The properties of a good primary standard include the following except
high molecular mass
low molecular mass
high degree of purity
readily available
Correct answer is B
Characters of a good primary standard include: high purity, low reactivity with the air or surrounding environment, low hygroscopicity, large molar mass, a predictable reactivity and readily available.
The bond angle in tetrahedral molecules such as tetrachloromethane is
180.0°
109.5°
105.5°
90.0°
Correct answer is B
No explanation has been provided for this answer.
The ionization energy is affected by the following factors except
distance of the outermost electron(s) from the nucleus
size of the positive nuclear charge
ability to attract shared electron(s)
screening effect of the inner electron(s)
Correct answer is C
These 3 factors affect the ionization energy:
The oxidation number of X in \(XO_{4}^{3-}\) is
+1
+3
+4
+5
Correct answer is D
\(XO_{4}^{3+}\) = \(X + (-2\times 4) = -3\)
\(X = -3+8 = +5\)
Which of the following substances does not have van der Waals' forces?
Copper
Graphite
Neon
Iodine crystals
Correct answer is A
No explanation has been provided for this answer.