burgundysheep393

If the natural abundance of is , what is the natural abundance of ?

Write chemical equations and corresponding equilibrium expressions for each of the three ionization steps of phosphoric acid.

A.) Write chemical equations for the first ionization step of phosphoric acid.

B.) Write chemical equations for the second ionization step of phosphoric acid.

C.) Write chemical equations for the third ionization step of phosphoric acid.

The molarity of pure HCl is ~ . What is the pH of this pure solution?

Which of the following is true about the half-life of a radioactive nuclide?

A. that period of time in which of the original number of atoms undergoes radioactive decay

B. the time at which the isotope becomes non-radioactive

C. that period of time in which of the original number of atoms undergoes radioactive decay

D. the period of time it takes to reduce the radioactivity by

What product is formed from the reaction of 1-butene and ?

Which one of the following statements is true?

A. Some real gases have lower pressures than that calculated for the ideal gas because of attraction between molecules.

B. For a real gas, is always less than .

C. Some real gases have lower pressures than that calculated for the ideal gas because of the finite volume occupied by the molecules.

D. For a real gas, is always greater than .

E. Gases are likely to be more real and less ideal at high temperatures.

the quantum model of the atom locates the electron
(a) at a specific distance from the nucleus
(b) in a definite path around the nucleus
(c) within a region of high probability

(d) at any distance from the nucleus

How do diastereomers and stereoisomers differ? How can a molecule be identified as either of these two in a Fischer projection?

Which of the following is FALSE about denaturation of proteins?

A. Heat is a good denaturant of proteins.

B. In denaturation the polypeptide chain is hydrolyzed.

C. Both low and high pH are good denaturants.

D. Denaturation results in the loss of activity of an enzyme.

A student designed a calorimetry experiment to find the molar enthalpy of combustion of methanol, . The student burned of methanol to heat  of water in the calorimeter and assumed that all the energy was transferred to the water. The initial and final thermometer readings, in degrees Celsius, are shown below. How much heat energy is released by the methanol?

What is the overall order for reaction if the rate law is written as ?

a.  
b.  
c.  
d.  
e.  

Use the following data to calculate (a) the molar concentration of B in (i) water,
(ii) benzene, (b) the molality of B in (i) water, (ii) benzene.
Mass of B used to make up  of solution:  
Molar mass of B:   
Density of solution in water:   
Density of solution in benzene: 

When of   is titrated with , what is the pH at the equivalence point?

How many ions of iron are present in formula units of iron(III) oxide?

In each case, indicate which acid or base must be added to create the buffer solution.

Which is used to create a buffer solution with:

a)  

b)  

c)  

Urea  , used in the production of fertilizer and explosives, is prepared by reacting ammonia with carbon dioxide:

If are allowed to react with .

a.) Which of the two reactants is the limiting reagent?

b.) How much (in grams) can be made?

c.) How much of the excess reagent (in grams) is left at the end of the reaction?

The replicate results (mg/L) obtained from calcium determination of a blood sample using atomic absorption spectrophotometry (AAS) and a new colorimetric method were as following: AAS : 11.2, 11.2, 10.6, 11.2, 9.7 and 10.0 Colorimetric : 9.2, 10.5, 9.7, 11.5, 11.6, 9.3, 10.1 and 11.2 Determine whether the mean of both methods have a significant difference at 95% confidence level. 

Which of the following is NOT a functional group in cholesterol?

A. alcohol

B. alkanes

C. alkene

D. aromatic hydrocarbon

How is tertiary alcohol converted into an Alkyl Halide? How about primary alcohol?

What is the molality of a (by mass) solution of ?

A solution is in , a weak acid, and in . The pH of the solution is . What is the Ka of ?

Which of the following is true about the bond length between atoms involved in resonance structures?

a. is exactly the same for all the same bonds in a population of molecules. 

b. changes in length every nanosecond or so, as the molecule switches from one resonance structure to another.

c. has one preferred position so that in each molecule, one of the bonds is shorter than the other.

d. has one preferred position so that one bond is shorter than the other, however, which bond is shorter may be different for each molecule, so the average of all resonance bonds in a mole of molecules is the same. 

Top fuel dragsters and funny cars burn nitromethane as fuel according to this balanced combustion equation:



The enthalpy of combustion for nitromethane is   (  for the reaction as written above).

Standard Enthalpies of Formation at 25 ∘C

Is the following set of quantum numbers allowed? Why or why not?

For the reaction 

Write the:

a. complete ionic equation

b. spectator ions

c. net ionic equation

For the reaction

Write the:

a. complete ionic equation

b. spectator ions

c. net ionic equation

A solution of Cu²⁺ has a volume of 2.50 L, and 48,246 C are required to reduce the Cu²⁺ to Cu⁺. What was the original molar concentration of copper? What is the molar concentration of Cu⁺ after the passage of 12,061 C?

In the mass spectrum of 2,6-dimethyl-4-heptanol, there are prominent peaks at . Propose reasonable structures for these fragment ions.

This reaction takes place with first-order kinetics
 
and is initially at equilibrium when the concentration of reactant is . The rate constant for the forward reaction is   and the reverse rate constant is . Some product is added to the reaction so that the amount of product in the mixture doubles. What is the rate of reaction for the backward reaction?
(A)  
(B)  
(C)  
(D)  
(E)  

Draw each of the following using line formulas: a. Dichlorodiiodomethane b. 1, 4-Diethylcyclohexane c. 2-Iodo-2, 4, 4-trimethylpentane

Ms. Allison was predicting the products for a double replacement reaction. She was given  for the reactants. Here is what she did.

Na2S + HCl → HNa + SCl 

What did she do wrong and what are the correct products?

Aqueous hydrochloric acid reacts with magnesium to produce hydrogen gas according to the balanced equation below.

If of is combined with , what volume of hydrogen gas can be produced? Assume the temperature and pressure of the gas are and , respectively.

A compound with the formula C₇H₁₄O₂.

Assign functional groups in IR spectrum.

Fully interpretation the NMR spectrum.

Write down the chemical structure of the compound.

A compound with the formula C₇H₁₄O₂.

Assign functional groups in the IR spectrum.

Full interpretation of the NMR spectrum.

Write down the chemical structure of the compound.

A compound with the formula .

Assign functional groups in the IR spectrum.

Fully interpret the NMR spectrum.

Write down the chemical structure of the compound.

Pressure in the atmosphere changes with altitude h according to the formula where M is is the molar mass of air and is the standard sea level, the pressure at the altitude is  ; g is the acceleration due to gravity = ; . Calculate in K the temperature at the altitude of  .

In an experiment, of powdered iron (III) oxide is mixed with carbon and heated to in a rigid reactor.

The following reaction occurred:  

Assume that the reaction is complete, the volume of Fe(s) and C(s) is small enough to be ignored, and the temperature of the reactor is maintained at .

1. Write the balanced reaction.

2. Calculate the number of moles of gas formed.

3. What will be the pressure of the gas in the reactor after the reaction?

In an experiment,  of powdered iron (III) oxide is mixed with  carbon and heated to  in a rigid  reactor.

The following reaction occurred:   

Assume that the reaction is  complete, the volume of and is small enough to be ignored, and the temperature of the reactor is maintained at  .

1. Write the balanced reaction.

2. Calculate the number of moles of gas formed.

3. What will be the pressure of the gas in the reactor after the reaction?

What is the structure using the following spectral data? 

What is the formula name and structure of ?