CHEM 103 CHAPTERS 1-4 QUESTIONS
AND ANSWERS WITH COMPLETE
SOLUTIONS 100% CORRECT RATED
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Question: How does Dalton's Atomic Theory describe what happens to atoms
during a chemical reaction?
Answer: ✔️✔️ It states that atoms are indestructible and unchangeable. In any
chemical process, atoms are simply rearranged, combined, or separated; they are
never created from scratch nor do they disappear.
Question: What is the primary concept behind the Law of Definite
Proportions (Proust's Law)?
Answer: ✔️✔️ This law dictates that a specific chemical compound always
consists of the exact same elements in the exact same mass ratio, regardless
of the source or how the sample was prepared. For example, pure water is
always approximately 88.8% oxygen and 11.2% hydrogen by mass.
Average mass equation -ANSWER ✔️✔️the sum of (fractional abundance x
isotopic mass)
Thompson -ANSWER ✔️✔️Cathode ray; atoms contain electrons
Millikan -ANSWER ✔️✔️Oil drop; fundamental electric charge
Rutherford -ANSWER ✔️✔️Gold foil; discovered the small, positively charged
nucleus
, What is an atomic mass unit? -ANSWER ✔️✔️1/12 the mass of a carbon-12
atom, equal to 1.6605 x 10^-24
What is the atomic number? -ANSWER ✔️✔️the number of protons in the
nucleus
What is the mass number? -ANSWER ✔️✔️The number of protons + the number
of neutrons
What is the atomic charge? -ANSWER ✔️✔️Number of protons - number of
electrons
What differs from one isotope to another? -ANSWER ✔️✔️The number of
neutrons in the nucleus
What is the molecular formula? -ANSWER ✔️✔️Uses chemical
symbols/subscripts to indicate the exact number of different atoms in a molecule
or compound
What is the empirical formula? -ANSWER ✔️✔️Gives the simplest whole
number ratio of atoms of each element present in a compound
Group 1 -ANSWER ✔️✔️Alkali metals
Group 2 -ANSWER ✔️✔️Alkaline earth metals
Group 15 -ANSWER ✔️✔️Pnictogens
AND ANSWERS WITH COMPLETE
SOLUTIONS 100% CORRECT RATED
A+
Question: How does Dalton's Atomic Theory describe what happens to atoms
during a chemical reaction?
Answer: ✔️✔️ It states that atoms are indestructible and unchangeable. In any
chemical process, atoms are simply rearranged, combined, or separated; they are
never created from scratch nor do they disappear.
Question: What is the primary concept behind the Law of Definite
Proportions (Proust's Law)?
Answer: ✔️✔️ This law dictates that a specific chemical compound always
consists of the exact same elements in the exact same mass ratio, regardless
of the source or how the sample was prepared. For example, pure water is
always approximately 88.8% oxygen and 11.2% hydrogen by mass.
Average mass equation -ANSWER ✔️✔️the sum of (fractional abundance x
isotopic mass)
Thompson -ANSWER ✔️✔️Cathode ray; atoms contain electrons
Millikan -ANSWER ✔️✔️Oil drop; fundamental electric charge
Rutherford -ANSWER ✔️✔️Gold foil; discovered the small, positively charged
nucleus
, What is an atomic mass unit? -ANSWER ✔️✔️1/12 the mass of a carbon-12
atom, equal to 1.6605 x 10^-24
What is the atomic number? -ANSWER ✔️✔️the number of protons in the
nucleus
What is the mass number? -ANSWER ✔️✔️The number of protons + the number
of neutrons
What is the atomic charge? -ANSWER ✔️✔️Number of protons - number of
electrons
What differs from one isotope to another? -ANSWER ✔️✔️The number of
neutrons in the nucleus
What is the molecular formula? -ANSWER ✔️✔️Uses chemical
symbols/subscripts to indicate the exact number of different atoms in a molecule
or compound
What is the empirical formula? -ANSWER ✔️✔️Gives the simplest whole
number ratio of atoms of each element present in a compound
Group 1 -ANSWER ✔️✔️Alkali metals
Group 2 -ANSWER ✔️✔️Alkaline earth metals
Group 15 -ANSWER ✔️✔️Pnictogens
