To treat the callus, you decide to shave off some of the excess epidermis. While doing this, you notice that there is no pain or bleeding. Why wouldn't it cause pain to remove the superficial layers of the epidermis? Why wouldn't it bleed?

yes, because even though a theory has a  lot of evidence to support it, it is not always true

propane is burned to provide the heat in many cooking grills. the chemical reaction for this process is shown in the equation below.

c3h8 + 5o2 ? 3 co2 + 4h2o + energy

what are the products in this chemical reaction?

3co2 + 4h2o + energy

answer denitrification;