CHM 1230 Lab Final MC

Identify the common indicators that a chemical reaction has occurred.

precipitate being formed bubbles being produced a color change a change in temperature

One calorie (cal) is the amount of heat needed to _____________ the temperature of one gram of water one degree Celsius.

raise

To identify a halide, you can react a solution with chlorine water in the presence of mineral oil. If the unknown halide is a ________ reducing agent than chlorine, the halide will be oxidized to ________ which would change the color of the ___________ layer.

stronger its elemental form mineral oil

Identify the equipment best suited for extinguishing each type of fire. small benchtop fire _______. large fire on floor ________. clothing fire _________.

- overturned beaker - fire extinguisher - fire blanket

It is often helpful to remember the acronym PASS when using a fire extinguisher. Fill in the word that corresponds with each letter to complete the steps needed for operation of this device. P: _______ the pin. A: _______ the nozzle at the base of the fire. S: _______ the lever slowly S: _______ the spray from side to side over the fire.

- pull - aim - squeeze - sweep

What should you do every time before you leave the lab?

- remove your labcoat, if you are wearing one. - remove your gloves - wash your hands

Identify the safety equipment designed to deal with each emergency listed. chemicals on clothes _____________. large fire on the benchtop _________. cuts or minor burns_________. fire on a person __________. chemicals in eyes __________.

- safety shower - fire extinguisher - first aid kit - fire blanket - eyewash station

Move to the safety shower if you spill hazardous chemicals on your ___________. Stand under the shower and ________ the level. Remove clothing and continue flushing the area for ___________.

- skin/clothing - pull - 15 mins

Match each lab incident to the item of PPE that will protect you from it. Each item of PPE will only be used once. 1. While transferring a solution from a flask to a beaker, the solution accidentally spills down the front of the lab bench. ___________________. 2. While checking on a stirring solution, the solution splashes up towards your face. ____________________. 3. While picking up a buret, an unknown solution left by a previous solution drips onto your hand. _________________. 4. While pulling an empty beaker off the shelf at the beginning of lab, it slips out of your hand onto the floor.

1. lab coat 2. goggles 3. gloves 4. closed-toe shoes

Determine whether each observation generally corresponds to a physical change or a chemical change. 1. A liquid freezes into a solid. ________ 2. A precipitate is formed from two solutions. ________ 3. A solid dissolves into water. ______ 4. The color of a substance changes over time. _________ 5. A solution heats up upon mixing with another. ________ 6. Bubbles are produced upon mixing two solutions. _______

1. physical change 2. chemical change 3. physical change 4. chemical change 5. chemical change 6. chemical change

Knowing that one day is 24 hours and one hour is 60 minutes, how many minutes are in 2.0 days?

2880

Which balanced redox reaction is occurring in the voltaic cell represented by the notation of Al(s)|Al3+(aq)||Pb2+(aq)|Pb(s)Al(s)|AlX3+(aq)||PbX2+(aq)|Pb(s) ?

2Al(s)+3Pb2+(aq)⟶2Al3+(aq)+3Pb(s)

For a spontaneous reaction within an electrochemical cell, E°cell _________ 0. For a non-spontaneous reaction within an electrochemical cell, E°cell _______ 0.

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Identify the precautions to take with exits in the lab. select one or more: A. keep the exit door locked at all times B. do not block a door with an exit sign C. make sure lab windows are always open. D. locate the exits prior to the start of lab.

B and D

while setting up a beaker to boil a solution on a hot plate, you notice that the stirring is erratic and unstable. What should you do to stabilize the stirring solution? A. completely turn off the stirring function. B. Clamp the beaker in place at the edge of the hot plate. C. Turn down the stirring speed. D. Move the beaker to the center of the hot plate.

C. turn down the stirring speed D. move the beaker tot he center of the hot plate

Predict the products of HBR reacting with Mg(OH)2

MgBr2 H2O

Identify the conditions for a standard electrochemical cell.

Pressure of 1 atm Temperature of 298 K Solution concentrations of 1 M

What is the general definition of heat capacity?

The change in heat required to change the temperature of something by one degree Celsius

What is the main precaution to take if a gas cylinder sign is present in the lab?

Visually check that the gas cylinder is restrained but keep a safe distance from it.

Identify the oxidation half reaction of Zn(s)Zn(s)

Zn(s)⟶Zn2+(aq)+2e−Zn(s)⟶ZnX2+(aq)+2eX−

Predict the products of hydrochloric acid reacting with zinc metal.

