HW 1: Chemistry

Which of the changes are chemical changes?

Gasoline is burned

A prospector panning for gold swirls a mixture of mud, gravel, and water in a pan. He looks for gold at the bottom because gold a. dissolves in water and sinks b. has a high density and sinks c. is less dense than rocks d. is repelled by the other minerals

Has a high density and sinks

Bending glass tubing in a hot flame involves a. Applied research b. A chemical change c. An experiment d. A physical change

A physical change

Creating solid ice from liquid water involves a. Adding energy to the water b. A physical change c. A chemical change d. Creating a new substance

A physical change

Which of the statements describes a chemical property?

Antacid tablets neutralize stomach acid.

A pebble and a lead sinker both sink when dropped into a pond. This shows that the two objects a. are both less dense than water b. are both more dense than water c. have different densities d. have the same density

Are both more dense than water

Ar is the symbol for a. Air b. Argon c. Aluminum d. Arsenic

Argon

Which of the following is not an example of matter? a. Methane gas b. Steam c. Silver d. A rainbow

Rainbow

A goal of green chemistry is to: a. Produce cheap green dyes b. Provide great wealth for corporations c. Reduce pollution d. Turn desserts into forests and grasslands

Reduce pollution

Heat is a. an element b. the energy flow from a hot object to a cold one c. a measure of energy intensity d. a temperature above room temperature

The energy flow from a hot object to a cold one

Which of the following is not a hypothesis a. UFOs frequent the Bermuda Triangle, which accounts for all o the oddities in the region b. Ice floats on water because of the air bubbles that get trapped during the freezing process c. Oxygen reacts with silver to form rust d. Synthetic hormones have the same effect in an organism as the naturally occurring ones

UFOs frequent the Bermuda Triangle, which accounts for all of the oddities in the region

Which of the following metals will sink in a pool of mercury (d= 13.534 6/cm^3) a. Aluminum (d= 2.6 g/cm^3) b. Iron (d= 7.9 g/cm^3) c. Lead (d= 11.34 g/cm^3) d. Uranium (d= 19.5 g/cm^3)

Uranium

The SI unit of length is the a. Foot b. Kilometer c. Pascal d. Meter

Meter

One cubic centimeter is equal to one a. Deciliter b. Liter c. Dram d. Milliliter

Milliliter

A rope is 5.775 cm long. What is the length in millimeters? a. .05775 mm b. .5775 mm c. 5.775 mm d. 57.75 mm

57.75

Converting KJ into Kcal:

4.184 KJ in 1 Kcal

Ice floats on liquid water. A reasonable value for the density of ice is a. .92 g/cm^3 b. 1.08 g/cm^3 c. 1.98 g/cm^3 d. 4.90 g/cm^3

.92 g/cm^3

Which of the following has a volume of roughly 250 mL (.250 L) a. 1 cup b. 1 gallon c. 1 pint d. 1 tablespoon

1 cup

Your doctor recommends that you take 1000 micrograms of vitamin B12. That is the same as a. 1 centigram b. 1 decigram c. 1 gram d. 1 milligram

1 milligram

Classify each of the following as basic research or applied research: 1. A chemical develops a better, longer lasting pain reliever 2. A researcher investigates the responses a plant has to drought conditions 3. A scientist seeks to extract biologically active compounds from sea sponges 4. Scientists create rBST to improve milk production in cows

1. Applied Research 2. Basic Research 3. Basic Research 4. Applied Research

The scientific method is a process that scientists use to understand the physical world. Place the four basic steps of the scientific method in the correct order, from start to finish.

1. Formulate question from observation. 2. Develop hypothesis about question. 3. Evaluate hypothesis predictions. 4. Publish result.

If the volume of a rock is 80 cm^3 and its mass is 160 g, its density is a. .05 g/cm^3 b. .50 g/cm^3 c. 2.0 g/cm^3 d. 20 g/cm^3

2.0 g/cm^3

Water boils at a. 0 degrees Celsius b. 273 degrees Celsius c. 100 degrees Fahrenheit d. 373 Kelvin

373 Kelvin

Which of the changes are chemical changes?

A candle is burned. A silver teapot turns black. Two clear colorless salt solutions are mixed and a bright orange precipitate forms

Which of the following as a thickness of roughly 1 cm? a. A brick b. A cell phone c. A knife blade d. This textbook

A cellphone

Which of the following has a mass of roughly 1g? a. An Ant b. An Orange c. A Peanut d. A Watermelon

A peanut

Which of the following is an example of a chemical change? a. An egg is broken and poured into an eggnog mix b. A tree is pruned, shortening some branches c. A tree is watered and fertilized and it grows larger d. Frost forms on a cold windowpane

A tree is watered and fertilized and it grows larger

To convert a temperature on the Kelvin scale to degrees Celsius, we a. add 100 b. add 273 c. subtract 100 d. subtract 273

Add 273

Converting Celsius to Kelvin:

Add 273.15 to Celsius

Which of the following is an example of matter? a. Sunlight b. Air pollution c. Magnetic field d. Ultraviolet light

Air pollution

The smallest part of an element is a(n) a. Atom b. Corpuscle c. Mass d. Molecule

Atom

Which of the following is not an element? a. Aluminum b. Brass c. Lead d. Sulfur

Brass

A compound can be separated into its elements a. by chemical means b. by mechanical means c. by physical means d. using a magnet

By chemical means

The prefix that means 10^-2 is a. centi- b. deci- c. micro- d. milli-

Centi-

An inch is about 250% longer than a a. Meter b. Millimeter c. Centimeter d. Decimeter

