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