4.1 h = 14760 s
<span>t 1/2 = ln 2 / k </span>
<span>k = rate reaction = 4.97 x 10^-5 </span>
<span>ln 0.045 / 0.36 = - 4.97 x 10^-5 t </span>
<span>2.08 = 4.97 x 10^-5 t </span>
<span>t = 41839.9 s = 11 h 37 min 19 s</span>
Answer is: formula of the complex is [Cr(NH₃)₂(SCN)₄<span>]</span>⁻<span>.
This complex has negative charge (-1) because chromium (central atom or metal) has oxidation number +3, first ligand ammonia has neutral charge and second ligand thiocyanate has negative oxidation number -1:
+3 + 2</span>·0 + 4·(-1) = -1.
CaCl2 is a good conductor of electricity when dissolved in water.
The question is incomplete, the complete question is;
Which statement describes a difference between electromagnetic and mechanical waves?
A. Mechanical waves cannot be longitudinal, but electromagnetic waves can.
B. Electromagnetic waves cannot move particles, but mechanical waves can.
C. Electromagnetic waves do not require a medium, but mechanical waves do.
D. Mechanical waves do not transfer energy, but electromagnetic waves do.
Answer:
Electromagnetic waves do not require a medium, but mechanical waves do.
Explanation:
A wave is defined as a disturbance along a medium which transfers energy. Waves may be classified as mechanical waves or electromagnetic waves based on their medium of propagation.
A mechanical wave requires a material medium for propagation. An example of a mechanical wave is sound waves. Sound waves are propagated in air.
Electromagnetic waves do not require a material medium for propagation. They can travel through space. An example of electromagnetic waves is light waves.
C. The action/reaction law states that a force is equal in both directions.