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