Chemistry 111 Test 2
Which element is a halogen? Kr, Br, Cr, Sr
Br
Which form of electromagnetic radiation has photons with the highest energy?
Gamma Rays
_________ tend to lose all their valence electrons to form in ionic compounds, therefore ________ tend to gain valence electrons (up to 8) to form anions in ionic compounds
Metals, nonmetals
Why is H2 non-polar?
Molecules that are made up of one single nonpolar bond because it is two Hydrogens compared to HCl which has one single polar bond
Which of the following compounds would have a linear molecular geometry? 1. N2 2. H2S 3. CO2
N2 and CO2
How many of each type of atoms are there in the formula NH4C2H3O2?
N=1, H=7, C=2, O=2
Identify the ionic compound that is soluble in water. Hg2Cl2, Na2CO3, Hg2I2, PbCO3
Na2CO3
True or False: The number of valence electrons increases as you go from left to right across a period in the periodic table. Thus, elements in group 1A have one valence electron, elements in group 2A have two valence electrons, group 3A elements have three valence electrons, and so on.
True
How many lone electron pairs does the CN (-1 charged) polyatomic anion have?
Two
How many valence electrons (dots) are shown in a formula for Magnesium?
Two
What is the correct Lewis structure for O2?
Two Oxygens with a double bond and each element has four dots
How do polar bonds get cancelled out as a result of geometry and become non-polar?
Two identical polar bonds that point in opposite directions cancel also if three identical polar bonds at 120 degrees will cancel and if there are four identical bonds in a tetrahedral arrangement they'll cancel
Which color of the visible spectrum has photons with the most energy?
Violet
From highest to lowest frequency, list the colors of light in the visible spectrum
Violet, indigo, blue, green, yellow, orange, red
What are some statements that follow the Bohr Model?
When energy is absorbed by atoms, the electrons are promoted to higher-energy orbits, electrons exist in specific, quantized orbits and when an atom emits light, electrons fall from a high orbit into a lower orbit
For the Lewis Dot Structure of KCl, how many dots where thill be? Are any of them bonded electrons? What is the Lewis Dot Structure?
When these two atoms bond, Potassium (K) transfers it's valence electrons. K has 1 valence electron and Cl has 7. There are a total of 8 dots in the formula. So, the formula is K+ [Cl]- (there are 8 dots around Chlorine)
How do polar bonds get cancelled out as a result of geometry and become polar?
When two polar bonds with angles of less than 180 degrees between them won't cancel and if there are three bonds in a trigonal pyramidal arrangement (109.5 degrees) it will not cancel
True or False: Each atom of a Lewis structure must have eight electrons
False
Which set of wavelengths for light are arranged in order of increasing frequency? 300 nm; 250 nm; 350 nm, 350 nm; 300 nm; 250 nm, 300 nm; 350 nm; 250 nm, 250 nm; 300 nm; 350 nm
350 nm; 300 nm; 250 nm
Which of the listed elements is most metallic? S, Ba, Ca, Al
Ba
Consider the following equation: CO + 2 H2 → CH3OH △Hrxn = -128 kJ Calculate the amount of heat (in kJ) associated with the complete reaction of 8.08 g H2.
-256 kJ
How many moles of chlorine gas are needed to make 0.6 moles of sodium chloride? 2Na + Cl2 → 2NaCl
0.3
What is the coefficient for calcium hydroxide in the balanced chemical equation for the reaction of aqueous phosphoric acid with aqueous calcium hydroxide forming solid calcium phosphate and liquid water?
3
How many atoms are there in 5.8 moles of barium?
3.49 x 1024
How many atoms are in 5.80 moles of He?
3.49 x 10^24
What is the formula for an ionic compound made of barium and nitrogen?
Ba3N2
What is an ionic compound that is soluble in water?
BaS
What is the molecular geometry of H2S?
Bent
How many core electrons are in a chlorine atom?
10
How many electrons does the predictable (most common) ion of oxygen contain?
10 because it's (-2)
What is the angle between electron groups in the tetrahedral geometry?
