The ancient Greek philosophers were probably the first to consider the behavior of matter in an organized way. What is the major distinction between the ʺGreek philosophersʺ and
ʺmodern scientistsʺ?
Experimentation
Modern chemistry is based primarily on
Experimentation
Archaeological evidence indicates that ancient Egyptians were brewing beer and other fermented beverages over 4000 years ago. In the mid-19th century, French scientist Louis
Pasteur discovered and explained the source of fermentation (yeast). This example illustrates
that
Technological knowledge may come before scientific knowledge.
Scientific results must be verified by
Further Experiments
Which of the following is NOT true for a scientific law?
A) It explains observed scientific data.
B) It summarizes observed scientific data.
C) It is often stated in mathematical terms.
D) It is universal and will hold everywhere under the stated conditions.
A) IT EXPLAINS OBSERVED SCIENTIFIC DATA
Saccharin is used in some artificial sweeteners. Saccharin has been shown to be a very weak carcinogen (a substance that causes cancer) in animal tests, but there is little evidence of carcinogenicity in humans. Studies have also shown that artificial sweeteners provide little
benefit to those who want to lose weight. The DQ for saccharin is
Moderate
Which of the following does NOT involve chemistry? A) increased agricultural yields C) materials for computers B) recycling of basic materials D) All of the above involve chemistry.
D) All of the above involve chemistry.
8) Which of the following is a physical change?
A) Water is decomposed by electricity into hydrogen and oxygen.
B) A red substance is decomposed by heat to form mercury and oxygen.
C) Carbon combines with oxygen to form carbon dioxide.
D) Ice melts at 0°C.
D) Ice melts at 0°C.
9) Methane can be decomposed into two simpler substances, hydrogen and carbon. Therefore,methane
Cannot be an element.
After many observations, Proust stated that elements combine in definite proportions to form compounds. Dalton explained these observations by proposing that matter must consist of
atoms. Daltonʹs explanation is called a(n)
Theory
The observation that 20 g of hydrogen gas always combines with 160 g of oxygen gas to form 11) 180 g of water, even when there is more than 160 g of oxygen present in the reaction container, illustrates the law of
Definite Proportions
Lavoisier performed many of the same experiments as his predecessors. The one thing that most distinguished Lavoisierʹs work was
The Mass Measurments
13) The ancient Greeks believed that matter was composed of four basic elements. Which one of the following was NOT one of the four?
Gold
14) What is the name of the element with the symbol N?
Nitrogen
A chemical change always involves a change in the ________ of a piece of matter.
Composition
Under conditions of limited oxygen, carbon burns to form carbon monoxide, a poisonous gas.In conditions with unlimited oxygen, carbon burns to form carbon dioxide. This illustrates the
law of
Multiple Proportions
What is the name of the Russian chemist who was a pioneer in the development of the periodic law?
Mendeleev
For which of the following would recycling of iron NOT be practical? A) Rust that flakes off a car body.
B) Wrought iron fences.
C) Steel beams that have been removed from a bridge. D) Old cars that are compressed in junkyards.
D) Berzelius
Rust that flakes off a car body.
Who first proposed the nuclear nature of the atom?
Rutherford
Ions are
Charged Atoms
Rutherford concluded that the nucleus of an atom is positively charged because 21)
Some positively charged alpha particles were deflected by the nucleus in the gold foil
experiment.
Relative to the mass of the nucleus of an atom, the mass of the electron is
Always much smaller.
How many nucleons are in this isotope of tin?
106
Which is an isotope of uranium?
233
U
92
How many protons are there in a phosphorus atom?
15
The proton has
A larger mass and opposite charge as the electron.
A line spectrum is NOT
Continuos
Elements in the same group have
The same number of valence electrons.
Which of the following molecules is NOT likely to exist?
He2
How many electrons are there in a double bond?
4