Which of the following elements exists as a diatomic gas in its standard state and contains a double covalent bond?

A. Krypton

B. Oxygen

C. Nitrogen

D. Bromine

E. Chlorine

B. Oxygen

The seven diatomic molecules are hydrogen, nitrogen, fluorine,  oxygen, iodine , chlorine and bromine

The mnemonic is Have No Fear Of Ice Cold Beer

Which of the following pairs are typically found in alkaline buffer solutions?

A) Weak base and its conjugate acid

B) Weak Acid and its conjugate base

C) Strong base and its conjugate acid

D) Strong acid and its conjugate base

A) Weak base and its conjugate acid

Typically weak bases and their conjugate acids are found in alkaline solutions ( pH>7)

Weak Acids and their conjugate bases are found in acid solutions (pH<7)

Which of the following is true for a reaction occurring at 25°C that has a positive ΔH value?

A) The reaction will be spontaneous if ΔH<ΔS

B) The reaction will be spontaneous if ΔH>ΔS

C) The reaction will be spontaneous for any value of ΔH

D) The reaction will be non-spontaneous for any value of ΔH

A) The reaction will be spontaneous if ΔH<ΔS

For a reaction to be spontaneous ΔG must be negative meaning ΔH needs to be negative (exothermic) and disorder (a positive ΔS)

Vaporization is which of the following types of processes?

A) Endothermic

B) Exothermic

C) Is a chemical change from solid to gas 

D) Is a chemical change from liquid to gas

E) Is a physical change from solid to gas

A) Endothermic

It is a liquid to gas physical phase change 

During vaporization bonds are broken as the molecules enter a less organized and higher entropic stage

Which of the following is not an intermolecular force?

A) Van de Waals forces

B) Covalent bonds

C) Ion-dipole

D) London dispersion forces

E) Hydrogen bonds

Step 1 :Obtain the mole fraction by dividing the moles of gas by the total moles in the system

Mole fraction of nitrogen is  1/3 

Step 2: Multiply the mole fraction by the total pressure

(1/3)*(180)= 60 kPa

Which of the following BEST describes a Bronsted-Lowry base?

A) Proton Donor

B) Proton Acceptor

C) Electron pair donor

D) Electron pair acceptor 

B) Proton Acceptor

Bronsted Base = Proton acceptor

Bronsted Acid= Proton donor

Lewis acid = Electron Acceptor

Lewis Base= Electron donor

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A) Rate =k [A][B]

B) Rate=k[A][B]²

C) Rate=k [A]²[B]

D) Rate=k [A]²[B]²

The rate equation is Rate=k [A]^x[B]^y

First we compare 2 rates with a common factor like Rate 2 and Rate 1 that share the same [B] concentration.

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When we simplify we get 16=4^x where x=2

Next we do the same for for reagent B by comparing rates 3 and 1

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When we simplify 4=2^y which gives us y=2

If we combine the 2 we get D) Rate=k [A]²[B]²

How many electrons are involved in the following basic redox reaction?

4Zn + NO₃^-+7OH^- + 6 H₂O → 4Zn(OH)₄^2- +NH₃

A) 2

B) 4

C) 6

D) 8

Since this a redox reaction we must break the reaction into oxidation and reduction half reactions

Oxidation : Zn →Zn(OH)₄^2-

Reduction : NO₃^- → NH₃

Then we balance the individual half-reactions. We first balance all non hydrogen and oxygen elements. Then add as much water as needed to balance the oxygens. Then add protons to balance the hydrogens. Then check charges and balance them.

This will reveal how many electrons are involved

Which one of the following molecules is polar?

A) CCl₄

B) PCl₅

C) CO₂

D) H₂S

E) CH₄

D) H₂S

The SH bonds are different in electronegativity and this are polar.

A point where the maximum temperature and pressure that allows gas  to remain at equilibrium between gaseous and liquid phase is known as __________.

A. Equivalence Point

B. Triple Point

C. Critical Point 

C. Critical Point 

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