Density Exam

Lily is conducting an experiment to find out which objects will float on water. She has objects with the following densities. Which one will float?

• 0.7 g/cm3

• 1.2 g/cm3

• 3.5 g/cm3

• 11.4 g/cm3

Answer explanation

An object will float on water if its density is less than that of water (1 g/cm³). Since 0.7 g/cm³ is less than 1 g/cm³, it will float, while the other densities (1.2, 3.5, and 11.4 g/cm³) will sink.

Avery and Isla are at a birthday party and notice that helium balloons rise into the sky. They wonder why this happens. Helium balloons rise on earth because

• helium is less dense than air

• helium is more dense than air

• helium is cooler than air

• helium is warmer than air

Answer explanation

Helium balloons rise because helium is less dense than air. This difference in density creates an upward buoyant force, allowing the balloon to float.

Aria is trying to find out how tightly packed the particles are in a rock. What two types of measurements should she use to calculate the DENSITY of the rock? 

• Mass and Volume

• Temperature and Mass

• Grams and Centimeters

• Volume and Weight

Answer explanation

Density is defined as mass per unit volume. Therefore, the two types of measurements that make up density are mass and volume, making 'Mass and Volume' the correct choice.

Daniel and Anika are comparing two boxes filled with identical balls. Which box has a greater density?  

• Box A

• Box B

Answer explanation

Box A has a greater density because density is defined as mass per unit volume. If Box A has more mass or less volume compared to Box B, it will have a higher density, making it the correct choice.

Grace wants to find the volume of Object X using displacement. What is the volume?

• 10.0 cm³

• 15.0 cm³

• 20.0 cm³

• 25.0 cm³

Answer explanation

To find the volume of Object X using displacement, submerge it in water and measure the rise in water level. The correct volume is 25.0 cm³, indicating that this is the amount of water displaced by the object.

Abigail and William each have a box of the same size. Abigail's box is filled with books, while William's box is filled with feathers. Which box will be more dense?

• The box with less weight.

• The box with more weight.

• The box with more mass.

• The box with less mass.

Answer explanation

Density is defined as mass per unit volume. Since both objects have the same volume, the object with more mass will have a higher density. Therefore, the object with more mass is the denser one.

Q. 

What is mass?

• The amount of matter an object has.

• The force of gravity pulling down on you.

• A large number of objects crowded together

Answer explanation

Mass is defined as the amount of matter an object has, making it the correct choice. The other options describe gravity and density, which are not definitions of mass.

As Grace and James move across the periodic table in their chemistry class, they notice that atoms tend to get smaller because, ______________.

• the atoms have more mass.

• the atoms have less mass

• the atoms have more protons.

• the atoms have less electrons.

Answer explanation

As you move across the periodic table, atoms have more protons, which increases the positive charge in the nucleus. This stronger attraction pulls electrons closer, resulting in smaller atomic size.

During a science class, Ava and Ethan were discussing periodic trends. Which statement correctly and completely identifies a trend?

• Atomic radius decreases across a period and increases down a group.

• Electronegativity decreases across a period and decreases down a group.

• Ionization energy increases across a period and increases down a group.

• Ionic radius increases across a period and increases down a group.

Answer explanation

The correct statement identifies that atomic radius decreases across a period due to increased nuclear charge, while it increases down a group due to added electron shells. The other statements are incorrect regarding their trends.

Tags

NGSS.HS-PS1-2

The more protons there are, the  ____ .

• Weaker the pull

• Smaller the electrons

• Stronger the pull

• The bigger the electrons

Answer explanation

The more protons present in an atom, the stronger the positive charge of the nucleus, which increases the pull on the electrons. Therefore, the correct choice is 'Stronger the pull'.