

The average distance from Earth to the Sun is 150 megameters. What is that distance in meters? A) 1.5 × 108 m B) 1.5 × 106 m C) 1.5 × 105 m D) 1.5 × 103 m E) 1.5 × 10-6 m

A) 1.5 × 108 m

The area of a 15-inch pizza is 176.7 in2. Express this area in square centimeters. A) 1140. cm2 B) 448.8 cm2 C) 96.8 cm2 D) 69.57 cm2 E) 27.39 cm2

A) 1140. cm2

At a pressure of one billionth (10-9) of atmospheric pressure, there are about 2.7 × 1010 molecules in one cubic centimeter of a gas. How many molecules is this per cubic meter? A) 2.7 × 1016 B) 2.7 × 1014 C) 2.7 × 1012 D) 2.7 × 108 E) 2.7 × 104

A) 2.7 × 1016

If the density of a certain spherical atomic nucleus is 1.0 × 1014 g cm-3 and its mass is 2.0 × 10-23 g, what is its radius in cm?

A) 3.6 10 -13 cm

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) 38 cm

Which of the following correctly expresses 52,030.2 m in scientific notation? A) 5.20302 x 10^4 m B) 5.20302 x 10^5 m C) 5.203 x 10^4 m D) 5.20 x10^4 m E) 5.2 x10^4 m

A) 5.20302 x 10^4 m

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

Select the best 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)Physical changes may be reversed by changing the temperature.

A detailed explanation of natural phenomena that is generally accepted and has been extensively tested is called a A) theory. B) hypothesis. C) law. D) fact. E) postulate

A. theory.

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

A student makes several measurements of the density of an unknown mineral sample. She then reports the average value of these measurements. The number of significant figures she uses in her result should be a measure of its A) accuracy. B) precision. C) systematic error. D) determinate error. E) human error

B) precision.

Express 96,342 m using 2 significant figures. A. 9.60 x 10 ^4 m B. 9.6 x 10^4 m C. 9.60 x 10^-4 m D. 9.6 x10^-4 m E. 96,000. m

B. 9.6 x 10^4 m

A dictionary has the following definition for a word: "A tentative explanation that accounts for a set of facts." Which of the following words best fits that definition? A) theory B) hypothesis C) law D) experiment E) definition

B. hypothesis

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 × 10-10 m

Which of the following represents the largest volume? A) 10,000 µL B) 1000 pL C) 100 mL D) 10 nL E) 10 cm3

C) 100 mL

Select the answer that expresses the result of this calculation with the correct number of significant figures and with correct units 16.18 cm × 9.6114 g ÷ 1.4783 cm2 A) 105.2 g/cm3 B) 105.2 g/cm2 C) 105.2 g/cm D) 72.13 g/cm2 E) 72.13 g/cm

C) 105.2 g/cm

Given that 1 inch = 2.54 cm, 1 cm3 is equal to A) 16.4 in3 B) 6.45 in3 C) 0.394 in3 D) 0.155 in3 E) 0.0610 in3

E) 0.0610 in3

Give an example of a physical property and a chemical property of each of the following: a. oxygen gas b. octane c. copper

boiling point, reaction with sodium b. boiling point, reaction with oxygen c. electrical conductivity, reaction with nitric acid

kinetic energy

energy due to the motion of the object

potential energy

energy due to the position of the object relative to another object

what happens to energy when it is converted from one form to the other?

it is conserved, not destroyed

6. During the swing of a frictionless pendulum, what energy form(s) remain constant?

kinetic plus potential energy

Water vapor is less dense than ice because

molecules in the gas phase have more space between them than in solids.

what is a stable situation?

situations of lower energy

what does the total energy of an object entail?

the sum of its potential energy and kinetic energy

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

Which of the following correctly shows how to convert a density of 20.1 g cm-3 to units of kg m-3?

E) 3 3 3 20.1 g 1 kg (1 cm) × × 1 cm 1000 g (0.01 m)

A dose of medication was prescribed to be 35 microliters. Which of the following expresses that volume in centiliters? A) 3.5 × 105 cL B) 3.5 × 104 cL C) 3.5 cL D) 3.5 × 10-4 cL E) 3.5 × 10-3 cL

E) 3.5 × 10-3 cL

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

Talc is a mineral that has low conductivity for heat and electricity and that is not attacked by acid. It is used as talcum powder and face powder. A sample of talc weighs 35.97 g in air and 13.65 g in mineral oil (d = 1.75 g/cm3). What is the density of talc? A) 4.61 g/cm3 B) 2.82 g/cm3 C) 2.63 g/cm3 D) 2.44 g/cm3 E) 1.61 g/cm3

B) 2.82 g/cm3

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

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

The average distance between the Earth and the Moon is 240,000 miles. Express this distance in kilometers. A) 6.1 × 105 km B) 5.3 × 105 km C) 3.9 × l05 km D) 1.5 × 105 km E) 9.4 × 104 km

C) 3.9 × l05 km

The mass of a sample is 550 milligrams. Which of the following expresses that mass in kilograms? A) 5.5 × 108 kg B) 5.5 × 105 kg C) 5.5 × 10-4 kg D) 5.5 × 10-6 kg E) 5.5 × 10-1 kg

C) 5.5 × 10-4 kg

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) Chemical changes always produce substances different from the starting materials.

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

4. The density of mercury, the only metal to exist as a liquid at room temperature, is 13.6 g/cm3. What is that density in pounds per cubic inch? A) 849 lb/in3 B) 491 lb/in3 C) 376 lb/in3 D) 0.491 lb/in3 E) 1.83 × 10-3 lb/in3

D) 0.491 lb/in3

The SI prefix mega- (M) means A) 10-6 B) 10-3 C) 103 D) 106 E) 109

D) 106

Acetic acid boils at 244.2°F. What is its boiling point in degrees Celsius? A) 382.0°C B) 167.7°C C) 153.4°C D) 117.9°C E) 103.7°C

D) 117.9°C

The appropriate number of significant figures in the result of 15.234 × 15.208 is A) 2 B) 3 C) 4 D) 5 E) 6

D) 5

Which of the following correctly expresses 0.000007913 g in scientific notation? A) 7.913 x10^6 g B) 7.913 x 10^5 g C) 7.913 x 10 ^-5 g D) 7.913 x 10 ^-6 g E) 7.913 x 10 ^-9 g

D) 7.913 x 10 ^-6 g

Which of the following is not an SI base unit? A) meter B) ampere C) second D) gram E) kelvin

D) gram

The SI unit of speed (velocity) is A) km/h B) km/s C) m/h D) m/s E) none of these choices is correct

D) m/s