Answer:
The salt is Zn(NO3)2
When the residue is allowed to cool, its colour changes from yellow to white
The equation of the reaction is; 2Zn(NO3)2(s) --->2ZnO(s) + 4NO2(g) + O2(g)
Explanation:
Decomposition of Zn(NO3)2 is one of the routes by which ZnO is obtained. ZnO is a white insoluble powder which has a yellow colour when hot and a white colour when cold. It is an amphoteric substance used as a white pigment in paints and as a filler for rubber.
In a very pure form, it is used in cosmetic powders and creams as well as in medicinal ointments and lotions.
Also recall that NO2 is a brown gas and oxygen gas rekindles a glowing splint.
1. <em>Describe</em>
Frequency (f) and wavelength (λ) are inversely related.
f ∝ 1/λ
As one goes up, the other goes down and vice versa.
2. <em>Infer
</em>
The frequency of infrared light is less than that of red light, so infra could mean something like less than or below or beneath.
Ultrahigh frequencies are extremely high compared with those of visible light. Ultrasound has frequencies that are far beyond what we can hear. An ultracentrifuge goes at extremely high speed, and an ultramicroscope can “see” tiny structures. Ultra could probably mean something like extremely or far beyond.
3. <em>Analyze
</em>
Energy is directly proportional to frequency (E ∝ f).
Frequency is inversely proportional to wavelength (f ∝ 1/λ).
Energy is inversely proportional to wavelength (E ∝ 1/λ).
Answer:
Scientific theories are testable and make falsifiable predictions. They describe the causes of a particular natural phenomenon and are used to explain and predict aspects of the physical universe or specific areas of inquiry (for example, electricity, chemistry, and astronomy).
A good theory in the theoretical sense is (1) consistent with empirical observations; is (2) precise, (3) parsimonious, (4) explanatorily broad, and (5) falsifiable; and (6) promotes scientific progress (among others; Table 1.1).
<span>Number of moles of Fe(CO)5 = mass/molar mass = (6.0 g) / (195.8955 g/mol) = 0.03 mol
Number of moles of PF3 = (4.0 g)/ (87.97 g/mol) = 0.0455 mol
Number of moles of H2 = (4.0 g) / (2.016 g/mol) = 1.984 mol
From the balanced equation
1 mol of Fe(CO)5 reacts with 2 mol of PF3 and 1 mol of H2
then 0.03 mol of Fe(CO)5 will need 0.03 (2/1) = 0.06 mol of PF3 and 0.03 mol of H2
Since we have less PF3 ( 0.0455 mol instead of 0.06 mol), that is the limiting agent</span>
