CHEM 1201 Chapter : Chapter 5 Quiz 2 (with Answers)

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azuremammoth471

15 Mar 2019

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Remember that pure elements such as o2 have a hf. A formation reaction is a very specific reaction. It means elements in their natural state 1 mole of products. The elements must be in their natural state at 1 atm, 0 c. We can deduce the reaction in this way. elements in their natural state n2h4 g . N and h will not work as reactants in a formation reaction because they are not the natural states of the elements. There are two different types of heat involved in this problem: heat of reaction which is calculated by qrxn erxn, heat of temperature change of the bomb calorimeter. This is calculated from qbomb ctotal t. The picture describing this problem shows that the heat leaving the reaction is the same heat entering the bomb. So the values are the same but the sign is different. (remember that for a bomb calorimeter where volume is constant work is zero.

Related Questions

For which of the following reactions is delta H rxn equal to Delta H formation of the products? THE HEAT OF FORMATION IS DEFINED BY A REACTION THAT FORMS ONE MOLE OF PRODUCT. Thank you. please help

1- The molar heat capacity of silver is 25.35 J/molâ âC. How much energy would it take to raise the temperature of 8.20 g of silver by 14.5 âC?

Express your answer with the appropriate units.

_____________

Part A

Calculate the enthalpy of the reaction

2NO(g)+O2(g)â2NO2(g)

given the following reactions and enthalpies of formation:

12N2(g)+O2(g)âNO2(g), ÎHâA=33.2 kJ

12N2(g)+12O2(g)âNO(g), ÎHâB=90.2 kJ

Express your answer with the appropriate units.

2- A total of 2.00 mol of a compound is allowed to react with water in a foam coffee cup and the reaction produces 196 g of solution. The reaction caused the temperature of the solution to rise from 21.00 to 24.70 âC. What is the enthalpy of this reaction? Assume that no heat is lost to the surroundings or to the coffee cup itself and that the specific heat of the solution is the same as that of pure water.

Enter your answer in kilojoules per mole of compound to three significant figures.

_________

3- A volume of 110. mL of H2O is initially at room temperature (22.00 âC). A chilled steel rod at 2.00 âCis placed in the water. If the final temperature of the system is 21.00 âC , what is the mass of the steel bar?

Use the following values:

specific heat of water = 4.18 J/(gâ âC)

specific heat of steel = 0.452 J/(gâ âC)

Express your answer to three significant figures and include the appropriate units.

Part B

The specific heat of water is 4.18 J/(gâ âC). Calculate the molar heat capacity of water.

Express your answer to three significant figures and include the appropriate units.

______-

4- What is the enthalpy for the following reaction?

overall: N2O4â2NO2

Express your answer numerically in kilojoules per mole.

____________

Part B

Calculate the enthalpy of the reaction

4B(s)+3O2(g)â2B2O3(s)

given the following pertinent information:

B2O3(s)+3H2O(g)â3O2(g)+B2H6(g), ÎHâA=+2035 kJ

2B(s)+3H2(g)âB2H6(g), ÎHâB=+36 kJ

H2(g)+12O2(g)âH2O(l), ÎHâC=â285 kJ

H2O(l)âH2O(g), ÎHâD=+44 kJ

Express your answer with the appropriate units.

_____________

5- What is the balanced chemical equation for the reaction used to calculate ÎHâf of MgCO3(s)?

If fractional coefficients are required, enter them as a fraction (i.e. 1/3). Indicate the physical states using the abbreviation (s), (l), or (g) for solid, liquid, or gas, respectively without indicating allotropes. Use (aq) for aqueous solution.

Express your answer as a chemical equation.

__________

6- Part A

Determine the enthalpy for this reaction:

Ca(OH)2(s)+CO2(g)âCaCO3(s)+H2O(l)

Express your answer in kilojoules per mole to one decimal place.

_______

Part B

Consider the reaction

Ca(OH)2(s)âCaO(s)+H2O(l)

with enthalpy of reaction

ÎHrxnâ=65.2kJ/mol

What is the enthalpy of formation of CaO(s)?

