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Unit 2 Quiz (first 2 concepts)

Terms in this set (41)

matter
Anything that has mass and takes up space
substance
all the particles are identical
molecule
two or more atoms held together by chemical bonds
monoatomic
elements that are stable as an individual atom (helium, margin, neon)
diatomic
elements that are stable as 2 atoms bonded together (oxygen, nitrogen)
mixture
material composed of two or more elements or compounds that are physically mixed together
homogeneous mixture
components are evenly distributed out on a microscopic level
heterogeneous mixture
sumbstances in a mixtture are NOT evenly spread out
element
simplest form of matter, CAN'T be broken down into other substances, all the atoms are the same/alike, ex: helium.
Compound
2 or more elements chemically combined in a fixed proportion, CAN be broken down only by a chemical reaction, ex: table salt, water, sugar
colloid
small particles remain evenly dispersed throughout mixture, larger particles than in a solution, ex: fog, milk, dusty air, humid air
suspension
larger particles that appear uniformly, distributed but will settle out of the mixture over time, if not mixed. ex: oil in water, sand in water, muddy water
solution
when one substance dissolves into another and appears blended ex: lemonade powder, bleach, blood, coffee
Tyndall effect
the scattering of light by a mixture. only colloids and suspensions have particles large enough to do this (solutions can't)
difference between a homogeneous and a heterogeneous mixture
...
difference between a compound and a mixture
A homogeneous mixture has the same uniform appearance and composition throughout. Many homogeneous mixtures are commonly referred to as solutions. A heterogeneous mixture consists of visibly different substances or phases. The three phases or states of matter are gas, liquid, and solid.
How can matter be classified?
Every sample of matter is either an element, a compound, or a mixture.
physical property
properties that can be observed directly or measured without changing the chemical identity of the substance
chemical property
properties that can only be observed/measured by changing the chemical identity of a substance. by observing it, a NEW substance is formed
melting point
The temperature at which a solid becomes a liquid
boiling point
The temperature at which a liquid changes to a gas
viscosity
a liquid's resistance to flow. a physical property only of liquids. Think: "how thick it is. can change w temp. Ex: the viscosity of syrup is high.
density
the measure of compactness or consistency of a material. mass per unit of volume. measured in g/cm3 or g/mL. density doesn't change regardless of size.
malleability
a substances ability to be hammered, pressured, or rolled into sheets
ductility
a substances ability to be drawn out or pulled into wires
solubility
A measure of how well a solute dissolves in a solvent
solute
what is being dissolved. ex: lemonade powder
solvent
what is doing the dissolving. ex: water
solution
the result. lemonade
Flammability
A material's ability to burn in the presence of oxygen
Reactivity
how easily a substance reacts, usually with an acid or base. ex: calcium carbide when combined with water, reacts by forming a flammable gas
Oxidation
how easily a substance reacts with oxygen
pH
- the measure of the acidity or alkalinity of a solution
- Represented as a number along a scale of 0-14
- Anything below 7.0 is considered acidic
- Anything above 7.0 is considered alkaline (basic)
- Neutral solutions are 7.0
physical change
a change in a substance that only affects its physical properties Ex. Cutting, coloring, crushing, melting, boiling, etc.
chemical change
a change in a substance that affects its chemical properties thus a chemical reaction occurs and a new substance is formed. Ex. Burning, rusting, decomposing, etc.
chemical reaction
process by which the atoms of one or more substances are rearranged to form different substances
precipitate
sudden appearence of a solid
law of conservation of matter
Matter is neither created or destroyed during a chemical change. It only changes forms. (Mass cannot be "lost", even when a chemical reaction happens.)
relationship between mass, volume, and density
Both of these measurements are dependent on the amount of material. However, the relationship between mass and volume is constant for a substance at a given temperature and pressure. This relationship between the mass and the volume of a substance is given as density
difference between physical properties and chemical properties
A physical property is an aspect of matter that can be observed or measured without changing its chemical composition. Examples of physical properties include color, molecular weight and volume. A chemical property may only be observed by changing the chemical identity of a substance.
the difference between physical changes and chemical changes
A physical change in a substance doesn't change what the substance is. In a chemical change where there is a chemical reaction, a new substance is formed and energy is either given off or absorbed.
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