Alchemy Quiz 03

What is the density of a block with a mass of 100.0g and a volume of 50.0 cm³?

• 0.5 g/cm³

• 2 g/cm³

• 50 g/cm³

• 100 g/cm³

• 150 g/cm³

Answer explanation

Density is mass divided by volume.

Two blocks, A and B, are on an equal-arm balance. The balance remains horizontal. Which block has the greater density?

• block A

• block B

• both have the same density

• you would need to know each substance

Answer explanation

If two objects have the same mass, the one with the smaller volume has more mass packed into a smaller space, resulting in a higher density.

Noah and Sophie were discussing the density of two pieces of pure gold. One is a small gold nugget and the other is a large sheet of gold foil. Noah says: "I think that the foil has a greater density because it has a large surface area." Sophie disagrees: "I think the nugget has the greater density because it is more compact." With whom do you agree?

• Noah

• Sophie

• Neither because the densities are the same.

• Neither because objects that are thicker have greater densities.

• Neither because you need to know mass and volume.

Answer explanation

Density is a characteristic property of a substance. Gold will always have the same density, no matter how larger or small the sample size.

Mary Anne noticed a metal object lying by the railroad tracks. She believes the object may have originally been a copper penny that was run over by a train. What information about the metal object would be most useful in determining if her hypothesis is correct?

• its weight

• its mass

• ts volume

• its density

Answer explanation

Any solid piece of copper will have the same density, no matter how large or small. Masses and volumes may change, but the density of copper will stay the same.

What is the density of a liquid if the volume is 25 mL and the mass is 20 g?

• 0.8 g/mL

• 1.25 g/mL

• 45 g/mL

• 500 g/mL

Answer explanation

Density is mass divided by volume.

The density of gold is 19.3 g/cm³ and lead is 11.4 g/cm³. What is true about the density of a lead block that is coated with gold?

• Its density is 11.4 g/ cm³.

• Its density is 19.3 g/ cm³.

• Its density is between 11.4 g/cm³ and 19.3 g/cm³.

• There is not enough information to determine the density of the block.

Answer explanation

The density of an object with two substances combined cannot be less than the lower density substance or more than the higher density substance.

You find an object that is made of a pure metal. What could you do to identify which metal the object is made of?

• Measure its length and compare it to the length of other metals.

• Determine its shape and compare it to the shape of other metals.

• Measure its mass and compare it to the mass of other metals.

• Measure its volume and compare it to the volume of other metals.

• Determine its density and compare it to the density of other metals.

Answer explanation

Mass and volume can change, but density is a characteristic property that will not change with the amount of the substance.

Which of these statements is true about two blocks of gold that are different shapes but have the same mass?

• They have the same volume and the same density.

• They have different volumes and different densities.

• They have different volumes, but the same density.

• They have the same volume, but different densities.

Answer explanation

Two items made out of gold will have the same density. Since they also have the same mass, the volume will also be the same.

An archeology student found a coin at a dig. She determined that the mass of the coin is 4.33 g and its volume is 0.48 cm³. What is the coin most likely made of?

• aluminum

• copper

• silver

• zinc

Answer explanation

First, calculate the density (mass divided by volume). Then, compare that value to the table of densities to see which substance it is closest to.

Tags

NGSS.MS-PS1-2

Two objects, one made only of substance A and the other made only of substance B, are dropped into a bucket of water. What will happen?

• Both objects will float.

• Both objects will sink.

• The object made of substance A will sink.

• The object made of substance B will sink.

• There is not enough information to tell.

Answer explanation

On a Mass vs. Volume graph, the steeper the slope, the greater the density. An object with a density greater than water will sink. An object with a density less than water will float.

Tags

NGSS.MS-PS1-2