Geological Time and Chemical Reactions Practice Flashcards

Fill-in-the-blank review flashcards covering Earth history, paleontology, fossil preservation, dating methods, reaction types, thermochemistry, and chemical kinetics.

The preserved evidence in rocks or soils of organisms that were once alive is called a __________.

fossil

Fossils formed when part of an organism is preserved with its chemical composition remaining unchanged are classified as __________ fossils.

original

A fossil formed when the calcium carbonate in bony shells or skeletons is replaced over time by silicon dioxide is a __________ fossil.

replacement

In fossilization, the external imprint shown on the left is a mold, while the 3D rock copy on the right is a __________.

cast

Footprints, tracks, burrows, and coprolites are all classified as __________ fossils.

indirect

The Tollund Man is an Iron Age corpse preserved remarkably well in a peat bog located in __________.

Denmark

Comparing the age of one fossil or rock layer against another without determining its exact age in years is known as __________ dating.

relative

To be useful as an index fossil, an organism must have been abundant, easy to identify, geographically widespread, and existed for a relatively __________ period of time.

short

Chemical testing via __________ analysis exposed the Piltdown Man fossil as a forgery in 1953.

fluorine

The radioactive isotope Carbon-14 has a known half-life of __________ years.

$$5730$$

The earliest evidence of living organisms on Earth consists of circular rocky structures called __________.

stromatolites

The fossil creature __________ displays features of both reptiles and birds, such as teeth and a bony tail along with feathers and a wishbone.

Archaeopteryx

In an __________ reaction, thermal energy is released from the system to the surroundings.

exothermic

In an endothermic reaction, thermal energy is absorbed from the surroundings, resulting in a __________ energy change for the system.

positive

Complete combustion of hydrocarbons in oxygen produces water vapour and __________.

carbon dioxide

The exothermic metabolic reaction in cells where glucose reacts with oxygen to release energy is called __________.

respiration

According to the activity series of metals, the element symbol representing the most reactive metal listed is __________.

$$\text{K}$$

Biofuels such as ethanol are manufactured when microorganisms like yeast break down plant sugars through __________.

fermentation

A chemical reaction in which a single compound breaks down into two or more simpler products is a __________ reaction.

decomposition

A reaction in which two clear solutions are mixed to form an insoluble solid is called a __________ reaction.

precipitation

According to general solubility rules, all ionic compounds containing the __________ anion are soluble in water.

nitrate

An acid-base neutralisation reaction involving a metal oxide or hydroxide always yields water and a __________.

salt

The minimum energy required by colliding reactant particles to break bonds and initiate a reaction is the __________ energy.

activation

Increasing the temperature of a reaction mixture increases the rate because particles gain more __________ energy.

kinetic

A chemical helper that accelerates the rate of a chemical reaction without being consumed is a __________.

catalyst

Naturally occurring biological catalysts that regulate metabolic processes inside living cells are known as __________.

enzymes