All the elements in the universe heavier than helium are/were created

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?

Achemical reaction is done in the setup shown, resulting in a change of mass. what will happen if the same reaction is done in a sealed container that is placed on the electronic balance?

Astudent states that 9.0 g of baking soda will form an unsaturated solution in 100 g of water. what do you need to know to decide whether this statement is correct? a. the temperature of the water and the molar mass of baking soda b. the percent by volume of the solution and the solubility of baking soda c. the temperature of the water and the solubility of baking soda at that temperature