Chem Test

The amount of energy needed to hear 2.00 g mercury from 50.0 C to 85.0 C is 9.87 J. The specific heat capacity of this sample of mercury is a. 0.141 J/g C b. 0.058 J/g C c. 0.282 J/g C d. 345 J/g C

A 0.141 J/g C

Which of the following statements about energy is FALSE? a. a reaction cannot be exothermic overall if activation energy is required b. a system is the most stable when it is at its lowest energy state c. energy can be defined as whatever is required to oppose a natural tendency d. energy transferred into a system can also be transferred out of the system

A. A reaction cannot be exothermic overall if activation energy is required

A measurement of 23,465 mg converted to grams equals a. 2.3456 g b. 23.456 g c. 234.56 g d. 0.23456 g

B. 23.456

Which of the following is an incorrect description? a. a homogeneous mixture b. a heterogeneous compound c. a solid element d. a mixture of solids

B. A heterogeneous compund

Which of the following involves no chemical change? a. burning paper b. boiling water c. baking a cake d. lighting a match

B. Boiling water

Which of the following is a homogeneous mixture? a. pure water b. gasoline c. jar of jelly beans d. soil

B. gasoline

If the temperature outside is 26 C, the temperature would be .... K a. 26 b. 273 c. 299 d. -247

C. 299

Water is an example of a. a homogenous mixture b. a heterogeneous mixture c. a compound d. an element

C. A compound

How many of the following are compounds? H2O, N2O2, NaOH, MnO2, HF a. 0 b. 1 c. 3 d. 5

D. 5

Which of the following is a chemical change? a. water condenses on a mirror b. a damp towel dries c. peanuts are crushed d. a "tin" can rusts

D. A "tin" can rusts

An example of a pure substance is a. elements b. compounds c. pure water d. all of these

D. All of these

Helium is an example of a. a homogeneous mixture b. a heterogeneous mixture c. a compound d. an element

D. An element

Which of the following is a physical change? a. Burning gasoline b. Cooking an egg c. decomposing meat d. Evaporating water

D. Evaporating water

Which of the following is an element? a. brass b. salt c. water d. oxygen

D. Oxygen

Which of the following is a chemical change? a. water boiling b. gasoline evaporating c. butter melting d. paper burning

D. paper burning

An example of a mixture is a. hydrogen fluoride b. purified water c. gold d. the air in this room

D. the air in this room

Gold is a relatively soft metal, which is a chemical property of the substance gold. True or False?

False

The greenhouse effect occurs only on the planet earth. True or False?

False

Two or more atoms bonded together always form a compound. True or False?

False

Energy can be classified as either potential or kinetic energy. True or False?

True

Juice freezing into a popsicle is an example of a physical change, True or False?

True

Metal rusting is an example of a chemical change. True or False?

True

The calorie is defined as the amount of energy (heat) required to raise the temperature of one gram of water by one degree Celsius. True or False?

True

The energy gained by the surroundings must be equal to the energy lost by the system. True or False?

True

Which of the following is an element? a. helium b. salt c. alcohol d. vinegar

A. Helium

A 4.60 g sample of iron is heated form 47.0 C to 75.0 C. The amount of energy required is 57.96 J. The specific heat capacity of this sample of iron is a. 0.450 J/g C b. 1.233 J/g C c. 2.07 J/g C d. 1623 J/g C

A. 0.450 J/g C

How many of the following are pure compounds? sodium, sugar, oxygen air, iron a. 1 b. 2 c. 3 d. 4

A. 1

A metal sample has a mass of 45.65 g. The volume of the sample is 16.9 cm3. the density of the sample is a. 2.7 g/cm3 b. 3.2 g/cm3 c. .37 g/cm3 d. 3.7 g/cm3

A. 2.7 g/cm3

Which of these is a chemical property? a. Helium is a very nonreactive b. Sodium is a soft shiny metal c. decomposing meat d. Glycerol is a viscous liquid

A. Helium is a very nonreactive

Which of the following is an element? a. iron b. wood c. water d. blood

A. Iron

Which is an example of a homogeneous mixture? a. koolaid b. oily water c. soil (dust) d. sodium chloride

A. Koolaid

Which of the following is only a physical change? a. Sugar dissolves in coffee b. cookies burn in the oven c. a banana ripens d. leaves turn colors in the fall

A. Sugar dissolves in coffee

A solution can be distinguished from a compound by its a. variable composition b. liquid state c. heterogeneous nature d. lack of color

A. Variable composition

Which of the following is a valid unit for specific heat (or specific heat capacity)? a. cal/g C b. cal c. cal/g d. C

A. cal/g C

Which of the following processes is endothermic? a. water droplets condensing on a soda can on a hot summer day b. an ice pack getting cold ( due to ammonium nitrate dissolving in water inside the pack) c. thermite reaction between iron (III) oxide and aluminum ( spectacular flames are observed) d. freezing water to make ice cubes

B. An ice pack getting cold (due to ammonium nitrate dissolving in water inside the pack)

Which of the following describes a chemical property of gold? a. gold is a yellow metal b. gold is an inert (nonreactive) metal c. gold is a soft metal d. gold is a very dense metal

B. Gold is an inert ( nonreactive) metal

which of the following processes is a chemical change? a. dry ice sublimes when left on the demo table in lecture b. the light on a candle burns until a bell jar is placed over it for a period of time c. when a few drops of red food coloring are added to a beaker of hot water, the water immediately turns red d. Liquid nitrogen dumped onto the floor vaporizes at room temperature.

B. The light on a candle burns until a bell jar is placed over it for a period of time

An example of a chemical change is a. boiling alcohol b. grinding coffee beans c. digesting a pizza d. coffee spilled on a shirt

C. Digesting a pizza

Which of the following processes require(s) chemical methods? a. separating a homogeneous mixture into pure substances b. separating a heterogeneous mixture into pure substances c. distilling a saltwater mixture d. Breaking a compound into its constituent elements

D. Breaking a compound into its constituent elements

Which of the following involves a chemical change? a. Boiling water b. Melting ice c. Chopping wood d. Cooking an egg

D. Cooking an egg

Which of the following processes is exothermic? a. rolling a ball up a hill b. boiling water in a beaker to make steam c. allowing meat to thaw after taking it out of the freezer d. reacting hydrogen and oxygen gases to make water

D. Reacting hydrogen and oxygen gases to make water

Which of these is an element? a. brass b. iron ore c. wood d. silver

D. Silver

In a chemical change a. a phase change must occur b. the original material can never be regenerated c. a phase change never occurs d. the products are different substances from the starting materials

D. The products are different substances from the starting materials

A compound can consist of one kind of element. True or False?

False

A solid substance is not considered matter. True or False?

False

An element consists of only single atoms of that element. True or False?

False

Carbon dioxide can exist only in gaseous state.True or False?

False

Dry ice sublimating ( turning from a solid straight into a gas) is an example of a chemical change. True or False?

False

The law of conservation of energy states that energy can be converted from one form to another but can be neither created nor destroyed. True or False?

True

The normal boiling point of water is 100 degrees C, which is a physical property of the substance water.

True