Pre-AP Chemistry Semester 1 Exam
Compound
A substance that can be separated into two or more substances only by a chemical change
Theory
A well-tested explanation for a broad set of observations is a(n)...
Higher
Compared with the electronegativities of the elements on the left side of a period, the electronegativities of elements on the right side of the same period tend to be ________
Compound
Composed of two or more substances chemically combined in a fixed proportion
Ionization energy
Energy required to remove an electron from an atom
3.2×10¹
Express the product of 4.0×10⁻² m and 8.1×10² using the correct number of significant digits
12.7 m
Express the sum of 7.68 m and 5.0 m using the correct number of significant digits?
Protons
The atomic number of an element is the total number of which particles in the nucleus?
The most unpaired electrons
The central atom in a Lewis structure is usually the atom with...
Accuracy
The closeness of a measurement to its true value is a measure of its what?
Hybridization
The combining of orbitals in an atom to form new identical orbitals
0.32 g/cm³
What is the density of an object having a mass of 8.0 g and a volume of 25 cm³?
Fluorine
What is the element with the highest electronegativity value?
Eight
What is the maximum number of electrons in the second principal energy level?
Seven
What is the maximum number of f orbitals in any single energy level in an atom?
1.0×10³ L
What is the measurement of 1042 L rounded off to two significant digits?
Atomic emission spectrum
Frequencies of light emitted by an element
Period
Horizontal row in the periodic table
They are proportional
How are frequency and wavelength of light related?
It tends to decrease
How does atomic radius change from left to right across a period in the periodic table?
It tends to increase
How does atomic radius change from top to bottom in a group in the periodic table?
The speeds are the same
How does the speed of visible light compare with the speed of gamma rays, when both speeds are measured in a vacuum?
50 protons, 50 electrons, and 75 neutrons
How many protons, electrons, and neutrons does an atom with atomic number 50 and mass number 125 contain?
Two
How many significant figures are in the measurement 0.0034 kg?
Five
How many significant figures are in the measurement 811.40 grams?
Reactant
Starting substance in a chemical reaction
Electrons
Subatomic particles that are transferred to form positive and negative ions
Element
Substance that cannot be changed into simpler substances by chemical means
Aufbau principle
Tendency of electrons to enter orbitals of lowest energy first
Kelvin temperature scale
The SI scale for temperature
Group
Vertical column in the periodic table
They have low melting points
What NOT a characteristic of most ionic compounds
Photons
What are quanta of light called?
Mass number
What does the number 84 in the name krypton-84 represent?
239 K
What is -34 C in Kelvin?
Liter
What is NOT an SI unit but often mistaken as one? (measures volume)
Kilogram
What is the SI unit of mass?
373 K
What is the boiling point of water in Kelvin?
Positive
What is the charge of a cation
Resonance
A condition that occurs when more than one valid Lewis structure can be drawn for a molecule
Scientific Method
A logical systematic approach to the solution of a scientific problem
Electron
A negatively charged subatomic particle
Mixture
A physical blend of two or more components
Proton
A positively charged subatomic particle
Experiment
A procedure that is used to test a hypothesis is a(n)...
Hypothesis
A proposed explanation for an observation is a(n)...
Periodic law
A repetition of properties occurs when elements are arranged in order of increasing atomic number
Octet Rule
A rule sating that an atom tends to gain, lose, or share electrons until its outer level s and p orbitals are filled with eight electrons (this gives an element the electron configuration of a noble gas)
Neutron
A subatomic particle with no charge
Product
A substance formed in a chemical reaction
Electronegativity
Ability of an atom to attract electrons when the atom is in a compound
Mass
Amount of matter an object contains
Crystal lattice
An orderly arrangement of ions in a three-dimensional pattern within a compound
Matter
Anything that has mass and occupies space
Electron configuration
Arrangement of electrons around atomic nucleus
Isotope
Atoms with the same number of protons but different numbers of neutrons in the nucleus of an atom
Polar covalent bonds
Bonds with unequally shared electrons
Mass; volume
Density is found by dividing _____ by ______
Homogeneous
Describes mixture with a uniform composition
Alchemists
Developed processes for separating mixtures and purifying chemicals and also designed equipment that is still in use today
Wavelength
Distance between wave crests
100 C
If the temperature changes by 100 K, by how much does it change in C?
