Hydrogen is a reducing agent. This property justifies its position in ___ group ( I A / VII A) fill in the blank

The grooves or folds of the brain are called

Element before carbon on the periodic table

When the chemicals iron sulfide (fes) and hydrochloric acid (hcl) are combined, bubbles appear from the mixture. 1. does the appearance of bubbles indicate a physical or chemical change? 2. why do the bubbles indicate this change? 3. what property is this?