What is matter?
Definition: anything physically real, occupies space, & has mass.
Give an example of a mixture. What is a mixture?
- a blend of 2 or more substances with
- individual chemical identities
What is a pure substance and give an example of one?
Uniform in composition & properties i.e. chemical elements & chemical compounds.
- Molecular O2, N2, etc...
Give and example of a physical property and a chemical property. What is the difference between them?
- Physical:color, size, boiling point
- Chemical:combustion, chemical reactivity
Physical properties describe the substance with out altering its chemical makeup, where as a chemical property of a substance describes how that substance interacts with other substances when a chemical change takes place.
Where would find the metals on the periodic chart? What are the characteristics of metals?
Found on the left side of the periodic table.
- -Solid at room temperature
- -Lustrous appearance
- -Good conductors of heat & electricity
Where are the nonmetal found on the periodic chart? What are the characteristics of non metals?
On the right side of the periodic table.
- -May be solid, liquid, or gas at room temperature.
- -Poor conductors of heat & electricity
What are the metalloids? Why are they classified as metalloids?
Form a zigzag band between metals & nonmetals on the periodic table.
- properties are intermediate
- between metals and nonmetals.
What are the four assumptions of the atomic theory?
-All matter is composed of atoms
- -Atoms of one element are alike but differ
- from atoms of all other elements
-Chemical compounds are composed of specific combinations of atoms
-Chemical reactions change only the way atoms are combined, not the atoms themselves
What is the mass of a neutron?
What is the mass of a proton?
How many electron can fit in the following subshells respectivley? s,p,d,f
What is the theory of octet?
Atoms tend to try and fill their valence shell with 8 electrons.
Characterize the difference between an ionic, covalent and hydrogen bond.
- Covalent is bonding through the sharing of an electron.
- Ionic is bonding by attraction of oppositely charged particles.
- Hydrogen bonding is an interaction between molecules that occurs because of polar differences between electron configurations of the molecules.
What are electrolytes?
Substances that produce ions and conduct electricity when dissolved in water.
What is ionization?
Changing of ionically bonded atoms to ions when dissolved in water.
What is ionization energy?
The energy required to remove an electron from an atom, forming a cation.
What is electron affinity?
The energy required to add an electron to an atom, forming an anion.
What is an ion?
an electrically charged atom or group of atoms.
What is a cation and what are some examples of common cations?
Positively charged ion (Na+) formed when electrically neutral atom loses an electron leaving a net positive charge (more protons than electrons).
What is an anion? What are some common anions?
Negatively charged ion (Cl-)formed when an electrically neutral atom gains an electron leaving a net negative charge (more electrons than protons).
- Common anions:
- Cl- Chloride
- Po43- Phosphate
What is molar mass?
A conversion factor between mass in grams and moles.
What is molarity?
- The number of moles of solute dissolved in 1
- liter of solution.
What does the Law of conservation of mass state?
Mass is neither created nor destroyed.
In a chemical reaction, what is a reactant?
- Substance that undergoes a change in a
- chemical reaction.
In a chemical reaction, what is a product?
- A substance that is formed in a chemical
What is the bond dissociation energy?
The amount of energy that must be supplied to break a bond and separate atoms from each other. Measures the strength of a covalent bond.
What is an endothermic reaction or process?
A reaction or process that absorbs heat.
What is an exothermic reaction or process?
A reaction or process that releases heat.
What is free energy?
- Released in a spontaneous (exergonic) process
- Absorbed in nonspontaneous (endergonic) process
- Potential energy
- Kinetic energy
In a reaction, what is the activation energy?
The amount of energy needed to overcome the barrier for a reaction to occur.
What does activation energy effect?
Determines the rate of a reaction.
What does adding heat to reaction do?
- ↑ temperature → ↑ energy in the system & more collisions.
- ↑ 10° C causes the rate of the reaction to double.
How can we decrease the activation energy for a particular reaction?
- Increase the concentration of reactants.
- Add a catalyst.
- Increase the temperature.
What is a catalyst?
A substance that speeds the rate of the reaction but is itself not changed.