BIOL 2P98 Lecture Notes - Lecture 23: Molecular Mass, Chemical Formula, Molar Concentration

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graybutterfly201

17 Feb 2016

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A mole (moles, a mass) is defined as 6. 02 x 1023 atoms, ions, or molecules of a substance. Thus, one mole of a substance has the same number of particles as one mole of any other substance; just as a dozen eggs has the same number of items as a dozen roses. However, the mass of 1 mole of a substance depends on the mass of the individual particles. From the chemical formula of a molecule, we can calculate its molecular mass. This is the mass of one molecule, expressed in atomic mass units or, more often in daltons (1amu = 1da). To calculate molecular mass, multiply the atomic mass of each element in the molecule by the number of atoms of the element in the molecule, then add the results. For example: the weight of a single carbon (c) atom is 12g, oxygen (o) is 16g, and hydrogen (h) is 1g.

Related Questions

1. (TCO 1) Control subjects in a double-blindtest of a new drug are (Points : 4) informed of what drug they aregetting.
informed of what drug they aregetting but their private physicians are not.
given larger doses of thedrug.
infected with a differentdisease than the experimental subjects.
not given the experimentaldrug but are otherwise treated the same as the experimentalsubjects.

Question 2. 2. (TCO 1) My dog will eat more ofher food when I pour bacon grease over the food before I give it toher. This is an example of a(n) _____. (Points : 4)

observation
hypothesis
experiment
theory
All of the above

Question 3. 3. (TCO 1) Deductive reasoning isused to make _____ based on a hypothesis. (Points : 4)

data
theories
statistical tests
correlations
predictions

Question 4. 4. (TCO 2) Which of the followingstatements about the periodic table is incorrect? (Points : 4)

A period is a horizontal rowon the periodic table.
A group is a column on theperiodic table.
The elements in each periodhave similar chemical properties.
The A groups contain therepresentative elements.
The B groups contain thetransition elements.

Question 5. 5. (TCO 2) How do you find themass number of an atom? (Points : 4)

Add up the number of protons,electrons, and neutrons in the atom.
Add up the number of protonsand neutrons in the atom.
It is equal to the number ofprotons in the atom.
It is equal to the number ofneutrons in the atom.
Find the net electrical chargeof the atom.

Question 6. 6. (TCO 2) An isotope of potassiumhas a mass number of 39. How many neutrons are present in thisisotope? (Points : 4)

19
20
24
44
58

Question 7. 7. (TCO 2) Which particles arefound in the nucleus of an atom? (Points : 4)

Only neutrons
Protons and electrons
Protons and neutrons
Only electrons
Only protons