Numbers of neutrons
Isotopes of the same element have different what?
Color, odor, malleability, hardness, melting point, boiling point
List the physical properties of a substance (six things)
Ground state
Lowest energy level
Frequency
Number of wave cycles passing a point per unit of time
Atomic mass unit
One-twelfth the mass of a carbon atom having six protons and six neutrons
Atomic orbital
Region of high probability of finding an electron
Do not
Polar bonds (DO/ DO NOT) always result in polar molecules (pick one)
Different
Polar covalent bonds result when the atoms sharing the electrons have (THE SAME/DIFFERENT) electronegativities (pick one)
Chemical reaction
Process in which substances are changed into different substances
1.54×10⁻¹⁰ m
The diameter of a carbon atom is 0.000 000 000 154 m. What is this number expressed in scientific notation?
Ionic Bond
The electrostatic attraction between two oppositely charged ions in a solid
5.008×10³ km
The expression of 5008 km in scientific notation is what?
Weight
The force of gravity on an object
Polarity
The greater the difference in electronegativity between two elements is, the greater the ________ of the resulting molecule
Absolute zero
The lowest point on the Kelvin scale
Number
The modern period table is arranged in order of increasing atomic ________
Atomic number
The number of protons in the nucleus of an element
Protons and neutrons
The particles that are found in the nucleus of an atom are...
Pure Chemistry
The pursuit of chemical knowledge for its own sake
Electron
The quantum mechanical model of the atom involves the probability of finding an ____________ in a certain position
Anion
The radius of a(n) (CATION/ANION) is greater than the radius of its neutral atom (pick one)
Formula Unit
The simplest ratio of elements in an ionic compound that describes its composition
Atom
The smallest particle of an element that retains the properties of that element
Chemistry
The study of the composition of matter and the changes that matter undergoes
Electronegativity
The tendency of an atom in a compound to attract electrons
Dependent Variable
The variable that is observed during the experiment is the...
Independent Variable
The variable that you change during an experiment is the...
Ability to rust
Three of these are physical properties. Which is not? Mass, color, melting point, ability to rust
Oil
To make a heterogeneous mixture, do you mix vinegar with water or oil?
Covalent bond
Two atoms held together in an ion or molecule by their attraction for the same pair of shared electrons
Cation
Type of ion formed by Group 2A elements
11 mm²
What is the product of 2.2 mm and 5.00 mm using the correct number of significant digits?
2.9×10³
What is the result of adding 2.5×10³ and 3.5×10²?
8.75×10³
What is the result of multiplying 2.5×10¹⁰ by 3.5×10⁻⁷?
1.1×10² mL
What is the volume of 80.0 g of ether if the density of ether is 0.70 g/mL?
2.9×10⁻⁷ m³
What is the volume of a salt crystal measuring 2.44×10⁻² m by 1.4×10⁻³ m by 8.4×10⁻³ m?
Atomic mass
What is the weighted average of the masses of the isotopes of the element?
Gas production, precipitate formation, energy transfer
What three things indicate that a chemical change may have taken place?
Sigma
What type of bond forms as a result of orbitals overlapping end to end?
Ionic bond
What type of bond would you expect in a compound of oxygen and sodium?
Solution
What's another term for a homogeneous mixture?
Least
When multiplying and dividing measured quantities, the number of significant figures in the result should be equal to the number of significant figures in the (MOST/LEAST) precise measurement (pick one)
Observation
When you use your senses to obtain information you make a(n)...
Salt water
Which is a homogeneous mixture? Salt water, beef stew, sand and water, soil
dg
Which is largest? dg, cg, ng, mg
Microliter
Which of the following is smallest? Milliliter, microliter, liter, deciliter
Erwin Schrodinger
Which scientist developed the quantum mechanical model of the atom?
Electron
Which subatomic partible plays the greats part in determining the properties of an element?
Dmitri Mendeleev
Who arranged the elements according to atomic mass and used the arrangement to predict the properties of missing elements?