<span>1. Which of the following does NOT indicate that a chemical change may have taken place?
A. fracture formation
B. gas production
C. precipitate formation
D. energy transfer
it is (a.)</span>
To find average atomic mass, multiply each isotope's atomic mass with its relative abundance and add it all up.
15.012*0.1423 + 16.988*0.3348 + 19.177*0.5229 = 17.851 (5 s.f.)
Answer:
1.70
Explanation:
The molar mass of perchloric acid is 100.46 g/mol. The moles corresponding to 484 mg (0.484 g) are:
0.484 g × (1 mol/100.46 g) = 4.82 × 10⁻³ mol
4.82 × 10⁻³ moles are dissolved in 240 mL (0.240 L) of solution. The molar concentration of perchloric acid is:
4.82 × 10⁻³ mol/0.240 L = 0.0201 M
Perchloric acid is a strong monoprotic acid, that is, it dissociates completely, so [H⁺] = 0.0201 M.
The pH is:
pH = -log [H⁺] = -log 0.0201 = 1.70
<u>We are given:</u>
Volume of gas = 3.8 L
Pressure = 460 mmHg
Temperature = 77°c = (77+273)K = 350K
<u>Converting the pressure to atm:</u>
Pressure(in atm) = Pressure(in mmHg) / 760
Pressure = 460/760 = 0.6 atm
<u>Finding the number of moles:</u>
using the ideal gas equation:
PV = nRT [where R is the universal gas constant]
<em>replacing the given values in this equation</em>
(0.6)(3.8) = n(0.082)(350)
n = (0.6*3.8)/(0.082*350)
n = 0.08 moles
SeCl2 is tetrahedral in shape. with 2 lone pairs on the Se, Tetrahedrals are sp3 hybridized
