Which Of These Is An Indication that a chemical reaction occurred

A. formation of gas

B. boiling of a substance

c. melting of a substance

d. freezing of a substance

Investigate why some element's symbols derived from their old names.

How can you determine an object mechanical energy

For an exothermic reaction, what would the potential energy diagram most likely look like? a curve with a negative slope indicating that the activation energy has a negative value a curve indicating that the amount of energy absorbed during the

Which statement best describes the conditions created by El Niño? Winds that normally blow to the west get stronger, waters off the coast of South America cool down, and upwelling increases, improving the nutrients in the water.

Large tides, called spring tides, are experienced in the Earth's oceans when the moon is in position A) A. B) B. C) A and C. D) B and D.

During an investigation, similar effervescent tablets were dropped into a beaker containing cold water and a beaker containing tap water. The table below shows an incomplete record of the investigation.

The air above earth's surface is at a different temperature what is responsible for this difference in temperature

The radioactive isotope tritium decays with a first-order rate constant k of 0.056 year-1. what fraction of the tritium initially in a sample is still present 30 years later?

A covalent bond in which electrons are shared unequally

Transferring or sharing electrons between atoms forms