Lab Flow - Chem 1A

The equation to calculate density is __1__, where D is the density, m is the __2__, and V is the __3__.

1. D=m/V 2. mass 3. volume

For each described liquid, determine the behavior of a hydrometer calibrated around the density of pure water. 1. In a liquid with the same density as water 2. In a liquid that is less dense than water 3. In a liquid that is more dense than water

1. Float in the same position as pure water 2. Float lower than position in pure water 3. Float higher than position in pure water

A concentrated salt solution has a mass of 5.35 g for a 5.00 mL sample. What is the specific gravity of this solution? Type answer:

1.07

Suppose 0.0350 g Mg is reacted with 10.00 mL of 6 M HCl to produce aqueous magnesium chloride and hydrogen gas. Mg(s)+2HCl(aq)→MgCl2(aq)+H2(g)Mg(s)+2HCl(aq)→MgClX2(aq)+HX2(g) What is the limiting reactant in this reaction? Select one: 1. Hydrochloric acid 2. Magnesium metal 3. Hydrogen gas 4. Magnesium chloride

2. Magnesium metal

Which statements are true concerning a substance with a high specific heat? Select one or more: 1. The substance easily gets hot when heat is applied. 2. The substance cools down slowly after heating. 3. An example substance is aluminum metal. 4. An example substance is water.

2. The substance cools down slowly after heating. 4. An example substance is water.

The temperature of a room is 22.5 °C. What is this temperature expressed in Kelvin (K)?

295.65 K

Calculate the mass percent of a vinegar solution with a total mass of 95.03 g that contains 2.93 g of acetic acid. Type answer:

3.08%

To convert between units, you need to know the relationship between units. For example, one mile equals 5280 feet. This relationship can now be used as a conversion factor, set up as required by the question. For each conversion, choose the correct arrangement of the conversion factor and complete the calculation. 1. Convert 7860 feet to miles 7860 feet x ( A / B ) 2. Convert 0.565 miles to feet 0.565 miles x ( C / D ) 0.565 miles=

A: 1 mile B: 5280 feet C: 5280 feet D: 1 mile 0.565 miles= 2983 feet

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: Pull the pin. A: Aim the nozzle at the base of the fire. S: Squeeze the lever slowly. S: Sweep the spray from side to side over the fire.

Identify the common indicators that a chemical reaction has occurred. Select one or more:

Precipitate being formed Bubbles being produced A color change A change in temperature

How should spill cleaning materials be discarded? Select one:

Seal in a labeled plastic bag, then place in the solid waste container.

The liquid dispensed from a burette is called

Titrant

What is the purpose of stirring a solution while it is being heated? Select one:

To help evenly distribute heat throughout the solution

What is the endpoint of a titration?

When the amount of acid and base are equal.

When should you start a new chemical waste container in the lab? Select one:

When the contents of the current container are a couple inches below the brim of the container

At the freezing point, the liquid form of a substance __________ the solid form of the substance.

is in equilibrium with

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

standard solution

The indicator phenolphthalein is added to the

Analyte

Using the letters on the image, identify each component of the liquid waste set-up.

A Funnel B Primary container C Waste label D Secondary container

Using the letters on the image, identify the significance of each section on the NFPA diamond.

A Health B Flammability C Reactivity D Special Hazards

Hydrochloric acid and sodium hydroxide react to form

NaCl(aq) + H2O(l)

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

Neutralization

Before running a titration, you calculate the expected endpoint. However, when performing the experiment, you pass the expected endpoint with no visible color change. What is the most likely problem with the titration set-up? Select one:

There is not enough indicator in the analyte.

Suppose you are working with a NaOH stock solution but you need a solution with a lower concentration for your experiment. Calculate the volume (in mL) of the 1.205 M stock NaOH solution needed to prepare 250.0 mL of 0.1157 M dilute NaOH solution.

24.00

When using the Tare function on a balance, start by __1___. Then, __2__ to cancel out that mass. Finally, __3__ and record the mass of your sample.

