Elements
a pure substance that cannot be separated into simpler substances by physical or chemical means
Element
A pure substance made of two or more elements that are chemically combined is called a(n
compound
combination of two or more substances that are not chemically combined
Mixture
process that separates a mixture based on the boiling points of the components
distillation
If a spoonful of salt is mixed in a glass of water, the salt is the ______________________
Solute
a sample of matter, either a single element or a single compound, that has definite chemical and physical properties
pure substance
A compound is different from the ______________________ that reacted to form it.
Elements
homogeneous mixture of two or more substances uniformly dispersed throughout a single phase
solution
Describe three ways to dissolve solids faster, and explain why each works.
Heating, stirring or creating more surface area
Solid solutions of metals or nonmetals dissolved in metals are called ______________________
Alloys
an element that is shiny and that conducts heat and electric current well
Metal
What type of change is needed to break down a compound?
Chemical Change
mixture in which particles of a material are more or less evenly dispersed throughout a liquid or gas
Suspension
machine that separates mixtures by the densities of the components
Centrifuge
substance in which a solute dissolves
solvent
A property that can be used to identify an element
Characteristic property
List three examples of compounds you encounter every day.
Salt, Water, Sugar, Carbon Dioxide, etc.
When solid Iodine is dissolved in alcohol which is the solute and which is the solvent
Iodine - solute
Alcohol - solvent
Describe a procedure to separate a mixture of salt, finely ground pepper, and pebbles
Pass the mixture through a screen that allows the salt and pepper to pass through but traps the pebbles. Mix the alt and pepper in water to dissolve the salt. Filter the mixture to trap the pepper. Evaporate the water to recover the salt.
ability of one substance to dissolve in another at a given temperature and pressure
Solubility
Compare the properties of metals, nonmetals, and metalloids.
Metals are shiny, are good conductors of heat and electric current, and are malleable and ductile. Nonmetals are dull, are poor conductors of heat and electric current, and tend to be brittle. Metalloids can be dull or shiny, may conduct heat and electric current, and are somewhat malleable and ductile.
Explain why compounds are considered pure substances
Compounds are considered pure sub-stances because they are composed of only one type of particle. The particles of a compound are made of atoms of two or more elements that are chemically combined. Different sam-ples of any compound have the same elements in the same proportion.
How do solutions, suspensions, and colloids differ?
A solution appears to be a single substance and contains particles evenly distributed among each other. The particles in a solution are very small and can’t be filtered out. A clear solution will not scatter light. A suspension has larger particles that are dispersed but will settle out. The particles in a sus-pension can be filtered out and are large enough to block or scatter light. Particles in a colloid are smaller than the particles in a suspension, but are still large enough to scatter light.
Most fresh water in Saudi Arabia is produced by removing salt from seawater. One method involves distillation. Explain how seawater could be purified by distillation, and tell whether it is a chemical or physical process.
Salt water is a mixture, so its components can be separated by physical methods. Distillation involves heating the water, which changes water into steam. When salt water is distilled, steam is condensed back into water, and salt is left behind.
compound