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Chem 123 Lab Final UBC Actual Verified Exam
Questions And Answers Practice Questions with
Solutions Newest | Already Graded A+||Newest
Exam!!!
What relationship exists between the mols of gas and the
collected volume of gas? - Answer-as the volume of gas
increases, the number of mols is increasing
In exploring the ideal gas law, the relationship between
pressure and moles of a gas is investigated, a 2-liter bottle
is pressurized. what is the recommended pressure for this
part of the experiment? - Answer-40-50psi
What occurs in endothermic reactions? - Answer-heat
energy is absorbed
when exothermic reactions occur - Answer-heat energy is
released
a calorimeter measures the ______ involved in reactions
or other processes by measuring the ______________ of
the materials __________ the process. The calorimeter is
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_____________ to prevent transfer of heat to outside the
device - Answer-heat, temperature change, surrounding,
insulated
This heat energy absorbed or released during a chemical
reaction is known as ________ enthalpy or delta H. A
reaction that is exothermic, or releasing energy, will have
delta H value that is __________ a reaction that is
endothermic, or absorbing energy, will have delta H value
that is _________ - Answer-enthalpy, negative, postive
HCl is a corrosive and a strong irritant. what measures
should be taken when working with this material? -
Answer-- Always wear gloves when handling this chemical
- always wear safety goggles when handling this chemical
What is the net ionic equation for the reaction between
HCl and NaOH? - Answer-H^+ + OH^- ----> H20
Identify two issues that can arise when measuring heat
changes for a chemical reaction using a calorimeter -
Answer-- heat can be lost to the calorimeter over time,
which is particularly an issue for reactions that proceed
slowly
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- heat can come from the reaction of interest as well as
any side reactions
Which method should be used when stirring the contents
of the calorimeter? - Answer-place a stir bar in the
calorimeter
Calculate the enthalpy change for CS2 + 3O2 ---> CO2 +
2SO2
from the reactions
C + O2 ----> CO2 = -393.6 KJ
S + O2 -----> SO2 = -296.8 KJ
C + 2S -----> CS2 = +87.9 KJ - Answer--393.6 + (-296.8 x
2) + -87.9 = -1075.1KJ/mol
To condition the buret, add a small volume of
______________ to the buret and rotate the barrel
________________ so that the liquid makes contact with
the full inner surface of the barrel. Complete this action
_____________ and discard each volume in a designated
waste container. - Answer-the titrant, at an angle close to
horizontal, two more times
Chem 123 Lab Final UBC Actual Verified Exam
Questions And Answers Practice Questions with
Solutions Newest | Already Graded A+||Newest
Exam!!!
What relationship exists between the mols of gas and the
collected volume of gas? - Answer-as the volume of gas
increases, the number of mols is increasing
In exploring the ideal gas law, the relationship between
pressure and moles of a gas is investigated, a 2-liter bottle
is pressurized. what is the recommended pressure for this
part of the experiment? - Answer-40-50psi
What occurs in endothermic reactions? - Answer-heat
energy is absorbed
when exothermic reactions occur - Answer-heat energy is
released
a calorimeter measures the ______ involved in reactions
or other processes by measuring the ______________ of
the materials __________ the process. The calorimeter is
,2|Page
_____________ to prevent transfer of heat to outside the
device - Answer-heat, temperature change, surrounding,
insulated
This heat energy absorbed or released during a chemical
reaction is known as ________ enthalpy or delta H. A
reaction that is exothermic, or releasing energy, will have
delta H value that is __________ a reaction that is
endothermic, or absorbing energy, will have delta H value
that is _________ - Answer-enthalpy, negative, postive
HCl is a corrosive and a strong irritant. what measures
should be taken when working with this material? -
Answer-- Always wear gloves when handling this chemical
- always wear safety goggles when handling this chemical
What is the net ionic equation for the reaction between
HCl and NaOH? - Answer-H^+ + OH^- ----> H20
Identify two issues that can arise when measuring heat
changes for a chemical reaction using a calorimeter -
Answer-- heat can be lost to the calorimeter over time,
which is particularly an issue for reactions that proceed
slowly
, 3|Page
- heat can come from the reaction of interest as well as
any side reactions
Which method should be used when stirring the contents
of the calorimeter? - Answer-place a stir bar in the
calorimeter
Calculate the enthalpy change for CS2 + 3O2 ---> CO2 +
2SO2
from the reactions
C + O2 ----> CO2 = -393.6 KJ
S + O2 -----> SO2 = -296.8 KJ
C + 2S -----> CS2 = +87.9 KJ - Answer--393.6 + (-296.8 x
2) + -87.9 = -1075.1KJ/mol
To condition the buret, add a small volume of
______________ to the buret and rotate the barrel
________________ so that the liquid makes contact with
the full inner surface of the barrel. Complete this action
_____________ and discard each volume in a designated
waste container. - Answer-the titrant, at an angle close to
horizontal, two more times
