Fall semester practice

Which of the following is a chemical change?

• Salt being dissolved in water

• Water boiling on the stove

• Gasoline combusts in an engine

• Copper metal is stretched into a long wire

Which of the following would best be described as a physical change associated with a lab activity conducted in chemistry class?

• The rusting of iron nails

• burning of propane gas

• sublimation of carbon dioxide

• Corrosion of zinc metal

The table above lists some properties of a sample of lauric acid. which of these is an intensive property of this sample?

• Volume

• Mass

• Boiling Point

• number of Moles

An atom of the isotope argon-40 contains how many neutrons in its nucleus?

• 18

• 40

• 21.948

• 22

Which of the following statements correctly explains the mation of atoms and molecules within the different states of matter?

• Only particles in liquids and gases are constantly moving.

• The particles of solids and liquids remain motionless.

• The particles of gas have the least freedom of movement of all three states.

• The particles within all three states of matter are constantly moving.

A student was asked to make observaions about a metal sample in his class. He noted the following observations about an unknown sample: Silvery, mass of 71.3 g, volume of 8 cm3, magnetic. Given the table above, what is the most likely identity of the metal?

• Nickel

• Gold

• Iron

• Aluminum

Some students used a varity of procedures to investigate four liquid samples. The students recorded the following information:

1. when the Sample W was cooled, solid particles settled out of the liquid.
2. the mass and volume of Sample X were measured, and the density of Sample X was calculated to be 1.6 g/mL.
3. Sample Y was heated, and the temperature was recorded. All the liquid boiled away at the same temperatue and left no residue in the container.
4. When a dilute acid ws added to Sample Z, gas bubbles formed and rapidly rose to the surface of the liquid.

Based on these obervations, which sample was clearly identifiable as a pure substance?

• Sample W

• Sample X

• Sample Y

• Sample Z

Which of the following statements does not accurately describe one of the three classical states of matter?

• Solids have a definite volume

• Liquids fill the volume of their container

• Solids are not as easily compressed as gases

• Gases take the shape of their container

A scientist filters a sample of river water. The data from this process are listed in the table. Which of the following data descriptions support the data from the table?

• It is a pure substance because solid particles cannot pass through the filter paper.

• It is a pure substance because the river water is composed only of free elements.

• It is a mixture because dissolved ions in the water pass through the filter paper.

• It is a mixture because solid particles are separated from the river water.

Which of the following properties identified by a student in the lab for a sample of sodium chloride is an extensive property?

• mass of 15 g

• White color

• Density of 2.17 g/cm3

• Solubility in water