1. placing the glassware on the balance 2. press the Tare/Zero button 3. add your sample to the glassware

Knowing that one day is 24 hours, how many days is 91.1 hours?

3.80

How can you improve your ability to see the indicator color change at the endpoint of a titration? Select one:

Place a piece of white paper under the analyte flask throughout the titration.

What color is phenolphthalein when the solution is acidic?

Colorless

When using the spectroscope to view the spectra of the discharge lamps, what observations are recorded? Select one:

The scale positions and colors of all bands

Suppose you are titrating vinegar, which is an acetic acid solution of unknown strength, with a sodium hydroxide solution according to the equation HC2H3O2+NaOH⟶H2O+NaC2H3O2HCX2HX3OX2+NaOH⟶HX2O+NaCX2HX3OX2 If you require 33.06 mL of 0.1233 M NaOHNaOH solution to titrate 10.0 mL of HC2H3O2HCX2HX3OX2 solution, what is the molar concentration of acetic acid in the vinegar? Type answer:

.408 M

What is the value of the gas constant, R, in units of L⋅atm/mol⋅K ? Report the value with at least three significant figures.

0.0821

How many liters is 83.5 mL?

0.0835

If 0.98 g of an unknown was dissolved in 10.30 g of solvent and the resulting solution has a molality of 0.45 m, what is the molar mass of the unknown?

211 g/mol

What mass, in grams, of NaCl needs to be added to 2.3 kg of water in order to create a solution with a freezing point of -6.1 °C? The freezing point depression constant of water is 1.86 ºC/m. Type answer:

220

Suppose you are titrating an acid of unknown concentration with a standardized base. At the beginning of the titration, you read the base titrant volume as 1.02 mL. After running the titration and reaching the endpoint, you read the base titrant volume as 25.39 mL. What volume, in mL, of base was required for the titration?

24.37 mL

What occurs in endothermic reactions? Select one: Heat energy is released. Water is produced. Heat energy is absorbed. Oxygen is produced.

Heat energy is absorbed.

Between flame tests, the nichrome wire is cleaned. What color should appear when a properly cleaned nichrome wire is introduced into the flame? Select one:

Light or faint yellow

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

Your lab partner

If you drop or break glassware in lab, first ___1___. Then, ___2___. Finally, place all that material into the ___3___.

1. get thick gloves or dustpan 2. carefully collect all the broken glassware 3. broken glass container

What is the correct reading of the temperature in the pictured thermometer? Make sure to report your reading with the appropriate significant figures.

44.4 C

Suppose you mix 100.0 g of water at 22.4 oC with 75.0 g of water at 76.4 oC. What will be the final temperature of the mixed water, in oC? Type answer:

45.5

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

Before handling any glassware or chemicals for the experiment

A 7.298 g sample of copper reacts with oxygen, forming a copper oxide. The final mass of the copper oxide is 8.217 g. What is the formula of the copper oxide?

Cu2O

Consider the trendline on a graph of Mass vs. Volume of a solid or a liquid. What information can be obtained about the substance from the slope of this line? Select one:

Density

When exothermic reactions occur, ______________. Select one: Oxygen is produced. Heat energy is released. Water is produced. Heat energy is absorbed.

Heat energy is released.

Which procedure cannot be performed on a hot plate, requiring a Bunsen burner instead? Select one:

Heating a crucible to remove water from a hydrate

Which species is responsible for the blue color that appears during the iodine clock reaction? Starch-triiodide complex Thiosulfate ion Iodide ion Hydrochloric acid

Starch-triiodide complex

What is the freezing point (in degrees Celcius) of 4.85 kg of water if it contains 172.8 g of CaBr2? The freezing point depression constant for water is 1.86 oC/m and the molar mass of CaBr2 is 199.89 g/mol.

-.995

What are the best practices for safely handling waste in the lab? Select one or more:

-Always wear appropriate Personal Protective Equipment. -Check labels or instructions before any disposal.

