Which of the following items represents a chemical change? burning

melting

evaporation

freezing

Which determines how atoms combine to form molecules? A: The number of protons B: The number of electrons C: The arrangement of electrons D: The configuration of electron shells E: All of the above

Each of the diagrams below shows an electrically neutral atom. fill in the missing number of protons (n) neutrons (and), electrons (e), and atomic mass (m). then complete the questions in the space below

Levi is conducting a comparative experiment where he is comparing the average temperature in cities and nearby rural areas. He finds that cities are on average one degree warmer than rural areas.

Which statement describes an electron?

For a particle to escape the liquid phase, which of the following must occur? Its kinetic energy must be equal to the average kinetic energy to the liquid particles. It must be moving toward the interior of the liquid.

When adjusted for any changes in δh and δs with temperature, the standard free energy change δg∘t at 2400 k is equal to 1.22*105j/mol. calculate the equilibrium constant at 2400 k.?

What symbol represents "yields" or "forms" in a chemical reaction?

Hydrazine (N2H4) is a chemical compound used in rocket fuel. Which of the following represents the correct balanced equation for the reaction of hydrazine liquid with oxygen gas to produce nitrogen gas and steam? A.

Boyle's law is represented by which equation

A hot-water heater has an 8-ohm element that operates at 240 V. The power that's consumed by this water heater is A. 1,920 W. B. 30 W. C. 900 W. D. 7,200 W.