ZnCl2 and H2

what visible signs indicate a precipitation reaction when two solutions are mixed?

a hazy or cloudy appearance solid settling out in the test tube

Suppose you mix two solutions in a test tube and the test tube becomes hot. This is _________ because ______________.

a sign of a chemical reaction chemical changes can release heat

When a known quantity of compound, at a known concentration, is added to a known volume of another compound to determine the concentration of the latter, the process is referred to as _____________.

a titration

what type of plot can be sued to determine wavelength max of a solution?

absorbance vs wavelength

A neutralization reaction is a reaction between ________ that results in the formation of _________ and ______________.

an acid and base water a salt

Which statements are true concerning a substance with a high specific heat?

an example substance is water the substance cools down slowly after heating

The indicator phenolphthalein is added to the _____________.

analyte

In the pictured cell, the side containing zinc is the _________ and the side containing copper is the __________. The purpose of the Na2SO4 is to ___________.

anode cathode act as a salt bridge

What parts are present in every chemical equation?

at least one product at least one reactant an arrow

In the titration setup in lab, the buret will be filled with _______. During the titration, a beaker placed underneath will contain _______ and ____

base acid indicator

Determine when to put on disposable gloves for work in the lab.

before handling any glassware or chemicals for the experiment

Determine the molecular geometry based on the description of bonding and lone pairs of electrons around the central atom. Two single bonds and two lone pairs of electrons. _______ Three single bonds and one lone pair of electrons ______ Two double bonds and no lone pairs of electrons _______ Six single bonds and no lone pairs of electrons ________ four single bonds and no lone pairs of electrons ________ Five single bonds and no lone pairs of electrons _____ Three double bonds and no lone pairs of electrons____

bent trigonal pyramidal linear octahedral tetrahedral trigonal bipyramidal trigonal planar

identify the color absorbed by a solution that appears the color given. orange ______ green _____ red _____ blue _______

blue red green orange

Determine whether each statement describes an anode or a cathode in a voltaic cell. the positive terminal ________ the negative terminal ________ where electrons flow to ________ where electrons flow form _________ where the oxidation occurs ________ where the reduction occurs __________

cathode anode cathode anode anode cathode

Electrochemical cell potential can be calculated using the Nernst equation. Ecell=Eocell−(RTnF)lnQEcell=Ecello−(RTnF)lnQ Ecell: E (degree) cell: R: T: n: F: Q:

cell potential under any conditions cell potential under any standards conditions gas constant, 8.314 J/mol temperature in Kelvin number of electrons Faraday constant, 9600 J/mol v Reaction quotient

What color is phenolphthalein when the solution is acidic?

colorless

Determine whether the stopcock should be completely open, partially open, or completely closed for each activity involved with titration. at the beginning of a titration _____ close to the calculated endpoint of a titration _______ filling the buret with titrant ________ conditioning the buret with titrant _______

completely open partially open completely closed completely closed

How should you prepare a buret for titration before loading it with titrant?

condition the buret with titrant solution

identify the necessary parts to build a calorimeter.

cover thermometer an interior Styrofoam cup an exterior styrofoam cup

identify each term as description of an electron geometry or a molecular geometry. Tetrahedral pyramidal for NF3 ____ Trigonal Pyramidal for NF3 _____- Arrangement of only the atoms in a molecule ______ Arrangement of bonding and non-bonding electron domians________

electron geometry molecular geometry molecular geometry electron geometry

Determine whether each described process is endothermic or exothermic. A process with a calculated positive q _________. Solid dissolves into solution, making ice pack feel cold ____________ Ice melts into liquid water _________. Acid and base are mixed, making test tube feel hot ___________ Wood burns in a fireplace _________. process with a calculated negative q _________.

endothermic endothermic endothermic exothermic exothermic exothermic

how do you determine the last digit in any measured number?

estimate one digit past the smallest precisely known digit or marking.

When drawing the lewis structure of a molecule, start by determining the total number of available valence based on each element's __________. Then, use the total number of electrons needed for each element to be stable, generally based on __________, to determine the ____________ by finding the difference between the number of needed and available electrons divided by two. Next, identify the central atom, which is the element with the ________ other than hydrogen. Finally, arrange the number of bonds around the central atom to fulfill the stable number of electrons from each element.

group number the octet rule total number of bonds fewest valence electrons

Identify the term that matches each electrochemistry definition. A chemical equation showing either oxidation or reduction ______ The electrode where oxidation occurs _____. An electrochemical cell powered by a spontaneous redox reaction _______. An electrochemical cell that takes in energy to carry out a nonspontaneous redox reaction _______. he electrode where reduction occurs ______.

half reaction anode galvanic cell electrolytic cell cathode

Suppose the reaction of chlorine water with a halide solution produces a halogen, X2, and a salt, NaCl In the presence of mineral oil, the _______ will dissolve in the oil and the ________ will remain in the aqueous layer

halogen salt

a calorimeter measures the ______ involved in reactions or other processes by measuring the _______ of the materials _______ the process. The calorimeter is ________ to prevent transfer of heat to outside the device.

heat temperature change surrounding insulated

What occurs in endothermic reactions?