Identify the types of information that are necessary to communicate with emergency responders. Select one or more:

-Any chemicals involved in an incident -How the incident happened -Any other hazards present in the lab

What parts are present in every chemical equation? Select one or more:

-At least one reactant -At least one product -An arrow

How should students prepare to use chemicals in the lab? Select one or more:

-Become familiar with the chemicals to be used, including exposure or spill hazards. -Locate the spill kits and understand how they are used.

What should you do after finishing work with a reagent bottle? Select one or more:

-Close the bottle. -Return the bottle to its proper storage location.

When using a properly stabilized balance, how should you ensure that you get the most accurate mass reading possible? Select one or more:

-Close the side shields on the balance during reading. -Measure the mass of the sample at room temperature.

In the reaction of magnesium metal with hydrochloric acid, how do you determine when the magnesium metal has reacted completely? Select one or more:

-Gas bubbles are no longer produced. -The magnesium metal is gone.

What information is necessary to review in order to be considered familiar with the Safety Data Sheet (SDS) of a substance? Select one or more:

-Identification and description of substance -Hazard warnings -Personal protection and first aid recommendations -Handling, storage, and reactivity information

Identify the precautions to take with exits in the lab. Select one or more:

-Locate the exits prior to the start of lab. -Do not block a door with an EXIT sign.

Which signs are typically posted in areas of active lab work? Select one or more:

-Locate the exits prior to the start of lab. -Do not block a door with an EXIT sign.

What information is needed in order to be prepared for an emergency? Select one or more:

-Location of all exits -Contact information for emergency personnel -Location of lab phone and first aid kit -Understanding of where to go should an emergency occur

Which signs are typically posted in areas of active lab work? Select one or more:

-Personal protective equipment (PPE) sign -Sign prohibiting food and drink -Safety equipment signs -Chemical storage signs

What should you do every time before you leave the lab? Select one or more:

-Remove your gloves. -Wash your hands. -Remove your lab coat, if you are wearing one.

Determine which items of personal protective equipment (PPE) you will likely use in a general chemistry lab. Select one or more:

-Safety googles -Lab Coat -Gloves

Suppose you are titrating a sulfuric acid solution of unknown concentration with a sodium hydroxide solution according to the equation H2SO4+2NaOH⟶2H2O+Na2SO4HX2SOX4+2NaOH⟶2HX2O+NaX2SOX4 If you require 30.40 mL of 0.814 M NaOHNaOH solution to titrate 221.0 mL of H2SO4HX2SOX4 solution, what is the concentration of the H2SO4HX2SOX4 solution? Type answer:

.0560

How many grams of KOHKOH are needed to neutralize 13.7 mL of 0.14 M HClHCl in stomach acid? Type answer:

.11 g

Glucose (molar mass=180.16 g/mol) is a simple, soluble sugar. Glucose solutions are used to treat patients with low blood sugar. Suppose you prepare a glucose solution using the described procedure. Step 1: Dissolve 203.6 g of glucose in enough water to make 500.0 mL of solution. Step 2: Transfer 24.5 mL of the solution to a new flask and add enough water to make 250.0 mL of dilute solution. What is the concentration (in M) of the glucose solution at the end of the procedure?

.222

How many moles of H2 can be formed if a 3.24 g sample of Mg reacts with excess HCl?

0.133 mol H2

Calculate the moles of ammonia present in a 2.860 g sample if the molar mass of ammonia is 17.030 g/mol. Type answer:

0.1679

If the freezing point depression for a solution is 2.5°C and Kf = 4.5°C/m, what is the molality of the solution?

