An aqueous solution contains 0.392 M ethylamine (C₂H₅NH₂).

How many mL of 0.313 M hydrobromic acid would have to be added to 225 mL of this solution in order to prepare a buffer with a pH of 10.700?

Why would a repeating unit of PET (polyethyleneterephthalate) be used to calculate the limiting reagent and yield instead of the molecular weight of the polymer? Is it just because it is a polymer and only its monomer needs to be taken into account?

Caffeine, a stimulant found in coffee, tea, and energy drinks, contains C, H, O, and N.
Combustion of 1.000 mg of caffeine produces 1.813 mg CO2, 0.4639 mg H2O, and 0.2885 mg N2.
Calculate the molecular formula of caffeine, whose molar mass lies between 150 and 200 g/mol.

In step four of glycolysis, the C6 species is split into two C3 species, the two trioses that are produced are not identicle. Name these two trioses. Which of these two C3 species is a glycolysis intermediate? What is the fate of the other triose?

In discussing molecular rotation, the quantum number JJ is used rather than ll. The bond length is 141.4pmpm.

Part A : Calculate E_rot/K_BT for ¹H^{_^81}Br  for J=0 at 334 KK .

Part B: Calculate E_rot/K_BT  for ¹H⁸¹Br for J =5 at 334 KK .

An empty glass container has a mass of 418.634 grams. It has a mass of 419.514 grams after it has been filled with nitrogen gas at a pressure of 790 mmHg and a temperature of 15^oC. When the container is evacuated and refilled with a certain element X at a pressure of 745 mmHg and a temperature of 26^oC, it has a mass of 420.652 grams.

            Compound Y, a gaseous organic compound that consists of 88.9% carbon and 11.1 % hydrogen by mass, is placed in a stainless steel vessel ( 10.68 L) with excess oxygen gas. The vessel is placed in a constant temperature bath at 22^oC. The pressure in the vessel is 9.970 atm. In the bottom of the vessel is a container that is packed with ascarite and a desiccant. Ascarite is asbestos impregnated with sodium hydroxide; it reacts with and quantitatively absorbs carbon dioxide:

               2NaOH (s) + CO₂ (g) → Na₂CO₃(s) + H₂O(l)

            The desiccant is anhydrous magnesium perchlorate, which quantitatively absorbs the water produced by the combustion reaction as well as the water produced by the above reaction. Neither the Ascarite nor the desiccant reacts with compound Y or oxygen. The total mass of the container with the Ascarite and the desiccant is 746.3 grams.

            The combustion of compound Y is initiated by a spark. The pressure in the container immediately rises, then begins to decrease and finally reaches a steady value of 1.51 atm.The stainless vessel is carefully opened and the mass of the container inside the vessel is found to be 878.7 grams.

            X and Y react quantitatively in a 2:1 mole ratio to form one mole of the single product, gas Z.

a)How many grams of Z will be produced if 11.0 L of X and 9.60 L of Y (each at STP) are reacted by opening a stopcock connecting the 2 sample containers?

b)What will be the total pressure in the system? Assume all reactants and products are gases. Temp = 0^oC

I have found that element x is cl2, but i think that element y is c4h6, but I'm not sure so i would appreciate the work, and i would also appreciate working on a and b in full detail. This is due tomorrow, so please help me! Thank you :)

Microwaves can cause tissue damage. For a microwave, emitting energy, wavelength = 12cm, how many photons must be absorbed to raise the temperature of a human eyeball 3 C? Mass of the eye =11g, specific heat of the eyeball is 4.0 J/g K.

1. Using average atomic masses calculate the number of atoms present in each of the following samples.

(a) 1.27 g of silver, Ag

(b) 0.0010 mol of copper, Cu

(c) 0.0010 g of copper, Cu

(d) 1.76 kg of magnesium, Mg

(e) 2.45 oz of calcium, Ca

(f) 2.45 g of calcium, Ca

(g) 2.45 mol of calcium, Ca

when salt crystal is dropped into water , how do the molecular properties of water and the ionic properties of salt interact.

What is the rate constant for a reaction based on the following experimental information?

1) The power company is considering installing a new plant using natural gas as fuel to generate the same amount of energy. If the natural gas to be used has an energy capacity of 43MJ/m³ (mega joules per cubic meter of gas)

a) Estimate the volume of natural gas needed in m3/yr.

b) Calculate the annual emissions of criteria pollutants including SO₂, NO_x, PM and green house gasses including CO₂ and CO using the appropriate emission factors given in the table below.

2) Given the cost of Bituminous coal is $750/MT and natural gas is $25/m³ calculate the operating costs for the plant per year.

3) Based on the emission estimates and costs which fuel would you recommend as the best fossil fuel power source for the plant? Why?

A 32.70-g sample of a solid is placed in a flask. Toluene, in which the solid is insoluble, is added to the flask so that the total volume of solid and liquid together is 49.00 mL . The solid and toluene together weigh 58.54 g . The density of toluene at the temperature of the experiment is 0.864 g/mL. What is the density of the solid?

8. Which of the following species have a zero reading for dipole moment? Give brief reasons for your answers, dealing with each species separately. a. BrF3 b. CH2F2 c. CO d. CO2 e. OF2 f. XeF4

What fraction of piperazine (perhydro-1,4-diazine) is in each of its three forms (H2A, HA–, A2–) at pH 6.67? The acid dissociation constant values for piperazine are Ka1 = 4.65×10–6 and Ka2 = 1.86×10–10.