If the theoretical yield of a reaction is 26.0 grams and you actually recovered 22.0 grams what is the precent yield

How have the greenhouse gasses increased from the year 2000 to 2018

Why does a plastic bottle that is sealed at a high altitude change it’s shape when taken to lower altitude

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?