Science Review

Which of the following statements about metals is correct?

• Metals are dull, solid at room temperature, malleable, and ductile.

• Metals are non-lustrous, hard, malleable, and have a high melting point.

• Metals are shiny, hard, malleable, and have a high melting point.

• Metals have a high luster, a low melting point, are solid at room temperature, and are not malleable.

Answer explanation

The correct statement is that metals are shiny, hard, malleable, and have a high melting point. This accurately describes the physical properties of metals, distinguishing them from non-metals.

It is easier to swim in the salt water of the ocean than in a fresh water of a lake. What statement explains this phenomena?

• Salt water is less dense than fresh water, so your body will float more easily in sea water.

• Salt water is more dense than fresh water, so your body will float more easily in sea water.

• Waves in the ocean make it easier to swim.

• Your body is less dense in sea water than in fresh water so you float easier.

• Your body is more dense in fresh water than in sea water so you float easier.

Answer explanation

Salt water is more dense than fresh water, which allows your body to float more easily in sea water. This increased buoyancy makes swimming in the ocean easier compared to a lake.

Which of the following liquids is the least dense?

• Ammonia

• Gasoline

• Glycerine

• Water

Answer explanation

Gasoline has a lower density than ammonia, glycerine, and water. This makes it the least dense liquid among the options provided.

Tags

NGSS.MS-PS1-2

Which of the following is true about the density of ammonia?

• It is higher than glycerine.

• It is lower than gasoline.

• It is higher than gasoline.

• It is the same as water.

Answer explanation

Ammonia has a density of about 0.73 g/cm³, which is higher than gasoline (approximately 0.7 g/cm³). Therefore, the correct statement is that ammonia is higher than gasoline.

Tags

NGSS.MS-PS1-2

Fill in the blank: State A is a ______ because the particles are evenly packed.

• solid

• liquid

• gas

Answer explanation

State A is a solid because solids have particles that are closely packed together, giving them a definite shape and volume. In contrast, liquids and gases have particles that are more spread out.

Tags

NGSS.MS-PS1-4

Fill in the blank: Gases fill the volume of their containers because their molecules are ______ packed.

• tightly

• loosely

• evenly

Answer explanation

Gases fill their containers because their molecules are loosely packed. This allows them to move freely and occupy the entire volume of the container, unlike solids or liquids where molecules are tightly packed.

Which state of matter is characterized by having a variable shape but a definite volume?

• Solid

• Liquid

• Gas

Answer explanation

A liquid has a definite volume but takes the shape of its container, making it distinct from solids, which have a fixed shape, and gases, which have neither a fixed shape nor volume.

Tags

NGSS.MS-PS1-4

Which of the following is a common use for metals?

• Semiconductors

• Alloys in metal

• Fertilizers

• Medicines

Answer explanation

Metals are commonly used to create alloys, which are mixtures of two or more metals that enhance properties like strength and durability. This makes 'Alloys in metal' the correct choice for common metal uses.

Rare earth elements are crucial for making ______.

• Medicines

• Strong magnets

• Jewelry

• Semiconductors

Answer explanation

Rare earth elements are essential for producing strong magnets, which are used in various applications like electric motors and hard drives. While they have roles in other areas, their primary significance lies in magnet production.

Tags

NGSS.MS-PS1-3

A student places a slice of carrot in fresh water and another slice of carrot in salt water. How do you explain these results?

• The density of fresh water is greater than the density of salt water. The density of the carrot is greater than salt water and less than fresh water.

• The density of fresh water is greater than the density of salt water. The density of the carrot is less than salt water and less than fresh water.

• The density of salt water is greater than the density of fresh water. The density of the carrot is greater than fresh water and less than salt water.

• The density of salt water is greater than the density of fresh water. The density of the carrot is less than fresh water and less than salt water.

Answer explanation

The density of salt water is greater than fresh water, causing the carrot to float in salt water. The carrot's density is greater than fresh water but less than salt water, explaining its behavior in both solutions.

Tags

NGSS.MS-PS1-2