How does the law of conservation of mass apply to this reaction: c2h4 + o2 → h2o + co2? a. the equation needs to be balanced. there are fewer oxygen atoms in the equation than hydrogen or carbon. b. only the oxygen needs to be balanced. there are equal numbers of hydrogen and carbon. c. the law of conservation of mass has already been applied. there is an equal number of each element on both sides of the equation. d. each element needs to be balanced.

What approach is required to balance the objectives of sustainable development? balancing the objectives of sustainable development requires a(n) .

Compare and contrast physical changes with chemical changes.

Ageochemist examines a piece of metal that he found in the soil. he performs tests to identify the metal from its density, electrical conductivity, and melting point. which statement best describes his investigation? a. he is determining physical properties that are sufficient to identify the metal. b. he is determining chemical properties that are sufficient to identify the metal. c. he is determining physical properties that are insufficient to identify the metal. d. he is determining chemical properties that are insufficient to identify the metal.