Answer:
10.76 grams
Explanation:
Given that the amount of
is 25.0 grams.
Mass of 1 mole of
= 158 grams
The number of atoms in 1 mole of
is 4.
Mass of oxygen in 1 mole of
= 16\times 4 = 68 grams.
Here, 158 grams of
has 68 grams of oxygen
So, the amount of oxygen in 1 gram of
= 68/158 grams
Therefore, the amount of oxygen in 1 gram of
=
grams
=10.76 grams
Hence, 25 grams of
has 10.76 grams of oxygen.
Ionic molecules have higher boiling point than covalent molecules.
So that leaves Na2SO4 and NaCl.
The ionic molecule with higher charge will have higher boiling point.
Na2SO4 have ions with charge +-2.
NaCl have ions with charge +-1.
So the answer is C.
2NaCN(s) + H₂SO₄(aq) --> Na₂SO₄(aq) + 2HCN(g)
The molar ratio between NaCN : HCN is 2:2 or 1:1
Mass of HCN = 16.7 g
Molar mass of HCN = 1 + 12 + 14 = 27 g/mol
Molar mass of NaCN = 49 g/mol
Therefore, the mass of NaCN is
16.7 g of HCN x 49 g/mol of NaCN / 27 g/mol of HCN = 30.3 grams of NaCN
Therefore, 30.3 grams of NaCN gives the lethal dose in the room.