X is usually representing time so years, days, etc
D. the student's conclusion shows experimental bias
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.
The answer is Metalloids!
<u>Question in English : </u>
<span>
<em>An atom X has 8 neutrons and its atomic number equals 8. Knowing that this atom is isotopes of Y, which has mass number 18, answer: What is the number of neutrons in atom Y?</em>
</span><span><u>Answer :</u>
</span>Isotopes are defined as the atoms which have same number of
protons but different number of neutrons of same element. Since the proton
number is same, the atomic number also same. Hence the atomic number of Y is 8.
Mass number = atomic number + neutron number
18 = 8 + neutron number
Neutron number = 10
Hence, there are 10 neutrons in Y.
