A 1.0 oz (30.0 mL, 1.00 g/mL) espresso contains 55.0 mg of caffeine (C8H10N4O2). Calculate the caffeine concentration in the following units. You may assume your espresso contains only caffeine and water for simplicity.

a. ppm

b. %w/w

c. ppb

d. Molarity

e. molality

f. Xcaffeine (mole fraction)

What is the prefix for a -SH group?

Use the Henderson–Hasselbalch equation to calculate the pH of each solution:

a solution that is 17.0 g of HF and 26.5 g of NaF in 125 mL of solution

PLEASE SHOW ME YOUR WORK

A 20 gram iron block at an initial temperature of 20oC is placed in 20 grams of water at an initial temperature of 80oC. Assuming no heat is lost to the surroundings, what would be the final temperature of the system once you reach thermal equilibrium?

CSiron=0.449JgoC

CSwater=4.18JgoC

74.2o C

80.0o C

25.8o C

50.0o C

112o C

To what volume (in mL) should you dilute 100.0 mL of a 5.00 M CaC2 solution to obtain a 0.750 M CaC2 solution?

The oxidation of copper(I) oxide, Cu2O(s), to copper(II) oxide, CuO(s), is an exothermic process.

2Cu2O + O2 = 4CuO

The change in enthalpy upon reaction of 85.49 g of Cu2O(s) is -87.23 kJ. Calculate the work, w, and energy change, ΔUrxn, when 85.49 g of Cu2O(s) is oxidized at a constant pressure of 1.00 bar and a constant temperature of 25 °C.

Answer in Kg.

Start by converting the mass of Cu2O that reacts (85.49 g) to the number of moles of O2 gas consumed in the reaction. Then use the ideal gas law to determine the change in volume (ΔV) during this reaction process, where Δngas is the actual amount of gas consumed. Values for R can be found at this link.

how many carbon dioxide molecules are produced for every gram of ethanol combusted?

Sodium burns in chlorine to form sodium chloride, NaCl. How many grams of sodium Chloride will be formed when 1.8 grams of sodium is burned in 2.00 grams of Chlorine? what is the excess reactant in this reaction? what is the limiting reactant? how much excess reactant remains unreacted?

1. How can the K_c of two possible reactions be compared to determine which reaction is occuring?

2. How are the equilibrium moles of reactants(ions remaining in solution) calculated?

3. What are the equilibrium constant equations for the below reactions?

Fe³⁺ + SCN^- <==> FeSCN²⁺

Fe³⁺ + 2SCN^- <==> Fe(SCN)₂+

4. How are initial moles of a reactant calculated?

5. How is the concentration of the product determined for a reaction?

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Given the following reaction and thermodynamic data, what is a reccomended temperature for a 1 L pilot scale reactor and how long (time) does it take for the reaction to take place?

CH3OCH2CH2CH2OCH2NH2 -> CH3OCH2CH2CH2OH + CH2=NH

Ions B and C to form the complex BC. If 35.0 mL of 1.00 M B is combined with 35.0 mL of 1.00 M C, 0.00500 mol of BC is formed. Determine the equilibrium constant fo this reaction.

Considering the reaction 2Al₂O₃+3C ----> 4Al +3CO₂

A- How many moles of C are needed to react with 7.75 moles of Al₂O₃?

B- How many grams of Al result when 355 grams of Al₂O₃ react?

6. You mix 50.0 mL of a weak monoprotic acid with 50.0 mL of NaOH solution in a coffee cup calorimeter. Both solutions (and the calorimeter) were initially at 22.0OC. The final temperature of the neutralization reaction was determined to be 22.5OC. a) What is the total amount of heat evolved in this reaction? Show all work. b) If 0.135 moles of the monoprotic acid were neutralized in this reaction, what is the molar heat of neutralization (enthalpy) for this reaction?