Centimeter

A successful theory a. Can be used to make predictions b. Eventually becomes a scientific law c. Is not subject to further testing d. Is permanently accepted as true

Can be used to make predictions

To gather information to support or discredit a hypothesis, a scientist a. Conducts experiments b. Consults an authority c. Establishes a scientific law d. Formulates a scientific theory

Conducts experiments

Social problems are difficult to solve because it is difficult to a. Control variables b. Discount paranormal events c. Form hypothesis d. Formulate theories

Control variables

Which of the following is a chemical property? a. Iodine vapor is purple b. Copper tarnishes c. Salt dissolves in water d. Balsa wood is easily carved

Copper tarnishes

Among the following, the highest risk of death is associated with a. Heart disease b. Peanut butter c. Cancer d. Car wreck

Heart disease

Classify each description as a hypothesis, theory, or law.

Hypothesis: An untested explanation based upon observation or known facts. A doctor thinks, but has not verified, that a patient with stomach pain has appendicitis. Theory: An explanation that has been tested and verified. Scientists, after many experiments, state that matter is composed of atoms. Law: A description that predicts what happens, but does not explain how.

Chemistry is called the central science because a. The chemical industry is based mainly in the US Midwest b. It is the core course in all college curricula c. It is fundamental to other scientific discipline d. It is the source of many environmental problems

It is fundamental to other scientific discipline

Which of the following is a requirement of scientific research? a. It must be approved by a committee of scientists and politicians b. It must benefit the Earth and improve human life c. It must be experimentally tested and peer reviewed for validity d. It must be balanced and weigh the pros and cons of the results

It must be experimentally tested and peer reviewed for validity

The SI unit of energy is the a. Calorie b. Coulomb c. Joule d. Watt

Joule

The SI scale for temperature is known as the a. Celsius scale b. Fahrenheit scale c. Kelvin scale d. Richter scale

Kelvin scale

The SI unit of mass is the a. Dram b. Gram c. Grain d. Kilogram

Kilogram

The statement that mass is always conserved when chemical changes occur is an example of a scientific a. Experiment b. Hypothesis c. Law d. Theory

Law

The density of a wood plank floating on a lake is a. Less than that of air b. Less than that of water c. More than that of water d. The same as that as water

Less than that of water

Which state of matter has a definite volume but not a definite shape? a. Gas b. Compound c. Liquid d. Solid

Liquid

One quart is slightly less than one a. Deciliter b. Kiloliter c. Liter d. Milliter

Liter

The symbol for sodium is a. S b. Na c. Sd d. So

Na

Identify the power of ten that defines each of the prefixes

Nano- 10^-9 Centi- 10^-2 Milli- 10^-3 Kilo- 10^3 Micro- 10^-6 Mega- 10^6

Our perception of risk is a. Always based on sound science b. Always higher than actual risk c. Always lower than actual risk d. Often different than actual risk

Often different from actual risk

The main theme of Rachel Carson's Silent Spring was that life on Earth would be destroyed by a. Botulism b. Nuclear war c. Overpopulation d. Pesticides

Pesticides

What kind of change alters the identity of a material a. Temperature b. Physical c. Pressure d. The other 3 do not change the identity

Physical

Which best exemplifies sustainable chemistry? a. Toluene, extracted from coal, is used to make TNT, an explosive. b. Paper is made from hardwood trees. c. Minerals mined in South America are used in China to make LCD screens d. Plastic bottles are made from both petroleum and recycled plastic

Plastic bottles are made from both petroleum and recycled plastic

Which of the following is an example of a physical change? a. A cake is baked from flour, baking powder, sugar, eggs, shortening, and milk b. Milk left outside a refrigerator overnight turns sour c. Sheep are sheared, and the wool is spun into yarn d. Spiders eat flies and make silk

Sheep are sheared and the wool is spun into yarn

Which of the following is a mixture? a. Carbon b. Copper c. Silver d. Soda water

Soda water

Which of the changes are chemical changes?

The copper roof turns green over time. Baking soda is dissolved in vinegar and bubbles form.

Which of the following would not be a technological advancement made possible by understanding chemistry? a. Cooking pans coated with a nonstick surface like Teflon b. The ability to change lead or other metals into gold c. Lengthening the life span of human beings using medicines d. Alternate fuel sources to lessen our dependence on petroleum

The ability to change lead or other metals into gold.

Alchemy is a. Philosophical speculation about nature b. Chemistry that is concerned with environmental issues c. The beginnings of modern chemistry d. The application of knowledge for practical purposes

The beginning of modern chemistry.

Which of the changes are chemical changes?

The nail heads in a desk rust. Milk turns sour in the refrigerator. A cheese sandwich is toasted.

Which of the following statements best describes density?

The ratio of a substance's mass to its volume, measured in g/mL and also equivalent to g/cm^3

Two identical items are taken from Earth to Mars, where they have a. Both the same mass and the same weight as on Earth b. Neither the same mass nor the same weight as on Earth c. The same mass but not the same weight as on Earth d. The same weight but not the same mass as on Earth

The same mass but not the same weight as on Earth

Classify each phrase about weight and mass as true or false.

True: Your mass on the moon is the same as your mass on the Earth. False: Mass and weight are the same thing. Your weight on the moon is the same as your weight on the Earth. Mass and weight both depend on gravity.

The US chemical industry is a. Patently unsafe b. The source of nearly all pollution c. The source of many consumer products d. Unimportant to the US economy

The source of many consumer products