jeah-03

Water is exposed to infrared radiation of wavelength   . Assume that all the radiation is absorbed and converted to heat. How many photons are required for the sample to absorb   of heat?

Rank the following elements in order of increasing ionization energy and increasing atomic size: 

Assuming that seawater is an aqueous solution of NaCl, what is its molarity? The density of seawater is 1.025 g/mL at 20 degrees Celcius, and the NaCl concentration is 3.50 mass %.

4. What is density of 20ml of a substance that weighs 736g?

What conclusion would you have come to if all of the reactions had a given precipitate?

Which one of the following contains    ?

A)  

B)  

C)  

D)  

E)  

How much energy must be add to of water in a pan if it is to be warmed from to its boiling temperature of ?

Assume heat capacity of water

Why is it important to maintain the reaction temperature low and the addition of nitric acid-sulfuric acid mixture carried out slowly?

When of   solution at   is mixed with of solution at in a calorimeter, the white solid forms, and the temperature of the mixture increases. What is the final temperature of the mixture if the enthalpy change is    formed? The specific heat of water is   , and the density of water is  

Which of the following is not characteristic of a gas?

a. indefinite and uniform expansion

b. highly compressible

c. indefinite shape and volume

d. high density

How do I express quantities using significant figures to imply errors? An example question is .

If I use of benzaldehyde, of a solution containing of acetone in ethanol.

What is the number of moles of benzaldehyde and what is the number of moles of acetone?

What is the symbol of a nucleus produced from the decay of atom's nucleus mass number , Atomic number  and the element of emission of (a). alpha-particle and (b). beta negative- particle?

What is the strongest interparticle force in a sample of ?

Ion-dipole forces

Induced dipole forces

Dispersion forces

Dipole-dipole forces

Hydrogen bonding forces

A ampule of a solution of naphthalene in hexane is excited with a flash of light. The naphthalene emits of energy at an average wavelength of . What percentage of the naphthalene molecules emitted a photon?

 Benzene and toluene form an ideal solution. At 298 K, what is the mole fraction of benzene in the liquid that is in equilibrium with a vapor that has equal partial pressures of benzene and toluene? At 298 K, the vapor pressures of pure benzene and pure toluene are 95 and 28 torr, respectively.

A flask of mercury contains . How many moles of mercury are in the flask?

An equilibrium mixture contains  of each of the products (carbon dioxide and hydrogen gas) and of each of the reactants (carbon monoxide and water vapor) in a container.

How many moles of carbon dioxide would have to be added at constant temperature and volume to increase the amount of carbon monoxide to   once equilibrium has been reestablished?

What is the density of water at ?

A person who has taken antibiotics for several weeks because of a severe bacterial infection may develop a deficiency of which vitamin?

Which is true about cholesterol or its connection with health risks?

A. High cholesterol is a health risk for development of a therosclerosis.

B. The chemical structure of cholesterol itself is the same in"good cholesterol" and "bad cholesterol."

C. Cholesterol levels can often be lowered by taking medicines called statins.

D. Cholesterol is circulated in the blood as part of complexes called lipoproteins.

E. All of the above are true.

Use boltzmann equation.

A given gas molecule can be arranged in different ways with equal energies. What is the entropy of a system composed of of this gas molecule at ?

Which of the following statements best describes effusion?
A) expansion of a gas when heated
B) movement of a gas through a very small opening
C) spontaneous mixing of gases
D) increasing vapor pressure due to increased temperature
E) pressure is proportional to moles of gas

A student placed    of glucose  in a volumetric flask, added enough water to dissolve the glucose by swirling, then carefully added additional water until the  mark on the neck of the flask was reached. The flask was then shaken until the solution was uniform. A   sample of this glucose solution was diluted to  . How many grams of glucose are in    of the final solution? [Molar mass of glucose =  ]

Convert to milligrams.    

(Answer should be in scientific notation to the correct number of significant figures. NO UNITS in answer)

Label each as a qualitative or quantitative measurement.

1. physical state

2. solubility

3. mass

4. color

5. reactivity

Which of the following is correct?

I. Pearlite consists of layers of ferrite and cementite

II. Bainite is made of rods of cementite in a matrix of ferrite

III. Pearlite is stronger than Bainite?

A. (I) only

B. (II) only

C. (III) only

D. (I and II)

E. (I and III)

The reaction that produces the water gas mixture is as follows:

  this reaction requires an input of of heat for every mole of carbon that reacts.

Is this equation endothermic or exothermic?

A sample of a material has radioactive particles in it today. Your aunt measure radioactive particles in it years ago.

A. years from today, how many radioactive particles will the sample have?

B. years from today, how many radioactive particles will the sample have?

5-

a) From the following sets of quantum numbers (n, L, mL, ms), identify the set that is correct and state the orbital designation for those quantum numbers. 

(3, 1, 1, 0) (2, 2, 1, -1/2) (0, 1, 1, ½) (3, 2, 0, ½)

b) For the following groups of elements, select the one that has the property noted 

-The largest atom: Mg, Mn, Mo, Ba, Bi, Br

-The lowest first ionization energy: B, Sr, Al, Br, Mg, Pb.

The liquid that is produced in a landfill can be acidic, one reason being the presence of large numbers of bacteria that respire, producing a significant amount of carbon dioxide, which can dissolve in pore water, reducing its pH. Given that the aqueous concentration of carbon dioxide, in the pore water of a landfill is 2.24 × 10^–3 mol/L, what is the partial pressure of CO₂ in the air of the pore spaces?  K_H = 3.38×10^–2 mol/L∙atm

Torque can be calculated by multiplying the force (N) applied at 90∘ to the lever arm at a distance (m) from the pivot point (point of rotation), the compound SI unit for the torque is N⋅m. If the force (at 90∘ to the lever arm) applied is 15 N and it is applied at 2.0 m from the pivot point (point of rotation), what is the torque on the lever?

A 5 mL sample of an unknown liquid is placed into a 250 mL flask that has had all of the air removed. The pressure measured in the flask is found to be 40.5kPa. In a seperate trial the student puts 214 mL of the same liquid into the same flask at the same conditions. What will the pressure measure (in kPa) in the second trial?

A mixture of nitrogen and hydrogen was allowed to come to equilibrium at a given temperature. The reaction equation is   .

An analysis of the mixture at equilibrium revealed 2.1 mol , 3.2 mol , and 1.8 mol . How many moles of were present at the beginning of the reaction?

A) 3.2

B) 4.8

C) 5.0

D) 5.9

E) 4.4

An equilibrium mixture contains of each of the products (carbon dioxide and hydrogen gas and of each of the reactants (carbon monoxide and water vapor) in a container.

How many moles of carbon dioxide would have to be added at constant temperature and volume to increase the amount of carbon monoxide to   once equilibrium has been reestablished?

A common way to make hydrogen gas in the laboratory is to place a metal such as zinc in hydrochloric acid (see the figure). The hydrochloric acid reacts with the metal to produce hydrogen gas, which is then collected over water. Suppose a student carries out this reaction and collects a total of 140.2 mL of gas at a pressure of 749 mmHg and a temperature of 25∘C. What mass of hydrogen gas (in mg) does the student collect? (The vapor pressure of water is 23.78 mmHg at 25∘C.)

At equilibrium, the concentrations in this system were found to be  and .

If more  is added, bringing its concentration to what will the final concentration of be after equilibrium is re‑established?