Which formula represents a hydronium ion?

(1) H3O + (3) OH-

(2) NH4 + (4) HCO3-

In the calvin cycle, why are fewer than six rubp molecules required to fix six molecules of co2?

Why might gold jewelry from the middle ages appear to be new while iron swords from the same time look ancient?

What would cause a balloon to expand if taken to the top of a mountain? O A. Increased molecular collision O B. Increased amount of molecules O C. Lowered temperature D. Lowered pressure

Name three ill effects of the industrial revolution

Over time heat and pressure can change quartz into quartzite quartzite is A. An ingenious rock B. A metamorphic rock

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