0.56 m

Refer to the periodic table to find the correct molar mass for each element and compound. 1. CH4CHX4 2. OO 3. SS 4. O2OX2 5. ClCl 6. C2H6CX2HX6

1. 16.042 g/mol 2. 15.999 g/mol 3. 32.059 g/mol 4. 31.998 g/mol 5. 35.446 g/mol 6. 30.067 g/mol

Choose the best graduated cylinder to make each measurement in a single use. 1. 5.75 mL of a sucrose solution 2. 36 mL of water 3. 18.5 mL of a NaCl solution

1. A 10 mL graduated cylinder with markings every 0.1 mL 36 mL of water 2. A 50 mL graduated cylinder with markings every 10 mL 3. A 25 mL graduated cylinder with markings every 1 mL

Identify which balance was used to make each mass reading. 1. 6.539 g 2. 0.90 g 3. 1.230 g 4. 5.43 g 5. 4.0000 g

1. A balance with ±0.001 g tolerance 2. A balance with ±0.01 g tolerance 3. A balance with ±0.001 g tolerance 4. A balance with ±0.01 g tolerance 5. A balance with ±0.0001 g tolerance

Determine each type of reaction. 1.) CO(g)+2H2(g)⟶CH3OH(l)CO(g)+2HX2(g)⟶CHX3OH(l) 2.)NH4NO3(s)⟶N2O(g)+2H2O(l)NHX4NOX3(s)⟶NX2O(g)+2HX2O(l) 3.)2C2H2(g)+5O2(g)⟶4CO2(g)+2H2O(l)2CX2HX2(g)+5OX2(g)⟶4COX2(g)+2HX2O(l) 4.)2Fe(s)+6HCl(aq)⟶2FeCl3(aq)+3H2(g)2Fe(s)+6HCl(aq)⟶2FeClX3(aq)+3HX2(g) 5.)CaCl2(aq)+Na2CO3(aq)⟶2NaCl(aq)+CaCO3(s)CaClX2(aq)+NaX2COX3(aq)⟶2NaCl(aq)+CaCOX3(s)

1. Combination 2. Decomposition 3. Combustion 4. Single replacement 5. Double replacement

For each reaction, determine whether it is an example of combustion or not. 1. C+O2⟶CO2C+OX2⟶COX2 2. 2NO+O2⟶2NO22NO+OX2⟶2NOX2 3. 2C2H6+7O2⟶4CO2+6H2O2CX2HX6+7OX2⟶4COX2+6HX2O 4. 2N2O5⟶4NO2+O22NX2OX5⟶4NOX2+OX2 5. CO2+4H2⟶CH4+2H2OCOX2+4HX2⟶CHX4+2HX2O

1. Combustion 2. Combustion 3. Combustion 4. Not combustion 5. Not combustion

Determine whether the stopcock should be completely open, partially open, or completely closed for each activity involved with titration. 1.Filling the burette with titrant 2.Conditioning the burette with titrant 3.Close to the calculated equivalence point of a titration 4.At the beginning of a titration

1. Completely closed 2. Completely closed 3. Partially open 4. Completely open

Determine what type of reaction each unbalanced chemical equation represents. 1. NaHCO3⟶CO2+NaOHNaHCOX3⟶COX2+NaOH 2. CaCl2+Na3PO4⟶Ca3(PO4)2+NaClCaClX2+NaX3POX4⟶CaX3(POX4)X2+NaCl 3. AgNO3+NaCl⟶NaNO3+AgClAgNOX3+NaCl⟶NaNOX3+AgCl 4. Mg+H2SO4⟶MgSO4+H2Mg+HX2SOX4⟶MgSOX4+HX2

1. Decomposition 2. Double replacement 3. Double replacement 4. Single replacement

Determine whether or not each chemical formula is an empirical formula. 1. NaMnO4 2. CaCO3 3. K2C2O4 4. Ba3(PO4)2 5. C6H12O6

1. Empirical formula 2. Empirical formula 3. Not an empirical formula 4. Empirical formula 5. Not an empirical formula

Determine whether each described process is endothermic or exothermic. 1. Ice melts into liquid water 2. Acid and base are mixed, making test tube feel hot 3. Wood burns in a fireplace 4. A process with a calculated negative q 5. Solid dissolves into solution, making ice pack feel cold 6. A process with a calculated positive q

1. Endothermic 2. Exothermic 3. Exothermic 4. Exothermic 5. Endothermic 6. Endothermic

Read each statement regarding food and beverages in the lab and determine if each is true or false. 1. Chewing gum is okay in the lab as long as you don't blow bubbles 2. Food items should not be brought into the lab. 3. Tobacco products of all kinds are prohibited in lab. 4. Beverages are allowed in lab as long as they are in containers with lids.

