Chemistry: Density Calculations and Lab Practice
Calculating density, mass, and volume from lab data
Chemistry: Density Calculations and Lab Practice
Calculating density, mass, and volume from lab data
Chemistry - Grade 6-8
- 1
A metal cube has a mass of 54 grams and a volume of 6 cubic centimeters. What is its density?
Use the formula density = mass divided by volume.
The density is 9 grams per cubic centimeter because 54 grams divided by 6 cubic centimeters equals 9 grams per cubic centimeter. - 2
A liquid sample has a mass of 40 grams and a volume of 50 milliliters. Calculate the density of the liquid.
The density of the liquid is 0.8 grams per milliliter because 40 grams divided by 50 milliliters equals 0.8 grams per milliliter. - 3
A student measures an unknown solid. The mass is 32 grams and the volume is 4 cubic centimeters. The student says the density is 128 grams per cubic centimeter. Explain the mistake and give the correct density.
Density is not found by multiplying mass and volume.
The student multiplied mass by volume instead of dividing mass by volume. The correct density is 8 grams per cubic centimeter because 32 divided by 4 equals 8. - 4
A rock has a mass of 75 grams. When placed in a graduated cylinder, the water level rises from 30 milliliters to 45 milliliters. What is the rock's volume and density?
Use water displacement to find the volume of the rock first.
The rock's volume is 15 milliliters because 45 milliliters minus 30 milliliters equals 15 milliliters. Its density is 5 grams per milliliter because 75 grams divided by 15 milliliters equals 5 grams per milliliter. - 5
An object has a density of 2 grams per cubic centimeter and a volume of 12 cubic centimeters. What is its mass?
The mass is 24 grams because mass equals density times volume, and 2 grams per cubic centimeter times 12 cubic centimeters equals 24 grams. - 6
A sample has a density of 4 grams per milliliter and a mass of 36 grams. What is its volume?
Rearrange the density formula to solve for volume.
The volume is 9 milliliters because volume equals mass divided by density, and 36 grams divided by 4 grams per milliliter equals 9 milliliters. - 7
Three liquids are poured into a container and form layers. Liquid A has a density of 1.2 grams per milliliter, Liquid B has a density of 0.8 grams per milliliter, and Liquid C has a density of 1.0 gram per milliliter. List the liquids from top to bottom.
Less dense liquids float above more dense liquids.
The liquids from top to bottom are Liquid B, Liquid C, and Liquid A. The least dense liquid floats on top, and the most dense liquid sinks to the bottom. - 8
A plastic block has a density of 0.7 grams per cubic centimeter. Water has a density of 1.0 gram per milliliter. Will the plastic block float or sink in water? Explain your answer.
The plastic block will float because its density is less than the density of water. - 9
A piece of aluminum has a mass of 27 grams and a density of 2.7 grams per cubic centimeter. What is its volume?
To find volume, divide mass by density.
The volume of the aluminum is 10 cubic centimeters because 27 grams divided by 2.7 grams per cubic centimeter equals 10 cubic centimeters. - 10
A student collects the following data for four objects: Object W has a mass of 20 grams and a volume of 10 cubic centimeters. Object X has a mass of 18 grams and a volume of 6 cubic centimeters. Object Y has a mass of 12 grams and a volume of 12 cubic centimeters. Object Z has a mass of 30 grams and a volume of 5 cubic centimeters. Which object has the greatest density?
Object Z has the greatest density. Its density is 6 grams per cubic centimeter, while W is 2 grams per cubic centimeter, X is 3 grams per cubic centimeter, and Y is 1 gram per cubic centimeter. - 11
A graduated cylinder contains 20 milliliters of water. A student adds a small object, and the water rises to 28 milliliters. The object has a mass of 24 grams. Draw or describe the steps needed to find the object's density, then calculate it.
The change in water level equals the object's volume.
First, find the object's volume by subtracting 20 milliliters from 28 milliliters, which gives 8 milliliters. Then divide the mass by the volume, so 24 grams divided by 8 milliliters equals 3 grams per milliliter. - 12
In a lab, two groups measure the same solid. Group 1 reports a density of 7.8 grams per cubic centimeter. Group 2 reports a density of 5.1 grams per cubic centimeter. Give one possible lab error that could explain the difference.
One possible lab error is that one group measured the volume incorrectly, such as reading the graduated cylinder at an angle or not recording the starting water level accurately. An incorrect volume would change the calculated density.