Exploring Matter and Its Properties

What is the smallest unit of matter that retains the properties of an element?

• Molecule

• Atom

• Compound

• Mixture

Answer explanation

The smallest unit of matter that retains the properties of an element is an atom. Atoms combine to form molecules, but only atoms represent the fundamental building blocks of elements.

Which state of matter has a definite shape and a definite volume?

• Solid

• Liquid

• Gas

• Plasma

Answer explanation

A solid has a definite shape and a definite volume, unlike liquids and gases which take the shape of their container and have variable volumes. Therefore, the correct answer is solid.

Which of the following is a physical property that does NOT depend on the amount of matter present?

• Mass

• Volume

• Density

• Weight

Answer explanation

Density is a physical property that is defined as mass per unit volume. It remains constant regardless of the amount of substance, unlike mass, volume, and weight, which all depend on the quantity of matter present.

What term describes a substance made up of only one kind of atom?

• Compound

• Mixture

• Element

• Solution

Answer explanation

An element is a pure substance that consists of only one type of atom. Unlike compounds, which are made of two or more different atoms, or mixtures and solutions, which contain multiple substances, elements are fundamental building blocks of matter.

Which of the following best describes what happens to the particles of a solid when it is heated and changes to a liquid?

• The particles stop moving.

• The particles move closer together.

• The particles move faster and slide past each other.

• The particles become larger.

Answer explanation

When a solid is heated, its particles gain energy, causing them to move faster. This increased movement allows the particles to slide past each other, leading to the transition from solid to liquid.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

A student measures the mass and volume of a rock and calculates its density. Which formula should the student use?

• Density = Mass + Volume

• Density = Mass ÷ Volume

• Density = Volume ÷ Mass

• Density = Mass × Volume

Answer explanation

The correct formula for density is Density = Mass ÷ Volume. This means density is calculated by dividing the mass of an object by its volume, which is a fundamental principle in physics.

If you have two samples of water, one with a mass of 50 g and another with a mass of 100 g, which property will be the same for both samples?

• Mass

• Volume

• Density

• Weight

Answer explanation

Density is the ratio of mass to volume and remains constant for a given substance at a specific temperature and pressure. Therefore, both water samples will have the same density, regardless of their different masses.

Which of the following is an example of a phase change caused by adding thermal energy?

• Water freezing

• Ice melting

• Water condensing

• Dew forming

Answer explanation

Ice melting is a phase change that occurs when thermal energy is added, causing solid ice to transition to liquid water. The other options involve either losing heat or are not phase changes.

Tags

NGSS.MS-PS1-4

A student observes that salt dissolves in water but sand does not. Which property is the student investigating?

• Melting point

• Solubility

• Density

• Boiling point

Answer explanation

The student is investigating solubility, as it refers to the ability of a substance (like salt) to dissolve in a solvent (water), while sand does not dissolve, demonstrating different solubility properties.

A teacher gives you a sample of an unknown pure substance. You measure its melting point and boiling point. How can these measurements help you identify the substance?

• By comparing them to known values for different substances

• By mixing the substance with water

• By measuring its color

• By observing its shape

Answer explanation

Measuring the melting and boiling points allows you to compare these values to known values for different substances, helping to identify the unknown substance accurately.

Tags

NGSS.MS-PS1-4