109.5 degrees
What is the angle between electron groups in the trigonal planar electron geometry?
120 degrees
A 24.0 g sample of nitrogen gas reacts with an excess of hydrogen gas to give an actual yield of 3.85g NH3. What is the percent yield for this reaction? N2(g) + 3 H2(g) → 2 NH3(g)
13.2%
How many grams of aluminum oxide are produced according to the reaction below given that you start with 10.0 grams of Al and 19.0 grams of O2?4Al + 3O2→ 2Al2O3
18.9
What is the angle between electron groups in the linear electron geometry?
180 degrees
The lowest energy orbital in the quantal-mechanical model is the:
1s orbital
How many electrons can exist in an orbital?
2 total electrons
What is the coefficient for nitric acid in the balanced chemical equation for the reaction of aqueous nitric acid with aqueous calcium hydroxide forming aqueous calcium nitrate and liquid water?
2HNO3(aq) + Ca(OH)2 (aq) -> Ca (NO3)2 (aq) + H2o( l) therefore 2
How many valence electrons does aluminum (Al) have?
3
How many subshells are there in the "n=4" principal shell?
4
How many valence electrons does tin (Sn) have?
4
How many moles of water are made from the complete reaction of 2.2 moles of oxygen gas with hydrogen gas? Given the reaction: 2H2 + O2 → 2H2O
4.4 Moles of water
How many significant figures are in the number 93.090?
5
How many bonding electrons are in the Lewis structure of N2?
6
How many moles of aluminum are needed to make 9 moles of molecular hydrogen? 2 Al + 6 HCl → 2 AlCl3 + 3H2
6 moles
How many valance electrons are in a chlorine atom?
7
Express the number 0.0000735 in scientific notation.
7.35 x 10^-5
What is the most number of dots that can be in an electron-dot formula?
8
If 16.0 grams of aluminum oxide were actually produced, what is the percent yield of the reaction below given that you start with 10.0 g of Al and 19.0 grams of O2? 4Al + 3O2→ 2Al2O3
84.7
What is the octet rule?
A rule that states that atoms transfer or share electrons to achieve an outer shell that contains eight electrons. However, some atoms, like Hydrogen are exceptions to this given rule.
In a Lewis structure.....
A single dot represents one electron, a pair of dots represents two electrons and a line between two atoms (one bond) represents two electrons
Which of the following statements about the water molecule is TRUE?
A water molecule is asymmetric and therefore is polar
What is the limiting reactant for the reaction below given that you start with 10.0 grams of Al and 19.0 grams of O2? 4Al + 3O2 → 2Al2O3
Al
Is a Nonmetal a cation or anion?
Anion
How are wavelength and frequency of light related?
As the wavelength increases, the frequency decreases
Renosance requires:
At least one double bond and at least two surrounding atoms that can accommodate a double bond
Which compound or polyatomic ion has two or more resonance structures? ClO- ,CS2 , CH4 ,SO32-
CS2
The Lewis model predicts that the formula for a compound between fluorine and calcium is:
CaF2
Is a Metal a cation or anion?
Cation
Which property of copper is most likely a chemical property?
Copper reacts with nitric acid to produce nitrogen dioxide gas.
Out of the atoms Li, Rb, K, Cs and Na, which is the largest?
Cs
Classify the reaction based on what the atoms/compounds do: CaSO4 (g) → CaO (s) + SO3 (g)
Decomposition
The size of an atom generally increases:
Down a group and from right to left across a period
What are some statements about the quantum-mechanical model?
Electrons do not behave as particles, orbitals are a probability map of finding electrons and electron paths cannot be described exactly
What are bonding electrons and what are the represented as?
Electrons that are shared between two atoms and are represented by lines
Is this true or false? Red light has a shorter wavelength than violet light
False
Which of the listed types of electromagnetic radiation has the shortest wavelength? visible light, radio waves, ultraviolet light, gamma rays
Gamma rays
Identify the spectator ions within the following chemical equation.H2S (aq) + CuSO4 (aq) → CuS(s) + H2SO4 (aq)
H+ (aq) and SO42- (aq)
Which molecule is polar? H2O, SiF4, CO2, CCl4
H2O
What is this known as: "When filling orbitals of equal energy, electrons fill them singly first with parallel spins"
Hund's rule
Which process is endothermic? A wood fire burning, ice melting, your body changing food to energy (metabolism), none of the above
Ice Melting
What is the relationship between frequency and wavelength?
