Question

PLease help! 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

Answer 1

Bubbles (gas formation) and color change are signs of a chemical change. Fire burning is an example of a chemical reaction in everyday life.

Step-by-step explanation:

Q1:

1. Bubbles (gas formation): When bubbles are formed during a reaction, it indicates the release of a gas, which is a sign of a chemical change.
2. Color change: If there is a color change during a reaction, it suggests that new substances with different chemical properties have been formed.

Q2:

Fire burning: Fire burning is an example of a chemical reaction because the substances involved (fuel and oxygen) are undergoing a chemical change to produce heat and light.

Q3:

1. Evaporating: Evaporation is a physical change as it involves the change of a substance from a liquid to a gas without altering its chemical composition.
2. Bubbles (gas formation): When bubbles are formed during a reaction, it indicates the release of a gas, which is a sign of a chemical change.
3. Color change: If there is a color change during a reaction, it suggests that new substances with different chemical properties have been formed.

Answer 2

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)

Step-by-step 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.