CHM 161

If you drop or break glassware in lab. first___. Then, ___. Finally, place all that material into the ___.

- get thick gloves or dustpan -carefully collect all the broken glassware -broken glass container

% difference formula

(I1st lab result - 2nd lab resultI/average of lab results) x100

Identify each category of substance as soluble or insoluble in water. Most carbonate and phosphate salts ___ Most halide (Br-, Cl-, and I-) salts___ Most silver salts___ Salts of Group 1 elements___ Most nitrate salts___

Insoluble Soluble Insoluble Soluble Soluble

copper

Cu(NO3)2

Spectra

White light broken into colors

Dilute to volume

add water

What is the name of the compound with the formula of AlCl3?

aluminum chloride

When preparing a dilute solution from a more concentrated one, be sure to carry out the necessary calculations___ getting started with any glassware. Use a ___ to transfer an aliquot of the concentrated solution into a clean, dry volumetric flask. Add a small amount of solvent, swirl the flask, then fill to the___. Mix the solution and label the flask.

before volumetric pipet volume marking

When an alarm sounds in the laboratory, it is important to respond___ and remain___. Listen for any other instructions, turn off any___ in use, and be prepared to leave immediately.

calmly, quiet, equipment

anions?

chloride, hydroxide, nitrate, carbonate, sulfate

quantitative transfer

complete transfer

% error equation

experimental-accepted/accepted x 100

magnesium

Mg(NO3)2

carbonate

Na2CO3

sulfate

Na2SO4

phosphate

Na3PO4

chloride

NaCl

nitrate

NaNO3

hydroxide

NaOH

qreaction =

Qg * mburned (Qg is constant)

When you are done using most glassware in the lab, what should you do?

Return the glassware to the appropriate location to dry. Dispose of any chemicals in the proper waste container. Clean the glassware with a detergent solution.

Identify the true statements describing the use of the fuel burners in the Thermochemistry experiment.

The cap should be left on the fuel burner whenever it is not in use. The burner wick should be about a few millimeters above the metal stem. The burner should be lit for 20 seconds after any change before proceeding.

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 purpose of stirring a solution while it is being heated?

To help evenly distribute heat throughout the solution

Burning 1.23 g1.23 g of a fuel causes the water in a calorimeter to increase by 11.0∘C11.0∘C. If the calorimeter has a heat capacity of 3.09 kJ/∘C3.09 kJ/∘C, what is the energy density of the fuel (in kJ/g)?

-27.63 The energy density of the fuel is also known as the enthalpy of combustion, Qg�g . The energy density is related to the heat of the reaction of burning the fuel, qreaction�reaction , and the mass of fuel burned, mburned�burned , according to the equation qreaction=Qg×mburned�reaction=�g×�burned The mass of fuel burned but the heat of the reaction needs to be calculated from the heat capacity of the calorimeter, Ccalorimeter�calorimeter , and the temperature change of the calorimeter set-up, ΔTΔ� , by the equation qreaction=−Ccalorimeter×ΔT�reaction=−�calorimeter×Δ� Using the given change in temperature and the heat capacity of the calorimeter, the heat of reaction is qreaction=−3.09 kJ/∘C×11.0∘C�reaction=−3.09 kJ/∘C×11.0∘C Then, use the calculated heat of reaction and the given mass of fuel burned in the first equation to calculate the fuel's energy density, or enthalpy of combustion. Qg=qreaction/1.23 g

qreaction =

-Ccalorimeter *Δ T

Write the chemical formula of the precipitates that will form from the chemical clue experiment AgCl(s) name of precipitate? write equations in molecular, ionic, and net ionic forms

-silver chloride -AgNO3(aq)+NaCl-(aq)->AgCl(s)+NaNO3(aq) -Ag++NO3-+Na++Cl-->AgCl(s)+Na++NO3- -Ag+(aq)+Cl-(aq)->AgCl(s)

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 270.7 g of glucose in enough water to make 500.0 mL of solution. Step 2: Transfer 23.2 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?

