Prelab 9: Due at the start of Lab 9

Name:________________________   Lab day________

Show all work, even simple addition and include units and sig figs where applicable.

1. To make solutions for the Beer's Law graph, you are provided with a 49.9 ppm Allura Red solution. You pipet 10.00 mL of this solution into a test tube and then you pipet 20.00 mL of deionized water into the same tube. After stirring, what is the Allura Red concentration of the new solution you've made? This is Allura Red Dilution 1.

V _final =

C _final =

2. If you pipet 10.00 mL of the solution you made in Question #1 into a test tube and then you pipet 10.00 mL of deionized water into the same tube. After stirring, what is the Allura Red concentration of the new solution you've made? Hint: use at least 2 extra significant figures from your answer to question #1 to calculate this answer to avoid rounding errors. Your final answer will be reported to the correct number of sf. This is Allura Red Dilution 2.

V _final =

C _final =

3. If you pipet 10.00 mL of the solution you made in Question #2 into a test tube and then you pipet 10.00 mL of deionized water into the same tube. After stirring, what is the Allura Red concentration of the new solution you've made? Hint: use at least 2 extra significant figures from your answer to question #2 to calculate this answer to avoid rounding errors. Your final answer will be reported to the correct number of sf. This is Allura Red Dilution 3.

V _final =

C _final =

4. To make solutions for the Density of KCl graph, you are provided with a 12.0% KCl solution. You pipet 30.00 mL of this solution into a test tube and then you pipet 10.00 mL of deionized water into the same tube. After stirring, what is the KCl concentration of the new solution you've made? This is KCl 2 solution.

V _final =

C _final =

5. To make solutions for the Density of KCl graph, you are provided with a 12.0% KCl solution. You pipet 20.00 mL of this solution into a test tube and then you pipet 20.00 mL of deionized water into the same tube. After stirring, what is the KCl concentration of the new solution you've made? This is KCl 3 solution.

V _final =

C _final =

6. To make solutions for the Density of KCl graph, you are provided with a 12.0% KCl solution. You pipet 10.00 mL of this solution into a test tube and then you pipet 30.00 mL of deionized water into the same tube. After stirring, what is the KCl concentration of the new solution you've made? This is KCl 4 solution.

V _final =

C _final =

7. Using the equation of the line in the graph below, calculate the concentration of Allura Red (in ppm) of the Buckeye-ade sample which has an absorbance of 0.415 a.u.

y= 0.0494x

R^2= 0.9861

When the following reaction was carried out, the student obtained 5 g of CO₂. If the student started with 10 g of CH₄ and 10 g of O₂, what is the % yield of the reaction?

CH₄ + 2 O₂ --> CO₂ + 2 H₂O

Calculate the number of milliliters of 0.469 M Ba(OH)₂ required to precipitate all of the Al³⁺ ions in 179 mL of 0.565 M AlCl₃ solution as Al(OH)₃. The equation for the reaction is:

2AlCl₃(aq) + 3Ba(OH)₂(aq) Al(OH)₃(s) + 3BaCl₂(aq)

When the following reaction was carried out, the student obtained 5 g of CO₂. If the student started with 10 g of CH₄ and 10 g of O₂, what is the % yield of the reaction?

CH₄ + 2 O₂ --> CO₂ + 2 H₂O

can u pls tell me how much it will cost to make 1 g of C₂H₅Br by using this reaction : ethane + Br2 & heat = CH3CH2BR

we have 398 grams of ethane and it costs 226.32 dollars

we have 684 grams of bromine and it costs 65.82 dollars

u can presume that we have a perfiect yeild and pls round the answer to the nearest cent

show all work pls ty

For 200.0 mL of a buffer solution that is 0.2975 M in CH3CH2NH2 and 0.2730 M in CH3CH2NH3Cl, calculate the initial pH and the final pH after adding 0.0100 mol of NaOH(Kb=6.46⋅10−4).

is the pka of a histidine side chain always the same as that of the free amino acid? Why?

how do titration curves differ between non ionizable and ionizable r groups? why?

Biochemistry

1a) A buffer solution is composed of 1.036 g of KH2PO4 and 4.424 g of na2hpo4. ( for dihydrogen phosphate ion is 6.2*10^-8.) What is the pH of the buffer solution?

b) What mass of KH2PO  must be added to decrease the buffer solution pH by 0.10 unit from the value calculated in part a?

Draw a molecular and particulate view of what is happening in the steep part of a general acid-base titration curve.

Please show picture!

A hydrocarbon of unknown structure has the formula C₉H₁₁N. If we hydrogenate the unknown compound over Lindlar catalyst, only 1 equivalent of H₂ is absorbed. If we hydrogenate the unknown compound over a Pd/C catalyst, 4 equivalents of H₂ are absorbed. Using this information, answer the questions below.

a) How many degrees of unsaturation are present in the unknown compound? (Show your work)

What is the lifetime of OH at the sea level, assuming that the following reactions are the principal sinks for OH in the troposphere. Answer in sec to two significant digits.

OH + CO → CO₂ + H (1)

OH + CH₄ → CH₃ + H₂O (2)

The density of air at the sea level is 2.69 ×10¹⁹ molecules cm^-3, the mixing ratios of CO and CH₄ are 80 ppbv and 1700 ppbv, respectively, and the reaction rate is k_CO= 1.5×10^-13 molecules^-1 cm³ s^-1 for (1) and k_CH4= 2.5×10^-15 molecules^-1 cm³ s^-1 for (2).

Provide the IUPAC names of these hydrocarbons.

CH3CH=CHC(insert triple bond)CCH=CHC(insert triple bond)

CH3CH=CHCH2C(insert triple bond)CCH2CH=CHCH3

The rate constants for the reactions of atomic chlorine and of hydroxyl radical with ozone are given by 3 x 10-11 e-250/T and 2 x 10-12 e-940/T, where T is the Kelvin temperature. Calculate the rate constant for ozone destruction by chlorine under conditions in the Antarctic ozone hole, when the temperature is about -80°C and the concentration of atomic chlorine increases by a factor of one hundred to about 4 x 105 molecules cm-3.

Autokinesetic events associated with a single point light source and optical illusions brought on by a lack of a reference horizon are common occurrences on moonless, overcast nights. Describe a documented autokinesetic incident involving nighttime illusions that led to a catastrophic event.

***Part1: Balance the following chemical equation using the lowest possible whole number coefficients. (Enter coefficients of one - blanks will be marked incorrect.)

( )CO2 + ( )H2O →( ) CH4 + ( )O2

( )Co(NO3)3 +( ) (NH4)2S → ( )Co2S3 +( ) NH4NO3

( ) NH3 + ( )O2 → ( )NO + ( )H2O

( ) NaCl + ( )H2SO4 →( ) Na2SO4 + ( )HCl

***Part2 : Consider the complete combustion of 2.91×10^-4 moles of C₆H₁₂O₆ with excess oxygen.

A. Balance the following chemical equation using the lowest possible whole number coefficients. (Enter coefficients of one - blanks will be marked incorrect.)

( ) C₆H₁₂O₆ + ( )O₂  → ( )CO₂ + ( )H₂O

B. How many moles of water are produced in this reaction? [ ]

***Part3 : Determine the mass of carbon dioxide (in g) produced from the complete combustion of 8.34×10^-1 g of C₈H₁₄O with excess oxygen.

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