What type of change occurs when water changes from a solid to a liquid? A. a phase change B. a physical change C. an irreversible change D. both a and b

Which of the following ions came from an atom that gained 2 electrons? A. 0^2- B. Li+ C. Mg^3+ D. N^3-

Explain how the law of conservation of energy might apply to energy use that you observe in your daily life

A metal weighing 7.101 g is placed in a graduated cylinder containing 33.0 mL of water. The water level rose to the 37.4 mL mark. a) Calculate the density of the metal (in g/mL).

Why is it important for forensic scientists to have as much information as possible about the place where a possible drug substance was found?

How does pH affect enzyme-catalyzed reactions? How does affect enzyme-catalyzed reactions? Energy stored in protons is used to drive endergonic reactions. The concentration of protons affects an enzyme's folded structure and reactivity.

Which of the following is true about a redox reaction? In a redox reaction, an electron is lost by the reducing agent. In a redox reaction an electron is lost by the oxidizing agent.

Is the equation above balanced? How do you know? Mg + 2HCl → MgCl2 + H2

What characteristics do atoms of carbon-12, carbon-13, and carbon-14 have in common?

Which of the following changes would decrease the rate at which a solid solute dissolves in a liquid solvent? A. Decreasing pressure B. Decreasing surface area C. Increasing rate of stirring D. Increasing temperature

Helium, neon, and argon are examples of A) metals B) metalloids C) noble gases D) transitional metals