1st Semester Exam Review

What is the change of one substance into another called?

• Physical property

• Chemical property

• Physical change

• Chemical change

Answer explanation

The change of one substance into another is called a chemical change. This process involves the breaking and forming of bonds, resulting in new substances with different properties, unlike physical changes which do not alter the substance's chemical identity.

Tags

NGSS.MS-PS1-2

Changing the size & shape of a piece of wood is an example of:

• Chemical property

• Chemical change

• Physical change

• physical property

Answer explanation

Changing the size and shape of a piece of wood involves altering its physical form without changing its chemical composition, making it a physical change.

The Statue of Liberty was originally made of a shiny, gold metal called copper. What happened to cause its color to become green?

• Chemical property

• Chemical change

• Physical change

• physical property

Answer explanation

The Statue of Liberty's color changed from shiny copper to green due to a chemical change. This occurred when the copper reacted with oxygen and moisture in the air, forming a green patina called copper carbonate.

Tags

NGSS.MS-PS1-2

Brian is making a cake for his friend's birthday. He combines the ingredients for the cake and then pours the batter into two pans and bakes them for 45 minutes in the oven. While the pans are in the oven, he combines butter, sugar, and milk and mixes them together to make the icing. What type of changes created the cake and the icing?

• Both the icing and the cake are formed by physical changes.

• The icing is formed by a chemical change and the cake is formed by a physical change.

• Both the icing and the cake are formed by chemical changes.

• The cake is formed by a chemical change and the icing is formed by a physical change.

Answer explanation

The cake undergoes a chemical change as it bakes, transforming the batter into a solid structure. The icing, made by mixing butter, sugar, and milk, is a physical change since it combines ingredients without altering their chemical composition.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

When a candle is lit, the wick burns, the wax melts. the candle changes shape, and the air around the candle heats up. Which of the following is an example of a chemical change?

• The wick burning

• The wax melting

• The candle changing shape

• The air around the candle heating up

Answer explanation

The wick burning is a chemical change because it involves a reaction that produces new substances (ash, gases) and cannot be reversed. In contrast, melting wax and changing shape are physical changes.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of the following is a property of an acid?

• sour taste

• soapy, slippery texture

• bitter taste

• pH of 8 - 14

Answer explanation

Acids are known for their sour taste, which is a characteristic property. The other options describe bases or neutral substances, as bases typically have a soapy texture and a bitter taste, while a pH of 8-14 indicates basicity.

What is the smallest most basic unit of matter?

• molecule

• atom

• compound

• mixture

Answer explanation

The smallest most basic unit of matter is the atom. Atoms are the building blocks of all matter, while molecules, compounds, and mixtures are made up of two or more atoms or combinations of different substances.

Tags

NGSS.MS-PS1-1

A timeline of some models of atoms throughout history is shown below. Which statement best summarizes the atomic theory over time?

• The discovery of new evidence resulted in changes to the atomic theory

• Advancements in models proved the atomic theory was always accurate

• The atomic theory was modified with the discovery of every new element

• Changes in atomic models showed that the theory was based on opinion

Answer explanation

The correct choice highlights that as new evidence emerged, the atomic theory evolved. This reflects the scientific process where theories are refined based on new discoveries, rather than being static or based on opinion.

Tags

NGSS.MS-PS1-1

What type of pure substance is made up of two or more DIFFERENT types of atoms chemically bonded?

• atom

• element

• mixture

• compound

Answer explanation

A compound is a pure substance formed when two or more different types of atoms are chemically bonded together. This distinguishes it from elements, which consist of only one type of atom, and mixtures, which are not chemically bonded.

Aluminum is a metal found on the periodic table and is made of a single type of atom. What is Aluminum?

• compound

• homogeneous mixture

• element

• heterogeneous mixture

Answer explanation

Aluminum is classified as an element because it consists of only one type of atom, as indicated on the periodic table. It is not a compound or mixture, which would involve multiple types of atoms or substances.