The molecular mass of helium is 4 g/mol, the Boltzmann’s constant is 1.38066 × 10−23 J/K, the universal gas constant is 8.31451 J/K · mol, and Avogadro’s number is 6.02214 × 1023 1/mol. Given: 1 atm = 101300 Pa. How many atoms of helium gas are required to fill a balloon to diameter 23 cm at 58◦C and 1.166 atm?

Answer asap need by wednesday morning explain how a buffer works, using an ethanoic acid/sodium ethanoate system including how the system resists changes in ph upon addition of a small amount of base and upon addition of a small amount of acid respectively. include the following calculations in your i. calculate the ph of a solution made by mixing 25cm3 0.1m ch3cooh and 40cm3 0.1m ch3coo-na+. [ka = 1.74 x 10-5 m] ii. calculate the ph following the addition of a 10cm3 portion of 0.08 m naoh to 500cm3 of this buffer solution. iii. calculate the ph following the addition of a 10cm3 portion of 0.08 m hcl to 200cm3 of the original buffer solution.

Which statement justifies that hydrogen peroxide (h2o2) is a polar molecule? the o – h bond is nonpolar and the molecule is asymmetric. the o – h bond is nonpolar and the molecule is symmetric. the o – h bond is polar and the molecule is asymmetric. the o – h bond is polar and the molecule is symmetric.

What is the body’s main processing system? it uses input from various parts to control voluntary and involutiontary movement. it’s composed of two main parts-the brain and spinal cord. a. nbs b.cns c. ans d. pns