1. Silicon has two isotopes: Silicon-27 and Silicon-28. a. Which isotope is more abundant? Give a reason for your choice.

b. Write the two isotopes of Silicon using complete symbol notation.

c. Why are these atoms considered to be isotopes?

9. write the chemical equation for the following word equations. include symbols for physical states in the equation. a. solid zinc sulfide + oxygen gas -> solid zinc oxide + sulfur dioxide gas b. aqueous hydrochloric acid + aqueous barium hydroxide -> aqueous barium chloride + water

Using data from seismic waves, geologists have learned that earth’s interior is made up of several

What is the percent composition of ca(oh)2? 37.7% ca, 53.0% o, and 10.3% h 45.5% ca, 38.2% o, and 16.3% h 54.0% ca, 43.0% o, and 2.7% h 64.7% ca, 27.0% o, and 8.3% h