Express your answer in kilojoules per mole to one decimal place.

________

7- Part A

Write a balanced chemical equation depicting the formation of one mole of H2O2(g) from its elements in their standard states.

Express your answer as a chemical equation. Identify all of the phases in your answer.

_____

Part B

For H2O2(g), find the value of ÎHâf. (Use Appendix C)

Express your answer using five significant figures.

_____

PART C: Write a balanced chemical equation depicting the formation of one mole of CaCO3(s) from its elements in their standard states.

Express your answer as a chemical equation. Identify all of the phases in your answer.

_____

Part D

For CaCO3(s), find the value of ÎHâf. (Use Appendix C)

Express your answer using five significant figures.

_____

Part E

Write a balanced chemical equation depicting the formation of one mole of POCl3(l) from its elements in their standard states.

Express your answer as a chemical equation. Identify all of the phases in your answer.

____

Part F

For POCl3(l), find the value of ÎHâf. (Use Appendix C)

Express your answer using four significant figures.

_____

Part G

Write a balanced chemical equation depicting the formation of one mole of C2H5OH(l) from its elements in their standard states.

Express your answer as a chemical equation. Identify all of the phases in your answer.

_____

Part H

For C2H5OH(l), find the value of ÎHâf. (Use Appendix C)

Express your answer using four significant figures.

How do you solve #8?

Brooklyn College of C.U.N.Y Spring 209 Chemistry 1.2 Makeup Midterm Exam Lab. Sectio Physical Constants R-0.0821 L.atrn /mM1 K: 1 atrm-760 Torr; h-6.626 x 10" Js. c-300 x 10' mis Multiple Choice Question4 points each. Circle the correct choice I. How many orbitals are there in the n - 3 shel 2. Which of the following is not a valid set of four b6 ( 4)12 e) none of the preceding choices quantum numbers to describe an electron in an atom? 3. Which pair of elements would you expect to exhibit the most similar physical and chemical peoperties? a) As and Se Na and ci As and Sb s) B and Bensnp 4) The rn unpaired electrons in the ground state of an atom of Co is... ree (C) five (D) seven (E) none of the preceding choices 0è®ä¸ä½å£ wch of the following processes is exothermic? a) lonization of a sodium atom b) Formation of gaseous Which of the following bonds is the most polar? a) N-O b)o-F ) B-o )so e)all are equally polar t what temperature (in C) will 25.0 g of carbon dioxide (at 1.00 atm) occupy 21.3 L? 8Â°C b) 461 C c) -263Â°C d)-270Â°C e) 113Â°C How many times more rapidly will hydrogen (H,) gas effuse through a pinhole than will deuterium ( Deuterium is an isotope of hydrogen with a molecular mass of 4.0 g'mole. (A) 2 (B)2 (C)2v2 (D)4 9, Which of the following arrangements from lowest to highest in first ionization energies is correct ? 10. In which of the following compounds obeys the octet rule? a) XeF b) BF, c) CIO d) SO, pone of the preceding choicees 11. The bright spectral lines observed in the emission spectrum of a flame or gas discharge tube are due to a) the absorption of light at specific wavelengths b) the formation of an excited state of atoms the transition of an atom from an excited state to a lower energy state d) the change from anti-parallel to parallel electron spins in an atom oxygen at 25 Â°C. Comparing the pressure of the hydrogen to the exygen, the ratio will be From Bond Dissociation Enthalpies: Î11D (CI-CI)-243 klinolalo (F-F )-159 kJ/mol; Î1lo (CHF)-25 12.A one-liter container is filled with one mole of hydrogen at 25 Â°C.A second one-liter container is filled with or 2CIF(R) alculate the enthalpy, AH, for the chemical reaction: Cl (g)+ F: (g) (a)-147 kJ (b)-108 kJ (c) +171 kJ (d) +912J (H lou, mory t,hes more rapidy wil, hydrogen w many tes more ro

CHEM 1201 Chapter : Chapter 5 Quiz 2 (with Answers)

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