The Chemistry of Life: The Chemical Context of Life
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- Mass and Weight are NOT the same. True or False?
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True.
Mass and Weight are different. Mass is the amount of matter an object has and weight is how strong an object's mass is pulled by gravity.
Example: On the moon, your mass would be the same but your weight wouldn't because the moon's pull of gravity on you would be different than when you would be on Earth. - Define mass.
- The amount of matter in an object.
- Define weight.
- How strong an object's mass is pulled by gravity
- Define matter.
- Anything that takes up space and has mass
- The basic forms of matter are elements. What are elements?
- Substances that cannot be chemically broken down to other types of matter
- What is a compound?
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Compounds are made up of 2 or more elements combined in a fixed ratio. They usually have characteristics that are different from its constituent elements.
Example:
Na + Cl = Salt - What is an atom?
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The smallest unit of an element retaining physical and chemical properties of that element.
Each element has its own unique atom - What are trace elements?
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Elements that are required by organisms in only small amounts.
Examples: iron & iodine - Atomic structure determines the behavior of an element. True or False?
- True
- What are the 3 subatomic particles? What type of charge do they have? What are their masses and where are they located?
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Neutron
-Charge: Negative
-Mass: 1 Dalton
-Location: nucleus
Proton
-Charge: positive
-Mass: 1 Dalton
-Location: nucleus
Electron
-Charge: negative
-Mass: negligible
-Location: cloud around nucleus -
What are the names of the element of the following symbols?
Ca: _____________
P: ______________
K: ______________
S: ______________
Na: _____________
Cl: _____________
Mg: _____________ -
Ca: Calcium
P: Phosphorus
K: Potassium
S: Sulfur
Na: Sodium
Cl: Chlorine
Mg: Magnesium - The difference between the mass number and the atomic number of an atom is equal to the number of (1)________. An atom of phosphorus contains (2)___ protons, (3)___ electrons, and (4)___neutrons. The atomic weight of phosphorus is (5)_________.
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(1) neutrons
(2) 15
(3) 15
(4) 16
(5) 31 Daltons -
To move to a shell farther from the nucleus, an electron must (absorb/release) energy; energy is (absorbed/released) when an electron moves to a closer shell.
Pick the correct term. -
Absorb
Released -
What are the valences of the following?
a) hydrogen
b) oxygen
c) nitrogen
d) carbon -
a) hydrogen: 1
b) oxygen: 2
c) nitrogen: 3
d) carbon: 4 -
Which of the following molecules contain non-polar covalent bonds? Polar covalent bonds?
1) nitrogen molecule
N = N
(there is a third line under the equal sign)
2) methane
...H
...|
H--C--H
...|
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1) non-polar
2) non-polar
3) polar
4) polar -
Which of the following is most related to the chemical behavior of an atom?
a)valence
b)atomic number
c)atomic weight
d)mass number -
a) valence
Valence has the ability for an atom to share electrons - Define valence.
- bonding capacity
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Each element has its own characteristic atom in which
a) the atomic weight is constant
b)the atomic number is constant
c)the mass number is constant
d)2 of the above are correct
e)all of the above are correct - b) the atomic number is constant
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Radioactive isotopes can be used in studies of metabolic pathways because
a)their half-life allows a researcher to time an experiment
b)they are more reactive
c)the cell doesn't recognize the extra protons in the nucleus, so isotopes - d) their location or quantity can be experimentally determined because of their radioactivity
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Oxygen has 8 electrons. You would expect the arrangement of these electrons to be:
a) 8 in the 2nd energy shell, creating an inert element
b) 2 in the 1st energy shell & 6in the 2nd, creating a valence of 6
c) 2 in the 1s orbital - e) 2 in the 1s orbital, 2 in both the 2s and 2px orbitals, and 1 each in the 2py and 2pz orbitals, creating a valence of 2
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A covalent bond between 2 atoms is likely to be polar if
a) 1 of the atoms is much more electronegative than the other
b) the 2 atoms are equally electronegative
c) the 2 atoms are of the same element
d) the bond is part of a te - a) 1 of the atoms is much more electronegative than the other
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A triple covalent bond would
a) be very polar
b) involve the bonding of 3 atoms
c) involve the bonding of 6 atoms
d) produce a triangularly shaped molecule
e) involve the sharing of 6 electrons - e) involve the sharing of 6 electrons
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A cation
a) has gained an electron
b) can easily form hydrogen bonds
c) is more likely to form from an atom with 6 or 7 electrons in its valence shell
d) has a positive charge
e) Both c and d are correct - d) has a positive charge
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Which of the following weak bonds may form between any closely aligned molecules?
a) nonpolar covalent
b) polar covalent
c) ionic
d) hydrogen
e) van der Waals interactions - e) van der Waals interactions
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The ability of morphine to mimic the effects of the body's endorphins is due to
a) a chemical equilibrium developing between morphine and endorphins
b) the one-way conversion of morphine into endorphin
c) molecular shape similarities - c) molecular shape similarities that allow morphine tobind to endorphin receptors
- How many electrons does phosphorus have in its valence shell?
- 5
- What is the atomic weight of phosphorus?
- 31
- A radioactive isotope of carbon has the mass number 14. How many neutrons does this isotope have?
- 8
- How many covalent bonds in a sulfur atom most likely to form?
- 2
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Based on electron configuration, which of these elements would have chemical behavior most like that of oxygen?
a) C
b) H
c) N
d) P
e) S - e) S
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How many of these elements are found next to each other (side by side) on the periodic table?
[elements: C O H N S P]
a) 1 group of 2
b) 2 groups of 2
c) 1 group of 2 and 1 group of 3
d) 1 group of 3
e) all of them - c) 1 group of 2 and 1 group of 3
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Taking into account the valences of carbon and oxygen, how many hydrogen must be added to complete the structural diagram of this molecule?
O.....................
\\..................
.....C-C-C-C=C-C-C
/...................
O... - 12
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Which of the following is a molecule capable of forming hydrogen bonds?
a) CH4
b) H2O
c) NaCl
d) H2
e) a,b, and d can form hydrogen - b) H2O
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A sodium ion (Na+) contains 10 electrons, 11 protons, and 12 neutrons. What is the atomic number of sodium?
a) 10
b) 11
c) 12
d) 23
e) 33 - b) 11
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Chlorine has an atomic number of 17 and a mass number of 35. How many electrons would a chloride ion have?
a) 16
b) 17
c) 18
d) 33
e) 34 - c) 18