Conservation of mass and balancing

What are the products in this chemical reaction?

• Propane

• Propane and oxygen

• Carbon dioxide and water

• Oxygen and carbon dioxide

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

What are the correct coefficients to balance this chemical equation?

Zn + HCl → ZnCl₂ + H₂.

• 1,2,1,1

• 1,2,1,2

• 2,1,2,1

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

What are the correct coefficients to balance this chemical equation?

Na + H₂O → NaOH + H₂.

• 1,2,2,1

• 1,1,2,1

• 2,2,2,1

Tags

NGSS.MS-PS1-5

What are the correct coefficients to balance this chemical equation? N₂ + H₂ → NH₃.

• 2,3,1

• 1,2,3

• 1,3,2

• 2,1,1

Tags

NGSS.MS-PS1-5

What is the total mass of the reactants in this chemical equation?

Oxygen = 16 amu Carbon = 12 amu Hydrogen = 1 amu.

• 204 amu

• 160 amu

• 44 amu

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-5

Does the chemical reaction shown below obey the Law of Conservation of Mass?

• No, because the mass of the reactants and products is NOT equal

• Yes, because number of Hydrogen, Carbon, and Oxygen atoms are equal before and after the reaction

• No, because number of Hydrogen, Carbon, and Oxygen atoms are NOT equal before and after the reaction

In order to obey the Law of Conservation of Mass, what is the mass of Magnesium have to be?

• 16 g

• 32 g

• 24.3 g

Tags

NGSS.MS-PS1-5

Are atoms created or destroyed in a chemical reaction?

• Yes, some atoms are created as others are destroyed.

• No atoms are created or destroyed.

• The atoms simply rearrange themselves and form new molecules.

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

Based on the information below, would you consider this to be an open or closed system? How can you tell?

• Open, because the mass of the system after the reaction is GREATER than it was before the reaction

• Open, because the mass of the system after the reaction is LESS than it was before the reaction

• Closed, because the mass of the system after the reaction is LESS than it was before the reaction

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

If someone performed a science experiment that produced a highly toxic gas and the mass did NOT change throughout the experiment, what could we say about the system and how do we know?

• Open, because mass did not change throughout the experiment

• Closed, because mass did not change throughout the experiment

• We cannot tell without more information such as mass of reactants and products

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5