Physical and chemical change Flashcards
What are the signs of physical change?
-No new substances are created
-They change shape or form
-They contract or expand
-They change state or dissolves without forming a new substance.
What are the signs of chemical change?
- New substances are created
-A permanent colour change
-A gas is given off
-Seeing a new solid (precipitation) forming in a clear solution.
-A change in temperature happens or light is produced
What is expansion?
When solids, liquids or gases are heated, they expand and take up more space. When expansion occurs, the volume increases and density decreases. ( escape their bonds)
What is contraction?
When a liquid, gas or solid cools down, it contracts and causes the volume of the substance to decrease while the density increases. (lose kinetic energy)
What are the properties of a solid?
The attraction between particles are packed tightly, incompressible and hold their shape. They vibrate on the spot, increasing based on the temperature.
What are the properties of a gas?
Not stuck together and can move freely in straight lines.
What are the properties of a liquid?
Particles are packed tightly together however as not as stuck as solids. Particles in a liquid vibrate however can still freely move.
What is diffusion
Is when the particles of 2 gases or liquids mix evenly without stirring.
What is mixing?
Mixing is putting two or more substances together to make a blend that can be separated by physical means.
What is dissolving?
When a solid (solute) breaks down into smaller particles (dissolves) in a liquid(solvent) they form a solution.
What is crystallisation?
If heat is applied to a solution, we can evaporate the solvent leaving behind the solute. It can be recovered using condensation with a distillation tube
What is deposition?
Is when a gas turns into a solid.
What is sublimation?
Is when a solid turns into a gas.
Why does your breath turn into fog on a cold day?
Because the water vapour in your breath is condensing into a mist.
What is a chemical reaction?
A chemical reaction is when substances change into new substances by breaking and forming bonds between atoms.
What is a reactant?
The old substance before a chemical reaction.
What is a product?
The new substance after a chemical reaction.
What is the worded formula for the forming of hydrogen chloride gas?
Hydrogen gas+ chlorine gas turns into hydrogen chlorine gas.
What is combustion?
Is any chemical reaction that involves burning oxygen to release light and heat.
Hydrogen gas +oxygen gas tuns into water vapour
What is photosynthesis?
the process where plants, using chlorophyll, convert sunlight, water, and carbon dioxide into oxygen and glucose.
What is glucose?
A form of sugar produced in photosynthesis and used in respiration to produce energy.
What is chlorophyll.
The substance found in plant leaves that makes leaves green and collects energy from the sun for photosynthesis.
What is the formula for photosynthesis?
carbon dioxide +water+sunlight turns into oxygen gas +glucose
What is respiration in plants?
The process of extracting energy from food by converting oxygen and glucose into carbon dioxide, water, and energy.
