Im really desperate right now 20pts

q1:
select all the signs of a chemical change from the list below. (you may need to select more than one for full points)

question 1 options:

evaporating

bubbles (gas formation)

dissolving

color change
q2:
which of the following is an example of a chemical reaction that you've seen in your everyday life?

question 5 options:

fire burning

ice melting

salt dissolving

water freezing
q3:
select all the signs of a chemical change from the list below. (you may need to select more than one for full points)

question 1 options:

evaporating

bubbles (gas formation)

dissolving

color change

Q1: Bubbles (gas formation)

     Dissolving ( if solute is an ionic compound)

     Color change

Q2: Fire burning

      Salt dissolving

Q3: Bubbles (gas formation)  

       Color change

      Dissolving ( if solute is an ionic compound)

Explanation:

Bubbles (gas formation)

Gas formation is mostly taken as an indicator for a chemical reaction, mostly in acid base reactions. Because when acid and base reacts water and carbon dioxide produces.

Dissolving of salt

Dissolving of salt in water is an example of a chemical change. Because when we put salt (NaCl) in water it changes into its ions (Na⁺ Cl⁻) by losing or gaining electrons. These Ions have totally different properties from the parent salt. So it is a chemical change.

Color change

Mostly we take color change as an indicator of a chemical change but it is not necessary. For example when we add two colors in a beaker its changes into a 3rd color without any chemical reaction.

Fire burning

Fire burning is an example of a chemical change. For example during wood burning, a chemical reaction takes place which changes the into ash and CO₂. the reactants and products have totally different properties.

answer: mercury

explanation:

c- cold periods in earth's history during which glaciers covered much of the surface.

explanation: