Phase Changes
The phase change from solid to liquid
What is melting?
Name two physical properties
density, color, malleability, hardness, elasticity, boiling point, conductivity, viscosity, transparency, and brittleness are all answers that are accepted
What is a reactant?
The substance present at the beginning of the experiment / before the chemical change
What is a molecule
The smallest chemical unit. Made up of atoms.
One example of a pure substance
Any element on the periodic table
Is energy added or taken away during condensation?
Taken away
What is conductivity and malleability?
Conductivity - allows heat to flow
Malleability - the ability to be shaped / bent and not break
What is the definition of exothermic?
A chemical change accompanied by the release of heat
(also counted - releasing of heat)
Where are all of the elements found?
What is the periodic table.
What are compounds?
2 or more types of atoms chemically bonded together
Solid to gas phase change
What is sublimation?
If an object has a density of 0.89, will it float or sink in water?
Float - water's density is 1 g/cm3
True or False
Ice cubes melting is endothermic.
True
Is O2 an element, compound, or molecule?
Molecule.
Name at least two matter substances
Name literally anything that has mass and takes up space
Do the atoms in a substance move faster or slower during evaporation?
Faster - liquid to gas
Name three chemical properties
flammability, toxicity, acidity, reactivity, and heat of combustion are all accepted answers
Is forming a precipitate evidence of a chemical change?
Yes, such as cottage cheese curdling.
What are the differences between compounds, elements, and molecules?
Compounds are 2 or more elements chemically combined
Elements cannot be broken down into smaller states
Molecules are made up of both compounds and elements (all compounds are molecules, but not all molecules are compounds)
What is the difference between a suspension and a solution?
Suspension - different sized particles that settle out of liquid
Solution - see-through or thin consistency / same size particles
True or False
Deposition is the solid to gas phase change
False
How does a chemical change happen?
when bonds are broken and/or formed between molecules or atoms (when it changes fully, like burning wood, you can't unburn the wood)
Is cutting and bleaching your hair a physical change, a chemical change, or both?
Both - the cutting of your hair is physical, but the bleaching is chemical.
What differentiates pure substances and mixtures?
Pure substances always have the exact same composition, whereas mixtures are two or more pure substances combined together
Name the types of mixtures
homogeneous, heterogeneous, suspension, solution, and colloid