1. False 2. True 3. True 4. False

A sample of gas is subject to changes in conditions. Predict the effect of each change. 1. The pressure and the temperature are both decreased by 50%. What will happen to the volume? 2. The pressure and volume are increased. What will happen to the temperature? 3. The volume and temperature remain constant, while some of the gas is let out of the container. What will happen to the pressure? 4. The pressure is kept constant, while the temperature is decreased. What will happen to the volume?

1. It will stay the same. 2. It will increase. 3. It will decrease. 4. It will decrease.

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 picking up a buret, an unknown solution left by a previous solution drips onto your hand. 3. While checking on a stirring solution, the solution splashes up towards your face. 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. Gloves 3. Googles 4. Closed-toe shoes

Determine whether each equation is balanced as written. 1. C6H12O6+O2⟶6CO2+6H2OCX6HX12OX6+OX2⟶6COX2+6HX2O 2. H2+O2⟶2H2OHX2+OX2⟶2HX2O 3. 2HCl+Mg(OH)2⟶2H2O+MgCl22HCl+Mg(OH)X2⟶2HX2O+MgClX2 4. CH4+O2⟶CO2+H2OCHX4+OX2⟶COX2+HX2O 5. Mg+H2SO4⟶MgSO4+H2Mg+HX2SOX4⟶MgSOX4+HX2 6. AgNO3+NaCl⟶NaNO3+AgClAgNOX3+NaCl⟶NaNOX3+AgCl

1. Not balanced 2. Not balanced 3. Balanced 4. Not balanced 5. Balanced 6. Balanced

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

1. Physical change 2. Physical change 3. Chemical change 4. Chemical change 5. Chemical change 6. Chemical change

Determine the best way to deal with each of the following items that may dangle into the way during lab work. 1. loose bracelets 2. flowy sleeves 3. long hair 4. long earrings 5. long necklaces

1. Remove 2. Tie back or secure 3. Tie back or secure 4. Remove 5. Remove

Determine where to dispose of each type of waste. 1. Syringe tips 2. broken flask 3. titrant solution 4. unused solid reagent

1. Sharps container 2. Box lined with puncture resistant bag 3. Nalgene bottle with cap 4. Solid waste container

Identify the meaning of each chemical equation symbol. 1. ⟶ 2. (l) 3. + 4. Δ→

1. Substances on the reactants side are converted to the substances on the products side. 2. The substance is a liquid. 3. There are two separate substances on either the products side or the reactants side 4. Heat is applied.

Review the Safety Data Sheet (SDS) for potassium hydroxide, then identify the best course of action for each type of chemical exposure. 1. In case of skin contact 2. If inhaled 3. In case of eye contact 4. If swallowed

1. Take off any contaminated clothing and rinse thoroughly 2. Move person to fresh air. 3. Rinse with water for 15 minutes. 4. Rinse mouth with water.

In the reaction of magnesium metal with hydrochloric acid, how do you determine when the magnesium metal has reacted completely? Select one or more: 1. The magnesium metal is gone. 2. All of the water has evaporated. 3. The dilute HCl is gone. 4. Gas bubbles are no longer produced.

1. The magnesium metal is gone. 4. Gas bubbles are no longer produced.

Suppose you mix two solutions in a test tube and the test tube becomes hot. This is ___1___ because __2__.

1. a sign of a chemical reaction 2. chemical changes can release heat.

When an alarm sounds in the laboratory, it is important to respond ___1___ and remain ___2___ Listen for any other instructions, turn off any ___3___ in use, and be prepared to leave immediately.

1. calmly 2. quiet 3. equipment

To find the order of a reaction with respect to one reactant, you will monitor the ___1____ as the ___2____ of ____3____ is changed.

