Chemistry Flashcards
what is the particle model of matter?
a model that describes the arrangement and movement of particles in a substance.
what is the particle model of matter used for?
To explain the physical properties of solids, liquids, and gasses.
What is matter?
anything that has mass, volume, and takes up space
What do atoms come together to form?
molecules
what does an atom contain in its nucleus?
protons and neutrons
what are the different states of matter?
solid, liquid, and gas
what are some characteristics of matter in the solid state?
- tightly packed
- vibrate
- retains a fixed volume and shape
- little free space between particles
- does not flow
- particles can not move or slide past each other
- low energy
- strong attractive forces
what are some characteristics of matter in the liquid state?
- close together
- vibrate
- move about and slide past each other
- assumes the shape of the par of its container that it
occupies - flows easily
- little free space between particles
what are some characteristics of matter in the gas state?
- weak attractive forces
- lots of energy
- vibrate
- move freely at high speeds
- assume the shape and volume of its container
- flows easily
- compressible
- particles can move past each other
- lots of free space between particles
what is a pure substance?
a single substance on its own
what are mixtures?
two or more substances that are not chemically combined
what are the two types of mixtures?
heterogeneous and homogenous
what is a homogenous mixture?
the composition is uniform throughout the mixture
what is a heterogeneous mixture?
a non-uniform mixture of constituent parts
what is a suspension?
a heterogeneous mixture that contains solid particles sufficiently large for sedimentation
what is a colloid?
a colloid is a phase-separated mixture in which one substance of microscopically dispersed insoluble to soluble particles is suspended throughout another substance
what is an emulsion?
a mixture of two or more liquids that are normally immiscible owing to liquid-liquid phase separation
what is the difference between quantitative and qualitative observations?
quantitative observations are properties that have numerical characteristics, whereas qualitative observations are properties that can be observed but are generally not measured with a numeric result
what is the difference between a physical property and a chemical property?
a physical property is a characteristic of a substance that can be observed or measured without changing its identity whereas a chemical property is a substances ability to undergo a chemical change
what is the difference between physical and chemical changes (reactions)?
In a physical change, the appearance or form of the matter changes but the kind of matter in the substance does not. They can be reversed. In chemical change the kind of matter changes and at least one new substance with new properties. This cannot be reversed.
what are some indicators of a chemical change?
- color change
- formation of a precipitate
- formation of gas
- odor change
- temperature change
- can not be reversed
- bubbles
what is reaction rate and how is it typically determined?
a measure of how fast a reaction occurs which is typically determined by assessing the amount of products released over a given period of time
what is galvanization?
a process that treats a metal to prevent rusting
list 4 things that can change reaction rate and how each of them affects the speed at which the reaction occurs
- agitation (increased agitation speeds up reactions rate)
- temperature (higher temperatures speed up reaction rate)
- reactant concentration (higher concentrations speed up reaction rate)
- surface area (reactants with a larger surface area exposed will speed up the reaction rate)
what is a catalyst?
something that is added to the reaction to speed up the reaction rate. It is not consumed or changed during the reaction, nor does it change the amount of product that results.
what is a law vs. a theory?
a law is used to summarize a scientific observation whereas a theory is the explanation of why an observation happens.
what is an atom?
atoms are the building blocks of matter and can be broken down into three types of subatomic particles:
- protons (positively charged particles found within the nucleus)
- neutrons (neutral particles found within the nucleus)
- electrons (negatively charged particles that orbit the nucleous
how was each atomic model developed?
each past model was developed on a set of observations that are eventually disproved and altered to fit a new set of observations
list the five atomic models in order of creation
daltons billiard balls, Thompsons plum pudding model, rutherfords planetary model, BHORS atomic model, quantum model
What is a neutron?
neutral particles found within the nucleus
what is an electron?
negatively charged particles that orbit the nucleus
what is a proton?
positively charged particles found within the nucleus
how do you know how many protons are in an atom’s nucleus?
based on the elements atomic number
how do you know how many electrons an atom has?
the number of electrons is equal to the number of protons within the nucleus, meaning you can determine the number of electrons based on the element’s atomic number.
how can the number of neutrons in the nucleus of an atom be determined?
by subtracting the atomic number from the elements atomic mass
what does the period represent?
the number of electrons shells
what does the family number (column) tell?
the number of valence electrons in the outer shell
what happens to an atom when it gains or loses electrons?
it becomes an ion
define physical change
a change in matter where no new molecules are formed, and where the properties do not change.
define chemical change
a change where a new type of matter is formed with new properties and a new chemical formula
what happens in a physical change?
the molecules don’t change, they move farther apart, closer together, or get mixed with another type of molecule
what happens during a chemical change?
atoms are rearranged to form new molecules with different chemical formulas
what are some signs of a physical change?
