Physical and Chemical Changes - 7.3 Chemical Reactions [ARCHIVE] Flashcards
What is produced during a chemical change?
New substances
How do explosions occur?
When combustion releases so much energy so quickly that an explosion occurs.
What do we use combustion for nowadays.
-To heat and cook
-Run cars
-To generate electricity in gas power stations
What is photosynthesis?
A series of chemical reactions that uses sunlight to convert water and carbon dioxide into oxygen gas, and form sugar called glucose.
What are common indicators of a chemical change?
- Permanent color change
- Gas release
- Precipitate formation
- Temperature change
- Light production.
How does a chemical change differ from a physical change?
A chemical change rearranges atoms, while a physical change does not.
Why do graphite and diamond have different properties?
They have different properties because the carbon atoms in each are arranged differently.
What is the key difference between water (H₂O) and hydrogen peroxide (H₂O₂)?
Water (H₂O) has two hydrogen atoms and one oxygen atom, while hydrogen peroxide (H₂O₂) has two of each, giving them different properties.
What is a chemical reaction?
The process of rearranging atoms to form new substances.
What are the reactants and products in a chemical reaction?
Reactants are the old substances, and products are the new substances formed.
What happens when magnesium burns in oxygen? (formula)
Magnesium + Oxygen → Magnesium Oxide
(releasing heat and light.)
What is produced when hydrogen gas reacts with chlorine gas?
Hydrogen chloride gas
Why is evaporation considered a physical change?
Because the water molecules rearrange but no new substance forms.
What is combustion?
A chemical reaction involving burning with oxygen to release heat and light.
What happens when methane burns in oxygen? (formula)
Methane + Oxygen → Carbon dioxide + Water vapor.
