Sig Figs/Measurements
How many sig figs are in 10.05?
Four sig figs.
Convert 3.5 cm3 to in3. (1 in= 2.54 cm)
(3.5 cm3/1)(1 in/2.54 cm)3= 0.21 in3
Which has a lower frequency, radio waves or ultraviolet waves?
Radio waves have a much lower frequency.
Why is the number of valence electrons in an atom important?
Because the number of valence electrons determines the chemical characteristics of the atom. Atoms in the same group on the periodic table (with the same number of valence electrons) will often have similar properties.
What is the electron configuration of the valance electrons for a ground-state Ge atom?
4s24p2.
How many sig figs are in 010.020300?
Eight sig figs.
23.0 g of Sodium and 100.0 g of Bromine react to form NaBr. If 23.0 g of Sodium are used up to form 102.9 g of NaBr, how much bromine is left over? What is the mass ratio of bromine to sodium in NaBr?
20.1 g of Bromine left over. The mass ratio of Br:Na in NaBr is 3.47.
Explain the relationship between wavelength, frequency, and energy of a light wave.
Wavelength and frequency are inversely proportional, and frequency increases with energy.
DAILY DOUBLE!
What is the charge on an alpha particle?
An alpha particle is 2 protons+2 neutrons, so +2 charge.
Which type of electron is described by the quantum numbers, n=3, l=2, ml= 1, and ms= +1/2?
l= 2 and n=3, so this set describes a 3d orbital.
Describe the proper components of a scientific measurement, describing an important rule regarding the "last" component.
1) Number, 2) Units, 3) Uncertainty
The uncertainty and measurement must end in the same place.
DAILY DOUBLE!
Convert 25 m2/sec to ft2/ hr.
(25 m2/sec)(3600 sec/1 hr)(100 cm/1 m)2(1 in/2.54 cm)2(1 ft/12 in)2= 9.7 *105 ft2/hr
If the energy of a photon is 8.54* 10-18 J, what is the photon's frequency? (E=hv) (h=6.626*10-34 J*sec)
1.29* 1016 sec-1
How many protons, electrons, and neutrons are in Bromine-79 with a -1 charge?
Protons=35, Electrons=36, Neutrons=44
Give the full electron configuration for Phosphorous (#15).
1s22s22p63s23p3.
The speed limit on part of 94 is 65 mph. Is this number exact or inexact?
As this number is a definition and is a counting number, it is exact. If "Joe is driving 64.5 mph", then it is inexact (measured).
Convert 2.46 cm3/sec to in3/minute.
(2.46 cm3/sec)(60 sec/min)(1 in/2.54 cm)3= 9.01 in3/min
Will a n=12 to n=11 jump or a n=3 to n=2 jump for an electron release more energy?
The n=3 to n=2 jump will release more energy.
Which is heavier, Carbon-13 or Nitrogen-13?
Carbon-13 is heavier.
Define and explain Hunt's Rule.
Hunt's Rule- Electrons in an orbital will remain unpaired with equivalent spins as long as possible.
Give a proper scientific measurement for the provided image.
67.0 +/- 0.2 mg.
(Uncertainty could be up to about 0.3 for this measurement)
An object that weights 1.00 kg is thrown at 46.0 MPH. What is its kinetic energy in Joules (kg* m2/sec2)? (Kinetic Energy= 0.5mv2)
(1/2)(1.00 kg)(46.0 mi/hr)2(1 hr/ 3600 sec)2(5280 ft/1 mi)2(12 in/1 ft)2(2.54 cm/1 in)2(1 m/100 cm)2= 211 Joules
A wave of light has a wavelength of 860. nm. What is its frequency? (wavelength* v= c = 3.00*108 m/sec)
v= 3.49*1014 Hz.
Which has a larger atomic radius, K+ or Na+2?
The K+ has a larger atomic radius.
Give the abbreviated electron configuration for Cu (#29).
[Ar] 4s13d10.