Answer:
Explanation:
%Carbon = mass of carbon / mas of C13H18O2) X100%
= 13X12/ (13X12+18+2X16)X100%
= 156/206) X100%= 75.7%
Answer:
B. 0.2.
Explanation:
<em>n = mass/molar mass</em>
mass of CaCO₃ = 20 g, molar mass of CaCO₃ = 100.0869 g/mol.
<em>∴ n = mass/molar mass = </em>(20 g)/(100.0869 g/mol) <em>= 0.1998 ≅ 0.2 mol.</em>
<em></em>
<em>So, the right choice is: B. 0.2.</em>
Answer:
0.4 * 10⁻⁶mol
Explanation:
The unit conversion required are ,
1 μ M = 10⁻⁶ M
1 L = 1000 mL
1 mol = 1000 mmol
molarity of a solution is given as -
Molarity (M) = ( w / m ) / V ( in L)
where ,
m = molecular mass ,
w = given mass ,
V = volume of solution ,
Hence , the unit is ,
M = mol / L
from the question ,
0.4 μ M = 0.4 * 10⁻⁶ M
Now,
0.4 * 10⁻⁶ M = 0.4 * 10⁻⁶ mol / L
Since ,
1 L = 1000 mL
and ,
1 mol = 1000 mmol
0.4 * 10⁻⁶ mol / L = 0.4 * 10⁻⁶ * 1000 mol / 1000 mL = 0.4 * 10⁻⁶mol