- no change in color, odor, taste
- temperature only changes if the substance has been heated or cooler
- may change state of matter
- may become part of a mixture
- usually can be reversed
what are some signs of a chemical change?
- change in color, odor, or taste
- a gas is produced
- temperature changes without being heated or cooled
- a precipitate is formed
- often can not be reversed
what are the 5 types of chemical reactions?
formation/synthesis, decomposition, single displacement, double displacement, combustion
what is formation/synthesis?
when two or more elements combine to form a compound
what is decomposition?
when a compound is broken down into its individual elements
what is single displacement?
when the metals switch place
what is double displacement?
a reaction between compounds where two new compounds are formed and the metals swap places
what is combustion?
a carbon-hydrogen compound (fuel) reacts with oxygen to produce water vapor, carbon dioxide, and heat
what are the 9 ‘types’ of elements?
transition metals, metalloids, non-metals, noble gasses, halogen gasses, alkali metals, alkaline earth metals, lanthanides, actinides
what do atoms do in order to become more stable?
they gain or lose electrons to form chemical bonds with other atoms, becoming more stable
what is an anion?
when an atom gains electrons and becomes negatively charged
what is a cation?
when an atom loses electrons and becomes positively charged
what is a compound?
two or more different elements bonded together
what is a diatomic molecule?
one molecule of an element that is equal to a single unit of two elements of the same substance bonded together
what is the relationship between atoms molecules and elements?
an element is a pure substance made up of one type of atom. A molecule is a compound where 2 or more atoms are bonded together.
what allows an ionic compound to exist?
when cations and anions come together to form a compound
what type of bonds do ionic compounds form?
ionic bonds
what type of bonds do molecular compounds form?
covalent bonds
which type of compound conducts electricity?
ionic
do insulators conduct electricity?
no
can two metals make a compound?
no. two metals can be brought together but this is a mixture, not a compounds
what are the 4 rules of naming ionic compounds?
- the name must include both elements within the compound
- the name of the metallic element always comes first
- the non-metallic element is listed second, its ending changed to “-ide”
- subscript numbers of the chemical formula that are used to indicate the ratio of ions in the compound are not included in the name ( no prefixes necessary)
how do you name a multivalent ion?
the version of ion found within the compound must be specified, which is done through the use of a Roman numeral to indicate the charge of the metal
what is the format for a multivalent ionic compound?
metal (number) non-metal
what are polyatomic ions?
a charged molecular compound that tends to act as a single unit during chemical change. they are named as a single entity as the ions are not rearranged when they bond to a metal ion
do you capitalize compound names?
not unless it is starting a sentence
what are the rules for naming molecular compounds?
- write the first element listed in the chemical formula, and change the second element to end in “-ide”
- use a prefix to indicate the number of each type of atom in the formula
what are the prefixes used in naming molecular compounds, and what does each of them mean?
1 = mono 2 = di 3 = tri 4 = tetra 5 = penta 6 = hexa 7 = hepta 8 = octa 9 = nona
what are all the diatomic molecules and are they the chemical formulas for?
H₂ --> Hydrogen N₂ --> Nitrogen F₂ --> Flourine O₂ --> Oxygen I₂ --> Iodine Cl₂ --> Chlorine Br₂ --> Bromine
how are electrons transferred in an ionic compound and what does this form?
they are transferred from the metal to the non-metal to form an ionic bond
what happens to an element after an ionic bond is formed?
it ends up with a full valence shell
how do elements within molecular compounds get a full valence shell?
by sharing their unpaired electrons
what type of atoms make up molecular compounds?
neutral atoms
what is created when atoms form covalent bonds?
molecules are formed
what do all chemical reactions involve?
energy
what are chemical reactions that release heat called?
exothermic
what is an exothermic reaction?
when energy, a reactant, is released during the formation of new chemical bonds
what are chemical reactions that absorb heat called?
endothermic
what is an endothermic reaction?
when energy, a product, is taken in to break chemical bonds
what can any chemical reaction be written as?
an equation
how do you write an equation that represents a chemical reaction?
with the state of matter recorded beside the compound formula, reactants are written on the left and products on the right, with the reactants going to products
what are the five components of the particle model of matter?
all matter is made up of tiny particles, each pure substance has its own kind of particle different from the particles of other substances, particles are attracted to each other, particles are always moving, particles on higher temperatures move faster on average than particles at a lower temperature
how many natural actinides are there and what are they?
5
thorium, protoactinium, uranium, neptunium, and plutonium
what is an element?
a pure substance made up of one type of atom
what determines an element’s properties?
the number of protons in its nucleus