1. change in rate of reaction 2. concentration 3. the reactant

Determine whether each of the examples represents a colligative property or a non-colligative property. 1. vapor pressure lowering 2. density 3. freezing point depression 4. boiling point elevation 5. color

1. colligative 2. non-colligative 3. colligative 4. colligative 5. non-colligative

Suppose you are given the mass of each element in a compound sample. To calculate the empirical formula, start by __1__ using __2__. Then, __3__ by __4__.

1. converting the mass of each element to moles 2. each element's molar mass 3. calculate the ratio between the elements 4. dividing the moles of each element by the smallest number of moles present

A hydrometer is a tool used to measure the __1__ of a liquid relative to that of __2__.

1. density 2. water

When cleaning a buret, begin by coating the inside with ___1___. Empty most of it out, then drain the rest by ___2___. Rinse with ___3___, then hang upside-down on a buret rack.

1. detergent solution 2. opening the stopcock 3. deionized water

Identify the safety equipment designed to deal with each emergency listed. 1. cuts or minor burns 2. chemicals in eyes 3. fire on a person 4. chemicals on clothes 5. large fire on the benchtop

1. first aid kit 2. eyewash station 3. fire blanket 4. safety shower 5. fire extinguisher

Concentration data is commonly monitored during a reaction to determine the order with respect to a reactant. Consider the types of observations listed, and determine which order is likely for that reactant. Assume all other factors are held constant. 1. The reaction rate increases in direct proportion to the concentration of the reactant in solution. 2. An increase in the concentration of the reactant in solution causes the reaction rate to increase exponentially. 3. The reaction rate is constant regardless of the amount of reactant in solution.

1. first order 2. second order 3. zero order

Changing gloves often will minimize the spread of chemicals. To properly remove gloves, first, ___1____, and then, ___2___ . Then insert ___3___ between the interior edge of the second glove and the skin, and remove the second glove.

1. grasp the exterior of one glove with a gloved hand 2. peel off the first glove 3. a bare finger

A calorimeter measures the ___1___ involved in reactions or other processes by measuring the ___2___ change of the materials ___3___ the process. The calorimeter is ___4___ to prevent transfer of heat to outside the device.

1. heat 2. temperature change 3. surrounding 4. insulated

A balloon is inflated outside on a cool morning. As the temperature rises, reaching its peak in the afternoon, the volume of the balloon will ___1___. As the temperature cools down again in the evening, the volume of the balloon will ___2___.

1. increase 2. decrease

1. What the relationship between frequency and wavelength of electromagnetic radiation? 2. If you double the wavelength of light, what happens to the energy of the photons? 3. Which has a greater energy, long wavelength red light or short wavelength UV light?

1. inverse 2. It will decrease by one-half 3. UV light

The relationship between pressure and volume of a gas is ___1___ so that as volume decreases, pressure ___2___.

1. inverse 2. increases

When a vinegar and oil salad dressing separates into two layers, the oil floats on top of the vinegar. The density of the oil __1__ the density of the vinegar.

1. is less than

Magnesium reacts with oxygen in the air when __1__. Unlike other reactions, you should not __2__ this reaction.

1. lit with a Bunsen burner 2. look directly at

The freezing point of a 1 m solution of FeCl3 is expected to be ___1___that of a 1 m solution of glucose. This is because FeCl3 ___2___ and ___3___ compared with glucose.

1. lower than 2. is an electrolyte 3. has a larger van't Hoff factor

Determine the relative order of the metric prefixes of kilo-, micro-, centi-, and milli-. For the same base unit, ___1___ is less than ___2___, which is less than ___3___, which is less than __4__.

1. micro- 2. milli- 3. centi- 4. kilo-

When using the method of initial rates for a kinetic study, the reaction is performed ___1___. One reactant concentration is kept constant, and the other ___2___.

1. several times 2. varies

Move to the safety shower if you spill hazardous chemicals on your ____1____. Stand under the shower and __2__ the lever. Remove clothing and continue flushing the area for ___3____.

1. skin or clothing 2. Pull 3. 15 minutes

When heating a solution to boiling on a hot plate, start by ___1___. Then, turn the heat to ___2___. If necessary, ___3___ after waiting about ten minutes without seeing boiling.

