Unit 1 Learning Checkpoint 1

The figure represents a solid block of copper metal in a beaker at 30 degrees C. Which of the following best represents the particle arrangement as a student tips the beaker, which is kept at 30 degrees C.

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Each of three containers contains a solid, a liquid, or a gaseous substance. One particle of each substance is represented in the diagrams. The arrows show the relative movement of the particles. Based on the movement of the particles, label each diagram with either SOLID, LIQUID, or GAS. Write for Example: Diagram 1-?? Diagram 2-?? Diagram 3-??

A student fills two syringes: one with air and the other with an equal volume of water. After capping the syringes, the student applies the same amount of pressure to the plungers and records observations about the change in volume.Based on the particle model of matter, which of the following statements best explains the student’s observations that the volume of the gas decreases greatly but the volume of the liquid does not change noticeably?

• Gases expand to fill their containers but liquids do not because particles of gases are free to move but particles of liquids are fixed in position.
• Gases take the shape of their containers but liquids do not because gas particles have the ability to flow but liquid particles do not.
• Gases can have larger changes in volume than liquids can because gas particles expand and contract but liquid particles do not.
• Gases are more readily compressed than liquids are because there is more space between the particles in a gas than in a liquid.

Four containers of gas are represented in the diagram. Based on information in the model, in which container are the molecules most likely to have the highest average kinetic energy?

• Container A
• Container B
• Container C
• Container D

A student has drawn this model and says it shows what happens when a liquid changes to a gas. The diagram can best be used to illustrate which of the following?

• Liquids have the ability to flow.
• The density of a gas is less than that of a liquid.
• When a liquid vaporizes, its mass and volume increase.
• The average size of the particles increases when the temperature increases.

The diagrams show two forms of the same substance, form X and form Z , that differ in the arrangement of their particles. Which of the following statements about the relative densities of the two forms is correct?

• Form X is more dense because the material is more ordered.
• Form Z is more dense because the mass of form Z is greater than the mass of the same volume of form X .
• The densities are the same because the mass and volume of forms X and Z are the same.
• The densities are the same because forms X and Z are made of the same type of particle.

Which of the following explains the observation that, for the same substance, the density of a gas is much less than the density of a solid?

• Particles of gases are free to move around, but particles of solids are fixed in position.
• A given number of gas particles will have a smaller mass than the same number of solid particles.
• Samples of gases have volumes that are smaller than samples of solids of equal mass.
• The average distance between particles in a gas is larger than the average distance between particles in a solid.

Chromium metal has a density of 7.2g/cm3 . Mass and volume data for five metals are given in the table. Which TWO of the metals have a density greater than that of chromium?

• Aluminum
• Copper
• Iron
• Titanium
• Vanadium

A student determines the mass and volume of several pieces of the same metal. To determine the volume, the student places the metal in the water, then calculates the volume of water displaced by the metal sample. The student plots the data, as shown on the graph.The density of the metal is closest to which of the following?

• 0.37g/mL
• 2.7g/mL
• 3.5g/mL
• 9.5g/mL

A student determines the mass and volume of several pieces of the same metal. To determine the volume, the student places the metal in the water, then calculates the volume of water displaced by the metal sample. The student plots the data, as shown on the graph.Which of the following pieces of glassware should the student use to determine the volume of the metal samples?

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