7th Term 3 Test Review

Four students performed four different investigations by combining different substances. Their results are shown in the table below. In which experiment did a chemical reaction take place?

• ​​​​​​​Experiment 1

• ​​​​​​​Experiment 2

• ​​​​​​​Experiment 3

• ​​​​​​​Experiment 4

Tags

NGSS.MS-PS1-2

Hydrogen and oxygen react to form water. At an atomic level, how do we know that a chemical reaction has occurred?

• For every oxygen atom, two hydrogen atoms are needed.

• ​​​​​​​The hydrogen and oxygen atoms regroup into a new molecule.

• Oxygen atoms are much larger than hydrogen atoms.

• Hydrogen molecules are negative, and oxygn positive.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

The chart below shows the results of combining various substances. Which of the following statements is true?

• We know that combining Substances A and B resulted in a chemical reaction because of the lack of temperature change.

• We know that combining Substances C and D resulted in a chemical reaction because of the lack of a temperature change.

• We know that combining Substances A and B resulted in a chemical reaction because a gas was formed.

• We know that neither combinations resulted in a chemical reaction because neither one had a color change.

Tags

NGSS.MS-PS1-2

​​​​​​​Which of the following is the best description of the results of a chemical reaction?

• ​​​​​​​The substance changes from liquid to solid at a low temperature.

• ​​​​​​​A new substance with different properties is formed.

• ​​​​​​​The substance seems to disappear after dissolving in water.

• The reaction can be reversed to get back to the original substance.

Tags

NGSS.MS-PS1-2

​​​​​​​Rust forming on a piece of iron is an example of which of the following?

• The natural process of decay as metallic ions age

• ​​​​​​​A chemical change because oxygen atoms from the atmosphere bonded with the iron atoms

• A violation of the laws of physics becauses new mass has been created

• ​​​​​​​A physical change because the process can be reversed

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of the following statements is true?

• Cutting paper is an example of a chemical reaction because a new substance is formed and the process cannot be undone.

• Freezing water is an example of a chemical reaction because a new substance is formed and the process cannot be undone.

• Burning paper is an example of a chemical reaction because a new substance is formed and the process cannot be undone.

• ​​​​​​​Melting ice is an example of a chemical reaction because a new substance is formed and the process cannot be undone.

Tags

NGSS.MS-PS1-2

Match the following

• Product

• A process that leads to the transformation of one set of chemical substances to another

• Reactants

• Formed when two or more atoms chemically combine

• Chemical reaction

• The substance initially involved in a chemical reaction

• Atom

• Smallest part of a substance

• Molecule

• The substance that is produced from a chemical reaction

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-2

Which of the following is good evidence that an unknown sample is a pure substance?

• ​​​​​​​Multiple samples of the unknown substance melt at the same temperature.

• ​​​​​​​Multiple samples of the unknown substance melt at different temperatures.

• ​​​​​​​After leaving a liquid to settle, it separates.

• ​​​​​​​After leaving a liquid to settle, it does not separate.

Tags

NGSS.MS-PS1-4

Match the following

• Chemical property

• A property that requires a chemical interaction to observe

• Physical property

• A large amount of something

• Chemical reaction

• Has definite composition and properties

• Pure substance

• A property that is observed without making changes to the substance

• Bulk quantities

• Occurs when one or more substances change to produce one or more different substances

Tags

NGSS.MS-PS1-2

Which of the following is true regarding the atoms involved in a chemical reaction?

• Some of the atoms will always be changed into a different type of atom by a chemical reaction.

• During a chemical reaction, atoms will always be combined into much larger molecules.

• The same number of each type of atom will always be present before and after a chemical reaction takes place.

• Some of the atoms present before the reaction will always be lost during a chemical reaction.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5