0.279 -Start the calculation by finding the concentration of the solution in Step 1. -Convert the given mass in grams to moles using the molar mass. -moles of glucose=270.7 g glucose×1 mol sugar180.16 g sugarmoles of glucose=270.7 g glucose×1 mol sugar/180.16 g sugar -Then, convert the volume of solution from milliliters to liters. -volume in liters=500.0 mL solution×1 L1000 mLvolume in liters=500.0 mL solution×1 L/1000 mL -Finally, divide the moles of sugar by the volume of solution in liters to calculate the molarity of the solution in Step 1. -For Step 2, use the dilution equation where the volume of stock used is 23.2 mL and the concentration of stock is from the first step. The dilute volume is 250.0 mL. -M1V1=M2V2 -Assuming solution 1 is the stock solution and solution 2 is the dilute solution, you can fill in the equation and solve for M2. -(molarity from Step 1)(23.2 mL)=(M2)(250.0 mL)(molarity from Step 1)(23.2 mL)=(M2)(250.0 mL) Rearrange this equation to solve for M2. M2=(molarity from Step 1)(23.2 mL)250.0 mLM2=(molarity from Step 1)(23.2 mL)/250.0 mL

Suppose you need to calibrate a calorimeter. You burn 0.751 g0.751 g of a fuel with an enthalpy of combustion of −48.7 kJ/g−48.7 kJ/g . If the temperature of water in the calorimeter increases by 14.8∘C14.8∘C during the reaction, what is the heat capacity of the calorimeter in kJ/C°?

2.47 The heat capacity of the calorimeter, Ccalorimeter�calorimeter , is related to the heat of the reaction of burning the fuel, qreaction�reaction , and the temperature change of the calorimeter set-up, ΔTΔ� , by the equation qreaction=−Ccalorimeter×ΔT�reaction=−�calorimeter×Δ� The change in temperature is given but the heat of the reaction needs to be calculated from the mass of fuel burned, mburned�burned , and its enthalpy of combustion, Qg�g , from the equation qreaction=Qg×mburned�reaction=�g×�burned Using the given change in mass and the enthalpy of combustion of the fuel, the heat of reaction is qreaction=−48.7 kJ/g×0.751 g*reaction=−48.7 kJ/g×0.751 g Then, use the calculated heat of reaction and the given change in temperature in the first equation to calculate the calorimeter's heat capacity. Ccalorimeter=−qreaction/14.8∘C

If a photon has a wavelength of 576.6 nm, what is the energy of the photon (in J)?

3.445e-19

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

A hazy or cloudy appearance Solid settling out in the test tube

Filtration

A process that separates materials based on the size of their particles.

silver

AgNO3

•C1 = concentration of stock solution in ppm = mg/L •Volume = 250.0mL = 0.2500L •Cmg/L * VL = mass in mg

Amount in mg of Fe in tablet

calcium

Ca(NO3)2

What is the correct net ionic equation to describe this precipitation reaction? CaCl2(aq)+Na2CO3(aq)⟶2NaCl(aq)+CaCO3(s)

Ca2+(aq)+CO32−(aq)⟶CaCO3(s)

filtrate

liquid that has passed through a filter

cations?

magnesium, calcium, copper, silver

•Qg =

qreaction / mburned

ΔHmol =

qreaction / nburned nburned = moles of fuel burned

-Ccalorimeter =

qreaction / ΔT

Most chemicals can be cleaned up with a general spill kit, but a few chemicals require specialized spill procedures. For each substance listed, determine whether a general spill kit is sufficient or if a specialized spill kit is needed. - hydrofluoric acid-___ -acetone-___ -phosphoric acid-___ -methanol-___ -mercury-___

special general general general special

all common nitrates (NO3) are soluble true or false

true

all common chlorides (Cl) are soluble true or false

true with the exception of Ag+

All common sulfates (SO42-) are soluble true or false

true with the exception of Ca and Ag

All common carbonates (CO32-) and phosphates (PO43-) are insoluble true or false

true with the exception of group 1A ions, NH4+

All common metal hydroxides (OH) are insoluble true or false

true with the exception of larger group 2A(2) ions beginning with Ca

Determine where each type of cleaning solution should be discarded after use. -Solvent used to rinse chemicals out of a beaker___ -Acid solution used to clean a crucible___ -Water used to rinse detergent out of a flask___

waste container waste container sink