Answer:
2.281*10^28 photons
Explanation:
Data
- Volume of coffee, V = 245 mL
- Temperature change of the coffee, ΔT = 62 - 25 = 37 °C
- Density of coffee, D = 0.997 g/mL
- Specific heat capacity of coffee, cp = 4.184 J/(g*K) = 4.184 J/(g* °C)
- wavelength of the microwave radiation, λ = 12 cm = 0.12 m
Mass of the coffee
m = D*V = 0.997 * 245 = 244.265 g
Energy (heat) absorbed by the coffee
Q = m*cp*ΔT = 244.265 * 4.184 * 37 = 37814.1761 J
Energy of the photon
E = h*c/λ
where h is the Planck constant ( 6.63 x 10^(-34) J*s) and c is the speed of light at vacuum (3*10^8 m/s)
E = 6.63 x 10^(-34)*3*10^8/0.12 = 1.6575*10^(-24) J
number of photons required = total energy required / energy per photon
n = 37814.1761/1.6575*10^(-24) = 2.281*10^28 photons
Answer:
A. {K}, {Ba}, {Ca}, {Na}
B. {Au}
C. {Na}
D. Image Missing
Explanation:
PART A:
The range of wavelengths in visible region is 380 nm to 740 nm. Thus, all the elements that emit light of wavelength in this region are the elements which emit radiation in visible part. They are:
{k}
{Ba}
{Ca}
{Na}
PART B:
The energy of a photon is inversely proportional to its wavelength (E = hc/λ). Therefore, the element, which emits the radiation of smallest wavelength, has the highest energy photons. <u>That element is {Au}</u>
<u></u>
PART C:
Similarly, the element which emits radiation of highest wavelength, has the lowest energy. <u>That element is {Na}</u>
PART D:
Image missing.
Answer: Option (c) is the correct answer.
Explanation:
Energy that is acquired by the molecules of a substance due to their motion is known as kinetic energy.
For example, when we heat water in excess then it starts to boil and it changes into vapors.
Hence, when molecules of a liquid gain kinetic energy then they start to collide rapidly with each other. As a result, molecules move away from each other and there occurs decrease in force of attraction between the molecules. This leads to change of liquid state into vapor or gaseous state.
Thus, we can conclude that the statement they move fast enough to overcome the forces of attraction that hold them together, becoming a gas, best explains what happens when the kinetic energy of particles in a liquid state increases.
Hey...
Use the molarity formula
M=moles/L and then convert to grams
0.07268*0.15=moles
<span>0.010902 mol
</span>Pb(NO3)2
1 mole=331.22g
0.010902 moles=
3.61 g