Ecosystems
When is there competition between eagles and bears?
Eagles and Bears hunt the same kind of salmon
Which of the following is true about how hydrogen and oxygen can combine to form molecules?
Hydrogen and oxygen can combine in many ways to form different molecules.
Hydrogen and oxygen react to form water. At an atomic level, how do we know that a chemical reaction has occurred?
The hydrogen and oxygen atoms regroup into a new molecule.
People try to conserve some resources, like fossil fuels, because they are not replaceable. Why can’t these resources be replaced?
Processes make them take a long time
Students want to gather evidence for the claim that the number of atoms present before a chemical reaction is equal to the number of atoms present after the chemical reaction. They decide to react vinegar and baking soda in a sealed plastic bag. Which of the following would provide the evidence the students need?
The mass of the plastic bag, baking soda, and vinegar before the reaction was equal to the mass after the reaction.
An increase in what is likely to contribute to competition between two members of the same species living in a certain habitat?
Population of the species
Which of the following best explains the relationship between molecules and atoms?
Molecules are made of two or more atoms
What is the best description of the results of a chemical reaction?
A new substance with different properties is formed.
People move into and begin living in an area that previously had no human activity. What will most likely be the effect on the amount of water?
There will be less available for other living things.
What is true regarding the atoms involved in a chemical reaction?
The same number of each type of atom will always be present before and after a chemical reaction takes place.
To investigate competition between two organisms they must...
require the same resources.
What change made to a sample of liquid would result in an increase in the distance between the individual molecules of the substance?
Adding heat to the substance
Rust forming on a piece of iron is an example of
A chemical change because oxygen atoms from the atmosphere bonded with the iron atoms
Metal ores are often formed in locations that had volcanic activity in the past. What information about an area would provide the best evidence that metal ores could be found there in the present?
Evidence that the area had active volcanoes long ago
How do you know if an equation is balanced?
The same number of atoms are on each side.
An increase in the population of an organism would most likely be associated with what?
An expansion in living space
As thermal energy is added to a substance, what change can be predicted?
Vibration of individual particles will increase
What is good evidence that an unknown sample is a pure substance?
Multiple samples of the unknown substance melt at the same temperature.
What data would be most helpful to support the claim that the population of a certain plant is dependent on the rainfall in its habitat?
Rainfall amounts and number of these plants in a certain habitat over several years
In science, the term “heat" is used to describe which of the following?
The transfer of thermal energy from one object to another
Density has the ___________ substances on the top?
lightest