1. starting and stabilizing the stir function 2. a medium heat setting to start 3. turn up the heat setting

In the context of a balanced chemical equation, a __1__ is a number to the lower right of an element or ion within formula and it applies to __2__. A __3__ is a number to the left of a formula and it applies to __4__. Only __5__ should be added or changed when balancing chemical equations.

1. subscript 2. only the part of the formula it follows 3. coefficient 4. the entire formula it precedes 5. coefficients

Mass is conserved in an experiment if the __1__ of the individual component masses equals the mass of the __2__.

1. sum 2. mixture of the components

When filling a burette for a titration, adjust the burette so that __1___ preferably over a sink. Then, __2__to add the titrant into the burette. The titrant should be filled __3__.

1. the opening is near or below eye level 2. use a funnel 3. almost to the zero mark

In the Kinetics of an Iodine Clock Reaction procedure, the initial rate is calculated by multiplying the initial concentration of ___1_____ by half, and dividing by the elapsed time as measured with a ____2____

1. the thiosulfate ion 2. a stopwatch

To measure out a volume of liquid, start by choosing the appropriate graduated cylinder and moving the bumper to the __1__ of the graduated cylinder to protect it from breakage. Then, pour the liquid into the graduated cylinder until the __2__ of the meniscus aligns with the desired volume marking when you look at the graduated cylinder from __3__.

1. top 2. bottom 3. eye level

Determine where each type of cleaning solution should be discarded after use. 1. Solvent used to rinse chemicals out of a beaker 2. Acid solution used to clean a crucible 3. Water used to rinse detergent out of a flask

1. waste container 2. waste container 3. sink

Suppose you are titrating an acid solution with a base solution of known concentration. To calculate the concentration of the acid solution, use three steps. 1. Use the ___1___of base __2__the endpoint and the known concentration of the base solution to find the __3__of base used. 2. Use the _______to find the moles of acid from the moles of base. 3. Divide the moles of acid by the volume of ________the titration to find the concentration of acid.

1.) 1.delivered volume 2. to reach 3. moles 2.) molar ratio 3.) acid solution before

What is the heat, q , in joules transferred by a chemical reaction to the reservoir of a calorimeter containing 85 g of dilute aqueous solution (c=4.184 J/g⋅ºCc=4.184 J/g·ºC) if the reaction causes the temperature of the reservoir to rise from 22.0 ºC 2 to 25.0 ºC? Type answer:

1067

Suppose that you add 25.0 g of an unknown molecular compound to 0.250 kg of benzene, which has a KfKf of 5.12oC/m. With the added solute, you find that there is a freezing point depression of 2.75oC compared to pure benzene. What is the molar mass (in g/mol) of the unknown compound? Type answer:

186

What is the general definition of heat capacity? Select one: 1. The ability of a reaction to consume or give off heat based on the mass of its reactants 2. The energy that exchanges with the surroundings due to a difference in temperature 3. The change in heat required to change the temperature of something by one degree Celsius 4. The determination of whether heat is consumed or given off from one gram of a substance

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

Visible light falls into wavelength ranges of 400-700 nm, for which 1 m=1×109 nm The energy and wavelength of light are related by the equationE=hcλ where E is energy in Joules, h is Planck's constant (6.626×10−34 J-s), c is the speed of light (2.998×108 m/s), and λ is the wavelength in m. If a visible light photon has a wavelength of 656.0 nm, what is the energy of the photon (in J)? Type answer:

3.028 x 10^-19

In the Ideal Gas Law lab, how is the temperature of the hydrogen gas determined? Select one: 1. The pressure of the gas is determined, which will allow you to calculate the temperature. 2. A thermometer is inserted into the eudiometer, measuring the hydrogen gas directly. 3. The volume of the gas is determined, which will allow you to calculate the temperature. 4. The temperature of the water bath is measured after the reaction, which is assumed to be the same temperature as the gas.

4. The temperature of the water bath is measured after the reaction, which is assumed to be the same temperature as the gas.

