The molecularweight of NaOH is 40. the molecularweight of a widely used buffer, HEPES, is 255. HEPES has a pK of 7.5 and is available in the acid form. how many grams og HEPES and NaOH are needed to produce one liter of a 0.5 molar solution of pH 7.5? of pH 7.0? of pH 8.5?
Calculate the constituent (a) mass, (b) mole fraction (c)average molecularweight of air at 25 degree centigrade, 1 atm, and molar density of all listed gases is 24.5 L/mol, and volume air is given to be 100 L.
Name Volume fraction
A 0.250g sample of a compound containing only carbon and hydrogen whose molecularweight is 16g/mol is burned in oxygen to yield 0.784g CO2 and 0,642g H2O. What is the molecular formula of the compound?
If gasoline had a hypothetical chemical formula of C8H17, and we knew the chemical formula of MTBE as CH3OC4H9, what weight (actual weightand percent by weight) of MTBE should be in the gasoline to achieve a final gasoline blend that has 2.7% oxygen by weight? Assume the densities of gasoline and MTBE equivalent at 0.75 g per c
What is the mole fraction of ethanol (C2H5OH) in a solution made by mixing a 20.0g sample of ethanol with 80.0g of water?
What is the mole fraction of methanol (CH3OH) in a 92.5m aqueous solution?
Please show all work and explain each step... It has been a while since I have taken chem and this is not my best subject.
A molecular compounds dissolves in water to give up H+ ions and SO4^2- ions. If the compounds dissolved was HSO4^-, what mass of SO4^2- exists in the solution if 10 moles of it were dissolved?
a) 96.07 g
b) 130.22 g
c) 192.14 g
The answer I came up with is (a), but what about the 10 moles. (a) is the mass of the c
The chlorophyll-a molecule, C55H72MgN4O5, is important in photosynthesis.
(a) Determine its molecular mass (in atomic mass units).
(b) What is the mass (in grams) of 3.00 moles of chlorophyll-a molecules?
1. A collection of atoms, molecules, or ions that contains Avogadro's number of these items is called what?
2. The initial substances that undergo change in chemical reaction are called what?
3. The law that states that atoms are neither created nor destroyed in a chemical reaction, but may be rearranged, is called what?
1. Calculate the number of grams of citric acid, C6H8O7, needed to make 2500mL of 0.4 M C6H8O7.
2. How many grams of sodium hydroxide, NaOH, would you have to dissolve in 250 mL of water to make a 0.5 M solution of NaOH?
3. How many liters of water are required to make a 0.2M solution sulfide, Na2S, using 200g of Na2S?