1. A sample of methane gas that occupies a volume
of 12.8 L at a temperature of 0 °C and a pressure
of 1 atm contains ________ moles of gas.
2. A mixture of argon and helium gases, in a 9.49 L flask at 39 °C, contains 6.75 grams of argon and 1.61 grams of helium. The partial pressure of helium in the flask is _______ atm and the total pressure in the flask is _______ atm.
In: Chemistry
Calculate the enthalpy of reaction for the following reaction using Hess's Law and the equations provided below.
Target Reaction: Sr(s)+C(graphite)+1 1/2 O2(g) -----> SrCO3(s) H(degrees)=?
C(Graphite)+ O2(g)-----> CO2(g) H(degrees)= -349kJ
Sr(s)+ 1/2 O2(G)-------> SrO(s) H(degrees)= -592kJ
SrO(s)+CO2(g)-------> SrCo3(s) H(degrees)= -234kJ
In: Chemistry
If 25.0 mL of a 0.238M FeO4^2- solution is allowed to react with 55.0 mL of 1.47 M aqueous ammonia, what volume of nitrogen gas can form at 25°C and 1.50 atm?
Volume = mL
In: Chemistry
Preparation of a buffer:
Dissolve in a beaker 27.3 g NaC2H3O2·3H2O in water containing 60 mL
of 1 M HCl (you need to make a 250- mL of 1 M hydrochloric acid
solution in advance by the appropriate dilution of concentrated
HCl) and dilute with the distilled water to 1 L. Invert the bottle
up to 20 times and keep the buffer in a 1 L glass bottle.
*help with dilution of concentrated hcl
In: Chemistry
Werecertainionstypicallyalwayssolubleoralwaysinsoluble?Howcouldyoutell?Includespecificexamples.
In: Chemistry
Describe in your own words how any two types of the following types of chromatography work: adsorption, partition, ion exchange, molecular exclusion, or affinity.
In: Chemistry
What volume, in liters, of O2 measured at 760 torr and 25o C is needed to completely react with 18.47 g of iron to give Fe2O3?
In: Chemistry
Describe the major properties, methods of analysis, and clinical use of:
AFP
CA-125
CEA
Beta-hCG
PSA
In: Chemistry
a. what is the difference between a flourescence excitation spectrum and a fluorescence emission spectrum?. which resembles an absorption spectrum.
b. consider a molecule that can fluoresce from the s1 state and phosphoresce from the t1state. which is emitted at longer wavelength?make a sketch showing absorption fluorescence and phosphorescence on a single spectrum.
In: Chemistry
Azulene is a beautiful blue hydrocarbon consisting of only C and H atoms. If 0.106 g of the compound is burned in oxygen, 0.364 g of CO2 and 0.0596 g of H2O are made. Determine the empirical formula of azulene from this data. [ Hint: First convert the masses of CO2 and H2O to moles, then convert the moles found to moles of C to H. ]
In: Chemistry
Provide a brief introduction/background of the molecule Oseltamivir (Tamiflu) and include a brief description of what the molecule is and how the molecule is used. Discuss how does the structure plays a role in its function and why is the shape of the molecule important to its function?
In: Chemistry
Part 1:
|
Trial |
Initial pH |
Final pH |
Final volume after titration |
Initial Buret Reading |
Total Volume Titrated |
|
#1 |
3.34 pH |
4.35 pH |
47.50 mL |
50 mL |
2.50 mL |
|
#2 |
3.39 pH |
4.20 pH |
47.90 mL |
50 mL |
2.10 mL |
|
#3 |
3.39 pH |
4.40 pH |
47.00 mL |
50 mL |
3.00 mL |
Part 2:
|
Trial |
Initial pH |
Final pH |
Final volume after titration |
Initial Buret Reading |
Total Volume Titrated |
|
#1 |
5.01 pH |
5.03 pH |
48.00 mL |
50 mL |
2.00 mL |
|
#2 |
5.01 pH |
5.04 pH |
47.00 mL |
50 mL |
3.00 mL |
|
#3 |
5.01 pH |
5.04 pH |
47.50 mL |
50 mL |
2.50 mL |
Part 3:
|
Trial |
Initial pH |
Final pH |
Final volume after titration |
Initial Buret Reading |
Total Volume Titrated |
|
#1 |
5.01 pH |
4.99 pH |
47.00 mL |
50 mL |
3.00 mL |
|
#2 |
5.01 pH |
4.98 pH |
46.80 mL |
50 mL |
3.20 mL |
|
#3 |
5.01 pH |
5.00 pH |
47.50 mL |
50 mL |
2.50 mL |
1.According to your observations, in Part 2 and Part 3, did your buret values agree with one another? If not, how would you explain the difference?
2. What conclusions can you draw when you compare Part 1 to Part 2? What about when comparing Part 1 to Part 3? Explain your reasoning.
3. Given the following, determine which set(s) correctly represents a buffer system. Explain your reasoning.
1. NaNO3
HF and KF
HCl and NaOH
HC2H3O2 and NaC2H3O2
4. What is the pH of a solution prepared by dissolving 1.00 g of Ca(OH)2 in water to make 875 mL of the solution? Show your calculations.
5. Given the following pair, determine which one is more basic. Explain your reasoning.
Photo developer with a pH of 12.0 or a solution of borax with a pH of 9.2
In: Chemistry
Chlorine gas reacts with ammonia to form nitrogen gas and ammonium chloride. If 70 g of chlorine and 50 g of ammonia form 6.2 grams of nitrogen, what is the percent yield of this reaction? What is oxidized? What is reduced?
In: Chemistry
define a buffer and give two examples of buffer solutions?
In: Chemistry
Aqueous hydrochloric acid (HCl) reacts with solid sodium hydroxide (NaOH) to produce aqueous sodium chloride (NaCl) and liquid water (H2O). If 12.9 g of sodium chloride is produced from the reaction of 19.7 g of hydrochloric acid and 40.8 g of sodium hydroxide, calculate the percent yield of sodium chloride. Round your answer to 3 significant figures.
In: Chemistry