What are the two main physical properties of materials that are critical when selecting materials for specific uses?

Melting point and boiling point are critical physical properties to consider when selecting materials for specific uses.

Fill in the blank: The temperature at which a material changes from a solid to a liquid is called the ___.

Melting point

True or False: Flammability is a physical property that indicates how likely a substance is to undergo a chemical reaction.

False. Flammability is a chemical property, not a physical property.

What is the method for measuring the melting point of a substance?

Melting point is measured using heating.

• Place material in container.

• Heat gradually and monitor.

• Record temperature when stable.

Fill in the blank: Reactivity refers to how likely a substance is to undergo a ___ reaction.

Chemical

What is the significance of knowing the chemical properties of materials?

Knowledge of chemical properties is useful for identifying unknown materials by testing their reactivity and flammability.

What does the boiling point of a material indicate?

The boiling point indicates the temperature at which a material transitions from a liquid to a gaseous state.

Fill in the blank: Materials like hydrogen are highly flammable, while materials like ___ or ___ are non-flammable.

Iron; nitrogen

What are some examples of physical properties of materials?

Examples of physical properties include mass, hardness, boiling point.

• Mass measures matter quantity.

• Hardness indicates scratch resistance.

• Boiling point defines phase change.

What is the significance of the pH scale in determining the acidity or alkalinity of a solution?

pH scale indicates acidity or alkalinity.

• Ranges from 0 to 14.

• Below 7 is acidic.

• Above 7 is alkaline.

Fill in the blank: Strong acids or alkalis, such as hydrochloric acid and sodium hydroxide, are highly ___ and must be handled with caution.

Corrosive

True or False: Weak acids and alkalis are generally harmful and should be handled with extreme caution.

False. Weak acids and alkalis, like those found in milk and toothpaste, are generally safe.

What color does litmus paper turn when it is dipped in an acidic solution?

Red

I am a solution that changes color from red to purple based on acidity, what am I?

Universal Indicator