Warm-Up Day 3

Which of the following is an example of a chemical property of matter?

• Solubility

• Reactivity with acid

• Boiling point

• Hardness

Answer explanation

Reactivity with acid is a chemical property because it describes how a substance interacts with acids, leading to a chemical change. In contrast, solubility, boiling point, and hardness are physical properties.

A block of metal has a mass of 200 grams and a volume of 50 cubic centimeters. What is its density?

• 2 g/cm³

• 4 g/cm³

• 5 g/cm³

• 10 g/cm³

Answer explanation

Density is calculated by dividing mass by volume. Here, density = 200 g / 50 cm³ = 4 g/cm³. Therefore, the correct answer is 4 g/cm³.

Which of the following is NOT a state of matter?

• Solid

• Liquid

• Plasma

• Light

Answer explanation

Light is not a state of matter; it is a form of electromagnetic radiation. The three primary states of matter are solid, liquid, and plasma.

Which tool would you use to measure the mass of an object?

• Thermometer

• Graduated cylinder

• Balance

• Stopwatch

Answer explanation

A balance is the correct tool to measure the mass of an object, as it compares the object to known masses. A thermometer measures temperature, a graduated cylinder measures volume, and a stopwatch measures time.

Which of the following best describes a chemical change?

• Melting ice

• Dissolving salt in water

• Burning wood

• Cutting paper

Answer explanation

Burning wood is a chemical change because it transforms the wood into ash and gases through combustion, altering its chemical structure. In contrast, melting ice, dissolving salt, and cutting paper are physical changes.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

What is the formula to calculate density?

• 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 that density is calculated by dividing the mass of an object by its volume, which is essential for understanding how compact or spread out matter is.

Which unit is commonly used to measure volume?

• Grams

• Meters

• Liters

• Celsius

Answer explanation

Liters are the standard unit for measuring volume, commonly used for liquids. Grams measure mass, meters measure length, and Celsius measures temperature, making liters the correct choice for volume.

Which of the following is an example of a pure substance?

• Air

• Saltwater

• Gold

• Salad

Answer explanation

Gold is a pure substance because it consists of only one type of atom, making it homogeneous. In contrast, air, saltwater, and salad are mixtures containing multiple components.

Which of the following is a physical change?

• Rusting iron

• Baking a cake

• Evaporating water

• Burning coal

Answer explanation

Evaporating water is a physical change because it involves a change in state from liquid to gas without altering the chemical composition. In contrast, rusting iron, baking a cake, and burning coal involve chemical changes.

Examples of physical properties include all of the following EXCEPT (2 examples).

​ ​ (a)   ​ (b)  

• reactivity
• flammability
• shape
• color
• mass
• texture
• density
• luster
• smell