Question

Calculate the mass of the of an object that has deBrogile wave length of 7.21timexs1036m if it is traveling at a speed of 163.2km/hr perform the following calculation Determine the mass represented by 6.43moles of ca(po)4 how many moles of co23 is equal of the gas? the analysis of an unknown sample determine that the sample contained 12.01grams of c and 4.04 grams of hydrogen. Determine the total mass of the unknown material needed to extract 23.1 of g of Carbon Determine the energy of a photon emitted when a hydrogen electron relaxes from n=6 down to n=3

Answer 1

16. DeBroglie equation,

m = h/lv

where,

m = mass

h = 6.626 x 10^-34 J.s

l = 7.21 x 10^-39 m (wavelength)

v = 163.2 km/hr = 163200/3600 m/s

Feed values,

m = 6.626 x 10^-34/(7.21 x 10^-39 x 45.33) = 2027.3 kg

17.

a. mass equivalent to 6.43 moles of Ca3(PO4)2 = 6.43 x 310.17 = 1994.40 g

b. moles of CO2 = g/molar mass = 63.2/44.01 = 1.44 moles

18. find moles

C = 12.01/12 = 1

H = 4.04/1.01 = 4

Divide by smallest factor

C = 1/1 = 1

H = 4/1 = 4

empirica formula = CH4

mass = 12 + 4 = 16 g

So to get, 23.1 g carbon, we would need = 2.0g of this compound.

19. energy = R[1/ni^2-1/nf^2]

with,

ni = 6

nf = 3

we have,

energy = 2.18 x 10^-18[1/36-1/9]

= -1.82 J