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Chem 120 exam 1 Review-Questions with Correct Answers/ Verified/ Latest Update (2024/2025)
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Chem 120 exam 1 Review-Questions with Correct Answers/ Verified/ Latest Update (2024/2025)
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Chem 120 exam 1 Review-Questions with Correct Answers/Verified/ Latest Update (2024/2025)
Hypothesis
A testable explanation.
Independent Variable
What you as the scientist are controlling or changing.
Dependent Variable
Depends on the independent variable. What you expect to change. What
you are measuring.
Positive Control
Group or condition with known outcome.
Negative Control
Condition for which no change is expected.
Expiramental Controls
All the conditions that are held constant.
Atom
smallest unit of an element that remain that element
Atoms
Made of protons, nuetrons, electrons
Molecules
Atoms can combine to form what?
Atomic number
An atoms identity is determined by what?
Number of protons the atom has
What is the atomic number?
Chemical Symbols
What are atoms of elements represented by?
Isotopes
, Different atoms of a given element can exist as what?
(mass number) / number of nuetrons
What is different abouit isotopes of given elements
Protons
+1 charge, 1 AMU mass
Neutrons
0 charge, 1 AMU mass
Electrons
-1 charge, ~0 AMU mass
same
By default an atom on the periodic table has the ______________ number of electrons as
protons
Nuetrons + Protons = mass number
Mass number formula
Atomic Number
an average of the masses of atoms of an element, taking abundance
of each isotope into account
-48 protons because of atomic number(# of protons) of 48
-48 electrons as we are assuming this is not an ion and therefore, we expect the protons and
electrons to balance out.
-Since mass number is p + n = A, then n= A-p = 130 - 48 p = 82 neutrons
-Element is Cd based on the 48 atomic number
I have an isotope with an atomic number of 48 and a mass number of 130. How many
protons, electrons, and neutrons would I expect this atom to have, and what is this
element?
-I know oxygen must have 8 protons because protons determine the element. So:
-p + n = A = 8 p + 9 n = 17
-So the mass number of this isotope is 17.
I have an isotope of Oxygen with 9 neutrons. What is the mass number of this isotope?
ION
This is a charged atom or molecule
ION
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