Chapter 9
To convert from moles of Reactant A to moles of Product B, what crucial ratio do you need from the balanced chemical equation?
The mole ratio (determined by the coefficients of the balanced equation).
This term describes a chemical reaction or process that releases heat energy into its surroundings, making the container feel hot.
Exothermic process.
This is the lowest possible energy state of an atom's electrons.
ground state.
This type of bond forms when electrons are completely transferred from a metal to a nonmetal, resulting in electrostatic attraction.
An ionic bond.
In a solution of saltwater, identify which substance is the solute and which is the solvent.
Salt NaCl is the solute; water H_2O is the solvent.
You mix reactants together and calculate that you should theoretically produce $10.0 \text{ g}$ of product. After the experiment, you weigh your dry product and find you actually obtained $8.5 \text{ g}$. What is your percent yield?
85%
What is the SI unit for energy and heat, and how many of them are in 1 calorie (cal)?
The Joule (J); 1{ cal} = 4.184 { J}.
According to the wave-mechanical model of the atom, what is an orbital?
A probability map showing a 90% chance of finding an electron in a specific region of space around the nucleus.
This is the relative ability of an atom in a molecule to attract shared electrons to itself.
Electronegativity
What is the formula for calculating Molarity (M), the most common concentration unit in chemistry?
Molarity (M) = Moles of solute/Liters of solution
Consider the balanced equation: 2(g) + 3H_2(g) =2NH_3(g). If you completely react 3.0{ moles}of H_2 with excess N_2, how many moles of NH_3 will you produce?
2.0 moles of NH_3 (The mole ratio is 2 moles NH_3 / 3 moles H_2).
This is the definition of Specific Heat Capacity.
The amount of energy required to raise the temperature of one gram of a substance by one degree Celsius.
State the maximum number of electrons that can occupy a single s orbital, a p subshell (3 orbitals), and a d subshell (5 orbitals).
Single orbital = 2 electrons; p subshell = 6 electrons; d subshell = 10 electrons.
What is the difference between a covalent bond and a polar covalent bond?
In a covalent bond, electrons are shared equally. In a polar covalent bond, electrons are shared unequally due to a difference in electronegativity.
You have 2.0 L of a 6.0 M stock solution of HCl. If you dilute it to a final volume of 4.0 L, what is the new molarity?
3.0 M M_1,V_1 = M_2V_2
If you are given the masses of both reactants in a problem, what type of stoichiometry problem are you solving, and what must you determine first?
A limiting reactant problem; you must determine which reactant will run out first.
Calculate the energy (in Joules) required to heat $10.0{ g} of liquid water from 20.0 C to $30.0 C. (Specific heat capacity of water = 4.184 J/gC.
418.4 Joules
What are valence electrons, and why are they so important in chemistry?
They are the electrons in the outermost principal energy level of an atom. They are important because they are involved in chemical bonding and reactions.
Draw or describe the Lewis structure for a molecule of Water H_2O. How many bonding pairs and how many lone pairs are on the central oxygen atom?
Oxygen is in the center bonded to two Hydrogen atoms. It has 2 bonding pairs and 2 lone pairs.
Explain the phrase "like dissolves like" in terms of polar and nonpolar substances.
Polar or ionic solutes will dissolve in polar solvents (like salt in water). Nonpolar solutes will dissolve in nonpolar solvents (like oil in hexane). They will not mix well with each other.
True or False: The limiting reactant is always the reactant that you have the fewest grams of at the start of the reaction.
False. The limiting reactant depends on both the molar mass and the mole ratios in the balanced equation, not just the starting mass.
Explain the difference between temperature and heat.
Temperature is a measure of the random motions (average kinetic energy) of the components of a substance. Heat is a flow of energy due to a temperature difference.
As you move from left to right across a period on the periodic table, what happens to the atomic size (radius) of the atoms, and why?
Atomic size decreases. This is because more protons are added to the nucleus, increasing the positive charge and pulling the same core shell of electrons in closer.
According to VSEPR theory, what are the molecular geometries (shapes) of CO_2 and BF_3?
CO_2 is linear; BF_3 is trigonal planar.
What does it mean if a solution is saturated?
The solution contains the maximum amount of dissolved solute possible at that specific temperature; any extra solute added will just sit at the bottom undissolved.