The emission spectrum of gold shows a line of wavelength 2.76x10^-7m. what is the corresponding frequency of this light? how much energy is emitted in production of this radiation?

The formula relating wavelength and frequency is:

f = c / ʎ

where f is frequency, c is speed of light = 3 x 10^8 m/s, and ʎ is wavelength of light = 2.76 x 10^-7 m

f = (3 x 10^8 m/s) / 2.76 x 10^-7 m

f = 1.09 x 10^15 s-

The energy can be calculated using the formula:

E = h f

where h is Planck’s constant = 6.626 x 10^-34 J s

E = (6.626 x 10^-34 J s) * 1.09 x 10^15 s-

E = 7.2 x 10^-19 J

when 25.0 ml of 0.700 mol/l naoh was mixed in a calorimeter with 25.0 ml of 0.700 mol/l hcl, both initially at 20.0 °c, the temperature increased to 22.1 °c. the heat capacity of the calorimeter is 279 j/°c.

the equation for the reaction is:

naoh + hcl → nacl + h₂o

moles of hcl = 0.0250 l hcl ×

0.700

mol hcl

1 l hcl = 0.0175 mol hcl

volume of solution = (25.0 + 25.0) ml = 50.0 ml

mass of solution = 50.0 ml soln ×

1.00

ml soln

= 50.0 g soln

δt=t2-t1

= (22.1 – 20.0) °c = 2.1 °c

the heats involved are

heat from neutralization + heat to warm solution + heat to warm calorimeter = 0

q1+q2+q3=0

nδh+mcδt+cδt=0

0.0175 mol ×

δh

+ 50.0 g × 4.184 j·g⁻¹°c⁻¹ × 2.1 °c + 279 j°c⁻¹ × 2.1 °c = 0

0.0175 mol ×

δh

+ 439.32 j + 585.9 j = 0

0.0175 mol ×

δh

= -1025.22 j

δh=1025.22j0.0175 mol= -58 600 j/mol = -58.6 kj/mol

the atomic number will stay the same no matter how many electrons it has, so it doesn’t decrease nor increase. it’ll only change with a different number of protons