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Which of the following is an endothermic process?

A. Water Evaporating

B. Wood Burning

C. Dynamite exploding

D. Gasoline combustion

Potassium and sodium chloride are similar in charge and they both have the same anion. When comparing sodium chloride ( at ) and potassium chloride, which has a higher solubility at ?

A. potassium chloride B. This cannot be determined from the data collected here. C. sodium chloride D. They are both equally soluble.

The label of a vitamin supplement indicates that the supplement contains biotin, pyridoxine, and linolenic acid. Explain why each of these might be included in the vitamin supplement by describing their usefulness in a specific metabolic process.

Which one of the formulas for ionic compounds below is incorrect?  SrCl2, AI3P2, Cs2S ,AICI3 ,Case

Hydrocarbons in the cab of an automobile were measured during trips on the New Jersey Turnpike and trips through the Lincoln Tunnel connecting New York and New Jersey. The total concentrations (± standard deviations) of m‐ and p‐xylene were Turnpike: 31.4 ± 30.0 μg/m3 (31 measurements) Tunnel: 52.9 ± 29.8 μg/m3 (31 measurements) Do these results differ at the 95% confidence level and at the 99% confidence level?

Explain why the retention time of the parabens (parahydroxy benzoic acid esters) increases with alkyl chain length in reverse phase partition chromatography.

The occurrence of dark lines (Fraunhofer lines) in the observed emission spectrum of the sun suggests:

a) that the composition of the sun lacks certain elements.

b) that there is no emission of certain frequencies because relaxation does not occur.

c) that the excitation energy available is discontinuous and limited.

d) that absorption of certain frequencies is occurring at some location between the emitter and the observer.

Which of the following statements is false?

- An atom in a body-centered cubic structure has a coordination number of .

- The most common cubic structure for crystalline solids is the simple cubic structure.

Broadly speaking, when do you choose a gravity filtration vs a vacuum filtration?

The chromatographic analysis of Sample A resulted in a peak at 8.95 minutes and a peak area of 24237396. When 10.0µL of Sample A was mixed with 5.00 µL of 20.0 ppm standard, chromatographic analysis of the resulting solution resulted in a peak with a retention time of 9.12 minutes and a peak area of 121220801. What is the concentration of analyte in the original sample?

For the hydrolysis equilibrium equation:

,  

Write the chemical formula of the stronger base. 

If you dissolve of a compound in of distilled water and the temperature is for , the liquid turns red. Why do we not sell a cold pack made of this compound?  

You are now the chemist responsible for describing the efficiency of a newly produced GC column that is long. You do this by injecting an aliquot of an octadecane standard into the column and observing its resultant chromatographic output. What type of chromatography are you performing in this experiment? (2 marks) What would you assume the polarity of the mobile and stationary phases are in this efficiency experiment? Why? (3 marks) You find that the retention time for the standard is and the width at half-height is . The chromatographic peak shape is Guassian. Calculate the number of theoretical plates per length () of column in this column. (5 marks)

You are in a lab and you find a bottle that contains . One of your coworkers wants to get a Geiger counter to

check and see if it is radioactive. You then tell them that they don't need to do that because you already know the

answer without testing it or looking up the answer.

a. Is the sample radioactive?

b. How do you know?

What would you expect to happen to your values if you doubled the amount of acetic acid?

An uncatalyzed reaction,    has a of -3000 J/mol. Which of the following statements must be true?

A. The activation energy of the reverse reaction is greater than that of the forward reaction.

B. The activation energy of the reverse reaction is lower than that of the forward reaction.

C. If a catalyst is added, the value of for the catalyzed reaction will be smaller in magnitude than the value of   for the uncatalyzed reaction.

D. If a catalyst is added, the value of  for the catalyzed reaction will be larger in magnitude than the value of ΔG for the uncatalyzed reaction.

E. Since the magnitude of is so large, the reaction occurs very rapidly.

What is undergoing oxidation in the redox reaction represented by the following cell notation:

An analytical chemist is titrating 52.3mL of a 0.2600M solution of aniline C6H5NH2 with a 0.9000M solution of HNO3. The pKb of aniline is 9.37. Calculate the pH of the base solution after the chemist has added 10.0mLof the HNO3 solution to it.

Pu-239 is used in nuclear bombs. Its half-life is 24110 years. Assuming that losing 17% of the original plutonium deactivates the bomb, estimate how many years it would take for the bomb to become 'safe'.

Balance the following equation in basic solution using the lowest possible integers and give the coefficient of water.

Cr³⁺(aq) + MnO₂(s) → Mn²⁺(aq) + CrO₄^2-(aq)

Balance the following equation in acidic solution using the lowest possible integers and give the coefficient of water. 

MnO₄^-(aq) + H₂SO₃(aq) → Mn²⁺(aq) + HSO₄^-(aq)

a) 2

Which of the following substances contains sulfur in the highest oxidation state?

a) NaHSO₄

How do you know if a solution is acidic, basic, or neutral?

What is the IUPAC name of the following substance?

What values of the angular momentum(l)and magnetic(ml) quantum numbers are allowed for a principle quantum number(n) of 4? how many orbitals are allowed

Gaseous ethane CH3CH3 will react with gaseous oxygen O2 to produce gaseous carbon dioxide CO2 and gaseous water H2O. Suppose 2.7 g of ethane is mixed with 16.5 g of oxygen. Calculate the maximum mass of water that could be produced by the chemical reaction. Be sure your answer has the correct number of significant digits.

A major component of gasoline is octane C8H18. When liquid octane is burned in air it reacts with oxygen O2 gas to produce carbon dioxide gas and water vapor. Calculate the moles of oxygen needed to produce 0.050mol of carbon dioxide. Be sure your answer has a unit symbol, if necessary, and round it to the correct number of significant digits.

Rank the following compounds in order of increasing boiling point. Which compound is the most water-soluble? Which compound is the least water soluble?

Explain physical changes and its give example 

How many grams of titanium may be formed by the passage of 26,450 C through an electrolytic cell that contains an aqueous Ti(IV) salt.  Give your answer to 2 decimal places.

What is the pH of a buffer made up to contain 0.57 M NH3 and 0.64 M NH4Cl? The pKa of ammonium ion is 9.26.

What is the mass in gas of .098L of SO 2 at STP? (m=\#L, molar mass of SO 2 /22.4L)

Use the following information to propose a molecular formula for nootkatone a compound partly responsible for the characteristic odor of grapefruit. Nootkatone contains the elements C, H, and O has five degrees of unsaturation and a molecular ion in its mass spectrum at m/z=218. 

solve equations by dimensional analysis method