Answer:
A compound contains atoms of different elements chemically combined together in a fixed ratio. An element is a pure chemical substance made of same type of atom. Compounds contain different elements in a fixed ratio arranged in a defined manner through chemical bonds. They contain only one type of molecule.
Take the 72 g and divid it by 6 which would equal 12 g each
hydrogen combines with sulfur is H2S
<span> hydrogen combines with
oxygen H2O</span>
<span>Hydrogen sulfide<span> <span>is the </span></span>chemical compound<span> <span>with the </span></span>formula <span>H<span>
2S</span></span>. It is a colorless gas<span> <span>with the characteristic foul odor of rotten </span></span>eggs<span>; it is heavier than air, very poisonous,
corrosive, flammable, and explosive; properties shared with the denser </span>hydrogen
chalcogenides</span>
<span> </span>
Answer:
2.25g of NaF are needed to prepare the buffer of pH = 3.2
Explanation:
The mixture of a weak acid (HF) with its conjugate base (NaF), produce a buffer. To find the pH of a buffer we must use H-H equation:
pH = pKa + log [A-] / [HA]
<em>Where pH is the pH of the buffer that you want = 3.2, pKa is the pKa of HF = 3.17, and [] could be taken as the moles of A-, the conjugate base (NaF) and the weak acid, HA, (HF). </em>
The moles of HF are:
500mL = 0.500L * (0.100mol/L) = 0.0500 moles HF
Replacing:
3.2 = 3.17 + log [A-] / [0.0500moles]
0.03 = log [A-] / [0.0500moles]
1.017152 = [A-] / [0.0500moles]
[A-] = 0.0500mol * 1.017152
[A-] = 0.0536 moles NaF
The mass could be obtained using the molar mass of NaF (41.99g/mol):
0.0536 moles NaF * (41.99g/mol) =
<h3>2.25g of NaF are needed to prepare the buffer of pH = 3.2</h3>