Need help please With this.

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?

Name 3 types of energy you see being used as you look around a classroom

Which of the following is described by the equation h2o(s)+ heat=h2o(i) a freezing melting condensing evaporating