Inversely proportional
What is the relationship between wavelength and energy?
Inversely proportional
The electronegativity value for Mg is 1.2 and the value for O is 3.5. Based on these values, what type of bond is expected for a compound formed between Mg and O?
Ionic
What is the relationship between energy and frequency?
It is directly proportional
How do you determine if a molecule is polar?
It must contain at least one polar covalent bond
What is the formula for potassium nitrite?
KNO3
What is the molecular geometry of CO2?
Linear
What is the molecular geometry of carbon dioxide, CO2?
Linear
Identify the spectator ions within the following chemical equation: (NH4)2SO4 (aq) + Ca(NO3)2 (aq) → CaSO4 (s) + 2 NH4NO3 (aq)
Nh4+ (aq) and NO3- (aq)
Which of the listed elements has the highest ionization energy?: O, As, C, Ba
O, Oxygen
What is an example of a compound with resonance structures?
O3
The phosphorous-to-hydrogen mass ratio is 10.2 for a compound. This ratio could correspond to the compound:
PH3
Out of the elements Na, C, Rb, F and He, which has the lowest ionization energy?
RbW
Classify the reaction based on what the atoms/compounds do.Pb (s) + 2 AgNO3 (aq) → Pb(NO3)2 (aq) + 2 Ag (s)
Single-displacement
How does soap work?
Soap works by having a polar end and a nonpolar end which allows the water and oil to interact indirectly.
The electron geometry and the molecular geometry of water are, respectively:
Tetrahedral and bent
The electron geometry and the molecular geometry of ammonia (NH3) are, respectively:
Tetrahedral and trigonal pyramidal
What happens to an atom when it absorbs energy?
The atom re-emits the energy as light
What are valence electrons?
The electrons in the outermost principal shell of an atom. These electrons are the ones that are involved in chemical bonding
How do you know how many electron dots are going to be in an electron-dot formula?
The number of valence electrons an element/atom has is the amount of dots that will be in the electron-dot formula for that given electron/atom
What are some of the criteria when recognizing a valid ionic Lewis structure?
The proper number of valence electrons (the dots) for each ion and the proper charge is shown for each ion
Which subshell letter corresponds to a spherical orbital?
The sub shell letter "s"
The elements with the highest electronegativity values tend to be found in the:
The upper-right side of the periodic table
What do the alkali metals all have in common?
They all form +1 ions, undergo similar reactions, have similar physical properties and the same number of valence electrons
What are lone electrons and what are they represented as?
They are electrons that are not shared between multiple atoms and are represented as dots
Why do Chlorine and Bromine have similar chemical properties?
This is best explained by the fact that they all have the same number of valence electrons
The reaction of one mole of nitrogen gas with three moles of hydrogen gas releases 92 kJ of thermal energy to the surroundings. Which of the following is TRUE?
This reaction is exothermic, it has negative enthalpy of reaction and it is a complete reaction of two of nitrogen gas would release 184 kJ of thermal energy in this rection
Is this true or false? The wavelength of light is inversely related to its energy
True
True or False: Electrons of covalent compounds must be shared between atoms
True
True or False: Hydrogen atoms can only form one bond because it is stable with two electrons in its outermost shell. Since it can only form one bond, it can't be the central atom in a structure meaning that hydrogen atoms are always terminal (at the end) of molecules
True
True or False: In a formula, the anion is usually placed in brackets, and the charges of both the cation and anion are written to the upper right corner of the element
True
What is the electron configuration of gallium (Ga)?
[Ar]4s23d104p1
What is the electron configuration of bromine (Br)?
[Ar]4s23d104p5
Which sequence below represents the proper order of increasing bond strength?
single < double < triple
