Which of these is indication that a chemical reaction has occurred?

A. Freezing of a substance

B. Melting of a substance

C. Boiling of a substance

D. Formation of a Preciptate

What are some common tools scientists use to measure length and mass?

How many atoms are in 3 moles of carbon?

The major portion of an atomic mass consist of

If a overscript right-arrow endscripts minus b overscript right-arrow endscripts = 3.8c overscript right-arrow endscripts, a overscript right-arrow endscripts plus b overscript right-arrow endscripts = 3.

A homogeneous mixture has the same composition throughout. a. True b. False

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