A student performed a density experiment in triplicate and recorded the data shown. Calculate the average density (in g/mL) for this experiment. Density Trial 1 5.08g/mL Trial 2 4.92g/mL Trial 3 5.13g/mL

5.04 g/mL

Suppose you are measuring the mass of a solid sample on a balance using a weigh boat. You record the data in a table. Mass of weigh boat2.288 g Mass of weigh boat and sample 9.461 g What is the mass of the solid sample (in g)?

7.173 grams

The H2 gas produced in a chemical reaction is collected through water in a eudiometer. If the pressure in the eudiometer is 760.0 torr and the vapor pressure of water under the experimental conditions is 20.9 torr, what is the pressure (torr) of the H2 gas?

739.1 torr

Knowing that one day is 24 hours and one hour is 60 minutes, how many minutes are in 5.2 days?

7500

Identify correctly formatted scientific notation. Select one or more:

8×10^6 4.532×10^−9 6.1×10^12

What information does not need to be included a chemical waste label? Select one:

A description of the experiment the chemicals were used for

What appearance of an acidic analyte solution containing phenolphthalein indicates the endpoint of titration with a basic solution? Select one:

A persistent pale pink color throughout the solution.

Potassium hydrogen phthalate is

A primary standard

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

Which compounds could be represented by the empirical formula CH2CHX2? Select one or more:

C3H6 C2H4 C8H16

Where should glassware be stored after it is cleaned? Select one:

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

Which warning about iodine is accurate? Select one: Iodine is highly flammable. Iodine reacts dangerously with water. Iodine can stain the body and other surfaces. Iodine is a biohazard.

Iodine can stain the body and other surfaces.

Identify the color flame each element that produces in a flame test. K Na

K = fleeting lavender flame Na = brilliant yellow flame

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

Raise

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

Which steps are necessary for cleaning a spill involving broken glass? Select one or more:

Stop the spread of the spill. Soak up any spilled liquid with absorbent material. Pick up large pieces of glass with gloved hands.

Read the Safety Data Sheet (SDS) (click the SDS icon below) of hydrogen peroxide to identify the type of eye protection recommended when handling this substance. https://storage.googleapis.com/lf-assets/quiz/docs/sds-h2o2.pdf

Tightly fitting safety goggles

What should you do if your Bunsen burner does not light after a few tries with the striker? Select one:

Turn off the gas cock for 10 seconds before trying again

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.

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

Determine when you should remove your goggles in the lab room. Select one:

When everyone in the room is done handling any chemicals or glassware

Predict the products of hydrochloric acid reacting with zinc metal. Select one or more:

ZnCl2 H2

Suppose you are studying the kinetics of the reaction between the peroxydisulfate ion and iodide ion. You perform the reaction multiple times with different starting concentrations and measure the initial rate for each, resulting in this table. Experiment [S2O82-] (M) [I-] (M) Initial Rate (M/s) 1 0.27 0.38 2.05 2 0.40 0.38 3.06 3 0.40 0.22 1.76 Based on the data, choose the correct exponents to complete the rate law. rate=k[S2O82-]^a [I-]^b a= ______ b=______

a= 1 b=1

Consider the Bohr model of the atom. Which transition would correspond to the highest frequency of light emitted? Select one:

n=4 to n=1

Suppose an air bubble is trapped in the eudiometer before starting the experiment. After the experiment is finished, the resulting value of R would be

too large

Suppose you are studying the kinetics of the reaction between nitrogen monoxide and hydrogen gas. You perform the reaction multiple times with different starting concentrations and measure the initial rate for each, resulting in this table. Experiment [NO] (M) [H2] (M) Initial Rate (M/s) 1 0.0050 0.0020 1.25 x 10^-5 2 0.010 0.0020 5.00 x 10^-5 3 0.0050 0.0040 2.50 x 10^-5 Based on the data, choose the correct exponents to complete the rate law. rate=k[NO]^x [H2]^y x=_____ y=______

x = 2 y = 1