Sig Figs
2.5(100)
300
What is an attempt to explain an observation?
Theory
what is 5.5cg in kilograms?
5.5*10-8kg
What is the charge of an electron?
1-
What is the equation for energy?
E=hc/λ or E=hv
(6.4-6.63)(1000.)
-200
What did Thomson's cathode ray experiments prove?
The existence of negatively charged particles(electrons) in an atom.
What is Avogadro's number?
6.022*1023atoms/mol
Determine the number of protons, neutrons, and electrons in Uranium-2353-.
92 protons, 143 neutrons, and 95 electrons.
Order these 4 waves from lowest to highest energy: red, microwaves, gamma rays, orange
microwaves, red, orange, gamma rays
(80.02-20.00)(3.99/2.100)
114
Two samples of carbon monoxide decompose into their constituent elements. One sample produces 17.2g of oxygen and 12.9g of carbon, and the other sample produces 10.5g of oxygen and 7.88g of carbon. Are these samples consistent with the law of definite proportions?
Yes
How many atoms are in 78.8L of water?(density of water is 1.00g/cm3)
2.64*1027
Which of the following is NOT true?
a) An isotope of calcium with 20 neutrons and 18 electrons must be a 2+ ion with mass number of 40.
b) A 3+ ion of the isotope Fe-53 must have 26 neutrons and 23 electrons.
c) An atom of chlorine for which mass = 37 would have 17 protons, 17 electrons, and 20 neutrons.
d) An atom that has an atomic number of 53 and 79 neutrons in its nucleus must be I-132.
e) All of the above are correct.
b
What is the wavelength in mm of the radiation emitted by a hydrogen atom moving from the n=4 to n=2 state?(EH=-2.178*10-18(1/n2f)-(1/n2o)
7.3*10-4mm
(5.99*102)(2.8*108)
1.7*1011
DAILY DOUBLE!!!!!!!!
A sample of a gaseous compound contains 11.8g of chlorine and 10.7g of oxygen. How many grams of chlorine are in a sample of the same gas that contains 25g of oxygen?
23g
What is the weight in pounds of an 18K gold necklace containing 2.76*1024 atoms? (18K=75% gold by mass, 1kg=2.2lb)
1.99lb
Chlorine has 2 common isotopes: 35Cl and 37Cl. If the molar mass of Chlorine is 35.45g, which isotope of Chlorine is most abundant?
35Cl
A golf ball has a velocity of 2.55ft/s and a mass of 46g. What is the De Broglie wavelength of the ball in nanometers? (1 meter=3.28 feet)
1.85*10-23nm
(10.330−230.0301)(39.64)−(1.358*104)
-13586
Which of these is NOT part of Dalton's Atomic Theory?
a)All atoms of a given element have the same mass and other properties that distinguish them from the atoms of other elements.
b) Atoms of one element cannot change into atoms of another element. In chemical reactions, atoms only change the way they are bound to other atoms.
c) Atoms combine in simple, whole-number ratios to form compounds.
d) Atoms are composed of a dense nucleus surrounded by a cloud of electrons.
e) Elements are composed of small indestructible particles called atoms.
d.
A solid copper cylinder contains 3.4*1024 atoms with a length of 2.9mm. What is the radius of the cylinder in inches? (1in=2.54cm, densityCu=8.96g/cm3, V=l*πr2)
2.61in
Bromine has two naturally occurring isotopes(Br-79 and Br-81), and an atomic mass of 79.904 amu. The mass of Br-81 is 80.9163 amu, and its natural abundance is 49.31%. Calculate the mass and natural abundance of Br-79
78.92g with a natural abundance of 50.69%
The binding energy of an unknown metal is 8.36*102kJ/mol. A photon with wavelength 1.55nm strikes the metal and an electron is released. What is the kinetic energy of the electron in kJ?
1.27*10-19kJ