Chemical Reactions Assessment Review

Carbon and oxygen combine to form carbon dioxide. At an atomic level, how do we know that a chemical reaction has occurred?

• Oxygen molecules are negative, and carbon positive.

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

• The carbon and oxygen atoms regroup into a new molecule.

• Oxygen atoms are much larger than carbon atoms.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A chemical reaction occurs that involves combining 5 atoms of zinc with 10 atoms hydrogen and 10 atoms of chlorine. After the reaction, how many atoms of each element will there be?

• 5 zinc, 10 hydrogen, 10 chlorine

• 10 zinc, 10 hydrogen, 10 chlorine

• 10 zinc, 5 hydrogen, 10 chlorine

• 15 zinc, 10 hydrogen, 10 chlorine

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

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

• A new substance with different properties is formed.

• The substance seems to disappear after dissolving in water.

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

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

Tags

NGSS.MS-PS1-2

We know rust forming on a chain is a chemical reaction because...

• the process can be reversed

• it is the natural process of decay as metallic ions age

• oxygen atoms from the atmosphere bonded with the iron atoms, forming a new molecule.

• new mass has been created

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

During a chemical reaction, substances (called reactants) are combined to form new substances (called products). Which of the following accurately describes the reactants and the products of a chemical reaction?

• The products contain a different number of atoms than the reactants but have the same properties.

• The number of atoms and the properties are the same in the reactants and the products.

• The products contain the same number of atoms as the reactants but have different properties.

• The number of atoms and the properties are different in the reactants and the products.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A student finds the mass and volume of four mystery substances. The data is provided. The student knows that the density of sulfur is about 2 g/mL. Which of the four mystery substances is sulfur? (Density = Mass/Volume)

• W

• X

• Y

• Z

Tags

NGSS.MS-PS1-2

A student mixes a solid powder into a beaker of fluid. If the fluid in the beaker starts to bubble and loses mass as a gas into the surrounding air, what most likely occurred?

• A physical change due to the movement of molecules

• A chemical change due to a change in color

• A physical change due to the liquid heating

• A chemical change due to a formation of a gas

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of the following is NOT an indicator of a chemical reaction?

• A phase change

• A temperature change

• A color change

• A gas being created

Tags

NGSS.MS-PS1-2

A table comparing four metals is provided. A sample known to be one of the four listed in the table was heated to a temperature of 232 degrees celcius and melted. The sample was found to have a density less than 6 g/cm3 and to be a fair conductor of electricity. Burning the sample produced a blue/white flame. Based on this information, what is the identity of this sample?

• Zinc

• Lead

• Tin

• Iron

Tags

NGSS.MS-PS1-2