Question

multiple choice
the table below shows the density of some common substances. use the table to
answer questions 21 through 25.
substance | density (g/cm³) | substance | density (g/cm³)
aluminum (solid) | 2.7 | ice (solid) | 0.93
pyrite (solid) | 5.02 | water (liquid) | 1.00
mercury (liquid) | 13.55 | zinc (solid) | 7.13
silver (solid) | 10.50 | wood (oak) | 0.85

1. a cube has a density of 2.7 g/cm³. what substance is the cube made of?

a. aluminum
b. ice
c. pyrite
d. wood

1. what substance has a density more than 13 times greater than water?

a. ice
b. silver
c. aluminum
d. mercury

1. why will ice float on top of liquid water?

a. ice has a lower density than water.
b. ice has a higher density than water.
c. ice is a solid.
d. ice is colder than water.

1. what is the density of oak wood?

a. 85 g/cm³
b. 5.02 g/cm³
c. 0.85 g/cm³
d. 0.93 g/cm³

1. what is the densest solid shown in the table?

a. mercury
b. silver
c. zinc
d. pyrite

Explanation:

Question 21

We look at the density values in the table. The cube has a density of \(2.7\space g/cm^3\). From the table, Aluminum (solid) has a density of \(2.7\space g/cm^3\), ice has \(0.93\space g/cm^3\), pyrite has \(5.02\space g/cm^3\), and wood has \(0.85\space g/cm^3\). So the substance with density \(2.7\space g/cm^3\) is aluminum.

First, find the density of water which is \(1.00\space g/cm^3\). 13 times the density of water is \(13\times1.00 = 13.00\space g/cm^3\). Now check the densities: ice is \(0.93\), silver is \(10.50\), aluminum is \(2.7\), mercury is \(13.55\). Mercury's density (\(13.55\)) is more than \(13\) times water's density (\(13.00\)).

Objects float on a liquid if their density is less than the liquid's density. Ice has a density of \(0.93\space g/cm^3\) and water (liquid) has \(1.00\space g/cm^3\). So ice has a lower density than water, which is why it floats.

Answer:

a. aluminum

Question 22