heat energy is absorbed

When determining the amount of an oxidant present by titration, you can use iodine and starch as an indicator. First, the oxidant, like hypochlorite, oxidizes ________. When starch and iodine are both present, the solution is __________. During the titration, the titrant, like thiosulfate, reduces the _________. When the iodine has completely reacted at the endpoint of the titration, the solution should become ___________.

iodine ion into neutral iodine blue black neutral iodine into iodide ion clear

In a voltaic cell, a salt bridge is needed to allow the motion of _______ between the terminals. In the salt bridge, ______ move toward the anode and ______ move toward the cathode.

ions anions cations

What practice will not help you make an accurate volume reading on a buret at the beginning of a titration?

make sure that the meniscus starts exactly at 0.00 mL

After clamping a buret to a ring stand, you notice that the set-up is tippy and unstable. What should you do to stabilize the set-up?

move the buret clamp to a ring stand with a larger base

The reaction between sodium hydroxide and hydrochloric acid is considered which type?

neutralization

the law of conservation of energy state that __________ an example of the law in the laboratory is __________

no energy can be created or destroyed, only transferred or transformed the water in a calorimeter absorbing heat given off by a reaction or hot object.

Suppose you light a bunsen burner and notice the flame is very yellow and too short. To get a blue flame, you should _______ the ________ further. To increase the size of the flame, you should ______ the _______ further

open air inlet open gas regulator

in the reaction Mg + 2HCL => MgCl2 + H2 Mg is ________ and H is _________

oxidized reduced

identify the expected color of each element in a model of a molecule oxygen _____ carbon _____ nitrogen ______ hydrogen ______

red black blue white

What steps are necessary for finishing up a spectrophotometry experiment?

remove the sample from the sample chamber clean up around the spectrophotometer turn off the light bulb

Which of the following forms precipitates with most halogens?

silver nitrate

in a precipitation reaction, what symbol identifies the precipitate product?

solid

identify the following silver salts as soluble or insoluble in water. AgNO3 _____ AgI______ AgCl_______

soluble insoluble insoluble

identify the term that matches each description. The energy needed to raise the temperature 1 gram of a substance by 1 C _________ energy that is transferred from one object to another __________ a measure of the amount of thermal energy in an object ________

specific heat heat temperature

Specific heat is the heat required to raise the temperature of 1 g of a substance by 1 oC. Based on this definition, what is the equation to calculate specific heat?

specific heat=heat(mass × temperature change)

Which term describes a solution having a very well-known concentration of solute?

standard solution

When equal moles of an acid and a base are mixed, after reaction the two are compounds are said to be at the _______________.

stoichiometric point

In the context of a balanced chemical equation, a ________ is a number to the lower right of an element or ion within formula and it applies to ___________. A ________ is a number to the left of a formula and it applies to ___________. Only _______ should be added or changed when balancing chemical equations.

subscript only the part of the formula it follows coefficient the entire formula it proceeds coefficients

Determine the safest option in the lab if you need your vision to be corrected.

wear corrective glasses or lenses under your safety goggles for the whole experiment, but always check with your TA or instructor for your school's policy

Hydrochloric acid and sodium hydroxide react to form _____________.

NaCl (aq) + H20 (l)

What is the equivalence point of a titration?

When the amount of acid and base are equal.

Potassium hydrogen phthalate is ____________.

a primary standard

In the Energy and Specific lab, what temperature should be recorded as the final temperature of the water when measuring the food sample?

the highest temperature the water reaches as the sample burns

Suppose you prepare a 5um solution of red fye and a 5 um solution of blue dye and observe them in two identical test tubes. Why might the blue dye solution appear more intensely colored than the red dye solution?

the molar absorptivity of the blue dye is greater than the molar absorptivity of the red dye

The liquid dispensed from a burette is called ___________.

titrant

Which is NOT a good source of information about the hazards that affect waste disposal in chemistry lab?

your lab partner

What are the best practices for safely handling waste in the lab? A. Remove gloves for better manipulation of the waste containers. B. Check Labels or instructions before any disposal. C. Always wear appropriate Personal Protective Equipment D. Place any paper towels from the clean-up in the trash.

B and C

When exothermic reactions occur, ______________.

heat energy is released

Which elements do not strictly follow the octet rule when they appear in the Lewis structure of a molecule?

hydrogen chlorine sulfur

Where should glassware be stored after it is cleaned?

in a drying oven, or designated locations such as drawers or buret racks

Match each titration term with its definition. Solution of known concentration that is slowly added to a solution of unknown concentration __________ When the required amount of one solution has been added to the second solution to complete the reaction _______ Solution of an unknown concentration that has another solution slowly added to it __________ Glassware that allows a solution to be precisely and slowly added to another solution__________ Process of slowly adding a solution to react with another solution and determine the concentration of one of the solutions based on the reaction between them __________ A reagent added to the analyte solution that changes color when the reaction is complete __________

titrant endpoint analyte buret titration indicator