Describing Chemical Reactions

What can the arrow in a chemical reaction be translated to mean? Check all that apply.

• yields

• accompanied by

• react to form

• added to

• except

Cecil writes the equation for the reaction of hydrogen and oxygen below. H2 + O2 → H2O Why does his teacher ask him to balance the equation by including the correct coefficients?

• to show that most molecules exist in pairs

• to show that most compounds exist in pairs

• to show that atoms are conserved in chemical reactions

• to show that atoms are created in chemical reactions

Tags

NGSS.MS-PS1-5

Franklin was performing an experiment by combining hydrochloric acid and sodium hydroxide. He measured the mass of his reactant materials to be 35g. The reaction resulted in the production of salt and water. He reported that his products weighed 32g. Which best describes the results of Franklin’s experiment?

• No error occurred, some of the products are always lost as heat.

• An error occurred, the mass of the reactants should equal the mass of the products.

• An error occurred, the products should weigh more than the reactants.

• No error occurred, water is not weighed when determining the weight of the products.

Tags

NGSS.MS-PS1-5

Rust results from iron’s reaction to oxygen. An iron nail gains mass when it rusts. How does this reaction support the law of conservation of mass?

• The mass of the rusted nail equals the mass of iron and the oxygen from the air it reacted with to form the rust.

• The mass of the rusted nail increases because iron attracts more protons from the air.

• The increased mass of the rusted nail is an exception to the law of conservation of mass since the rusted nail’s mass increases.

• The increased mass of the rusted nail results from the rearrangement of protons and neutrons within oxygen, according to the law of conservation of mass.

Tags

NGSS.MS-PS1-5

What type of reaction involves the breaking down of a substance into simpler substances?

• Single Displacement Reaction

• Double Displacement Reaction

• Synthesis Reaction

• Decomposition Reaction

Tags

NGSS.MS-PS1-2

What is the main characteristic of a combustion reaction?

• It involves the formation of a precipitate

• It involves the release of energy in the form of heat and light

• It involves the absorption of energy

• It involves the formation of a gas

Tags

NGSS.MS-PS3-5

Which of the following is a type of chemical reaction?

• Melting

• Combustion

• Freezing

• Evaporation

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A copper penny turning greenish after a few years is an example of ...

• Chemical Change

• Physical Change

Tags

NGSS.MS-PS1-2

Which is the correct balanced equation for the reaction of rust, Fe2O3, and hydrochloric acid, HCl?

• Fe2O3 + HCl → FeCl3 + H2O

• Fe2O3 +3 HCl → 2 FeCl3 + H2O

• Fe2O3 + 6 HCl → 2 FeCl3 + 3 H2O

• Fe2O3 + 3 HCl → 2 FeCl3 + 3 H2O

Tags

NGSS.MS-PS1-5

Examine the chemical reaction.

What coefficient of O2 should be added so the number of atoms of oxygen is conserved on both sides of the reaction equation?

• 3

• 5

• 7

• 10

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-5