1. The molecular weight of anhydrous calcium chloride is 110.99 grams/mol. How many grams do you need for 750 ml of 250uM calcium chloride?

2. Ethanol is supplied in a 90% solution. You need 275 mL of 75% Ethanol for your experiment. How would you make this solution?

3.You have 12 mL of cells you need to treat with Hydrogen Peroxide (H₂O₂), such that the final concentration of H₂O₂ is 50 uM. How much of a 30 mM stock solution of H₂O₂ would you add to your cells?

4. You need to prepare a stock solution of medium for your culture cells, which usually includes liquid salt solution and bovine serum. Your liquid salt solution is supplied in a 50X concentration, and you need to dilute it to 1X for use. You also need to add 75% fetal bovine serum for a final concentration of 15%. How would you make up 0.80 liters of this culture media using water as your solvent?

5. You need to treat cells with arsenite such that it has a final concentration of 25 uM once it has been added to the cells. You need to treat 10mL of cells, and you don't want your treatment volume to be more than 7 uL per 1mL of cells. What concentration should you make your stock solution?

I am wondering what the rule is for determining functional group positions for the most stable chair and boat conformations of cyclohexanes; meaning basically is there a pattern as to whether the functional group will be axial or equatorial for the most stable conformation based on which C # it is attached to (i.e. C- 1, 2, 3, 4, 5, or 6)?

What's the most stable for chair and boat of cis-1-bromo-4-methylcyclohexane as well as the trans-1-bromo-4-methylcyclohexane? (which group is axial and which is equatorial) Thank you

A 0.100 M solution of a weak base has a pH of 9.95. What is the base hydrolysis constant, Kb, for the weak base?

When 2.65 g of an unknown weak acid (HA) with a molar mass of 85.0 g/mol is dissolved in 250.0 g of water, the freezing point of the resulting solution is -0.257 ∘C.

1. Calculate the pH of a solution prepared by mixing 2.50 L of 2.35 M HF with 4.50 L of 1.56 M NaF.

2. A 4.00-g sample of NaOH is added to 2.00 L of the solution prepared in problem 1. Calculate the pH of the new solution. Assume any volume change is negligible.

What volumes of 1.0 M NH4NO3 and 1.0 M NH3 would be required to prepare 2.00 L of a buffer

with a pH of 9.00? The Kb of NH3 is 1.8 × 10–5.

How many grams of solid NaOH would need to be added to 5.00 L of 0.50 M acetic acid to

prepare a buffer with a pH of 5.00, assuming no volume change occurs upon the addition? The Ka of

acetic acid is 1.8 × 10–5.

After recrystallizing an impure sample of benzoic acid, a student scratched it off the filter paper and took a melting point. Most of the compound melted between 121 and 122 degrees Celsius. A small amount remained un-melted even at temperatures above 200 degrees celsius. Explain this behavior.

A)

Titration of an acidic solution of Na2C2O4 with KMnO4(aq).

Which species is the reducing agent?

Express your answer as an ion.

I know the reducing agent is the Na2C2O4 but I need the ION form.

B)A voltaic cell utilizes the following reaction:
2Fe3+(aq)+H2(g)→2Fe2+(aq)+2H+(aq)

.What is the emf for this cell when [Fe3+]= 3.50 M , PH2= 0.99 atm , [Fe2+]= 1.1×10⁻³ M , and the pHin both compartments is 4.15?

Express your answer using two significant figures.

0.771 V is not correct

With an H2SO4 concentration of 85% how many moles of water will be available to the reaction when 9.0 mL of 85% H2SO4 is used? (Density of 85% H2SO4 is 1.7 g/mL) calculations please This is used with the hydration of 1-hexene that has a density of 0.67 g/mL Also what is the theoretical yield in moles and grams of hexanol. Calculations please.

1) A first-order reaction has a half-life of 15.5 s . How long does it take for the concentration of the reactant in the reaction to fall to one-eighth of its initial value?

2) The rate constant for a certain reaction is k = 4.30×10−3 s−1 . If the initial reactant concentration was 0.350 M, what will the concentration be after 8.00 minutes?

Ionization energy is an inconsistent trend. For instance, the ionization energy of oxygen is lower than that of nitrogen and the ionization energy gallium is less than that for zinc. Suggest reasons this occurs and indicate other regions on the periodic table that this may occur.

The automobile fuel called E85 consists of 85% ethanol and 15% gasoline. E85 can be used in so-called flex-fuel vehicles (FFVs), which can use gasoline, ethanol, or a mix as fuels. Assume that gasoline consists of a mixture of octanes (different isomers of C8H18), that the average heat of combustion of C8H18(l) is 5400 kJ/mol, and that gasoline has an average density of 0.70 g/mL. The density of ethanol is 0.79 g/mL.

Part A: By using the information given, calculate the energy produced by combustion of 1.5 L of gasoline.

Part B: By using the information given as well as data in Appendix C, calculate the energy produced by combustion of 1.5 L of ethanol. Consider that water is in the gaseous state.

A 40.0 mL of 2.00 M Fe^{3+ (aq)} solution are mixed with 60.0 mL of 3.00 M SCN^- (aq) solution. What is the equibrium concentratio of FeSCN²⁺ (aq), if the complex formation constanst is 189 for the reaction: Fe³⁺(aq) + SCN^- (aq) -----> FeSCN^{2+ (aq)} , Kf=189

A) 7mL of a 0.1M CaCl2 solution was diluted to a final volume of 150mL. Please determine the concentration of Cl- in this solution.

B) Explain why creating a standard curve is better than simply using the Beer-Lambert law directly. Assume that a value for molar absorptivity is readily available.

Quiz

Page 10 of 10

A sample of an unknown metal with a mass of 17.8 grams is heated in boiling water to a temperature of 98.0°C. The piece of metal is transferred to a sample of water with a mass of 15.0 grams at a temperature of 26.0°C. The metal cools to 30.5°C and the water warms up to 30.5°C. Calculate the specific heat of the metal. Use the table of specific heat values to identify the metal.

Options: