Lesson 12 - Quiz #6
The half-life of carbon-14 is 5,730 years. If a 1-g sample of old carbon is 1/8 as radioactive as 1-g of a current sample, the age of the old sample is about
17,200
When radium (A = 88) emits an alpha particle, the resulting nucleus has atomic number
86
When U-235 undergoes fission, the two nuclei that result have a total of
92 protons
Which radiation has no electric charge associated with it
Gamma Rays
Different isotopes of an element have different numbers of
Neutrons
The name for the chemical compound of the formula NaNO3 is
Sodium nitrate
An element emits one alpha particle, one positron, and three beta particles. Its atomic number
Stays the same
How is a physical change different from a chemical change?
The chemical identity of a substance is not altered during a physical change.
A certain radioactive isotope placed near a Geiger counter registers 160 counts per second. Eight hours later, the counter registers 10 counts per second. What is the half-life of the isotope?
Two hours
An atom with an imbalance of electrons to protons is
an ion
As you move across the periodic table from left to right, the ________ and ________ of elements tend to increase.
atomic mass; atomic number
Chemistry primarily focuses on
atoms and their interactions
If you want to cook eggs by boiling them while in the mountains, compared to sea level cooking, you should
boil eggs for a longer time
When a nucleus emits a beta particle, its atomic number
changes, but its mass number remains constant
In the fissioning of uranium, a chain reaction is caused by
ejected neutrons
The half-life of an isotope is one day. At the end of two days the amount that remains is
one-eighth
Oxygen atoms are used to make water molecules. Does this mean that oxygen, O2, and water, (H2O), have similar properties?
No, compounds are uniquely different from the elements from which they're made.
The phase in which atoms and molecules no longer move is
None of the above, which were, solid phase, liquid phase or gas phase
What chemical change occurs when a wax candle burns?
The heated wax molecules combine with oxygen molecules.
Evaporation is a cooling process because
energy is required when liquid changes to gas and the energy is taken from the surroundings.
The proper name for the chemical compound N2O is
dinitrogen monoxide.
When two different elements combine to form a compound, the resulting properties of the compound are
not necessarily anything like those of the elements.
Carbon dating requires that the object being tested contains
organic material
A row of the periodic table is called a ________; a column is known as a ________.
period; group
When thorium (A = 90) emits a beta particle, the resulting nucleus has atomic number
88. 89. 92. 90. none of the above Answer: None of the above
