Isotopes/ Early Content
Determine the number of protons and neutrons in N-14
7, 7
How many sig figs are in 0.000312?
3
Density is what type of property?
Intensive Property
The distance from the sun to Earth is 1.496 x 108 km. How long does it take light to travel from the sun to Earth?
499 s
The amount of carbon-14 in ancient artifacts and fossils are often used to establish their age. Determine the number of protons and the number of neutrons in a carbon-14 isotope, then write its symbol in the ZAX format.
146C
When measuring a substance using a tool, how far do you specify its measurement reading to?
The next value below the available/measured one on the instrument.
Ethylene glycol (antifreeze) has a density of 1.11 g/cm3. What is the mass in g of 417 mL of this liquid?
463g
Determine the energy of 1 mol of photons for infrared radiation (wavelength of 1500 nm).
79.8 kJ/mol
Which state of matter has a fixed volume, an indefinite shape, and is compressible?
Liquid
43.7-2.341
41.4
A solid gold cylinder sits on a weight-sensitive alarm. A thief replaces the gold with a cylinder of sand. The can of sand and gold both have identical dimensions (length=22 cm and radius=3.8cm). Calculate the mass of the gold cylinder and cylinder of sand (Sand density= 3g/cm3; Gold density=19.3g/cm3). Did the thief set off the alarm?
mass of gold can: 1.9 x 104 g.
mass of sand can: 3x 103 g.
The thief sets off the alarm because the sand is lighter than the gold.
What is the de Broglie wavelength of an electron traveling at 1.35 x 105 m/s?
5.39 nm
Carbon forms several compounds with oxygen. In carbon monoxide, 0.75 g of carbon are formed for every 1 g of oxygen. In carbon dioxide, 0.375 g of carbon are formed for every 1 g of oxygen. Are these results consistent with the law of multiple proportions?
Yes.
(24.6681 x 2.38) + 332.58
391.3
How many gold atoms are in a 0.268 ounce, 18K gold bracelet? 18K gold is 75% gold by mass.
(Hint: 1oz=28.35g)
1.7 x 1022 atoms
The binding energy of a metal is 203 kJ/mol. Find the threshold frequency of the metal.
5.09 x 1014 Hz
Two samples of sodium chloride are decomposed into their constituent elements. One sample produces 15.3 g of sodium and 212 g of chlorine, and the other sample produces 11.5g of sodium and 101 g of chlorine. Are these consistent with the law of definite proportions?
No.
(85.3- 21.489) / 0.0059
1.1 x 104
Find the number of atoms in a copper rod with a length of 8.55 cm and a radius of 1.30 cm. The density of copper is 8.96 g/cm3 (Hint: Volume of a cylinder is pi x r2 x h).
3.85 x 1024 Cu atoms
A photon of wavelength 8.42 nm strikes a metal surface. What is the KE of the emitted electrons in J/mol if the binding energy is 5.300 x 103 kJ/mole of electron?
8.91 x 106 J/mol