Answer:
C. 17 grams.
Explanation:
∵ mass % = [mass of solute/mass of solution] x 100.
mass of solute (NaCl) = ??? g & mass of solution = 140.0 g.
<em>∴ mass of NaCl = (mass %)(mass of solution)/100 </em>= (12.0)(140.0)/100 = <em>16.80 g ≅ 17.0 g.</em>
Answer:
Explanation:
Hello there!
In this case, since these problems about gas mixtures are based off Dalton's law in terms of mole fraction, partial pressure and total pressure, we can write the following for hydrogen, we are given its partial pressure:
And can be solved for the total pressure as follows:
However, we first calculate the mole fraction of hydrogen by subtracting that of nitrogen to 1 due to:
Then, we can plug in to obtain the total pressure:
Regards!
The most appropriate answer is C !!
In the presence of heat, copper (II) hydroxide decomposes in to copper (II) oxide.
Cu(OH)₂ (s) ----> CuO (s) + H₂O (l)
upon decomposition, water is removed from Cu(OH)₂
the amount of Cu(OH)₂ decomposed - 3.67 g
number of moles of Cu(OH)₂ - 3.67 g / 97.5 g/mol = 0.038 mol
stoichiometry of Cu(OH)₂ to CuO is 1:1
therefore number of CuO moles formed are - 0.038 mol
CuO reacts with sulfuric acid to form CuSO₄
CuO + H₂SO₄ ---> CuSO₄ + H₂O
stoichiometry of CuO to H₂SO₄ is 1:1
therefore number of H₂SO₄ moles that should react is 0.038 mol
the molarity of H₂SO₄ is 3M
this means that in 1000 ml - 3 mol of H₂SO₄ present
so if 3 mol are present in 1000 ml
then volume for 0.038 mol = 1000/3 * 0.038
= 12.67 ml
