Validity and Soundness

Answers

1. Invalid. Counterexample: Katie is severely mentally handicapped and so is not smarter than a chimpanzee.
   
2. Invalid. Counterexample: suppose Bob just became a fireman, so he has never actually put out any fires.
3. Invalid. Counterexample: Although Gerald probably knows how to teach mathematics, suppose he has just had a traumatic brain injury and no longer knows how to teach mathematics. And suppose the injury is recent enough for him not to have lost his job as a mathematics professor yet.
4. Invalid. Counterexample: A similar counterexample as #3 would work equally as well here.
   
5. Valid.
   
6. Invalid. Counterexample: Perhaps Craig and Linda are married, but Monique is Linda's secret lover and Craig just finds about it and is angry and hates Monique (but still loves Linda).
   
7. Invalid. Counterexample: suppose that although Orel Hershizer believes that God exists, in fact God doesn't exist. In that case, Orel can't communicate with God, since you can't communicate with something that doesn't exist (i.e., communication is a two-way interaction).
8. Valid.
9. Valid.
   
10. Valid.